Hirahara AM

The musculoskeletal (MSK) ultrasound evaluation of the shoulder provides a cost- and time-efficient imaging modality with similar diagnostic power as magnetic resonance imaging (MRI).^1,2 Its portable point-of-care applications can be used in the office, in the operating room, and in sideline athletic event coverage, as we discussed in Part 1 of this series.³

MSK ultrasound may seem difficult and daunting, and many articles have quoted steep learning curves.^4,5 However, in our experience in teaching many ultrasound courses, this modality can be learned quite quickly with the proper instruction. Physicians are already familiar with anatomy and usually have had some exposure to MRI.⁴ Taking courses in MSK ultrasound or simply learning the basic concepts of ultrasound and then learning the machine controls is usually a good start.^5-8 Practice scanning normal individuals, comparing the images from an MRI to learn how to reproduce the same planes and images. This will allow the user to become familiar with normal anatomy and how to see the images on the ultrasound screen.^5-8 Vollman and colleagues⁹ showed that in trainees, combining MRI images with sonograms enhances the ability to correctly identify MSK ultrasound anatomy from 40.9% to 72.5%, when compared with learning from ultrasound images alone.

There are currently no certifications necessary to perform ultrasound scans or bill for them; however, some insurance carriers may require demonstrating relevant, documented training for reimbursement.³ Various organizations are trying to develop certifications and regulations for ultrasound to standardize the use of this modality. In the United States, the American Institute of Ultrasound in Medicine (AIUM) and the American Registry for Diagnostic Medical Sonography (ARDMS) provide guidelines and particular MSK ultrasound certifications.^10,11

Basic Ultrasound Principles

The ultrasound machine creates electrical impulses that are turned into sound waves by piezoelectric crystals at the probe’s footprint. These sound waves bounce off tissues and return to the probe, where they are converted electronically to an image on the monitor. Depending on the echogenicity of the scanned tissue, the ultrasound beam will either reflect or be absorbed at different rates. This variance is transmitted on the monitor as a grayscale image. When ultrasound waves are highly reflective, like in bone or fat, they are characterized as hyperechoic. The opposite occurs when ultrasound waves are absorbed like in the fluid of a cystic cavity or joint effusion, and the image appears black. This is described as anechoic.¹² Intermediate tissues such as tendons that are less reflective are seen as hypoechoic and appear gray. When a tissue has a similar echogenicity to its surrounding tissues, it is called isoechoic.¹²

The transducer is the scanning component of the ultrasound machine. Transducers come in 2 shapes: linear and curvilinear. The linear probe creates a straight image that is equal to the size of the transducer footprint. The curvilinear probe creates a wider, wedge-shaped panoramic image.

Linear probes are of higher frequency and generate higher resolution images of shallower structures, while curvilinear probes have greater depth penetration but generate lower resolution images. A high frequency of 10 to 15 MHz is preferred for anatomy between 2 cm to 4 cm depth.¹³ Midrange frequency of 5 to 10 MHz is preferred at 5 cm to 6 cm depth, and low-frequency 2 to 5 MHz probes are preferred for anatomical structures >6 cm depth.¹³

Anisotropy is the property of being directionally dependent, as opposed to isotropy, which implies identical properties in all directions. This anisotropic effect is dependent on the angle of the insonating beam. The maximum return echo occurs when the ultrasound beam is perpendicular to the tendon. Decreasing the insonating angle on a normal tendon will cause it to change from brightly hyperechoic (the actual echo from tightly bound tendon fibers) to darkly hypoechoic. If the angle is then increased, the tendon will again appear hyperechoic. If the artifact causes a normal tendon to appear hypoechoic, it may falsely lead to a diagnosis of tendinosis or tear.

Posterior acoustic shadowing is present when a hyperechoic structure reflects the ultrasound beam so much that it creates a dark shadow underneath it.^12,14 This phenomenon is possible since the ultrasound beam cannot penetrate the hyperechoic structure and reflects off its inferior tissues. Reverberation is when the beam is repeated back and forth between 2 parallel highly reflective surfaces. The initial reflection will be displayed correctly, while the subsequent ultrasound waves will be delayed and appear at a farther distance from the transducer.^12,14

The point where the beam is at its narrowest point generates the section of the image that is best visualized.¹⁵ This is called the focal zone, and it can be adjusted to highlight the desired area of evaluation. Gain controls adjust the amount of black, gray, and white on the monitor and can be adjusted to focus the desired image.¹³ Depth settings are fundamental in finding the desired targets. It is recommended to start with a higher depth setting to get an overview and progressively decrease the depth to key in on the desired anatomy.¹³ Color Doppler can be used to view movement within structures and to identify vessels, synovitis, and neovascularization in tendinopathy.¹³

Ultrasound of the Shoulder

Patients should be seated, if possible, on a rotating seat. The examiner’s shoulder should be higher than the patient’s shoulder.¹⁶ The user holds the ultrasound probe between the thumb and index fingers while resting the hypothenar eminence on the patient to serve as a fulcrum and steadying force. The examination should take 5 to 15 minutes, depending on the examiner’s expertise and the amount of anatomy being scanned.

Examining the body requires knowledge of anatomy. The examination and accuracy are determined by the technician using the probe. The probe can be angled any direction and be placed obliquely on the subject. The advantage here is that anatomy in the human body is not always planar. Muscles and tissues can run obliquely or even perpendicular to each other. When evaluating anatomy, the examiner should keep in mind what structure he or she is looking for; where it should be found; what landmarks can be used to easily locate it; what orientation it has; and what the normal anatomy should look like.

Muscle appears as a lattice with larger areas of hypoechoic muscle tissue and hyperechoic fascial perimysium layers traversing through it.¹⁷ The actual muscle tissue appears hypoechoic from the fluid or blood found within. Scarring, fibrosis, calcification, or chronic injury will change the tissue to appear denser or hyperechoic.¹⁷ Acute injury will appear hypoechoic from the inflammatory response and influx of blood. Tendon appears dense and hyperechoic with striations within the tissue, sometimes referred to as a horse’s tail.¹⁷ When torn, there will be a disassociation of the tissue with a hypoechoic region between the 2 ends. The attachment to the bone and muscle tissue should appear uniform. Hyperechoic areas within the tendon may be from calcification. Ligament appears similar to tendon but is more isoechoic and connects bone to bone. Evaluation of the entire length and the attachments to the bone are critical to evaluate for disease.

Bone appears bright hyperechoic, smooth, and flat, while hyaline cartilage is hypoechoic, smooth, and runs superiorly in a parallel pattern to its respective inferior cortical bone.¹⁷

Fibrocartilage is hyperechoic and typically triangularly shaped, such as in the glenohumeral labrum. Nerves appear fascicular and hypoechoic surrounded by hyperechoic epineurium.¹⁴

The epidermis and dermis are the most superficial structure on top of the screen, and are also hyperechoic.¹⁷

The Diagnostic Shoulder Examination

The proximal long head of the biceps tendon (LHBT) is the easiest structure in the shoulder to identify because of the anatomic structure, the bicipital groove. By keeping the arm relaxed, perpendicular to the ground, and in neutral rotation, the probe can be placed perpendicular to the arm over the proximal shoulder (Figure 1A).^16-20 By finding the groove, the biceps tendon will usually be found resting within the groove (Figure 1B). This is the short axis view and is equivalent to an MRI in the axial plane.

The long axis view of the proximal biceps tendon is found by keeping the tendon in the center of the screen/probe. The probe is then rotated 90° on its center axis, keeping the tendon centered on the probe. The user should be sure to visualize the entire tendon on the screen. If only part of the tendon is seen along only part of the screen, then the probe is oblique to the tendon. In this case, the probe area showing the tendon must be stabilized as the center or set point. The other part of the probe will then pivot until all of the tendon is seen on the screen. The MRI equivalent to the long axis of the proximal biceps tendon is the sagittal view.

Ultrasound is a dynamic evaluation. Moving the probe or moving the patient will change what and how something is imaged. The proximal biceps tendon is a good example of this concept. The bicipital groove is very deep proximally and flattens out as it travels distally to the mid-humerus. The examiner should continually adjust his or her hand/probe/patient position as well as depth/gain and other console functions to adapt to the dynamics of the scan. While keeping the bicep tendon in a short axis view, the tendon can be dynamically evaluated for subluxation by internally and externally rotating the arm.

To find the subscapularis, the arm remains in a neutral position with the hand supinated and the probe is held parallel with the ground. After finding the bicipital groove, the subscapularis tendon insertion is just medial to the groove (Figure 1B). By externally rotating the arm, the subscapularis tendon/muscle will come into a long axis view.^16-20 The MRI equivalent to the long axis view of the subscapularis is the axial view. Dynamic testing can be done by internally and externally rotating the arm to evaluate for impingement of the subscapularis tendon as it slides underneath the coracoid process. To view the subscapularis tendon in short axis, the tendon is kept in the center of the screen/probe, and the probe is then rotated 90° on its center axis, keeping the tendon centered on the probe. The MRI equivalent is the sagittal view.

Some have recommended using the modified Crass or Middleton position to evaluate the supraspinatus, where the hand is in the “back pocket”.¹⁹ However, many patients with shoulder pain have trouble with this position. By resting the ipsilateral hand on the ipsilateral hip and then dropping the elbow, the supraspinatus insertion can still be brought out from under the acromion. This does bring the insertion anterior out of the scapular plane, so an adjustment is required in probe positioning to properly see the supraspinatus short and long axis. To find the long axis, the probe is placed parallel to a plane that spans the contralateral shoulder and ipsilateral hip (Figure 2A). The fibers of the supraspinatus should be inserting directly lateral to the humeral head without any intervening space (Figure 2B). If any space exists, a partial articular supraspinatus tendon avulsion (PASTA) lesion is present, and its thickness can be directly measured. Moving more posterior will show the flattening of the tuberosity and the fibers of the infraspinatus moving away from the humeral head—the bare spot. The MRI equivalent is the coronal view.

To view the supraspinatus tendon in short axis, maintain the arm in the same position, keeping the tendon in the center of the screen/probe. The probe is then rotated 90° on its center axis, keeping the tendon centered on the probe. The probe should now be in a parallel plane between the ipsilateral shoulder and the contralateral hip. The biceps tendon in cross-section will be found anteriorly, and the articular cartilage will appear as a black layer over the bone. Dynamic testing includes placing the probe in a coronal plane between the acromion and greater tuberosity. When the patient abducts the arm while in internal rotation, the supraspinatus tendon will slide underneath the coracoacromial arch showing potential external impingement.¹⁵ The MRI equivalent is the sagittal plane.

The glenohumeral joint is best viewed posteriorly, limiting how much of the intra-articular portion of the joint can be imaged. The arm remains in a neutral position; palpate for the posterior acromion and place the probe just inferior to it, wedging up against it (Figure 3A). The glenohumeral joint will be seen by keeping the probe parallel to the ground (Figure 3B). The MRI equivalent is the axial plane. If a joint effusion exists, it can be seen in the posterior recess.¹⁵ A hyperechoic triangular region in between the humeral head and the glenoid will represent the glenoid labrum (Figure 3B). By internally and externally rotating the arm, the joint and labrum complex can be dynamically examined. From the labrum, scanning superior and medial can sometimes show the spinoglenoid notch where a paralabral cyst might be seen.¹⁵

Using the glenohumeral joint as a reference, the infraspinatus muscle is easily visualized. Maintaining the arm in neutral position with the probe over the glenohumeral joint, the infraspinatus will become apparent as it lays in long axis view superficially between the posterior deltoid and glenohumeral joint (Figure 3B).^16-20 The teres minor lies just inferiorly. The MRI equivalent is the axial plane. To view the infraspinatus and teres minor in short axis, the probe is then rotated 90° on its center axis. The infraspinatus (superiorly) and teres minor (inferiorly) muscles will be visible in short axis within the infraspinatus fossa.¹⁵ The MRI equivalent is the sagittal view.

The acromioclavicular joint is superficial and easy to image. The arm remains in a neutral position, and we can palpate the joint for easy localization. The probe is placed anteriorly in a coronal plane over the acromion and clavicle. By scanning anteriorly and posteriorly, a joint effusion referred to as a Geyser sign might be seen. The MRI equivalent is the coronal view.

Available Certifications

The AIUM certification is a voluntary peer reviewed process that acknowledges that a practice is meeting national standards and aids in improving their respective MSK ultrasound protocols. They also provide guidelines on demonstrating training and competence on performing and/or interpreting diagnostic MSK examinations (Table).¹⁰ The ARDMS certification provides an actual individual certification referred to as “Registered” in MSK ultrasound.¹¹ The physician must perform 150 diagnostic MSK ultrasound evaluations within 36 months of applying and pass a 200-question examination that is offered twice per year.¹¹ None of these certifications are mandated by the American Medical Association (AMA) or American Osteopathic Association (AOA).

Maintenance and Continuing Medical Education (CME)

The AIUM recommends that a minimum of 50 diagnostic MSK ultrasound evaluations be performed per year for skill maintenance.¹⁰ Furthermore, 10 hours of AMA PRA Category 1 Credits™ or American Osteopathic Association Category 1-A Credits specific to MSK ultrasound must be completed by physicians performing and/or interpreting these examinations every 3 years.¹⁰ ARDMS recommends a minimum of 30 MSK ultrasound-specific CMEs in preparation for their “Registered” MSK evaluation.¹

Conclusion

MSK ultrasound is a dynamic, real-time imaging modality that can improve cost efficiency and patient care. Its portability allows for its use anywhere. Learning the skill may seem daunting, but with the proper courses and education, the technology can be easily learned. By correlating a known modality like MRI, the user will easily begin to read ultrasound images. No current certification is needed to use or bill for ultrasound, but various institutions are developing criteria and testing. Two organizations, AIUM and ARDMS, provide guidelines and certifications to demonstrate competency, which may become necessary in the very near future.

The musculoskeletal (MSK) ultrasound evaluation of the shoulder provides a cost- and time-efficient imaging modality with similar diagnostic power as magnetic resonance imaging (MRI).^1,2 Its portable point-of-care applications can be used in the office, in the operating room, and in sideline athletic event coverage, as we discussed in Part 1 of this series.³

MSK ultrasound may seem difficult and daunting, and many articles have quoted steep learning curves.^4,5 However, in our experience in teaching many ultrasound courses, this modality can be learned quite quickly with the proper instruction. Physicians are already familiar with anatomy and usually have had some exposure to MRI.⁴ Taking courses in MSK ultrasound or simply learning the basic concepts of ultrasound and then learning the machine controls is usually a good start.^5-8 Practice scanning normal individuals, comparing the images from an MRI to learn how to reproduce the same planes and images. This will allow the user to become familiar with normal anatomy and how to see the images on the ultrasound screen.^5-8 Vollman and colleagues⁹ showed that in trainees, combining MRI images with sonograms enhances the ability to correctly identify MSK ultrasound anatomy from 40.9% to 72.5%, when compared with learning from ultrasound images alone.

There are currently no certifications necessary to perform ultrasound scans or bill for them; however, some insurance carriers may require demonstrating relevant, documented training for reimbursement.³ Various organizations are trying to develop certifications and regulations for ultrasound to standardize the use of this modality. In the United States, the American Institute of Ultrasound in Medicine (AIUM) and the American Registry for Diagnostic Medical Sonography (ARDMS) provide guidelines and particular MSK ultrasound certifications.^10,11

Basic Ultrasound Principles

The ultrasound machine creates electrical impulses that are turned into sound waves by piezoelectric crystals at the probe’s footprint. These sound waves bounce off tissues and return to the probe, where they are converted electronically to an image on the monitor. Depending on the echogenicity of the scanned tissue, the ultrasound beam will either reflect or be absorbed at different rates. This variance is transmitted on the monitor as a grayscale image. When ultrasound waves are highly reflective, like in bone or fat, they are characterized as hyperechoic. The opposite occurs when ultrasound waves are absorbed like in the fluid of a cystic cavity or joint effusion, and the image appears black. This is described as anechoic.¹² Intermediate tissues such as tendons that are less reflective are seen as hypoechoic and appear gray. When a tissue has a similar echogenicity to its surrounding tissues, it is called isoechoic.¹²

The transducer is the scanning component of the ultrasound machine. Transducers come in 2 shapes: linear and curvilinear. The linear probe creates a straight image that is equal to the size of the transducer footprint. The curvilinear probe creates a wider, wedge-shaped panoramic image.

Linear probes are of higher frequency and generate higher resolution images of shallower structures, while curvilinear probes have greater depth penetration but generate lower resolution images. A high frequency of 10 to 15 MHz is preferred for anatomy between 2 cm to 4 cm depth.¹³ Midrange frequency of 5 to 10 MHz is preferred at 5 cm to 6 cm depth, and low-frequency 2 to 5 MHz probes are preferred for anatomical structures >6 cm depth.¹³

Anisotropy is the property of being directionally dependent, as opposed to isotropy, which implies identical properties in all directions. This anisotropic effect is dependent on the angle of the insonating beam. The maximum return echo occurs when the ultrasound beam is perpendicular to the tendon. Decreasing the insonating angle on a normal tendon will cause it to change from brightly hyperechoic (the actual echo from tightly bound tendon fibers) to darkly hypoechoic. If the angle is then increased, the tendon will again appear hyperechoic. If the artifact causes a normal tendon to appear hypoechoic, it may falsely lead to a diagnosis of tendinosis or tear.

Posterior acoustic shadowing is present when a hyperechoic structure reflects the ultrasound beam so much that it creates a dark shadow underneath it.^12,14 This phenomenon is possible since the ultrasound beam cannot penetrate the hyperechoic structure and reflects off its inferior tissues. Reverberation is when the beam is repeated back and forth between 2 parallel highly reflective surfaces. The initial reflection will be displayed correctly, while the subsequent ultrasound waves will be delayed and appear at a farther distance from the transducer.^12,14

The point where the beam is at its narrowest point generates the section of the image that is best visualized.¹⁵ This is called the focal zone, and it can be adjusted to highlight the desired area of evaluation. Gain controls adjust the amount of black, gray, and white on the monitor and can be adjusted to focus the desired image.¹³ Depth settings are fundamental in finding the desired targets. It is recommended to start with a higher depth setting to get an overview and progressively decrease the depth to key in on the desired anatomy.¹³ Color Doppler can be used to view movement within structures and to identify vessels, synovitis, and neovascularization in tendinopathy.¹³

Ultrasound of the Shoulder

Patients should be seated, if possible, on a rotating seat. The examiner’s shoulder should be higher than the patient’s shoulder.¹⁶ The user holds the ultrasound probe between the thumb and index fingers while resting the hypothenar eminence on the patient to serve as a fulcrum and steadying force. The examination should take 5 to 15 minutes, depending on the examiner’s expertise and the amount of anatomy being scanned.

Examining the body requires knowledge of anatomy. The examination and accuracy are determined by the technician using the probe. The probe can be angled any direction and be placed obliquely on the subject. The advantage here is that anatomy in the human body is not always planar. Muscles and tissues can run obliquely or even perpendicular to each other. When evaluating anatomy, the examiner should keep in mind what structure he or she is looking for; where it should be found; what landmarks can be used to easily locate it; what orientation it has; and what the normal anatomy should look like.

Muscle appears as a lattice with larger areas of hypoechoic muscle tissue and hyperechoic fascial perimysium layers traversing through it.¹⁷ The actual muscle tissue appears hypoechoic from the fluid or blood found within. Scarring, fibrosis, calcification, or chronic injury will change the tissue to appear denser or hyperechoic.¹⁷ Acute injury will appear hypoechoic from the inflammatory response and influx of blood. Tendon appears dense and hyperechoic with striations within the tissue, sometimes referred to as a horse’s tail.¹⁷ When torn, there will be a disassociation of the tissue with a hypoechoic region between the 2 ends. The attachment to the bone and muscle tissue should appear uniform. Hyperechoic areas within the tendon may be from calcification. Ligament appears similar to tendon but is more isoechoic and connects bone to bone. Evaluation of the entire length and the attachments to the bone are critical to evaluate for disease.

Bone appears bright hyperechoic, smooth, and flat, while hyaline cartilage is hypoechoic, smooth, and runs superiorly in a parallel pattern to its respective inferior cortical bone.¹⁷

Fibrocartilage is hyperechoic and typically triangularly shaped, such as in the glenohumeral labrum. Nerves appear fascicular and hypoechoic surrounded by hyperechoic epineurium.¹⁴

The epidermis and dermis are the most superficial structure on top of the screen, and are also hyperechoic.¹⁷

The Diagnostic Shoulder Examination

The proximal long head of the biceps tendon (LHBT) is the easiest structure in the shoulder to identify because of the anatomic structure, the bicipital groove. By keeping the arm relaxed, perpendicular to the ground, and in neutral rotation, the probe can be placed perpendicular to the arm over the proximal shoulder (Figure 1A).^16-20 By finding the groove, the biceps tendon will usually be found resting within the groove (Figure 1B). This is the short axis view and is equivalent to an MRI in the axial plane.

The long axis view of the proximal biceps tendon is found by keeping the tendon in the center of the screen/probe. The probe is then rotated 90° on its center axis, keeping the tendon centered on the probe. The user should be sure to visualize the entire tendon on the screen. If only part of the tendon is seen along only part of the screen, then the probe is oblique to the tendon. In this case, the probe area showing the tendon must be stabilized as the center or set point. The other part of the probe will then pivot until all of the tendon is seen on the screen. The MRI equivalent to the long axis of the proximal biceps tendon is the sagittal view.

Ultrasound is a dynamic evaluation. Moving the probe or moving the patient will change what and how something is imaged. The proximal biceps tendon is a good example of this concept. The bicipital groove is very deep proximally and flattens out as it travels distally to the mid-humerus. The examiner should continually adjust his or her hand/probe/patient position as well as depth/gain and other console functions to adapt to the dynamics of the scan. While keeping the bicep tendon in a short axis view, the tendon can be dynamically evaluated for subluxation by internally and externally rotating the arm.

To find the subscapularis, the arm remains in a neutral position with the hand supinated and the probe is held parallel with the ground. After finding the bicipital groove, the subscapularis tendon insertion is just medial to the groove (Figure 1B). By externally rotating the arm, the subscapularis tendon/muscle will come into a long axis view.^16-20 The MRI equivalent to the long axis view of the subscapularis is the axial view. Dynamic testing can be done by internally and externally rotating the arm to evaluate for impingement of the subscapularis tendon as it slides underneath the coracoid process. To view the subscapularis tendon in short axis, the tendon is kept in the center of the screen/probe, and the probe is then rotated 90° on its center axis, keeping the tendon centered on the probe. The MRI equivalent is the sagittal view.

Some have recommended using the modified Crass or Middleton position to evaluate the supraspinatus, where the hand is in the “back pocket”.¹⁹ However, many patients with shoulder pain have trouble with this position. By resting the ipsilateral hand on the ipsilateral hip and then dropping the elbow, the supraspinatus insertion can still be brought out from under the acromion. This does bring the insertion anterior out of the scapular plane, so an adjustment is required in probe positioning to properly see the supraspinatus short and long axis. To find the long axis, the probe is placed parallel to a plane that spans the contralateral shoulder and ipsilateral hip (Figure 2A). The fibers of the supraspinatus should be inserting directly lateral to the humeral head without any intervening space (Figure 2B). If any space exists, a partial articular supraspinatus tendon avulsion (PASTA) lesion is present, and its thickness can be directly measured. Moving more posterior will show the flattening of the tuberosity and the fibers of the infraspinatus moving away from the humeral head—the bare spot. The MRI equivalent is the coronal view.

To view the supraspinatus tendon in short axis, maintain the arm in the same position, keeping the tendon in the center of the screen/probe. The probe is then rotated 90° on its center axis, keeping the tendon centered on the probe. The probe should now be in a parallel plane between the ipsilateral shoulder and the contralateral hip. The biceps tendon in cross-section will be found anteriorly, and the articular cartilage will appear as a black layer over the bone. Dynamic testing includes placing the probe in a coronal plane between the acromion and greater tuberosity. When the patient abducts the arm while in internal rotation, the supraspinatus tendon will slide underneath the coracoacromial arch showing potential external impingement.¹⁵ The MRI equivalent is the sagittal plane.

The glenohumeral joint is best viewed posteriorly, limiting how much of the intra-articular portion of the joint can be imaged. The arm remains in a neutral position; palpate for the posterior acromion and place the probe just inferior to it, wedging up against it (Figure 3A). The glenohumeral joint will be seen by keeping the probe parallel to the ground (Figure 3B). The MRI equivalent is the axial plane. If a joint effusion exists, it can be seen in the posterior recess.¹⁵ A hyperechoic triangular region in between the humeral head and the glenoid will represent the glenoid labrum (Figure 3B). By internally and externally rotating the arm, the joint and labrum complex can be dynamically examined. From the labrum, scanning superior and medial can sometimes show the spinoglenoid notch where a paralabral cyst might be seen.¹⁵

Using the glenohumeral joint as a reference, the infraspinatus muscle is easily visualized. Maintaining the arm in neutral position with the probe over the glenohumeral joint, the infraspinatus will become apparent as it lays in long axis view superficially between the posterior deltoid and glenohumeral joint (Figure 3B).^16-20 The teres minor lies just inferiorly. The MRI equivalent is the axial plane. To view the infraspinatus and teres minor in short axis, the probe is then rotated 90° on its center axis. The infraspinatus (superiorly) and teres minor (inferiorly) muscles will be visible in short axis within the infraspinatus fossa.¹⁵ The MRI equivalent is the sagittal view.

The acromioclavicular joint is superficial and easy to image. The arm remains in a neutral position, and we can palpate the joint for easy localization. The probe is placed anteriorly in a coronal plane over the acromion and clavicle. By scanning anteriorly and posteriorly, a joint effusion referred to as a Geyser sign might be seen. The MRI equivalent is the coronal view.

Available Certifications

The AIUM certification is a voluntary peer reviewed process that acknowledges that a practice is meeting national standards and aids in improving their respective MSK ultrasound protocols. They also provide guidelines on demonstrating training and competence on performing and/or interpreting diagnostic MSK examinations (Table).¹⁰ The ARDMS certification provides an actual individual certification referred to as “Registered” in MSK ultrasound.¹¹ The physician must perform 150 diagnostic MSK ultrasound evaluations within 36 months of applying and pass a 200-question examination that is offered twice per year.¹¹ None of these certifications are mandated by the American Medical Association (AMA) or American Osteopathic Association (AOA).

Maintenance and Continuing Medical Education (CME)

The AIUM recommends that a minimum of 50 diagnostic MSK ultrasound evaluations be performed per year for skill maintenance.¹⁰ Furthermore, 10 hours of AMA PRA Category 1 Credits™ or American Osteopathic Association Category 1-A Credits specific to MSK ultrasound must be completed by physicians performing and/or interpreting these examinations every 3 years.¹⁰ ARDMS recommends a minimum of 30 MSK ultrasound-specific CMEs in preparation for their “Registered” MSK evaluation.¹

Conclusion

MSK ultrasound is a dynamic, real-time imaging modality that can improve cost efficiency and patient care. Its portability allows for its use anywhere. Learning the skill may seem daunting, but with the proper courses and education, the technology can be easily learned. By correlating a known modality like MRI, the user will easily begin to read ultrasound images. No current certification is needed to use or bill for ultrasound, but various institutions are developing criteria and testing. Two organizations, AIUM and ARDMS, provide guidelines and certifications to demonstrate competency, which may become necessary in the very near future.

The musculoskeletal (MSK) ultrasound evaluation of the shoulder provides a cost- and time-efficient imaging modality with similar diagnostic power as magnetic resonance imaging (MRI).^1,2 Its portable point-of-care applications can be used in the office, in the operating room, and in sideline athletic event coverage, as we discussed in Part 1 of this series.³

MSK ultrasound may seem difficult and daunting, and many articles have quoted steep learning curves.^4,5 However, in our experience in teaching many ultrasound courses, this modality can be learned quite quickly with the proper instruction. Physicians are already familiar with anatomy and usually have had some exposure to MRI.⁴ Taking courses in MSK ultrasound or simply learning the basic concepts of ultrasound and then learning the machine controls is usually a good start.^5-8 Practice scanning normal individuals, comparing the images from an MRI to learn how to reproduce the same planes and images. This will allow the user to become familiar with normal anatomy and how to see the images on the ultrasound screen.^5-8 Vollman and colleagues⁹ showed that in trainees, combining MRI images with sonograms enhances the ability to correctly identify MSK ultrasound anatomy from 40.9% to 72.5%, when compared with learning from ultrasound images alone.

There are currently no certifications necessary to perform ultrasound scans or bill for them; however, some insurance carriers may require demonstrating relevant, documented training for reimbursement.³ Various organizations are trying to develop certifications and regulations for ultrasound to standardize the use of this modality. In the United States, the American Institute of Ultrasound in Medicine (AIUM) and the American Registry for Diagnostic Medical Sonography (ARDMS) provide guidelines and particular MSK ultrasound certifications.^10,11

Basic Ultrasound Principles

The ultrasound machine creates electrical impulses that are turned into sound waves by piezoelectric crystals at the probe’s footprint. These sound waves bounce off tissues and return to the probe, where they are converted electronically to an image on the monitor. Depending on the echogenicity of the scanned tissue, the ultrasound beam will either reflect or be absorbed at different rates. This variance is transmitted on the monitor as a grayscale image. When ultrasound waves are highly reflective, like in bone or fat, they are characterized as hyperechoic. The opposite occurs when ultrasound waves are absorbed like in the fluid of a cystic cavity or joint effusion, and the image appears black. This is described as anechoic.¹² Intermediate tissues such as tendons that are less reflective are seen as hypoechoic and appear gray. When a tissue has a similar echogenicity to its surrounding tissues, it is called isoechoic.¹²

The transducer is the scanning component of the ultrasound machine. Transducers come in 2 shapes: linear and curvilinear. The linear probe creates a straight image that is equal to the size of the transducer footprint. The curvilinear probe creates a wider, wedge-shaped panoramic image.

Linear probes are of higher frequency and generate higher resolution images of shallower structures, while curvilinear probes have greater depth penetration but generate lower resolution images. A high frequency of 10 to 15 MHz is preferred for anatomy between 2 cm to 4 cm depth.¹³ Midrange frequency of 5 to 10 MHz is preferred at 5 cm to 6 cm depth, and low-frequency 2 to 5 MHz probes are preferred for anatomical structures >6 cm depth.¹³

Anisotropy is the property of being directionally dependent, as opposed to isotropy, which implies identical properties in all directions. This anisotropic effect is dependent on the angle of the insonating beam. The maximum return echo occurs when the ultrasound beam is perpendicular to the tendon. Decreasing the insonating angle on a normal tendon will cause it to change from brightly hyperechoic (the actual echo from tightly bound tendon fibers) to darkly hypoechoic. If the angle is then increased, the tendon will again appear hyperechoic. If the artifact causes a normal tendon to appear hypoechoic, it may falsely lead to a diagnosis of tendinosis or tear.

Posterior acoustic shadowing is present when a hyperechoic structure reflects the ultrasound beam so much that it creates a dark shadow underneath it.^12,14 This phenomenon is possible since the ultrasound beam cannot penetrate the hyperechoic structure and reflects off its inferior tissues. Reverberation is when the beam is repeated back and forth between 2 parallel highly reflective surfaces. The initial reflection will be displayed correctly, while the subsequent ultrasound waves will be delayed and appear at a farther distance from the transducer.^12,14

The point where the beam is at its narrowest point generates the section of the image that is best visualized.¹⁵ This is called the focal zone, and it can be adjusted to highlight the desired area of evaluation. Gain controls adjust the amount of black, gray, and white on the monitor and can be adjusted to focus the desired image.¹³ Depth settings are fundamental in finding the desired targets. It is recommended to start with a higher depth setting to get an overview and progressively decrease the depth to key in on the desired anatomy.¹³ Color Doppler can be used to view movement within structures and to identify vessels, synovitis, and neovascularization in tendinopathy.¹³

Ultrasound of the Shoulder

Patients should be seated, if possible, on a rotating seat. The examiner’s shoulder should be higher than the patient’s shoulder.¹⁶ The user holds the ultrasound probe between the thumb and index fingers while resting the hypothenar eminence on the patient to serve as a fulcrum and steadying force. The examination should take 5 to 15 minutes, depending on the examiner’s expertise and the amount of anatomy being scanned.

Examining the body requires knowledge of anatomy. The examination and accuracy are determined by the technician using the probe. The probe can be angled any direction and be placed obliquely on the subject. The advantage here is that anatomy in the human body is not always planar. Muscles and tissues can run obliquely or even perpendicular to each other. When evaluating anatomy, the examiner should keep in mind what structure he or she is looking for; where it should be found; what landmarks can be used to easily locate it; what orientation it has; and what the normal anatomy should look like.

Muscle appears as a lattice with larger areas of hypoechoic muscle tissue and hyperechoic fascial perimysium layers traversing through it.¹⁷ The actual muscle tissue appears hypoechoic from the fluid or blood found within. Scarring, fibrosis, calcification, or chronic injury will change the tissue to appear denser or hyperechoic.¹⁷ Acute injury will appear hypoechoic from the inflammatory response and influx of blood. Tendon appears dense and hyperechoic with striations within the tissue, sometimes referred to as a horse’s tail.¹⁷ When torn, there will be a disassociation of the tissue with a hypoechoic region between the 2 ends. The attachment to the bone and muscle tissue should appear uniform. Hyperechoic areas within the tendon may be from calcification. Ligament appears similar to tendon but is more isoechoic and connects bone to bone. Evaluation of the entire length and the attachments to the bone are critical to evaluate for disease.

Bone appears bright hyperechoic, smooth, and flat, while hyaline cartilage is hypoechoic, smooth, and runs superiorly in a parallel pattern to its respective inferior cortical bone.¹⁷

Fibrocartilage is hyperechoic and typically triangularly shaped, such as in the glenohumeral labrum. Nerves appear fascicular and hypoechoic surrounded by hyperechoic epineurium.¹⁴

The epidermis and dermis are the most superficial structure on top of the screen, and are also hyperechoic.¹⁷

The Diagnostic Shoulder Examination

The proximal long head of the biceps tendon (LHBT) is the easiest structure in the shoulder to identify because of the anatomic structure, the bicipital groove. By keeping the arm relaxed, perpendicular to the ground, and in neutral rotation, the probe can be placed perpendicular to the arm over the proximal shoulder (Figure 1A).^16-20 By finding the groove, the biceps tendon will usually be found resting within the groove (Figure 1B). This is the short axis view and is equivalent to an MRI in the axial plane.

The long axis view of the proximal biceps tendon is found by keeping the tendon in the center of the screen/probe. The probe is then rotated 90° on its center axis, keeping the tendon centered on the probe. The user should be sure to visualize the entire tendon on the screen. If only part of the tendon is seen along only part of the screen, then the probe is oblique to the tendon. In this case, the probe area showing the tendon must be stabilized as the center or set point. The other part of the probe will then pivot until all of the tendon is seen on the screen. The MRI equivalent to the long axis of the proximal biceps tendon is the sagittal view.

Ultrasound is a dynamic evaluation. Moving the probe or moving the patient will change what and how something is imaged. The proximal biceps tendon is a good example of this concept. The bicipital groove is very deep proximally and flattens out as it travels distally to the mid-humerus. The examiner should continually adjust his or her hand/probe/patient position as well as depth/gain and other console functions to adapt to the dynamics of the scan. While keeping the bicep tendon in a short axis view, the tendon can be dynamically evaluated for subluxation by internally and externally rotating the arm.

To find the subscapularis, the arm remains in a neutral position with the hand supinated and the probe is held parallel with the ground. After finding the bicipital groove, the subscapularis tendon insertion is just medial to the groove (Figure 1B). By externally rotating the arm, the subscapularis tendon/muscle will come into a long axis view.^16-20 The MRI equivalent to the long axis view of the subscapularis is the axial view. Dynamic testing can be done by internally and externally rotating the arm to evaluate for impingement of the subscapularis tendon as it slides underneath the coracoid process. To view the subscapularis tendon in short axis, the tendon is kept in the center of the screen/probe, and the probe is then rotated 90° on its center axis, keeping the tendon centered on the probe. The MRI equivalent is the sagittal view.

Some have recommended using the modified Crass or Middleton position to evaluate the supraspinatus, where the hand is in the “back pocket”.¹⁹ However, many patients with shoulder pain have trouble with this position. By resting the ipsilateral hand on the ipsilateral hip and then dropping the elbow, the supraspinatus insertion can still be brought out from under the acromion. This does bring the insertion anterior out of the scapular plane, so an adjustment is required in probe positioning to properly see the supraspinatus short and long axis. To find the long axis, the probe is placed parallel to a plane that spans the contralateral shoulder and ipsilateral hip (Figure 2A). The fibers of the supraspinatus should be inserting directly lateral to the humeral head without any intervening space (Figure 2B). If any space exists, a partial articular supraspinatus tendon avulsion (PASTA) lesion is present, and its thickness can be directly measured. Moving more posterior will show the flattening of the tuberosity and the fibers of the infraspinatus moving away from the humeral head—the bare spot. The MRI equivalent is the coronal view.

To view the supraspinatus tendon in short axis, maintain the arm in the same position, keeping the tendon in the center of the screen/probe. The probe is then rotated 90° on its center axis, keeping the tendon centered on the probe. The probe should now be in a parallel plane between the ipsilateral shoulder and the contralateral hip. The biceps tendon in cross-section will be found anteriorly, and the articular cartilage will appear as a black layer over the bone. Dynamic testing includes placing the probe in a coronal plane between the acromion and greater tuberosity. When the patient abducts the arm while in internal rotation, the supraspinatus tendon will slide underneath the coracoacromial arch showing potential external impingement.¹⁵ The MRI equivalent is the sagittal plane.

The glenohumeral joint is best viewed posteriorly, limiting how much of the intra-articular portion of the joint can be imaged. The arm remains in a neutral position; palpate for the posterior acromion and place the probe just inferior to it, wedging up against it (Figure 3A). The glenohumeral joint will be seen by keeping the probe parallel to the ground (Figure 3B). The MRI equivalent is the axial plane. If a joint effusion exists, it can be seen in the posterior recess.¹⁵ A hyperechoic triangular region in between the humeral head and the glenoid will represent the glenoid labrum (Figure 3B). By internally and externally rotating the arm, the joint and labrum complex can be dynamically examined. From the labrum, scanning superior and medial can sometimes show the spinoglenoid notch where a paralabral cyst might be seen.¹⁵

Using the glenohumeral joint as a reference, the infraspinatus muscle is easily visualized. Maintaining the arm in neutral position with the probe over the glenohumeral joint, the infraspinatus will become apparent as it lays in long axis view superficially between the posterior deltoid and glenohumeral joint (Figure 3B).^16-20 The teres minor lies just inferiorly. The MRI equivalent is the axial plane. To view the infraspinatus and teres minor in short axis, the probe is then rotated 90° on its center axis. The infraspinatus (superiorly) and teres minor (inferiorly) muscles will be visible in short axis within the infraspinatus fossa.¹⁵ The MRI equivalent is the sagittal view.

The acromioclavicular joint is superficial and easy to image. The arm remains in a neutral position, and we can palpate the joint for easy localization. The probe is placed anteriorly in a coronal plane over the acromion and clavicle. By scanning anteriorly and posteriorly, a joint effusion referred to as a Geyser sign might be seen. The MRI equivalent is the coronal view.

Available Certifications

The AIUM certification is a voluntary peer reviewed process that acknowledges that a practice is meeting national standards and aids in improving their respective MSK ultrasound protocols. They also provide guidelines on demonstrating training and competence on performing and/or interpreting diagnostic MSK examinations (Table).¹⁰ The ARDMS certification provides an actual individual certification referred to as “Registered” in MSK ultrasound.¹¹ The physician must perform 150 diagnostic MSK ultrasound evaluations within 36 months of applying and pass a 200-question examination that is offered twice per year.¹¹ None of these certifications are mandated by the American Medical Association (AMA) or American Osteopathic Association (AOA).

Maintenance and Continuing Medical Education (CME)

The AIUM recommends that a minimum of 50 diagnostic MSK ultrasound evaluations be performed per year for skill maintenance.¹⁰ Furthermore, 10 hours of AMA PRA Category 1 Credits™ or American Osteopathic Association Category 1-A Credits specific to MSK ultrasound must be completed by physicians performing and/or interpreting these examinations every 3 years.¹⁰ ARDMS recommends a minimum of 30 MSK ultrasound-specific CMEs in preparation for their “Registered” MSK evaluation.¹

Conclusion

MSK ultrasound is a dynamic, real-time imaging modality that can improve cost efficiency and patient care. Its portability allows for its use anywhere. Learning the skill may seem daunting, but with the proper courses and education, the technology can be easily learned. By correlating a known modality like MRI, the user will easily begin to read ultrasound images. No current certification is needed to use or bill for ultrasound, but various institutions are developing criteria and testing. Two organizations, AIUM and ARDMS, provide guidelines and certifications to demonstrate competency, which may become necessary in the very near future.

Although ultrasound has been around for many years, the technology is underutilized. It has been used primarily by the radiologists and obstetricians-gynecologists. However, orthopedic surgeons and sports medicine doctors are beginning to realize the utility of this imaging modality for their specialties. Ultrasound has classically been used as a diagnostic tool. This usage is beneficial to sports medicine specialists for on-field coverage at sports competitions to efficiently evaluate injuries without the need for taking the athletes back to the locker room for an x-ray or magnetic resonance imaging (MRI). Ultrasound can quickly assess for damage to soft tissue, joints, and superficial bones. Another of ultrasound’s benefits is its use as an adjunct to treatment. Ultrasound has been shown to vastly increase the accuracy of injections and can be used in surgery to accurately guide percutaneous techniques or to identify structures that previously required radiation-exposing fluoroscopy or large incisions to find by feel or eye.

Ultrasound is a technician-dependent modality. The surgeon and physician must become facile with the use of the probe and how ultrasound works. The use of the probe is similar to an arthroscope, requiring small movements of the hand to reveal the best imaging of the tissues. Rather than relying on just the patient’s position with an immobile machine, the user must use the probe position and the placement of the patient’s limb or body to optimize the use of ultrasound. Doing so saves time, money, and exposure to dangerous radiation. In a retrospective study of 1012 patients treated over a 10-month period, Sivan and colleagues¹ concluded that the use of clinic-based musculoskeletal (MSK) ultrasound enables a one-stop approach, reduces repeat hospital appointments, and improves quality of care.With the increased use of ultrasound comes the need to accurately code and bill for the use of ultrasound. According to the College of Radiology, Medicare reimbursements for MSK ultrasound studies has increased by 316% from 2000-2009.² Paradoxically, ultrasound has still been relatively underutilized when compared to the use of MSK MRI.

Diagnostic Ultrasound

Ultrasound is based off sound waves, emitted from a transducer, which are then bounced back off the underlying structures based on the density of that structure. The computer interprets the returning sound waves and produces an image reflecting the quality and strength of those returning waves. When the sound waves are bounced back strongly and quickly, like when hitting bone, we see an image that is intensely white (“hyperechoic”). When the sound waves encounter a substance that transmits those waves easily and do not return, like air or fluid, the image is dark (“hypoechoic”).

Ultrasound’s fundamental advantages start with every patient being able to have an ultrasound: no interference from metal, pacemakers, claustrophobia, or obesity. Contralateral comparisons, sono-palpation at the site of pathology, and real-time dynamic studies allow for a more comprehensive diagnostic evaluation. Doppler capabilities can further expand the usefulness of the evaluation and guide safer interventions. With the advent of high-resolution portable ultrasound machines, these studies can essentially be performed anywhere, and are typically done in a timely and cost-effective manner.

Ultrasound has many diagnostic uses for soft tissue, joint, and bone disorders. For soft tissues, ultrasound can image tears of muscles, tendons, and ligaments; show inflammation like tenosynovitis; demonstrate masses like hematomas, cysts, solid tumors, or calcific tendonitis; display nerve disorders like Morton’s neuroma; or confirm foreign bodies or infections.^3-5 For joint disorders, ultrasound can show erosions on bones, loose bodies, pannus, inflammation, or effusions. For bone disorders, ultrasound can diagnose fractures and, sometimes, even stress fractures. Tomer and colleagues⁶ compared 51 patients with bone contusions and fractures; they determined that ultrasound was most reliable in the diagnosis of long bone diaphyseal fractures. The one disadvantage, especially when compared to MRI, is ultrasound’s inability to fully evaluate intra-articular or deep structures such as articular cartilage, the glenohumeral labrum, the biceps’ anchor, etc.

Magnetic Resonance Imaging

Ultrasound is similar to MRI as it images tissues and gives us ideas whether that tissue is normal, damaged, or diseased (Figures 1A, 1B). MRI is based on magnetics and large machines that cannot be moved. MRI yields planar images that can only be changed by changing the position of the limb or body in the MRI tube. This can create an issue with obese patients or with postoperative patients who cannot maintain the operated body part in one position for the length of the MRI scan. Ultrasound is better tolerated by patients without the need for claustrophobic large machines (Table 1). In 2004, Middleton and colleagues⁷ surveyed 118 patients who obtained an ultrasound and MRI of the shoulder for suspected rotator cuff pathology; ultrasound had higher satisfaction levels, and 93% of patients preferred ultrasound to MRI.

For rotator cuff tears, ultrasound is also comparable diagnostically with MRI (Figures 2A, 2B). In a prospective study of 124 patients, MRI and ultrasound had comparable accuracy for identifying and measuring the size of full-thickness and partial-thickness rotator cuff tears, with arthroscopic findings used as the standard.⁸ A 2015 meta-analysis published in the British Journal of Sports Medicine showed that the diagnostic accuracy of ultrasound, MRI, and MR arthrography in the characterization of full thickness rotator cuff tears had >90% sensitivity and specificity. As for partial rotator cuff tears and tendinopathy, overall estimates of specificity were also high (>90%), while sensitivity was as high as 83%. Diagnostic accuracy of ultrasound was similar whether it was performed by a trained radiologist, sonographer, or orthopedist.⁹

Medicare reimbursements for MSK ultrasound studies has increased by 316% in the past decade.² Private practice MSK ultrasound procedures increased from 19,372 in 2000 to 158,351 in 2009.² In 2010, non-radiologists accounted for more ultrasound-guided procedures than radiologists for the first time.¹⁰ MSK ultrasound is still underutilized compared to MRI. This underutilization is also unfortunate economically. The cost of MRIs is significantly higher. According to Parker and colleagues¹⁰, the projected Medicare cost for MSK imaging in 2020 is $3.6 billion, with MRI accounting for $2 billion. They also concluded that replacing MSK MRI with MSK ultrasound when clinically indicated could save over $6.9 billion between 2006 and 2020.¹¹

Ultrasound-Guided Procedures

MSK ultrasound has gained significant ground on other imaging modalities when it comes to procedures, both in office and in the operating room. The ability to have a small, mobile, inexpensive machine that can be used in real time has dramatically changed how interventions are done. Most imaging modalities used to perform injections or percutaneous surgery use fluoroscopy machines. This exposes the patients to significant radiation, costs significantly more, and usually requires a secondary consultation with radiologists in a different facility. This wastes time and money, and results in potentially unnecessary exposure to radiation.

Accuracy is the most common reason for referral for guided injections. The guidance can help avoid nerves, vessels, and other sensitive tissues. However, accuracy is also important to make sure the injection is placed in the correct location. When injections are placed into a muscle, tendon, or ligament, it causes significant pain; however, injections placed into a bursal space or joint do not cause pain. Numerous studies have shown that even in the hands of experts, “simple” injections can still miss their mark over 30% of the time.^12-19 Therefore, if a patient experiences pain during a bursal space or joint injection, the injection was not placed properly.

The American Medical Society for Sports Medicine Position Paper on MSK ultrasound is based on a systematic review of the literature, including 124 studies. It states that ultrasound-guided joint injections (USGI) are more accurate and efficacious than landmark guided injections (LMGI), with a strength of recommendation taxonomy (SORT) evidence rating of A and B, respectively.¹⁹ In terms of patient satisfaction, in a randomized controlled trial of 148 patients undergoing knee injections, Sibbitt and colleagues²⁰ showed that USGI had a 48% reduction (P < .001) in procedural pain, a 58.5% reduction (P < .001) in absolute pain scores at the 2-week outcome mark, and a 75% reduction (P < .001) in significant pain and 62% reduction in nonresponder rate.²⁰ From a financial point of view, Sibbitt and colleagues²⁰ also demonstrated a 13% reduction in cost per patient per year, and a 58% reduction in cost per responder per year for a hospital outpatient center (P < .001).

Coding

Coding for diagnostic MSK ultrasound requires an understanding of a few current procedural terminology (CPT) codes (Table 2). Ultrasound usage should follow the usual requirements of medical necessity and the CPT code selected should be based on the elements of the study performed. A complete examination, described by CPT code 76881, includes the examination and documentation of the muscles, tendons, joint, and other soft tissue structures and any identifiable abnormality of the joint being evaluated. If anything less is done, then the CPT code 76882 should be used.

New CPT codes for joint injections became effective January 2015 (Table 3). The new changes affect only the joint injection series (20600-20610). Previously, injections could be billed with CPT code 76942, which was “Ultrasonic guidance for needle placement (eg, biopsy, aspiration, injection, localization device), imaging supervision and interpretation.” This code can still be used, but with only specific injections, when the verbiage “with ultrasound/image guidance” is not included in the injection CPT code descriptor (Table 4).

Under the National Correct Coding Initiative (NCCI), which sets Centers for Medicare & Medicaid Services (CMS) payment policy as well as that of many private payers, one unit of service is allowed for CPT code 76942 in a single patient encounter regardless of the number of needle placements performed. Per NCCI, “The unit of service for these codes is the patient encounter, not number of lesions, number of aspirations, number of biopsies, number of injections, or number of localizations.”

Per the Radiology section of the NCCI, “Ultrasound guidance and diagnostic ultrasound (echography) procedures may be reported separately only if each service is distinct and separate. If a diagnostic ultrasound study identifies a previously unknown abnormality that requires a therapeutic procedure with ultrasound guidance at the same patient encounter, both the diagnostic ultrasound and ultrasound guidance procedure codes may be reported separately. However, a previously unknown abnormality identified during ultrasound guidance for a procedure should not be reported separately as a diagnostic ultrasound procedure.”

Under the Medicare program, the International Classification of Diseases 10th Revision (ICD-10) code selected should be based on the test results, with 2 exceptions. If the test does not yield a diagnosis or was normal, the physician should use the pre-service signs, symptoms, and conditions that prompted the study. If the test is a screening examination ordered in the absence of any signs or symptoms of illness or injury, the physician should select “screening” as the primary reason for the service and record the test results, if any, as additional diagnoses.

Modifiers must be used in specific settings. In the office, physicians who own the equipment and perform the service themselves (or the service is performed by an employed or contracted sonographer) may bill the global fee without any modifiers. However, if billing for a procedure on the same day as an office visit, the -25 modifier must be used. This indicates “[a] significant, separately identifiable evaluation and management service.” This modifier should not be used routinely. If the service is performed in a hospital, the -26 modifier must be used to indicate that the professional service only was provided when the physician does not own the machine (Tables 2, 3, 4). The payers will not reimburse physicians for the technical component in the hospital setting.

Reimbursement

In general, medical insurance plans will cover ultrasound studies when they are medically indicated. However, we recommend checking with each individual private payer directly, including Medicare. Medicare Part B will generally reimburse physicians for medically necessary diagnostic ultrasound services, provided the services are within the scope of the physician’s license. Some Medicare contractors require that the physician who performs and/or interprets some types of ultrasound examinations be capable of demonstrating relevant, documented training through recent residency training or post-graduate continuing medical education (CME) and experience. Medicare does not differentiate by medical specialty with respect to billing medically necessary diagnostic ultrasound services, provided the services are within the scope of the physician’s license. Some Medicare contractors have coverage policies regarding either the diagnostic study or ultrasound guidance of certain injections, or both.

Payment policies for beneficiaries enrolled in Medicare Part C, known as the Medicare Advantage plans, will reflect those of the private insurance administrator. The Medicare Advantage plan may be either a health maintenance organization (HMO) or a preferred provider organization (PPO). Private insurance payment rules vary by payer and plan with respect to which specialties may perform and receive reimbursement for ultrasound services. Some payers will reimburse providers of any specialty for ultrasound services, while others may restrict imaging procedures to specific specialties or providers possessing specific certifications or accreditations. Some insurers require physicians to submit applications requesting ultrasound be added to their list of services performed in their practice. Physicians should contact private payers before submitting claims to determine their requirements and request that they add ultrasound to the list of services.

When contacting the private payers, ask the following questions:

• What do I need to do to have ultrasound added to my practice’s contract or list of services?
• Are there any specific training requirements that I must meet or credentials that I must obtain in order to be privileged to perform ultrasound in my office?
• Do I need to send a letter or can I submit the request verbally?
• Is there an application that must be completed?
• If there is a privileging program, how long will it take after submission of the application before we are accepted?
• What is the fee schedule associated with these codes?
• Are there any bundling edits in place covering any of the services I am considering performing? (Be prepared to provide the codes for any non-ultrasound services you will be performing in conjunction with the ultrasound services.)
• Are there any preauthorization requirements for specific ultrasound studies?
• Are there any preauthorization requirements for specific ultrasound studies?

Documentation Requirements

All diagnostic ultrasound examinations, including those when ultrasound is used to guide a procedure, require that permanently recorded images be maintained in the patient record. The images can be kept in the patient record or some other archive—they do not need to be submitted with the claim. Images can be stored as printed images, on a tape or electronic medium. Documentation of the study must be available to the insurer upon request.

A written report of all ultrasound studies should be maintained in the patient’s record. In the case of ultrasound guidance, the written report may be filed as a separate item in the patient’s record or it may be included within the report of the procedure for which the guidance is utilized.

As examples of our documentation in the office, copies of 3 of our standard forms are available: “Ultrasound report of the shoulder” (Appendix 1), “Procedure note for an ultrasound-guided injection of cortisone” (Appendix 2), and “Procedure note for an ultrasound-guided injection of platelet-rich plasma” (Appendix 3).

Appropriate Use Criteria (AUC)

The Protecting Access to Medicare Act of 2014 was an effort to help reduce unnecessary imaging services and reduce costs; the Secretary of Health and Human Services was to establish a program to promote the use of “appropriate use criteria” (AUC) for advanced imaging services such as MRI, computed tomography, positron emission tomography, and nuclear cardiology. AUC are criteria that are developed or endorsed by national professional medical specialty societies or other provider-led entities to assist ordering professionals and furnishing professionals in making the most appropriate treatment decision for a specific clinical condition for an individual. The law also noted that the criteria should be evidence-based, meaning they should have stakeholder consensus, be scientifically valid, and be based on studies that are published and reviewable by stakeholders.

By April 2016, the Secretary will identify and publish the list of qualified clinical decision support mechanisms, which are tools that could be used by ordering professionals to ensure that AUC is met for applicable imaging services. These may include certified health electronic record technology, private sector clinical decision support mechanisms, and others. Actual use of the AUC will begin in January 2017. This legislation applies only to Medicare services, but other payers have cited concerns and may follow in the future.

Conclusion

Ultrasound is being increasingly used in varying specialties, especially orthopedic surgery. It provides a time- and cost-efficient modality with diagnostic power comparable to MRI. Portability and a high safety profile allows for ease of implementation as an in-office or sideline tool. Needle guidance and other intraoperative applications highlight its versatility as an adjunct to orthopedic treatments. This article provides a comprehensive guide to billing and coding for both diagnostic and therapeutic MSK ultrasound of the shoulder. Providers should stay up to date with upcoming appropriate use criteria and adjustments to current billing procedures.

Although ultrasound has been around for many years, the technology is underutilized. It has been used primarily by the radiologists and obstetricians-gynecologists. However, orthopedic surgeons and sports medicine doctors are beginning to realize the utility of this imaging modality for their specialties. Ultrasound has classically been used as a diagnostic tool. This usage is beneficial to sports medicine specialists for on-field coverage at sports competitions to efficiently evaluate injuries without the need for taking the athletes back to the locker room for an x-ray or magnetic resonance imaging (MRI). Ultrasound can quickly assess for damage to soft tissue, joints, and superficial bones. Another of ultrasound’s benefits is its use as an adjunct to treatment. Ultrasound has been shown to vastly increase the accuracy of injections and can be used in surgery to accurately guide percutaneous techniques or to identify structures that previously required radiation-exposing fluoroscopy or large incisions to find by feel or eye.

Ultrasound is a technician-dependent modality. The surgeon and physician must become facile with the use of the probe and how ultrasound works. The use of the probe is similar to an arthroscope, requiring small movements of the hand to reveal the best imaging of the tissues. Rather than relying on just the patient’s position with an immobile machine, the user must use the probe position and the placement of the patient’s limb or body to optimize the use of ultrasound. Doing so saves time, money, and exposure to dangerous radiation. In a retrospective study of 1012 patients treated over a 10-month period, Sivan and colleagues¹ concluded that the use of clinic-based musculoskeletal (MSK) ultrasound enables a one-stop approach, reduces repeat hospital appointments, and improves quality of care.With the increased use of ultrasound comes the need to accurately code and bill for the use of ultrasound. According to the College of Radiology, Medicare reimbursements for MSK ultrasound studies has increased by 316% from 2000-2009.² Paradoxically, ultrasound has still been relatively underutilized when compared to the use of MSK MRI.

Diagnostic Ultrasound

Ultrasound is based off sound waves, emitted from a transducer, which are then bounced back off the underlying structures based on the density of that structure. The computer interprets the returning sound waves and produces an image reflecting the quality and strength of those returning waves. When the sound waves are bounced back strongly and quickly, like when hitting bone, we see an image that is intensely white (“hyperechoic”). When the sound waves encounter a substance that transmits those waves easily and do not return, like air or fluid, the image is dark (“hypoechoic”).

Ultrasound’s fundamental advantages start with every patient being able to have an ultrasound: no interference from metal, pacemakers, claustrophobia, or obesity. Contralateral comparisons, sono-palpation at the site of pathology, and real-time dynamic studies allow for a more comprehensive diagnostic evaluation. Doppler capabilities can further expand the usefulness of the evaluation and guide safer interventions. With the advent of high-resolution portable ultrasound machines, these studies can essentially be performed anywhere, and are typically done in a timely and cost-effective manner.

Ultrasound has many diagnostic uses for soft tissue, joint, and bone disorders. For soft tissues, ultrasound can image tears of muscles, tendons, and ligaments; show inflammation like tenosynovitis; demonstrate masses like hematomas, cysts, solid tumors, or calcific tendonitis; display nerve disorders like Morton’s neuroma; or confirm foreign bodies or infections.^3-5 For joint disorders, ultrasound can show erosions on bones, loose bodies, pannus, inflammation, or effusions. For bone disorders, ultrasound can diagnose fractures and, sometimes, even stress fractures. Tomer and colleagues⁶ compared 51 patients with bone contusions and fractures; they determined that ultrasound was most reliable in the diagnosis of long bone diaphyseal fractures. The one disadvantage, especially when compared to MRI, is ultrasound’s inability to fully evaluate intra-articular or deep structures such as articular cartilage, the glenohumeral labrum, the biceps’ anchor, etc.

Magnetic Resonance Imaging

Ultrasound is similar to MRI as it images tissues and gives us ideas whether that tissue is normal, damaged, or diseased (Figures 1A, 1B). MRI is based on magnetics and large machines that cannot be moved. MRI yields planar images that can only be changed by changing the position of the limb or body in the MRI tube. This can create an issue with obese patients or with postoperative patients who cannot maintain the operated body part in one position for the length of the MRI scan. Ultrasound is better tolerated by patients without the need for claustrophobic large machines (Table 1). In 2004, Middleton and colleagues⁷ surveyed 118 patients who obtained an ultrasound and MRI of the shoulder for suspected rotator cuff pathology; ultrasound had higher satisfaction levels, and 93% of patients preferred ultrasound to MRI.

For rotator cuff tears, ultrasound is also comparable diagnostically with MRI (Figures 2A, 2B). In a prospective study of 124 patients, MRI and ultrasound had comparable accuracy for identifying and measuring the size of full-thickness and partial-thickness rotator cuff tears, with arthroscopic findings used as the standard.⁸ A 2015 meta-analysis published in the British Journal of Sports Medicine showed that the diagnostic accuracy of ultrasound, MRI, and MR arthrography in the characterization of full thickness rotator cuff tears had >90% sensitivity and specificity. As for partial rotator cuff tears and tendinopathy, overall estimates of specificity were also high (>90%), while sensitivity was as high as 83%. Diagnostic accuracy of ultrasound was similar whether it was performed by a trained radiologist, sonographer, or orthopedist.⁹

Medicare reimbursements for MSK ultrasound studies has increased by 316% in the past decade.² Private practice MSK ultrasound procedures increased from 19,372 in 2000 to 158,351 in 2009.² In 2010, non-radiologists accounted for more ultrasound-guided procedures than radiologists for the first time.¹⁰ MSK ultrasound is still underutilized compared to MRI. This underutilization is also unfortunate economically. The cost of MRIs is significantly higher. According to Parker and colleagues¹⁰, the projected Medicare cost for MSK imaging in 2020 is $3.6 billion, with MRI accounting for $2 billion. They also concluded that replacing MSK MRI with MSK ultrasound when clinically indicated could save over $6.9 billion between 2006 and 2020.¹¹

Ultrasound-Guided Procedures

MSK ultrasound has gained significant ground on other imaging modalities when it comes to procedures, both in office and in the operating room. The ability to have a small, mobile, inexpensive machine that can be used in real time has dramatically changed how interventions are done. Most imaging modalities used to perform injections or percutaneous surgery use fluoroscopy machines. This exposes the patients to significant radiation, costs significantly more, and usually requires a secondary consultation with radiologists in a different facility. This wastes time and money, and results in potentially unnecessary exposure to radiation.

Accuracy is the most common reason for referral for guided injections. The guidance can help avoid nerves, vessels, and other sensitive tissues. However, accuracy is also important to make sure the injection is placed in the correct location. When injections are placed into a muscle, tendon, or ligament, it causes significant pain; however, injections placed into a bursal space or joint do not cause pain. Numerous studies have shown that even in the hands of experts, “simple” injections can still miss their mark over 30% of the time.^12-19 Therefore, if a patient experiences pain during a bursal space or joint injection, the injection was not placed properly.

The American Medical Society for Sports Medicine Position Paper on MSK ultrasound is based on a systematic review of the literature, including 124 studies. It states that ultrasound-guided joint injections (USGI) are more accurate and efficacious than landmark guided injections (LMGI), with a strength of recommendation taxonomy (SORT) evidence rating of A and B, respectively.¹⁹ In terms of patient satisfaction, in a randomized controlled trial of 148 patients undergoing knee injections, Sibbitt and colleagues²⁰ showed that USGI had a 48% reduction (P < .001) in procedural pain, a 58.5% reduction (P < .001) in absolute pain scores at the 2-week outcome mark, and a 75% reduction (P < .001) in significant pain and 62% reduction in nonresponder rate.²⁰ From a financial point of view, Sibbitt and colleagues²⁰ also demonstrated a 13% reduction in cost per patient per year, and a 58% reduction in cost per responder per year for a hospital outpatient center (P < .001).

Coding

Coding for diagnostic MSK ultrasound requires an understanding of a few current procedural terminology (CPT) codes (Table 2). Ultrasound usage should follow the usual requirements of medical necessity and the CPT code selected should be based on the elements of the study performed. A complete examination, described by CPT code 76881, includes the examination and documentation of the muscles, tendons, joint, and other soft tissue structures and any identifiable abnormality of the joint being evaluated. If anything less is done, then the CPT code 76882 should be used.

New CPT codes for joint injections became effective January 2015 (Table 3). The new changes affect only the joint injection series (20600-20610). Previously, injections could be billed with CPT code 76942, which was “Ultrasonic guidance for needle placement (eg, biopsy, aspiration, injection, localization device), imaging supervision and interpretation.” This code can still be used, but with only specific injections, when the verbiage “with ultrasound/image guidance” is not included in the injection CPT code descriptor (Table 4).

Under the National Correct Coding Initiative (NCCI), which sets Centers for Medicare & Medicaid Services (CMS) payment policy as well as that of many private payers, one unit of service is allowed for CPT code 76942 in a single patient encounter regardless of the number of needle placements performed. Per NCCI, “The unit of service for these codes is the patient encounter, not number of lesions, number of aspirations, number of biopsies, number of injections, or number of localizations.”

Per the Radiology section of the NCCI, “Ultrasound guidance and diagnostic ultrasound (echography) procedures may be reported separately only if each service is distinct and separate. If a diagnostic ultrasound study identifies a previously unknown abnormality that requires a therapeutic procedure with ultrasound guidance at the same patient encounter, both the diagnostic ultrasound and ultrasound guidance procedure codes may be reported separately. However, a previously unknown abnormality identified during ultrasound guidance for a procedure should not be reported separately as a diagnostic ultrasound procedure.”

Under the Medicare program, the International Classification of Diseases 10th Revision (ICD-10) code selected should be based on the test results, with 2 exceptions. If the test does not yield a diagnosis or was normal, the physician should use the pre-service signs, symptoms, and conditions that prompted the study. If the test is a screening examination ordered in the absence of any signs or symptoms of illness or injury, the physician should select “screening” as the primary reason for the service and record the test results, if any, as additional diagnoses.

Modifiers must be used in specific settings. In the office, physicians who own the equipment and perform the service themselves (or the service is performed by an employed or contracted sonographer) may bill the global fee without any modifiers. However, if billing for a procedure on the same day as an office visit, the -25 modifier must be used. This indicates “[a] significant, separately identifiable evaluation and management service.” This modifier should not be used routinely. If the service is performed in a hospital, the -26 modifier must be used to indicate that the professional service only was provided when the physician does not own the machine (Tables 2, 3, 4). The payers will not reimburse physicians for the technical component in the hospital setting.

Reimbursement

In general, medical insurance plans will cover ultrasound studies when they are medically indicated. However, we recommend checking with each individual private payer directly, including Medicare. Medicare Part B will generally reimburse physicians for medically necessary diagnostic ultrasound services, provided the services are within the scope of the physician’s license. Some Medicare contractors require that the physician who performs and/or interprets some types of ultrasound examinations be capable of demonstrating relevant, documented training through recent residency training or post-graduate continuing medical education (CME) and experience. Medicare does not differentiate by medical specialty with respect to billing medically necessary diagnostic ultrasound services, provided the services are within the scope of the physician’s license. Some Medicare contractors have coverage policies regarding either the diagnostic study or ultrasound guidance of certain injections, or both.

Payment policies for beneficiaries enrolled in Medicare Part C, known as the Medicare Advantage plans, will reflect those of the private insurance administrator. The Medicare Advantage plan may be either a health maintenance organization (HMO) or a preferred provider organization (PPO). Private insurance payment rules vary by payer and plan with respect to which specialties may perform and receive reimbursement for ultrasound services. Some payers will reimburse providers of any specialty for ultrasound services, while others may restrict imaging procedures to specific specialties or providers possessing specific certifications or accreditations. Some insurers require physicians to submit applications requesting ultrasound be added to their list of services performed in their practice. Physicians should contact private payers before submitting claims to determine their requirements and request that they add ultrasound to the list of services.

When contacting the private payers, ask the following questions:

• What do I need to do to have ultrasound added to my practice’s contract or list of services?
• Are there any specific training requirements that I must meet or credentials that I must obtain in order to be privileged to perform ultrasound in my office?
• Do I need to send a letter or can I submit the request verbally?
• Is there an application that must be completed?
• If there is a privileging program, how long will it take after submission of the application before we are accepted?
• What is the fee schedule associated with these codes?
• Are there any bundling edits in place covering any of the services I am considering performing? (Be prepared to provide the codes for any non-ultrasound services you will be performing in conjunction with the ultrasound services.)
• Are there any preauthorization requirements for specific ultrasound studies?
• Are there any preauthorization requirements for specific ultrasound studies?

Documentation Requirements

All diagnostic ultrasound examinations, including those when ultrasound is used to guide a procedure, require that permanently recorded images be maintained in the patient record. The images can be kept in the patient record or some other archive—they do not need to be submitted with the claim. Images can be stored as printed images, on a tape or electronic medium. Documentation of the study must be available to the insurer upon request.

A written report of all ultrasound studies should be maintained in the patient’s record. In the case of ultrasound guidance, the written report may be filed as a separate item in the patient’s record or it may be included within the report of the procedure for which the guidance is utilized.

As examples of our documentation in the office, copies of 3 of our standard forms are available: “Ultrasound report of the shoulder” (Appendix 1), “Procedure note for an ultrasound-guided injection of cortisone” (Appendix 2), and “Procedure note for an ultrasound-guided injection of platelet-rich plasma” (Appendix 3).

Appropriate Use Criteria (AUC)

The Protecting Access to Medicare Act of 2014 was an effort to help reduce unnecessary imaging services and reduce costs; the Secretary of Health and Human Services was to establish a program to promote the use of “appropriate use criteria” (AUC) for advanced imaging services such as MRI, computed tomography, positron emission tomography, and nuclear cardiology. AUC are criteria that are developed or endorsed by national professional medical specialty societies or other provider-led entities to assist ordering professionals and furnishing professionals in making the most appropriate treatment decision for a specific clinical condition for an individual. The law also noted that the criteria should be evidence-based, meaning they should have stakeholder consensus, be scientifically valid, and be based on studies that are published and reviewable by stakeholders.

By April 2016, the Secretary will identify and publish the list of qualified clinical decision support mechanisms, which are tools that could be used by ordering professionals to ensure that AUC is met for applicable imaging services. These may include certified health electronic record technology, private sector clinical decision support mechanisms, and others. Actual use of the AUC will begin in January 2017. This legislation applies only to Medicare services, but other payers have cited concerns and may follow in the future.

Conclusion

Ultrasound is being increasingly used in varying specialties, especially orthopedic surgery. It provides a time- and cost-efficient modality with diagnostic power comparable to MRI. Portability and a high safety profile allows for ease of implementation as an in-office or sideline tool. Needle guidance and other intraoperative applications highlight its versatility as an adjunct to orthopedic treatments. This article provides a comprehensive guide to billing and coding for both diagnostic and therapeutic MSK ultrasound of the shoulder. Providers should stay up to date with upcoming appropriate use criteria and adjustments to current billing procedures.

Although ultrasound has been around for many years, the technology is underutilized. It has been used primarily by the radiologists and obstetricians-gynecologists. However, orthopedic surgeons and sports medicine doctors are beginning to realize the utility of this imaging modality for their specialties. Ultrasound has classically been used as a diagnostic tool. This usage is beneficial to sports medicine specialists for on-field coverage at sports competitions to efficiently evaluate injuries without the need for taking the athletes back to the locker room for an x-ray or magnetic resonance imaging (MRI). Ultrasound can quickly assess for damage to soft tissue, joints, and superficial bones. Another of ultrasound’s benefits is its use as an adjunct to treatment. Ultrasound has been shown to vastly increase the accuracy of injections and can be used in surgery to accurately guide percutaneous techniques or to identify structures that previously required radiation-exposing fluoroscopy or large incisions to find by feel or eye.

Ultrasound is a technician-dependent modality. The surgeon and physician must become facile with the use of the probe and how ultrasound works. The use of the probe is similar to an arthroscope, requiring small movements of the hand to reveal the best imaging of the tissues. Rather than relying on just the patient’s position with an immobile machine, the user must use the probe position and the placement of the patient’s limb or body to optimize the use of ultrasound. Doing so saves time, money, and exposure to dangerous radiation. In a retrospective study of 1012 patients treated over a 10-month period, Sivan and colleagues¹ concluded that the use of clinic-based musculoskeletal (MSK) ultrasound enables a one-stop approach, reduces repeat hospital appointments, and improves quality of care.With the increased use of ultrasound comes the need to accurately code and bill for the use of ultrasound. According to the College of Radiology, Medicare reimbursements for MSK ultrasound studies has increased by 316% from 2000-2009.² Paradoxically, ultrasound has still been relatively underutilized when compared to the use of MSK MRI.

Diagnostic Ultrasound

Ultrasound is based off sound waves, emitted from a transducer, which are then bounced back off the underlying structures based on the density of that structure. The computer interprets the returning sound waves and produces an image reflecting the quality and strength of those returning waves. When the sound waves are bounced back strongly and quickly, like when hitting bone, we see an image that is intensely white (“hyperechoic”). When the sound waves encounter a substance that transmits those waves easily and do not return, like air or fluid, the image is dark (“hypoechoic”).

Ultrasound’s fundamental advantages start with every patient being able to have an ultrasound: no interference from metal, pacemakers, claustrophobia, or obesity. Contralateral comparisons, sono-palpation at the site of pathology, and real-time dynamic studies allow for a more comprehensive diagnostic evaluation. Doppler capabilities can further expand the usefulness of the evaluation and guide safer interventions. With the advent of high-resolution portable ultrasound machines, these studies can essentially be performed anywhere, and are typically done in a timely and cost-effective manner.

Ultrasound has many diagnostic uses for soft tissue, joint, and bone disorders. For soft tissues, ultrasound can image tears of muscles, tendons, and ligaments; show inflammation like tenosynovitis; demonstrate masses like hematomas, cysts, solid tumors, or calcific tendonitis; display nerve disorders like Morton’s neuroma; or confirm foreign bodies or infections.^3-5 For joint disorders, ultrasound can show erosions on bones, loose bodies, pannus, inflammation, or effusions. For bone disorders, ultrasound can diagnose fractures and, sometimes, even stress fractures. Tomer and colleagues⁶ compared 51 patients with bone contusions and fractures; they determined that ultrasound was most reliable in the diagnosis of long bone diaphyseal fractures. The one disadvantage, especially when compared to MRI, is ultrasound’s inability to fully evaluate intra-articular or deep structures such as articular cartilage, the glenohumeral labrum, the biceps’ anchor, etc.

Magnetic Resonance Imaging

Ultrasound is similar to MRI as it images tissues and gives us ideas whether that tissue is normal, damaged, or diseased (Figures 1A, 1B). MRI is based on magnetics and large machines that cannot be moved. MRI yields planar images that can only be changed by changing the position of the limb or body in the MRI tube. This can create an issue with obese patients or with postoperative patients who cannot maintain the operated body part in one position for the length of the MRI scan. Ultrasound is better tolerated by patients without the need for claustrophobic large machines (Table 1). In 2004, Middleton and colleagues⁷ surveyed 118 patients who obtained an ultrasound and MRI of the shoulder for suspected rotator cuff pathology; ultrasound had higher satisfaction levels, and 93% of patients preferred ultrasound to MRI.

For rotator cuff tears, ultrasound is also comparable diagnostically with MRI (Figures 2A, 2B). In a prospective study of 124 patients, MRI and ultrasound had comparable accuracy for identifying and measuring the size of full-thickness and partial-thickness rotator cuff tears, with arthroscopic findings used as the standard.⁸ A 2015 meta-analysis published in the British Journal of Sports Medicine showed that the diagnostic accuracy of ultrasound, MRI, and MR arthrography in the characterization of full thickness rotator cuff tears had >90% sensitivity and specificity. As for partial rotator cuff tears and tendinopathy, overall estimates of specificity were also high (>90%), while sensitivity was as high as 83%. Diagnostic accuracy of ultrasound was similar whether it was performed by a trained radiologist, sonographer, or orthopedist.⁹

Medicare reimbursements for MSK ultrasound studies has increased by 316% in the past decade.² Private practice MSK ultrasound procedures increased from 19,372 in 2000 to 158,351 in 2009.² In 2010, non-radiologists accounted for more ultrasound-guided procedures than radiologists for the first time.¹⁰ MSK ultrasound is still underutilized compared to MRI. This underutilization is also unfortunate economically. The cost of MRIs is significantly higher. According to Parker and colleagues¹⁰, the projected Medicare cost for MSK imaging in 2020 is $3.6 billion, with MRI accounting for $2 billion. They also concluded that replacing MSK MRI with MSK ultrasound when clinically indicated could save over $6.9 billion between 2006 and 2020.¹¹

Ultrasound-Guided Procedures

MSK ultrasound has gained significant ground on other imaging modalities when it comes to procedures, both in office and in the operating room. The ability to have a small, mobile, inexpensive machine that can be used in real time has dramatically changed how interventions are done. Most imaging modalities used to perform injections or percutaneous surgery use fluoroscopy machines. This exposes the patients to significant radiation, costs significantly more, and usually requires a secondary consultation with radiologists in a different facility. This wastes time and money, and results in potentially unnecessary exposure to radiation.

Accuracy is the most common reason for referral for guided injections. The guidance can help avoid nerves, vessels, and other sensitive tissues. However, accuracy is also important to make sure the injection is placed in the correct location. When injections are placed into a muscle, tendon, or ligament, it causes significant pain; however, injections placed into a bursal space or joint do not cause pain. Numerous studies have shown that even in the hands of experts, “simple” injections can still miss their mark over 30% of the time.^12-19 Therefore, if a patient experiences pain during a bursal space or joint injection, the injection was not placed properly.

The American Medical Society for Sports Medicine Position Paper on MSK ultrasound is based on a systematic review of the literature, including 124 studies. It states that ultrasound-guided joint injections (USGI) are more accurate and efficacious than landmark guided injections (LMGI), with a strength of recommendation taxonomy (SORT) evidence rating of A and B, respectively.¹⁹ In terms of patient satisfaction, in a randomized controlled trial of 148 patients undergoing knee injections, Sibbitt and colleagues²⁰ showed that USGI had a 48% reduction (P < .001) in procedural pain, a 58.5% reduction (P < .001) in absolute pain scores at the 2-week outcome mark, and a 75% reduction (P < .001) in significant pain and 62% reduction in nonresponder rate.²⁰ From a financial point of view, Sibbitt and colleagues²⁰ also demonstrated a 13% reduction in cost per patient per year, and a 58% reduction in cost per responder per year for a hospital outpatient center (P < .001).

Coding

Coding for diagnostic MSK ultrasound requires an understanding of a few current procedural terminology (CPT) codes (Table 2). Ultrasound usage should follow the usual requirements of medical necessity and the CPT code selected should be based on the elements of the study performed. A complete examination, described by CPT code 76881, includes the examination and documentation of the muscles, tendons, joint, and other soft tissue structures and any identifiable abnormality of the joint being evaluated. If anything less is done, then the CPT code 76882 should be used.

New CPT codes for joint injections became effective January 2015 (Table 3). The new changes affect only the joint injection series (20600-20610). Previously, injections could be billed with CPT code 76942, which was “Ultrasonic guidance for needle placement (eg, biopsy, aspiration, injection, localization device), imaging supervision and interpretation.” This code can still be used, but with only specific injections, when the verbiage “with ultrasound/image guidance” is not included in the injection CPT code descriptor (Table 4).

Under the National Correct Coding Initiative (NCCI), which sets Centers for Medicare & Medicaid Services (CMS) payment policy as well as that of many private payers, one unit of service is allowed for CPT code 76942 in a single patient encounter regardless of the number of needle placements performed. Per NCCI, “The unit of service for these codes is the patient encounter, not number of lesions, number of aspirations, number of biopsies, number of injections, or number of localizations.”

Per the Radiology section of the NCCI, “Ultrasound guidance and diagnostic ultrasound (echography) procedures may be reported separately only if each service is distinct and separate. If a diagnostic ultrasound study identifies a previously unknown abnormality that requires a therapeutic procedure with ultrasound guidance at the same patient encounter, both the diagnostic ultrasound and ultrasound guidance procedure codes may be reported separately. However, a previously unknown abnormality identified during ultrasound guidance for a procedure should not be reported separately as a diagnostic ultrasound procedure.”

Under the Medicare program, the International Classification of Diseases 10th Revision (ICD-10) code selected should be based on the test results, with 2 exceptions. If the test does not yield a diagnosis or was normal, the physician should use the pre-service signs, symptoms, and conditions that prompted the study. If the test is a screening examination ordered in the absence of any signs or symptoms of illness or injury, the physician should select “screening” as the primary reason for the service and record the test results, if any, as additional diagnoses.

Modifiers must be used in specific settings. In the office, physicians who own the equipment and perform the service themselves (or the service is performed by an employed or contracted sonographer) may bill the global fee without any modifiers. However, if billing for a procedure on the same day as an office visit, the -25 modifier must be used. This indicates “[a] significant, separately identifiable evaluation and management service.” This modifier should not be used routinely. If the service is performed in a hospital, the -26 modifier must be used to indicate that the professional service only was provided when the physician does not own the machine (Tables 2, 3, 4). The payers will not reimburse physicians for the technical component in the hospital setting.

Reimbursement

In general, medical insurance plans will cover ultrasound studies when they are medically indicated. However, we recommend checking with each individual private payer directly, including Medicare. Medicare Part B will generally reimburse physicians for medically necessary diagnostic ultrasound services, provided the services are within the scope of the physician’s license. Some Medicare contractors require that the physician who performs and/or interprets some types of ultrasound examinations be capable of demonstrating relevant, documented training through recent residency training or post-graduate continuing medical education (CME) and experience. Medicare does not differentiate by medical specialty with respect to billing medically necessary diagnostic ultrasound services, provided the services are within the scope of the physician’s license. Some Medicare contractors have coverage policies regarding either the diagnostic study or ultrasound guidance of certain injections, or both.

Payment policies for beneficiaries enrolled in Medicare Part C, known as the Medicare Advantage plans, will reflect those of the private insurance administrator. The Medicare Advantage plan may be either a health maintenance organization (HMO) or a preferred provider organization (PPO). Private insurance payment rules vary by payer and plan with respect to which specialties may perform and receive reimbursement for ultrasound services. Some payers will reimburse providers of any specialty for ultrasound services, while others may restrict imaging procedures to specific specialties or providers possessing specific certifications or accreditations. Some insurers require physicians to submit applications requesting ultrasound be added to their list of services performed in their practice. Physicians should contact private payers before submitting claims to determine their requirements and request that they add ultrasound to the list of services.

When contacting the private payers, ask the following questions:

• What do I need to do to have ultrasound added to my practice’s contract or list of services?
• Are there any specific training requirements that I must meet or credentials that I must obtain in order to be privileged to perform ultrasound in my office?
• Do I need to send a letter or can I submit the request verbally?
• Is there an application that must be completed?
• If there is a privileging program, how long will it take after submission of the application before we are accepted?
• What is the fee schedule associated with these codes?
• Are there any bundling edits in place covering any of the services I am considering performing? (Be prepared to provide the codes for any non-ultrasound services you will be performing in conjunction with the ultrasound services.)
• Are there any preauthorization requirements for specific ultrasound studies?
• Are there any preauthorization requirements for specific ultrasound studies?

Documentation Requirements

All diagnostic ultrasound examinations, including those when ultrasound is used to guide a procedure, require that permanently recorded images be maintained in the patient record. The images can be kept in the patient record or some other archive—they do not need to be submitted with the claim. Images can be stored as printed images, on a tape or electronic medium. Documentation of the study must be available to the insurer upon request.

A written report of all ultrasound studies should be maintained in the patient’s record. In the case of ultrasound guidance, the written report may be filed as a separate item in the patient’s record or it may be included within the report of the procedure for which the guidance is utilized.

As examples of our documentation in the office, copies of 3 of our standard forms are available: “Ultrasound report of the shoulder” (Appendix 1), “Procedure note for an ultrasound-guided injection of cortisone” (Appendix 2), and “Procedure note for an ultrasound-guided injection of platelet-rich plasma” (Appendix 3).

Appropriate Use Criteria (AUC)

The Protecting Access to Medicare Act of 2014 was an effort to help reduce unnecessary imaging services and reduce costs; the Secretary of Health and Human Services was to establish a program to promote the use of “appropriate use criteria” (AUC) for advanced imaging services such as MRI, computed tomography, positron emission tomography, and nuclear cardiology. AUC are criteria that are developed or endorsed by national professional medical specialty societies or other provider-led entities to assist ordering professionals and furnishing professionals in making the most appropriate treatment decision for a specific clinical condition for an individual. The law also noted that the criteria should be evidence-based, meaning they should have stakeholder consensus, be scientifically valid, and be based on studies that are published and reviewable by stakeholders.

By April 2016, the Secretary will identify and publish the list of qualified clinical decision support mechanisms, which are tools that could be used by ordering professionals to ensure that AUC is met for applicable imaging services. These may include certified health electronic record technology, private sector clinical decision support mechanisms, and others. Actual use of the AUC will begin in January 2017. This legislation applies only to Medicare services, but other payers have cited concerns and may follow in the future.

Conclusion

Ultrasound is being increasingly used in varying specialties, especially orthopedic surgery. It provides a time- and cost-efficient modality with diagnostic power comparable to MRI. Portability and a high safety profile allows for ease of implementation as an in-office or sideline tool. Needle guidance and other intraoperative applications highlight its versatility as an adjunct to orthopedic treatments. This article provides a comprehensive guide to billing and coding for both diagnostic and therapeutic MSK ultrasound of the shoulder. Providers should stay up to date with upcoming appropriate use criteria and adjustments to current billing procedures.