Chapter 6
Imaging for Rotator Cuff Pathology
Joey LaMartina II , Benjamin Ma, and Drew Lansdown
Radiographs
Plain radiographs offer an indirect evaluation of the rotator cuff and soft tissue of the shoulder joint, and this imaging modality is an important tool in the diagnosis of shoulder pathology. There are multiple imaging findings that can provide indirect information on the status of the rotator cuff and shoulder joint. This is a good first-line evaluation for shoulder pathology.
Indications
- • It is our preference to obtain initial radiographs on all patients with concern for rotator cuff pathology due to the ease with which these images are acquired, the relative low cost of this modality, and the ability to evaluate for other conditions, such as arthritis or evidence of previous trauma or surgical interventions.
- • A complete radiographic evaluation of the shoulder, when concerned about potential rotator cuff pathology, includes anteroposterior (AP), Grashey, supraspinatus outlet, and axillary lateral views (Fig. 6.1). We will also add an AP active-abduction view when we have suspicion of large rotator cuff tears or concerns with advanced shoulder osteoarthritis.
- • The Grashey view is a true AP of the glenohumeral joint and is obtained with the patient rotated posteriorly 35–45 degrees so that the plane of the scapula is parallel to the imaging cassette.
- • The axillary lateral image provides an orthogonal image to evaluate the condition of the glenoid, humeral head, and acromion.
- • The supraspinatus outlet view shows acromion morphology, which is classified according to Bigliani.
- • The AP active-abduction image is obtained with the patient holding a 1–2 lb weight in 45 degrees of abduction to better evaluate for humeral head migration and joint space narrowing. Patients with anterior-superior escape or dynamic instability will show very clear superior migration of the humeral head on this view (Fig. 6.2).
Radiographs: Pathology
- • The acromiohumeral interval (AHI) can be measured (Fig. 6.3). An AHI less than 7 mm is associated with rotator cuff pathology. In one cohort of patients, for patients with an AHI less than 7 mm, 90% had a supraspinatus tear, 67% had an infraspinatus tear, and 43% had subscapularis tears.
- • An increased critical shoulder angle, defined as a combined measurement between the glenoid inclination and lateral extension of the acromion, has been associated with rotator cuff pathology (Fig. 6.4). Conversely, a decreased critical shoulder angle was associated with primary glenohumeral osteoarthritis. A group of asymptomatic patients had a critical shoulder angle of 33.1 degrees, while for those with rotator cuff tears it was 38.0 degrees and for those with glenohumeral arthritis it was 28.1 degrees.
- • The acromion shape may have an association with presence of a rotator cuff tear. In one retrospective analysis, 88.9% of patients with a type 3 acromion had an associated rotator cuff tear.
- • Patients with calcific tendonitis, which is visible on radiographs, may present with symptoms similar to impingement syndrome or rotator cuff pathology (Fig. 6.5).
- • Chronic bony changes may be apparent in the setting of a chronic massive rotator cuff tear. The humeral head begins to undergo changes described as femoralization. The acromion also shows evidence of remodeling, known as acetabularization (Fig. 6.3).
- • An os acromiale (Fig. 6.6), which is a failure of fusion of one of the ossification centers of the acromion, is best seen on an axillary lateral radiograph. This finding has been associated with rotator cuff pathology.
- • In the setting of an acute traumatic injury, a radiographic evaluation will diagnose a proximal humerus fracture. An isolated greater tuberosity fracture may appear similar clinically to a patient with an acute rotator cuff injury (Fig. 6.6).
Advantages of Radiographs
Disadvantages of Radiographs
Musculoskeletal Ultrasound
The evolution of musculoskeletal ultrasound over the past two decades has allowed for its successful use in thoroughly evaluating the rotator cuff. Ultrasound is very effective in evaluating the dynamic stabilizers of the shoulder, including the rotator cuff musculature, the biceps tendon, the deltoid, and the pectoralis muscles. Unique among other imaging techniques, ultrasound allows for both a static and dynamic evaluation of the shoulder anatomy, potentially providing for a better understanding of the function of the surrounding structures and musculature. Ultrasound is even useful for identifying secondary signs of rotator cuff pathology, such as greater tuberosity cortical roughening, and evaluating the integrity of rotator cuff repair after surgery. Lastly, ultrasound can be used to assist with nonoperative interventions for rotator cuff pathology or impingement. Such interventions include image-guided corticosteroid injections and needling procedures for rotator cuff calcifications.
Ultrasound Modality
- • Sound waves of a certain frequency are generated from an ultrasound transducer and reflected back from the underlying structures to the ultrasound transducer to generate an image.
- • Musculoskeletal ultrasound wave frequency averages 5–12 MHz (range 4–17 MHz).
- • High-frequency sonographic waves are attenuated more quickly as they pass through tissue, meaning that higher-frequency ultrasound transducers have less imaging depth but the benefit of higher resolution capabilities.
- • Sound waves best create an image when they are oriented perpendicular to the collagen fibrils that make up the particular tissue or tendon being evaluated. This perpendicular orientation produces the characteristic bright reflective echo that is seen on ultrasound images. Deviation from the perpendicular results in an area of decreased echogenicity, possibly giving the false impression of tendon pathology. This concept is termed anisotropy.
- • The following parameters can be adjusted for better image quality:
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- • Depth of field of view
- • Depth of focus
- • Gain and time gain compensation (i.e., change in amplitude)
- • Frequency of the probe
- • Convention for recording and viewing ultrasound images:
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- • The left side of the screen represents posterior and superior
- • The right side of the screen represents anterior and inferior
TABLE 6.1
Sequential Ultrasound Protocol in Evaluating the Structures of the Shoulder Sequential Protocol to Perform Dynamic Ultrasound Evaluation of the Shoulder Step Structures Standard Scans Dynamic Maneuver 1 Long head biceps tendon; pectoralis major tendon Anterior transverse and longitudinal scan in neutral position Active and/or passive external rotation of the humerus with 90-degree flexed elbow 2 Subscapularis tendon: long head biceps tendon subluxation-dislocation Anterior transverse and longitudinal scan in maximal external rotation of the humerus Active and/or passive external rotation of the humerus with 90-degree flexed elbow 3 Supraspinatus tendon: subacrominal-subdeltoid bursa; rotator interval; rotator cable crescent complex Anterior transverse and longitudinal scan in Crass/Crass-modified position Crass/crass-modified position with medical stress on the flexed elbow 4 Acromioclavicular joint: coracoacromial ligament; impingement evaluation Superior/anterosuperior longitudinal scan in neutral position. Abduction of the arm with 90-degree flexed elbow 5 Infraspinatus tendon: teres minor tendon: posterior glenoid labrum, suprascapular nerve Posterior transverse and longitudinal scan with raised arm External rotation of the arm with the elbow adherent to the chest 
From Corazza A, Orlandi D, Fabbro E, et al. Dynamic high-resolution ultrasound of the shoulder: how we do it. Eur J Radiol. 2015;84:266–277.
- • Always obtain orthogonal views of the structure of interest
- • Label findings both in the long and short axes
Shoulder Ultrasound: Normal Anatomy
Structures
- • Long head of the biceps (Figs. 6.7A and 6.8)
- • Rotator interval (Fig. 6.9)
- • Subscapularis tendon (Fig. 6.10)
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- • Normal tendon thickness on ultrasound averages 4.4 mm in males and 3.8 mm in females.
- • Evaluated for tears, mainly in the superior aspect of the tendon.
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FIG. 6.8 Long-axis view of the biceps tendon (double arrow). D, Deltoid muscle; H, humerus. From Corazza A, Orlandi D, Fabbro E, et al. Dynamic high-resolution ultrasound of the shoulder: how we do it. Eur J Radiol. 2015;84:266–277. -
FIG. 6.9 Ultrasound view of the rotator interval. The arrow represents the superior glenohumeral ligament medial and deep to the long head of the biceps (asterisk). The arrowheads represent the coracohumeral ligament superficially. D, Deltoid; H, humerus; SS, supraspinatus; SubS, subscapularis. From Corazza A, Orlandi D, Fabbro E, et al. Dynamic high-resolution ultrasound of the shoulder: how we do it. Eur J Radiol. 2015;84:266–277. -
FIG. 6.10 (A) Long-axis representation of the subscapularis traveling posterior to the coracoid and inserting on the lesser tuberosity of the humerus. Arrowheads, Coracohumeral ligament. (B) Short-axis representation demonstrating the multiple fascicles (arrows) of the tendon of the subscapularis. Arrowheads, Intervening muscle of the subscapularis between tendons. (C) Another example of a long-axis image of the subscapularis demonstrating the close relationship with the bicipital groove. Arrow, Bicipital groove. C, Coracoid; D, deltoid; subS, subscapularis; LT, lesser tuberosity. From Corazza A, Orlandi D, Fabbro E, et al. Dynamic high-resolution ultrasound of the shoulder: how we do it. Eur J Radiol. 2015;84:266–277. - • Supraspinatus (Fig. 6.11)
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- • Normal tendon thickness on ultrasound averages 5.6 mm in males and 4.9 mm in females.
- • Rotator cable and crescent (Fig. 6.12)
- • Infraspinatus/teres minor (Fig. 6.13)
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- • Normal infraspinatus tendon thickness on ultrasound averages 4.9 mm in males and 4.4 mm in females.
- • Evaluated for tears.
- • The posterior supraspinatus and anterior infraspinatus overlap by approximately 1 cm.
- • Glenohumeral joint posterior recess (Fig. 6.14)
- • Suprascapular nerve (Fig. 6.15)
- • Acromioclavicular joint (Fig. 6.16)
- • Impingement evaluation
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- • Ultrasound can be used to evaluate for subacromial impingement, coracoacromial impingement (Fig. 6.17), anteromedial (subcoracoid) impingement, and posterosuperior impingement. This is completed by ultrasound evaluation with the arm placed in the provocative positions respective of each type of impingement.
Pathologic Findings on Ultrasound
- • Biceps tendon
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- • Tendinopathy: enlargement of the tendon, decreased tendon echogenicity, and splitting.
- • Fluid in the tendon sheath (just proximal to musculotendinous junction): seen with rotator cuff tears (70%) or glenohumeral joint effusion (Fig. 6.18).
- • Proximal tear: acutely can be intrasubstance, longitudinal, and linear.
- • Chronic tear: loss of normal fiber motion in the groove and can often only visualize the tendon longitudinally while flexing the elbow.
- • Subluxation: at least two supporting structures have been torn (Fig. 6.19).
- • Dislocation: tendon often resting on the subscapularis or posterior to the subscapularis if a large subscapularis tear has occurred (Fig. 6.20).
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FIG. 6.13 (A) Short-axis view of the infraspinatus and teres minor. (B) Long-axis view of the infraspinatus (arrowheads). Asterisk, posterior glenohumeral recess. (C) Long-axis view of the teres minor (asterisks). D, Deltoid; H, humerus; IS, infraspinatus; J, musculotendinous junction; S, scapula; TM, teres minor. From Corazza A, Orlandi D, Fabbro E, et al. Dynamic high-resolution ultrasound of the shoulder: how we do it. Eur J Radiol. 2015;84:266–277. - • Subdeltoid/subacromial bursa
- • Rotator cuff tendinosis
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- • Patients usually 40 years or younger.
- • May have asymptomatic tears.
- • Typically demonstrate degenerative changes to the rotator cuff:
- • Supraspinatus tendinosis can be commonly seen at the coracoacromial ligament or acromioclavicular joint.
- • Subscapularis tendinosis can be seen at coracoid level, especially in the case of a narrow coracohumeral interval.
- • Rotator cuff tears
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- • Can involve any of the four rotator cuff muscles in isolation or combination.
- • The supraspinatus is most commonly torn, while the teres minor is rarely torn.
- • Can be partial or full thickness.
- • More common with aging patients.
- • Bursal or articular.
- • Classification:
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- • Grade 1: <3 mm deep.
- • Grade 2: 3–6 mm deep (50% thickness).
- • Grade 3: 6 mm deep (>50% thickness).
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FIG. 6.14 Transverse ultrasound image overlying the posterior glenohumeral joint recess. Arrow, Posterior joint recess; asterisk, labrum; D, deltoid; G, glenoid; H, humerus; IS, infraspinatus. From Corazza A, Orlandi D, Fabbro E, et al. Dynamic high-resolution ultrasound of the shoulder: how we do it. Eur J Radiol. 2015;84:266–277. - • Primary findings on ultrasound:
- • Secondary findings on ultrasound
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- • Flattened bursal surface with focal tendon thinning, allowing the deltoid to dip into the tear.
- • Cartilage interface/naked cartilage sign: produced due to a loss of rotator cuff tendon overlying the humeral articular cartilage, resulting in more sound being transmitted to and reflected off the humeral head.
- • More common with aging patients.
- • Similar findings to partial tears but usually more pronounced.
- • Primary findings on ultrasound
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- • Well-defined focal full-thickness hypoechoic (more common)/hyperechoic (less common) defect.
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FIG. 6.15 (A) The nerve course in the supraspinous notch (bent arrow). Asterisk, Suprascapular nerve. (B) The course of the nerve through the spinoglenoid notch (bent arrow). Asterisk, suprascapular nerve. D, Deltoid; G, glenoid; IS, infraspinatus; S, scapula; SS, supraspinatus. From Corazza A, Orlandi D, Fabbro E, et al. Dynamic high-resolution ultrasound of the shoulder: how we do it. Eur J Radiol. 2015;84:266–277. -
FIG. 6.16 Coronal ultrasound image of the acromioclavicular joint. Arrowheads, Joint capsule; A, acromion; C, clavicle. From Corazza A, Orlandi D, Fabbro E, et al. Dynamic high-resolution ultrasound of the shoulder: how we do it. Eur J Radiol. 2015;84:266–277. -
FIG. 6.17 The coracoacromial ligament (arrowheads) is the hypoechoic fibrillar structure running from the coracoid (C) to the acromion (A). D, Deltoid; SS, supraspinatus. From Corazza A, Orlandi D, Fabbro E, et al. Dynamic high-resolution ultrasound of the shoulder: how we do it. Eur J Radiol. 2015;84:266–277. -
FIG. 6.18 (A) Short-axis view demonstrating fluid (long arrow) in the tendon sheath of the long head of the biceps (short arrow). (B) Fluid in the tendon sheath (short arrow) and adjacent subdeltoid bursa (long arrow). (C) is a long-axis view of fluid (short arrow) in the tendon sheath of the biceps (long arrow). From Allen GM. Shoulder ultrasound imaging–integrating anatomy, biomechanics, and disease processes. Eur J Radiol. 2008;68:137–146. - • Deltoid lies directly on humeral head without visualization of the rotator cuff tendon.
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- • Often seen in complete (chronic) tears where the bare bone is exposed and the deltoid fills the void of the supraspinatus tendon (Fig. 6.29).
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FIG. 6.19 The biceps tendon (long arrow) is subluxated out of the groove and resting on the lesser tuberosity (short arrow). This is seen with tearing of the upper portion of the subscapularis tendon. From Allen GM. Shoulder ultrasound imaging—integrating anatomy, biomechanics, and disease processes. Eur J Radiol. 2008;68:137–146.
- • Tendon retraction.
- • Secondary findings on ultrasound
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- • Muscle volume loss with herniation of deltoid muscle into the defect.
- • Cartilage interface/naked cartilage sign: see partial-thickness tears.
- • Excessive fluid in the subacromial/subdeltoid bursa.
- • Fluid in the biceps tendon sheath.
- • Joint effusion: seen in 60% of tears (95% specific).
- • Can be related to impingement/ischemia
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- • Depending on the chronicity and mode of failure, supraspinatus tears related to external (subacromial) impingement may be accompanied by greater tuberosity cortical roughening (Fig. 6.30) or bursal-sided without associated humeral head changes but a thickened coracoacromial ligament and narrowed subacromial space (Fig. 6.31).
- • Tears related to internal (posterosuperior) impingement are often located in the posterior supraspinatus and/or infraspinatus and often seen with overhead throwing athletes.
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FIG. 6.20 (A) Long-axis ultrasound image demonstrating a tear (arrow) of the subscapularis (SCC) off the lesser tuberosity of the humerus (H). Co, coracoid process. (B) A dislocation of the long head of the biceps (arrow) that often accompanies tears of the subscapularis as seen in (A). LT, lesser tuberosity. From Armstrong A, MD, Teefey SA, MD, Wu T, MD, et al. The efficacy of ultrasound in the diagnosis of long head of the biceps tendon pathology. J Shoulder Elbow Surg. 2006;15:7–11; and Fischer CA, Weber MA, Neubecker C, Bruckner T, Tanner M, Zeifang F. Ultrasound vs. MRI in the assessment of rotator cuff structure prior to shoulder arthroplasty. J Orthop. 2015;12:23–30. Related posts:
Patient Positioning and Anesthesia for Rotator Cuff Surgery
Arthroscopic Trillat Procedure for Recurrent Anterior Shoulder Instability With Associated Irreparable Rotator Cuff Tear
Nonoperative Care of Rotator Cuff Disorders: Physical Therapy, Modalities, and Injectables
What Type of Rotator Cuff Tear Is This? Tear Pattern Recognition and Soft-Tissue Releases
Subscapularis Tendon Tears: Arthroscopic Management
Arthroscopic Rotator Cuff Repair: Double Row
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