Imaging for Rotator Cuff Pathology


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



Radiographs: Pathology





  1. • 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.
  2. • 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.
  3. • 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.
  4. • Patients with calcific tendonitis, which is visible on radiographs, may present with symptoms similar to impingement syndrome or rotator cuff pathology (Fig. 6.5).
  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).
  6. • 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.
  7. • 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





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FIG. 6.1 Standard radiographic views of the shoulder obtained for a patient with suspected rotator cuff pathology, including (A) Grashey, (B) anteroposterior–weighted abduction, (C) anteroposterior shoulder, (D) axillary lateral, and (E) supraspinatus outlet views. 
From Goud A, Segal D, Hedayati P, Pan JJ, Weissman BN. Radiographic evaluation of the shoulder. Eur J Radiol. 2008;68:2–15. Figs. 1B, 3B, 4B.

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FIG. 6.2 These radiographs show superior migration of the humeral head with weighted abduction. The difference in humeral position is clear when comparing the unweighted (A) and weighted (B) images.

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FIG. 6.3 An anteroposterior radiograph of a shoulder with chronic changes due to a massive rotator cuff tear. The acromiohumeral interval, or the distance between curved arrow and arrowhead, can be measured. The acromion has undergone acetabularization, with femoralization of the humeral head, both changes consistent with chronic massive rotator cuff tears. 
From Farid N, Bruce D, Chung CB. Miscellaneous conditions of the shoulder: anatomical, clinical, and pictorial review emphasizing potential pitfalls in imaging diagnosis. Eur J Radiol. 2008;68:88–105. Fig. 10D.

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FIG. 6.4 The critical shoulder angle, measured as the angle between the glenoid inclination and the lateral aspect of the acromion, is associated with rotator cuff pathology. 
From Moore BK, Wieser K, Slankamenac K, Gerber C, Bouaicha S. Relationship of individual scapular anatomy and degenerative rotator cuff tears. J Shoulder Elbow Surg. 2014;23:536–541.

image
FIG. 6.5 Large calcific tendonitis lesions can have multiple calcium deposits. 
From Barber FA, Cowden III CH. Arthroscopic treatment of calcific tendonitis. Arthroscopic Tech. 2014;3:237–240.

Disadvantages of Radiographs



Musculoskeletal Ultrasound



image
FIG. 6.6 Os acromiale is shown in these (A) anteroposterior and (B) axillary views of the shoulder. 
From Peckett WRC, Gunther SB, Harper GD, Hughes JS, Sonnabend DH. Internal fixation of symptomatic os acromiale: a series of twenty-six cases. J Shoulder Elbow Surg. 2004;13:381–385.

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FIG. 6.7 (A) Shows the long head of the biceps (asterisk) as a hyperechoic structure when the ultrasound transducer is placed over the bicipital groove, perfectly perpendicular to the long axis of the tendon. (B) An example of the “empty groove” sign secondary to anisotropy. The transducer is placed in the wrong position, resulting in an increased number of diffracted echoes and a hypoechoic appearance. D, Deltoid; GT, greater tuberosity; 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.

Ultrasound Modality





  1. • 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.
  2. • Musculoskeletal ultrasound wave frequency averages 5–12 MHz (range 4–17 MHz).
  3. • 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.
  4. • 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.


    1. • An example of anisotropy is seen in evaluating the biceps tendon in Fig. 6.7.

  6. • The following parameters can be adjusted for better image quality:


    1. • Depth of field of view
    2. • Depth of focus
    3. • Gain and time gain compensation (i.e., change in amplitude)
    4. • Frequency of the probe

  8. • Convention for recording and viewing ultrasound images:


    1. • The left side of the screen represents posterior and superior
    2. • 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


      image


      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.


    3. • Always obtain orthogonal views of the structure of interest
    4. • Label findings both in the long and short axes

Shoulder Ultrasound: Normal Anatomy




Structures





  1. • Long head of the biceps (Figs. 6.7A and 6.8)


    1. • Evaluated for tendinosis, instability, fluid within the synovial sheath, or synovial hypertrophy.

  3. • Rotator interval (Fig. 6.9)


    1. • Triangular-shaped area between subscapularis and supraspinatus containing the long head of the biceps stabilized medially and deeply by the superior glenohumeral ligament (SGHL) and superficially by the coracohumeral ligament (CHL).

  5. • Subscapularis tendon (Fig. 6.10)


    1. • Normal tendon thickness on ultrasound averages 4.4 mm in males and 3.8 mm in females.
    2. • Evaluated for tears, mainly in the superior aspect of the tendon.


  7. image
    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.


  8. image
    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.


  9. image
    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.

  10. • Supraspinatus (Fig. 6.11)


    1. • Normal tendon thickness on ultrasound averages 5.6 mm in males and 4.9 mm in females.
    2. • Rotator cable and crescent (Fig. 6.12)


      1. • Cable: thick, deep bundle of fibers originating from the CHL and traveling anterior to posterior deep to the supraspinatus and infraspinatus.
      2. • Crescent: portion of the tendon distal to the cable.
      3. • Evaluated for tears, both partial- and full-thickness.

  12. • Infraspinatus/teres minor (Fig. 6.13)


    1. • Normal infraspinatus tendon thickness on ultrasound averages 4.9 mm in males and 4.4 mm in females.
    2. • Evaluated for tears.
    3. • The posterior supraspinatus and anterior infraspinatus overlap by approximately 1 cm.

  14. • Glenohumeral joint posterior recess (Fig. 6.14)


    1. • Evaluated for effusion and for image-guided intraarticular injections.

  16. • Suprascapular nerve (Fig. 6.15)


    1. • Evaluated at the two most common points of compression (i.e., suprascapular notch and spinoglenoid notch) by ganglia arising from a torn labrum.

  18. • Acromioclavicular joint (Fig. 6.16)
  19. • Impingement evaluation


    1. • 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.


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FIG. 6.11 (A) Long-axis view of the supraspinatus. Arrowheads, Articular cartilage; arrows, subacromial/subdeltoid bursa; asterisk, insertional fibers; circle, hypoechoic artifact (anisotropy). (B) Short-axis view of the supraspinatus. Asterisks, articular cartilage; arrowheads, subacromial/subdeltoid bursa. (C) Another long-axis example of an intact supraspinatus as it transitions from its proximal muscular portion to its distal tendinous insertion overlying the humeral head. D, Deltoid; GT, greater tuberosity of the humerus; 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.

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FIG. 6.12 Long-axis view of the supraspinatus, with the hyperechoic rotator cable (arrows) medial to the hypovascular rotator crescent (asterisks) inserting on the greater tuberosity. D, Deltoid; GT, greater 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.

Pathologic Findings on Ultrasound





  1. • Biceps tendon


    1. • Tendinopathy: enlargement of the tendon, decreased tendon echogenicity, and splitting.
    2. • Fluid in the tendon sheath (just proximal to musculotendinous junction): seen with rotator cuff tears (70%) or glenohumeral joint effusion (Fig. 6.18).
    3. • Proximal tear: acutely can be intrasubstance, longitudinal, and linear.
    4. • Chronic tear: loss of normal fiber motion in the groove and can often only visualize the tendon longitudinally while flexing the elbow.
    5. • Subluxation: at least two supporting structures have been torn (Fig. 6.19).
    6. • Dislocation: tendon often resting on the subscapularis or posterior to the subscapularis if a large subscapularis tear has occurred (Fig. 6.20).




  5. image
    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.

  6. • Subdeltoid/subacromial bursa


    1. • Commonly affected in rotator cuff disease.
    2. • Can become inflamed with thickened bursal walls and fluid within the bursa (Figs. 6.21 and 6.22).

  8. • Rotator cuff tendinosis


    1. • Patients usually 40 years or younger.
    2. • May have asymptomatic tears.
    3. • Typically demonstrate degenerative changes to the rotator cuff:


      1. • Ill-defined hypoechoic region.
      2. • Focal enlargement of the tendon due to edema (Fig. 6.23).
      3. • Loss of normal fibrillary structure.
      4. • Calcification.
      5. • Neovascularity on power Doppler (Fig. 6.24).

    5. • Supraspinatus tendinosis can be commonly seen at the coracoacromial ligament or acromioclavicular joint.
    6. • Subscapularis tendinosis can be seen at coracoid level, especially in the case of a narrow coracohumeral interval.

  10. • Rotator cuff tears


    1. • Can involve any of the four rotator cuff muscles in isolation or combination.
    2. • The supraspinatus is most commonly torn, while the teres minor is rarely torn.
    3. • Can be partial or full thickness.


      1. • Partial-thickness rotator cuff tears



  14. • More common with aging patients.
  15. • Bursal or articular.
  16. • Classification:


    1. • Grade 1: <3 mm deep.
    2. • Grade 2: 3–6 mm deep (50% thickness).
    3. • Grade 3: 6 mm deep (>50% thickness).


  18. image
    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.

  19. • Primary findings on ultrasound:


    1. • Well-defined hypoechoic defect on bursal or articular side or intrasubstance.


      1. • Fig. 6.25 is a partial undersurface/articular tear of the supraspinatus.

    3. • Sometimes mixed hyper- and hypoechoic or purely hyperechoic.
    4. • Intrasubstance tears are confined within the tendon and do not communicate with the articular or bursal surfaces.


      1. • Figs. 6.26 and 6.27 demonstrate cuff delamination or intrasubstance tearing and cyst formation within the supraspinatus.

  21. • Secondary findings on ultrasound


    1. • Flattened bursal surface with focal tendon thinning, allowing the deltoid to dip into the tear.
    2. • 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.


      1. • Full-thickness rotator cuff tears

  23. • More common with aging patients.
  24. • Similar findings to partial tears but usually more pronounced.
  25. • Primary findings on ultrasound


    1. • Well-defined focal full-thickness hypoechoic (more common)/hyperechoic (less common) defect.

    2. image
      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.


    3. image
      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.


    4. image
      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.


    5. image
      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.



      1. • Fig. 6.28 demonstrates a full-thickness supraspinatus tear extending from the superior to inferior surface of the tendon.

    7. • Deltoid lies directly on humeral head without visualization of the rotator cuff tendon.


      1. • 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).

      2. image
        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.

    9. • Tendon retraction.

  27. • Secondary findings on ultrasound


    1. • Muscle volume loss with herniation of deltoid muscle into the defect.
    2. • Cartilage interface/naked cartilage sign: see partial-thickness tears.
    3. • Excessive fluid in the subacromial/subdeltoid bursa.
    4. • Fluid in the biceps tendon sheath.
    5. • Joint effusion: seen in 60% of tears (95% specific).
    6. • Can be related to impingement/ischemia


      1. • 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).
      2. • Tears related to internal (posterosuperior) impingement are often located in the posterior supraspinatus and/or infraspinatus and often seen with overhead throwing athletes.

      3. image
        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.

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Mar 28, 2020 | Posted by in ORTHOPEDIC | Comments Off on Imaging for Rotator Cuff Pathology

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