A - Z of Rotator cuff radiology

Transcription

1 A - Z of Rotator cuff radiology Poster No.: C-1296 Congress: ECR 2016 Type: Educational Exhibit Authors: Z. Al-Ani, A. Madhavan, J. Naqvi, D. Temperley, S. Basu ; Manchester/UK, Wrightington/UK Keywords: Musculoskeletal system, Musculoskeletal soft tissue, Anatomy, MR, CT, Ultrasound, Diagnostic procedure, Trauma, Artifacts, Inflammation DOI: /ecr2016/C-1296 Any information contained in this pdf file is automatically generated from digital material submitted to EPOS by third parties in the form of scientific presentations. References to any names, marks, products, or services of third parties or hypertext links to thirdparty sites or information are provided solely as a convenience to you and do not in any way constitute or imply ECR's endorsement, sponsorship or recommendation of the third party, information, product or service. ECR is not responsible for the content of these pages and does not make any representations regarding the content or accuracy of material in this file. As per copyright regulations, any unauthorised use of the material or parts thereof as well as commercial reproduction or multiple distribution by any traditional or electronically based reproduction/publication method ist strictly prohibited. You agree to defend, indemnify, and hold ECR harmless from and against any and all claims, damages, costs, and expenses, including attorneys' fees, arising from or related to your use of these pages. Please note: Links to movies, ppt slideshows and any other multimedia files are not available in the pdf version of presentations. Page 1 of 41

2 Learning objectives This electronic poster aims to revise the reader's knowledge of the important topics and features surrounding the rotator cuff of the shoulder. For each letter of the alphabet, a salient fact or piece of information/trivia is assigned relating to the rotator cuff, to enhance the learning experience for the reader in a snapshot. The information aims to provide an overview of a variety of topics ranging from clinical information to historical facts as well as the important imaging features. Background The rotator cuff comprises a group of 4 muscles around the shoulder joint which connect the shoulder blade to the humerus, acting to stabilise the shoulder and permit smooth motion. The four muscles, namely supraspinatus, infraspinatus, subscapularis and teres minor arise from the scapula and insert on the humeral head where they form a cuff. They receive much attention as they are at particular risk from injury secondary to activities of daily living, sports injuries or trauma. In this educational exhibit, we will take a different approach by discussing facts relating to the rotator cuff in an alphabetical order. We will not only cover the anatomy and radiology but also the clinical, surgical and historical relavance to make this an interesting and memorable read for all imaging practitioners. Multiple imaging modalities (radiographs, ultrasound, CT and MRI) will be used to demonstrate radiological abnormalities of the rotator cuff including tendon tears, degeneration, impingement, trauma, tendinopathy, muscle atrophy and inflammation. In addition, we will describe important anatomical variants, rotator cuff surgical procedures with normal and abnormal post operative appearances and commonly encountered imaging artefacts such as anisotropy on ultrasound and magic angle phenomena on MR. Page 2 of 41

3 Findings and procedure details A natomy The rotator cuff (RC) is comprised of four muscles: Supraspinatus (SST), Infraspinatus (IST), Teres Minor (TM) and Subscapularis (SSC). The tendons of SST, IST and TM insert onto the greater tuberosity of the humerus. The SSC tendon inserts onto the lesser tuberosity of the humerus and is involved in the support of the long head of biceps tendon (LHBT). See Fig. 1 on page and Fig. 2 on page below. Fig. 1: Diagram illustrating the coronal anatomy of the rotator cuff tendons (A: anterior view, B: posterior view). SASD- subacromial subdeltoid bursa, G TUB-greater tuberosity, L TUB-lesser tuberosity. References: Illustrations courtesy of medical illustration department, Wrightington, Wigan and Leigh NHS Foundation Trust Page 3 of 41

4 Fig. 2: Diagram illustrating the sagittal anatomy of the rotator cuff tendons at their attachment to the greater tuberosity of the humerus. The supraspinatus tendon (SST) attaches mainly to the superior facet and the infraspinatus tendon (IST) attaches mainly to the middle facet. However the is considerable overlap between the two tendons which is sometimes referred to as junctional zone (arrows). Teres minor attaches to the inferior facet. LHBT: Long head of biceps tendon. References: Illustrations courtesy of medical illustration department, Wrightington, Wigan and Leigh NHS Foundation Trust B ony spur Page 4 of 41

5 Bony spurring of the acromion or clavicle can impinge on the RC tendons leading to RC tears. See Fig. 3 on page 21. The shape of the acromion can be divided into 4 subtypes: Type I: Flat under surface. Type II: Concave under surface (the most common type). Type III: Anterior hook. This has an association with impingement and RC tears. See Fig. 4 on page 22. Type IV: Convex under surface. C ortisone injection USS-guided steroid and local anaesthetic injection into the subacromial/ subdeltoid bursa (SASD bursa) is a commonly established early and conservative treatment option for impingement and bursitis alongside physiotherapy. USS assessment of RC tendons for tendinosis, partial or full-thickness tears is important prior to any steroid injection particularly if surgical decompression or repair is considered in the presence of a sizeable tear depending on the Orthopaedic surgeon. See Fig. 5 on page 23. D enervation Suprascapular nerve entrapment may be secondary to ganglion cyst (usually associated with labral tear), prominent or large veins, tumour or fracture. MRI changes of the innervated muscles can depend on the duration of pathology (e.g. muscle oedema in subacute nerve compression, fatty atrophy in chronic compression). See Fig. 6 on page 24. E xamination Hawkins-Kennedy test: Examiner internally rotates the patient's arm with the patient's o shoulder and elbow flexed at 90. Pain suggests subacromial impingement. See Fig. 7 on page below. Page 5 of 41

6 Fig. 7: Hawkins-Kennedy Test. References: Radiology department, Wrightington, Wigan and Leigh NHS Foundation Trust o Empty Can Test: Patient abducts the shoulders to 90 in forward flexion and internally rotates the arm so thumbs point downward. The examiner then places downward resistance on their arm; test is positive for supraspinatus pathology if significant pain +/weakness. See Fig. 8 on page below. Page 6 of 41

7 Fig. 8: Empty Can Test. Page 7 of 41

8 References: Radiology department, Wrightington, Wigan and Leigh NHS Foundation Trust F unction The rotator cuff acts to stabilize the shoulder joint and assist in holding the humeral head within the glenoid cavity of the scapula during movements. o Supraspinatus - initiates & assists deltoid in first 15 of abduction Infraspinatus and Teres Minor - lateral rotation of the arm Subscapularis - medial rotation of the arm G eyser sign Fluid 'spurts' like a geyser from the glenohumeral joint into the acromioclavicular joint (ACJ) in shoulder arthrography. This can be seen in chronic full thickness RC tears. See Fig. 9 on page 25 for an MR image demonstrating the Geyser sign and Fig. 10 on page 25 for a photo of a natural Geyser. H ydroxyapatite of Calcium deposition disease (Calcific tendinitis) The supraspinatus tendon is commonly affected by calcific tendinitis. This can be treated by USS-guided Barbotage which involves fenestrating the calcium focus several times and trying to extract the calcium pieces with a syringe. See Fig. 11 on page 26. I nnervation Suprascapular nerve (C4, C5, C6) are the main nerves supplying the RC muscles (supraspinatus and infraspinatus). Subscapularis is supplied by the upper and lower subscapular nerves and Teres minor is innervated by the axillary nerve. See Fig. 12 on page and Fig. 13 on page below. Page 8 of 41

9 Fig. 12: The suprascapular nerve passes through the suprascapular notch inferior to the superior transverse ligament where it gives its branches to the supraspinatus. Then it courses along the lateral border of the scapula through the spinoglenoid notch and ends in the infraspinatus fossa to supply infraspinatus. References: Illustrations courtesy of medical illustration department, Wrightington, Wigan and Leigh NHS Foundation Trust Page 9 of 41

10 Fig. 13: Coronal Oblique T1W MR image of the left shoulder outlining the normal suprascapular nerve surrounded by fat, within the suprascapular notch (arrow). References: Radiology department, Wrightington, Wigan and Leigh NHS Foundation Trust J G Smith Mr John Gregory Smith was one of the first surgeons to publish about rotator cuff pathology in 1834 in the London Medical Gazette. See Fig. 14 on page below. Page 10 of 41

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12 Page 12 of 41

13 Fig. 14: Cover of London Medical Gazette References: K ey MRI protocol sequences MRI is a very sensitive examination for assessment of RC pathology. Protocols will vary in different departments but the key sequences for assessment of the RC are: Coronal oblique T2W with fat suppression (parallel to the glenoid): Excellent for assessment of supraspinatus and infraspinatus tendons and footprint. Tears and tendinopathic changes are easily assessed on this sequence. Coronal oblique PD FS: Very good overall assessment for glenohumeral joint chondral surfaces and RC tendons (although it is sometimes difficult to differentiate mdoerately-severe tendinosis from a small partial-thickness tear on this sequence due to magic angle artefact and therefore a fat suppressed T2W sequence can be used as an alternative). Sagittal oblique T2W (90 degrees to coronal oblique): Will help to confirm/ further assess any abnormality seen on the previous sequence as all the RC tendons will be seen in short axis. Degree of fatty changes/atrophy of RC muscles can be assessed on this sequence. Axial T2W: This sequence and orientation is specficially good to review the long head of biceps and subscapularis tendons. L aproscopic cuff repair This is a very common orthopaedic procedure which involves RC tendon repair or reanchoring of the footprint to the greater tuberosity. Reporting radiologists need to be aware of expected post surgical appearances of RC repair. See Fig. 15 on page 27 for an example of intact RC repair and Fig. 16 on page 28 for an example of re-tear at the site of previous repair. M agic angle effect Page 13 of 41

14 This phenomena happens when the imaged structure is at approximately 55 degrees to the main magnetic field (B0) on low TE sequences (TE less than 30). It results in a similar signal characterstic (intermediate signal) to degeneration/tendinopathic changes. It charactersitically happens 1 cm from the supraspinatus tendon insertion (also known as the critical zone). See Fig. 17 on page 28. N eer Mr Charles Neer (see Fig. 18 on page below) first described the syndrome of 'chronic impingement' in 1972 and postulated that chronic impingement/rotator cuff degeneration lead to rotator cuff tears. Page 14 of 41

15 Fig. 18: Charles Neer References: Page 15 of 41

16 O s acromiale An accessory ossification centre of the acromion that normally fuses by the age of 25 years. Unfused os acromiale after this age can be seen in up to 15% of the population. If it is unstable/mobile, then it can increase the risk of impingement and RC tear. It is important to recognise and comment on this when visualised to alert the Orthopaedic surgeon which may then impact on planning for surgical approach. See Fig. 19 on page 29. P arsonage-turner Syndrome Rare condition (also known as brachial plexus neuropathy) presents with sudden onset shoulder/arm pain followed by weakness and sensory loss. Unclear aetiology but has been associated with viral illness, previous vaccinations and general anaesthesia. Often involves suprascapular nerve; hence affects the supraspinatus and infraspinatus muscles. See Fig. 20 on page 30 Q uiz Right shoulder Pain. What is the diagnosis? Go to Y for answer. Page 16 of 41

17 Fig. 21: Quiz. (A) Sagittal oblique PD fat suppressed MR image of Right shoulder. (B) Axial PD fat suppressed MR image of right shoulder. References: Radiology department, Wrightington, Wigan and Leigh NHS Foundation Trust R otator interval A triangular-shaped space between the superior border of the subscapularis tendon and the anterior border of the supraspinatus tendon. Contains the long head of biceps tendon (LHBT) and the bicipital sling or biceps pulley complex which comprises the superior glenohumeral ligament (SGHL), coracohumeral ligament (CHL), and distal subscapularis tendon attachment. It is best appreciated on a Sagittal Oblique MR Arthrogram image. Rotator interval injury may be associated with subscapularis/supraspinatus tear or long head of biceps subluxation/dislocation due to biceps pulley injury. See Fig. 22 on page 31 for normal rotator interval and Fig. 23 on page 32 for an example of rotator interval injury. S ubacromial impingement Page 17 of 41

18 Narrowing of the subacromial space due to abnormalities of the coracoacromial arch will result in impingement on the underlying RC tendons. This could be due to inferior osteophytes of the ACJ, abnormal orientation or under surface of the acromion, os acromiale, thickening of the coracoacromial ligament or muscle hypertrophy. See Fig. 24 on page 33. T ear RC tear is one of the most common pathologies of RC tendons. Tears can be full thickness or partial thickness. For detailed anatomy of the RC tendon, please see Z (zones). Tendon rupture and retraction should also be commented on. See Fig. 25 on page 34. U ltrasound pitfalls (Anisotropy) Aniostropy is an artefact commonly encountered in USS examinations of the tendons due to their reflective properties causing reflection of USS waves away from the transducer, resulting in hypoechoic appearance of the tendon that may misinterpreted as tear or tendinopathy. Probe placement perpendicular to the tendon will avoid this artefact. See Fig. 26 on page 35. V s frozen shoulder (Adhesive capsulitis) This is a common condition that is often confused with RC pathology. Characterised by shoulder pain and stiffness with limitation of movements (mainly external rotation). It is mainly a clinical diagnosis however there are a few described radiological signs: Soft tissue thickening with obliteration of the fat in the rotator interval on MR. Neovascularity around the rotator interval on power Doppler assessment. Obliteration of the axillary pouch indicating tight joint capsule. Hydrodilatation is a procedure currently used to treat frozen shoulder in combination with physiotherapy. This involves injecting normal saline, steroids and local anasthetic into the glenohumeral joint under fluoroscopic or USS guidance. Page 18 of 41

19 See Fig. 27 on page 35 (A) for hydrodilation procedure in a patient with adhesive capsulitis. Compare this appearance to Fig. 27 on page 35 (B) which shows a normal fluoroscopic appearance in a patient without adhesive capsulitis. W asting Wasting of RC muscles is an important sign that should be commented on as it will affect treatment decisions. Atrophy of the muscle can be a sequelae of chronic tendon tear/ rupture or chronic denervation. The Goutallier classification system is used to grade RC muscle fatty atrophic changes. Grade 0: Normal muscle Grade I: Few fatty streaks Grade II: < 50% fatty muscle atrophy Grade III: 50% fatty muscle atrophy Grade IV: > 50% fatty muscle atrophy See Fig. 28 on page 36 (A) for an example of grade II atrophy and Fig. 28 on page 36 (B) for an example of grade IV atrophy. X -ray Findings Radiographs of the shoulder can help to evaluate for RC pathology by looking for any changes within the subacromial space and calcification in line with the RC tendons. See Fig. 29 on page 36. Y our quiz question answer is: Subscapularis tendon tear with medial intra articular dislocation of the LHBT. See Fig. 30 on page 37. Page 19 of 41

20 Fig. 30: Right shoulder MR examination showing Subscapularis tendon tear with medial, intra articular dislocation of the long head of biceps tendon (LHBT). (A) Sagittal oblique PD fat suppressed MR demonstrates tearing of the cranial fibres of subscapularis tendon with intrinsic fluid (arrows). (B) Axial PD fat suppressed MR showing the dislocated long head of biceps tendon (arrow head) indicating injury to the transverse ligament/biceps pulley complex. Note fluid signal changes within the LHBT. References: Radiology department, Wrightington, Wigan and Leigh NHS Foundation Trust Z ones of rotator cuff tendon The RC tendon has articular-sided fibres (opposing the glenohumeral joint), bursal-sided fibres (opposing the SASD bursa) and a footprint. Pathologies such as tears can affect one or multiple parts of the tendon and should be described accordingly. See Fig. 31 on page below for normal RC tendon anatomy and Fig. 32 on page 38 for examples of RC tears. Page 20 of 41

21 Fig. 31: Normal supraspinatus tendon zones. (A) A drawing illustrating the different parts of the tendon and the footprint with corresponding ultrasound picture (B). Note that the articular cartilage (arrow) just extends to the footprint and should not be misinterpreted as a tear. References: Image (A): Illustrations courtesy of medical illustration department, Wrightington, Wigan and Leigh NHS Foundation Trust Images for this section: Page 21 of 41

22 Fig. 3: Coronal oblique T1W MR image of the left shoulder showing inferior bony spur of the lateral clavicle (arrow) impinging on the supraspinatus myotendinous junction. The patient had a full thickness supraspinatus tear. Page 22 of 41

23 Fig. 4: Sagittal oblique PD fat suppressed MR image of the left shoulder showing anterior acromion hook/type III acromion (arrow). This has an association with impingement and RC tears. Page 23 of 41

24 Fig. 5: USS-guided injection into the SASD bursa. Fig. 6: Coronal Oblique STIR images of the right shoulder demonstrating subacute RC denervation changes. (A) High signal changes within supraspinatus muscle (SS) in subacute suprascapular nerve compression. (B) High signal changes in supraspinatus Page 24 of 41

25 (SS) and infraspinatus muscles (IS). Compare their signal to the normal signal within the trapezius muscle (TR). Note the prominent veins (arrow) in the suprascapular notch compressing the suprascapular nerve. Fig. 9: Coronal Oblique PD fat-suppressed MR image of the right shoulder. Fluid seen tracking into the AC joint (arrow) from the glenohumeral joint, passing through a defect relating to a full-thickness supraspinatus tear with tendon retraction. There is also superior migration of the humeral head with loss of the normal acromio-humeral distance. Page 25 of 41

26 Fig. 10: Photo of a geyser in Yellowstone national park (USA). Case courtesy of Dr Matt A. Morgan, Radiopaedia.org. From the case rid: Page 26 of 41

27 Fig. 11: Supraspinatus calcific tendinitis. (A) Right shoulder radiograph shows large area of calcification (arrow) in the region of rotator cuff tendons. (B) USS image of the same shoulder shows the curvilinear area of calcification within the supraspinatus tendon (arrows). Fig. 15: (A) coronal oblique and (B) sagittal oblique fat suppressed T1W MR arthrogram of the right shoulder in an intact RC repair. Intact RC tendon with screws anchoring the supraspinatus footprint (arrows). Note the contrast in the SASD bursa (*). Although contrast in the SASD bursa on an arthrogram is usually associated with full thickness RC tear, this rule does not apply in post surgical RC repair as contrast can often leak from the Page 27 of 41

28 glenohumeral joint to the bursa without any re-tear. Tiny filling defects (arrow head) within the repaired tendon are also common and should not be misinterpreted as a re-tear. Fig. 16: Coronal oblique STIR MR left shoulder showing re-tear of previously repaired RC tendon. Note the empty greater tuberosity at site of repair with granulation tissue (arrow) at the expected site of the tendon. The torn tendon has retracted (*). Page 28 of 41

29 Fig. 17: Coronal oblique MR of the right shoulder demonstrating the magic angle effect. (A) Fat suppressed PD image (TE 19) shows heterogenous intermediate signal changes within the supraspinatus tendon (arrow) due to magic angle effect. This disappears on (B) T2W image with TE of 81. Page 29 of 41

30 Fig. 19: Axial PD fat suppressed MR of the left shoulder showing an unfused os acromiale with high signal changes at its unfused articulation with the scapula. Page 30 of 41

31 Fig. 20: Axial T2W Gradient Echo fat suppressed MR Image of the right shoulder. Note the high signal changes (*) within the infraspinatus muscle in keeping with subacute denervation oedema in Parsonage Turner syndrome. Page 31 of 41

32 Fig. 22: Sagittal oblique T1W fat suppressed shoulder MR arthrogram demonstrating the normal rotator interval anatomy. SS: supraspinatus, SC: subscapularis, IS: infraspinatus, TM: teres minor, RI: Rotator interval, CHL: coracohumeral ligament, SGHL: superior glenohumeral ligament, LHB: long head of biceps tendon. Page 32 of 41

33 Fig. 23: Sagittal oblique PD fat suppressed shoulder arthrogram shows an abnormal appearance of the rotator interval with contrast leaking outside the rotator interval capsule (arrow) in keeping with rotator interval injury. Page 33 of 41

34 Fig. 24: MR Shoulder examinations showing abnormal orientation of the acromion impinging on the RC tendons. (A) Sagittal oblique T1W fat suppressed right shoulder MR showing anterior downsloping acromion (arrow). (B) Coronal oblique T2W left shoulder MR in a different patient shoing inferolateral sloping acromion (*). Page 34 of 41

35 Fig. 25: Coronal oblique image of right shoulder CT arthrogram shows full thickness supraspinatus tear (arrow). Note the empty greater tuberosity at supposed site of supraspinatus footplate attachment, which is now filled with contrast. The tendon shows retraction (*). Fig. 26: USS of the left supraspinatus tendon demonstrating anisotropy. (A) hypoechoic changes of the supraspinatus footprint. The footprint (especially its medial fibres) have a different orientation compared to the rest of the tendon resulting in anisotropy (arrow). This was corrected in (B) by correct placement of the USS probe perpendicular to the footprint. Fig. 27: (A) Fluoroscopic guided right shoulder hydrodilatation procedure showing signs of adhesive capsulitis. No contrast is seen within the axillary pouch and most of the Page 35 of 41

36 injected contrast is seen in the superior subscapular recess and within the long head of biceps tendon sheath indicating tight and stiff capsule. (B) Shoulder arthrogram in a different patient showing the normal capsule appearance. Note filling of the axillary pouch (arrow). Fig. 28: (A) Sagittal oblique T1W MR shoulder shows grade II supraspinatus atrophy (arrow). (B) Sagittal oblique T1W MR shoulder in a different patient shows severe grade IV atrophy of the supraspinatus muscle (arrow). Page 36 of 41

37 Fig. 29: AP projection Right shoulder radiograph. This shows loss of the normal subacromial space with superior humeral head migration relating to a full-thickness rotator cuff tear Page 37 of 41

38 Fig. 30: Right shoulder MR examination showing Subscapularis tendon tear with medial, intra articular dislocation of the long head of biceps tendon (LHBT). (A) Sagittal oblique PD fat suppressed MR demonstrates tearing of the cranial fibres of subscapularis tendon with intrinsic fluid (arrows). (B) Axial PD fat suppressed MR showing the dislocated long head of biceps tendon (arrow head) indicating injury to the transverse ligament/biceps pulley complex. Note fluid signal changes within the LHBT. Fig. 32: Coronal oblique PD fat suppressed MR images of the left shoulder. (A) shows a partial thickness bursal sided supraspinatus tear (arrow). (B) shows partial thickness articular sided tear of supraspinatus (arrow) extending to the foot print. Note Page 38 of 41

39 the irregularity of the greater tuberosity at the site of tendon attachment which is often seen in association with articular sided tears. Page 39 of 41

40 Conclusion In this educational exhibit, we have described various important facts relating to the rotator cuff utilising a snaphot alphabetical approach. We have covered not only the anatomy and radiological aspects but also provided information on the clinical, surgical and historical relevance of the rotator cuff. The authorship hope all readers enjoy the learning experience about a common yet important topic encountered by all Musculoskeletal imaging practitioners, in a novel yet fun portrayal of the information. Personal information References 1) Helms C.A., Major N.M., Anderson M.W., Kaplan P, Dussault R Musculoskeletal MRI. 2nd ed. Philadelphia: Elsevier Saunders. 2) Moore K.L., Dalley A.F Clinically Oriented Anatomy. 5th ed. USA: Lippincott Williams & Wilkins. 3) AAFP. The Painful Shoulder: Part I. Clinical Evaluation. (Accessed on 8/12/15). 4) Geyser sign. (Accessed on 15/12/15). nd 5) Neer CS 2. Anterior acromioplasty for the Chronic Impingement in the Shoulder. J Bone Joint Surg Am, 1972 Jan; 54 (1): ) Smith JG. The Classic: Pathological Appearances of Seven Cases of Injury of the Shoulder-Joint: With Remarks. Clin Orthop Relat Res Jun; 468(6): Page 40 of 41

41 7) Charles Neer. (Accessed on 8/12/15). 8) London Medical Gazette. (Accessed on 15/12/15). 9) Feinberg JH, Radecki J. Pasronage-Turner Syndrome. HSS J Sep; 6(2): ) Anatomical illustrations courtesy of Medical Illustration Department, Wrightington, Wigan and Leigh NHS Foundation Trust. Page 41 of 41