CT arthrography of the shoulder: how "to do it"

Transcription

1 CT arthrography of the shoulder: how "to do it" Poster No.: C-1694 Congress: ECR 2015 Type: Educational Exhibit Authors: A. Shah, R. Botchu, W. J. Rennie; Leicester/UK Keywords: Education and training, Arthrography, CT, Musculoskeletal joint DOI: /ecr2015/C-1694 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 28

2 Learning objectives To review the technique in performing a CT arthrogram of the shoulder. In this poster we discuss: Normal anatomy of the gleno-humeral joint Indications of CT arthrogram Interventional techniques using the anterior and posterior approach Pictorial review of the common pathologies Background Magnetic Resonance (MR) is typically the favoured modality for shoulder arthrography. Computed tomography arthrography (CTAr) is an effective alternative in salvaging a failed attempted MR arthrogram, when MR is contraindicated or in the post-operative shoulder with suture anchors. Studies suggest CTAr can offer an advantage over MR in detecting osseous or detecting hyaline cartilage defects. Different clinical scenarios require different imaging modalities to visualise the joint and the purpose of this poster is to discuss the role of CTAr of the shoulder. Findings and procedure details Normal Gleno-humeral joint (GHJ)anatomy: GHJ is supported by (Fig.1): Superiorly: Coraco-humeral arch and ligament Long head of the biceps tendon Supraspinatus tendon Anteriorly: Page 2 of 28

3 Anterior labrum Gleno-humeral ligaments (GHL)- superior (SGHL), middle (MGHL) and inferior (IGHL) (anterior band) Subscapularis tendon Posteriorly: Posterior labrum IGHL (posterior band) Infraspinatus and teres minor tendons Page 3 of 28

4 Page 4 of 28

5 Fig. 1: A) Drawing of the supporting labrocapsular ligamentous complex of the GH joint. GHL = glenohumeral ligament B) Anterior graphic of the shoulder. The tendon of the subscapularis muscle attaches both to the lesser tubercle aswell as to the greater tubercle giving support to the long head of the biceps in the bicipital groove. The rotator cuff is made of the tendons of subscapularis, supraspinatus, infraspinatus and teres minor muscle. References: Massengill AD et al. (1994) Labrocapsular ligamentous complex of the shoulder: normal anatomy, anatomic variation, and pitfalls of MR imaging and MR arthrography. Radiographics 14: & the Radiology Assistant Rotator cuff interval: Triangular anatomic area in the anterosuperior aspect of the shoulder (Fig.2) defined by: BASE: the coracoid process SUPERIORLY: the anterior margin of the supraspinatus tendon INFERIORLY: the superior margin of the subscapularis tendon Page 5 of 28

6 Fig. 2: Diagram of rotator cuff interval shows left shoulder in external rotation. Rotator cuff interval (star) lies between supraspinatus muscle and subscapularis muscle. Long head of biceps tendon (arrow) courses in bicipital groove and is displaced laterally away from target site for needle. The boundaries of rotator interval,defined by coracoid process at its base, superiorly by anterior margin of supraspinatus tendon and inferiorly by superior margin of subscapularis tendon. Contents of rotator interval include long head of biceps tendon, coracohumeral ligament, superior glenohumeral ligament, and rotator interval capsule. Rotator interval capsule is anterosuperior aspect of glenohumeral joint capsule, which merges with CHL and SGHL insertions medial and lateral to bicipital groove. CHL arises from base of coracoid process, traverses through subcoracoid fat, and inserts on anterior humerus. Key: GHL = glenohumeral ligament. References: Radiology, NHS Trust, University Hospitals of Leicester - Leicester/UK CT vs MR arthrography: advantages and indications: Initially CTAr primarily used as a bailout for MR for example in patients who are claustrophobic or if MR is contraindicated such as patients with pacemaker or in the post-operative shoulder with metallic anchor sutures. Recent studies using CTAr have demonstrated equivalency or supremacy over MR in diagnosing various pathologies [1] including: articular surface rotator cuff tears [2], labral lesions [3], osseous or cartilaginous defects [4] or calcified structures such as Bennett lesions or chondrocalcinosis. CT advantages over MR are due to advances in helical scanning and multirow detectors with resultant faster scanning times thus reducing motion artefact, sub-millimetre spatial resolution and better metal artefact reducing algorithms. CT is quicker and easier to perform and is generally more accessible than MR. Disadvantages: Use of ionising radiation Inferior tissue contrast resolution Technique: Anterior approach: The anterior approach is based on intra-articular needle placement through the rotator cuff interval (Fig. 2) [5]. Page 6 of 28

7 The patient is positioned on the fluoroscopy table in the supine position with the in external rotation (palm facing upwards). External rotation rotates the long head of the biceps tendon laterally avoiding injury during needle advancement. With the X-ray tube perpendicular to the GHJ, the skin is marked at the superomedial aspect of the humeral head, just lateral to the medial articular cortex of the humerus at the level of the coracoid process Fig. 3 on page 17. The operator, under standard aseptic precautions, prepares the trolley as shown in Figure 4. This includes: surgical cleaning solution to clean the skin, standard 21G needle, 5mls syringe with 1% lidocaine, 20mls syringe with non-ionic iodinated contrast, an extension tube and sterile drapes. The skin is cleaned and sterile drapes placed, leaving the entry site exposed. The skin and subcutaneous tissues are anaesthetised and with a 21G completely perpendicular to the shoulder, is inserted down to the humeral head. Once contact with the bone is made, a small amount of local anaesthetic is injected which should be without resistance if the needle is in an intraarticular position. The extension tube is connected to the needle, ensuring a tight seal to avoid external contrast leak. With intermittent screening, inject the positive contrast, which should flow freely away from the needle tip with no resistance during injection. The contrast will outline the GHJ Fig. 4 on page 17. Instil 12-15mls of the contrast and this will fill the axillary Fig. 5 on page 18 and posterior recesses Fig. 6 on page 19. It is normal to see contrast in the long head of the biceps tendon sheath as it has an intra-articular course Fig. 7 on page 20. The patient is transferred to CT immediately after the procedure with minimal exertion of the injected joint. If contrast pools around the needle tip, the bevel is not in an intra-articular position. Rotate the needle 180 degrees and ensure the needle is in contact with the bone. Minimal manipulation should allow the needle tip to insert into the joint capsule. No resistance should be met with contrast injection and contrast should flow away freely outlining the joint capsule when in correct position. Malposition needle with extra-articular contrast injection can occur in the subscapularis muscle (linear contrast fill) Fig. 8 on page 21 & Fig. 9 on page 22 or in the subacromial subdeltoid bursa Fig. 10 on page 23. Pathologies can be seen/inferred during the arthrogram. If contrast is seen in normal intra-articular position and subsequent extravastion into the subacromial subdeltoid space, a full-thickness rotator cuff tendon tear is inferred Fig. 11 on page 24. Hill-Sachs lesions can be identified Fig. 12 on page 25. Page 7 of 28

8 Posterior approach: Contrast material inadvertently injected into the extracapsular soft tissues during conventional anterior approach may cause interpretative difficulties. If anterior instability is suspected, a posterior approach may be used to preserve the anterior stabilising structures [6]. Fig. 13: Posterior graphic of the shoulder. References: Robin Smithuis and Henk Jan van der Woude. Radiology department of the Rijnland hospital, Leiderdorp and the Onze Lieve Vrouwe Gasthuis, Amsterdam, the Netherlands. The patient is positioned prone on the fluoroscopy table with the arm by the side and palm facing down onto the table. Page 8 of 28

9 With the X-ray tube perpendicular to the GHJ, the skin is marked just lateral to the medial articular cortex of the humerus at the level of the coracoid process. Under aseptic precautions, steps 3-9 described in the anterior approach are followed. Fig. 14: Supine CT arthrogram demonstrating the direction of needle insertion with a posterior approach. References: Radiology, NHS Trust, University Hospitals of Leicester - Leicester/UK CT scanning parameters: Acquire one volume data set with arm in neutral position. Reconstruct axial images 0.625mm thick at 0.3mm intervals. Multiplanar reformats are created obliqued parallel and perpendicular to the plane of the supraspinatus muscle belly. Case examples: Page 9 of 28

10 Normal CT arthrogram: Fig. 15: Normal axial (A), coronal (B) and sagittal (C) CT arthrogram. KEY: Red C; corocoid process, red arrows; anchor sutures. References: Radiology, NHS Trust, University Hospitals of Leicester - Leicester/UK Fig. 16: Normal CT arthrogram demonstrating the articular cartilage (red arrow), contrast within the subscapular recess (blue arrow) and the tendon sheath of the long head of the biceps tendon. References: Radiology, NHS Trust, University Hospitals of Leicester - Leicester/UK Page 10 of 28

11 Fig. 17: CT arthrogram demonstrating normaal intact anterior and posterior glenoid labrum (red arrows) References: Radiology, NHS Trust, University Hospitals of Leicester - Leicester/UK Hill-Sachs lesion (Fig. 19): 1. Posterolateral humeral head indentation fracture subsequent to anterior shoulder dislocation causing the soft base of humeral head to impact against relatively hard anterior glenoid. Occurs in 35-40% of anterior dislocations & up to 80 % of recurrent dislocations. Hill-Sachs lesion occurs through the cartilaginous surface of the humeral head and often there will remain a small island of cartilage located between the bare area and the Hill-Sachs lesion. Hill-Sachs Lesion can destabilise the GHJ & predispose to further dislocation. Reverse Hill-Sachs is defined as an impaction fracture of anteromedial aspect of humeral head following posterior shoulder dislocation Page 11 of 28

12 Fig. 18: CT arthrogram demonstrating a large Hill-Sachs lesion. References: Radiology, NHS Trust, University Hospitals of Leicester - Leicester/UK Bony Bankart lesion (Fig. 20): 1. Bankart lesion is avulsion of the anteroinferior glenoid labrum at its attachment to the IGHL complex. May be labral only or involve the bony margin (impaction fracture; bony Bankart). 2. Page 12 of 28

13 Secondary to anterior shoulder dislocation and impaction of the humeral head with the glenoid. Commonest cause of anterior shoulder instability. Reverse Bankart lesion, the posteroinferior labrum is detached from its glenoid attachment with avulsive tear of the scapular periosteum. Perthes lesion is a variant of a Bankart lesion; in which the anterior labrum is lifted from the edge of the glenoid along with a sleeve of periosteum which is undermined but not torn. Fig. 19: CT arthrogram: displaced osseous fragment of the anteroinferior glenoid labrum seen (bony Bankart). Note contrast is extra-articular and within the subacromial subdeltoid bursa rather then in the GHJ. References: Radiology, NHS Trust, University Hospitals of Leicester - Leicester/UK Page 13 of 28

14 Cartilaginous injury (Fig. 21): Fig. 20: Oblique coronal reformation from multidetector CT arthrogram demonstrates a focal full-thickness chondral defect of the humeral head (red arrows). Compare with normal adjacent articular cartilage (yellow arrow). References: Radiology, NHS Trust, University Hospitals of Leicester - Leicester/UK Articular surface supraspinatus tear (Fig. 22): Page 14 of 28

15 Fig. 21: Animated oblique coronal reformation from multidetector CT arthrogram demonstrates an example of a longitudinal contrast extension into the supraspinatus tendon consistent with a delaminating articular surface partial tear (yellow arrows). Contrast is also seen in the subacromial-subdeltoid bursa from a coexisting fullthickness anterior supraspinatus tendon tear (red arrow). References: Radiology, NHS Trust, University Hospitals of Leicester - Leicester/UK Bennett Lesion (Fig 23): 1. Bennett lesion is an extra-articular curvilinear calcification along the posteroinferior glenoid near the attachment of the posterior band of the IGHL. Page 15 of 28

16 2. 3. Associated with posterior labral tear, posterior undersurface rotator cuff tear and posterior subluxation of the humeral head. More common in overhead throwing athletes with subsequent traction injury of the posterior band of the IGHL. Fig. 22: Axial CT arthrogram demonstrating a Bennett lesion secondary to posterior instability after traumatic injury. There is linear calcification posterior band of the inferior glenohumeral ligament (blue arrow) adjacent to focal sclerosis in posterior osseous glenoid (red curved arrow). References: Radiology, NHS Trust, University Hospitals of Leicester - Leicester/UK Page 16 of 28

17 Images for this section: Fig. 3: AP fluoroscopic screen grab demonstrating the target area for needle position (blue triangle) at the rotator cuff interval at the level of the coracoid process (yellow line). The long head of the biceps tendon (red line) is lateral with external rotation. Anchor sutures from previous labral repair (arrows). Page 17 of 28

18 Fig. 4: The extension tube is connected to the needle, which is seen end-on when inserted perpendicular to the x-ray beam (black arrow). Initial contrast injection is seen outlining the articular surface of the humeral head (red arrow). Page 18 of 28

19 Fig. 5: Intra-articular contrast is demonstrated with contrast extending into the normally into the axillary recess (red arrow). Page 19 of 28

20 Fig. 6: Normal fluoroscopic image of contrast filling the joint capsule. Anchor sutures can be seen in the glenoid. Page 20 of 28

21 Fig. 7: Normal intra-articular demonstrated. Contrast is seen extending into the tendon sheath of the long head of the biceps tendon (star), which is normal as it is an extrasynovial intra-articular structure. Page 21 of 28

22 Fig. 8: AP fluoroscopic image demonstrating linear contrast extravasation into the subscapularis muscle. The contrast follows the course of the muscle (dotted lines). Page 22 of 28

23 Fig. 9: AP fluoroscopic image demonstrating linear contrast extravasation into the subscapularis muscle. Note how the contrast follows the course of the muscle. Page 23 of 28

24 Fig. 10: Fluoroscopic image demonstrating contrast in the subacromial subdeltoid bursa (red arrow) extending into the acromioclavicular joint confirmed on subsequent CT. No contrast is seen outlining the GHJ. Note malposition of the needle tip beyond the humeral head (yellow arrow). Page 24 of 28

25 Fig. 11: Fluoroscopic image demonstrating intra-articular contrast fill with filling of the long head of the biceps tendon sheath (yellow star). Subsequent extrasvastion of contrast into the subacromial subdeltoid space (red arrows) was seen inferring full thickness rotator cuff tear. Page 25 of 28

26 Fig. 12: Intra-articular contrast is demonstrated. Note the large Hill-Sachs defect (yellow arrow). Page 26 of 28

27 Conclusion Advances in CT helical imaging allows the acquisition of submillimetre thin slices with isotropic imaging voxels permitting multiplanar reformations with high spatial resolution. CTAr, therefore, plays a larger role in shoulder arthrography. It has advantages over MRI including faster imaging for reduced motion artefact, detecting osseous or hyaline defects and situations with in situ metal. Being aware of its role and the imaging findings can help the radiologist choose the optimal imaging technique to help the clinician in the management of patients. Personal information A Shah, Department of Musculoskeletal Radiology, University Hospitals of Leicster, Leicester Royal Infirmary, Infirmary Square, Leicester, LE1 5WW, UK. R Botchu, Department of Radiology, Royal Orthopaedic Hospital, Birmingham, B31 2AP, UK. WJ Rennie, Department of Musculoskeletal Radiology, University Hospitals of Leicster, Leicester Royal Infirmary, Infirmary Square, Leicester, LE1 5WW, UK. References Omoumi P, Rubini A, Dubuc JE, Vande Berg BC, Lecouvet FE. Diagnostic performance of CT-arthrography and 1.5T MR-arthrography for the assessment of glenohumeral joint cartilage: a comparative study with arthroscopic correlation. European radiology Nov 8. PubMed PMID: Epub 2014/11/08. Eng. Lecouvet FE, Simoni P, Koutaissoff S, Vande Berg BC, Malghem J, Dubuc JE. Multidetector spiral CT arthrography of the shoulder. Clinical applications and limits, with MR arthrography and arthroscopic correlations. European journal of radiology Oct;68(1): PubMed PMID: Epub 2008/04/11. eng. Kim YJ, Choi JA, Oh JH, Hwang SI, Hong SH, Kang HS. Superior labral anteroposterior tears: accuracy and interobserver reliability of multidetector CT arthrography for diagnosis. Radiology Jul;260(1): PubMed PMID: Epub 2011/04/27. eng. Page 27 of 28

28 Lecouvet FE, Dorzee B, Dubuc JE, Vande Berg BC, Jamart J, Malghem J. Cartilage lesions of the glenohumeral joint: diagnostic effectiveness of multidetector spiral CT arthrography and comparison with arthroscopy. European radiology Jul;17(7): PubMed PMID: Epub 2006/12/23. eng. Depelteau H, Bureau NJ, Cardinal E, Aubin B, Brassard P. Arthrography of the shoulder: a simple fluoroscopically guided approach for targeting the rotator cuff interval. AJR American journal of roentgenology Feb;182(2): PubMed PMID: Epub 2004/01/23. eng. Chung CB, Dwek JR, Feng S, Resnick D. MR arthrography of the glenohumeral joint: a tailored approach. AJR American journal of roentgenology Jul;177(1): PubMed PMID: Epub 2001/06/22. eng. Page 28 of 28