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The Ultimate Rotator Cuff Training Guide

Most Effective Rotator Cuff Treatments

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CT arthrography of the shoulder is an old technique, first developed for the assessment of the glenoid labrum [2]. Following the introduction and eventual widespread use of MRI for shoulder imaging, CTA was for all intents and purposes an antiquated study. Although a noncontrast MRI is excellent for the evaluation of rotator cuff disease, intra-articular pathology such as labral and biceps tendon tears is best evaluated with MRA, which is an invasive examination. As with other joints, a failed MRA can be converted to a CTA if sufficient iodinated contrast media is injected along with the gadolinium contrast agent. Although CTA has not been shown to be superior to MRA in the shoulder, it is

Arthrogram Cartilage
Fig 4. (A) Axial image, single-contrast CT arthrogram, shows pitting and fissuring of lateral patellar articular facet (arrows). (B) Coronal reformation of same patient shows a focal, >50% thickness cartilage defect (arrowhead) in the lateral tibial plateau surface.

viable as a backup study, and has value in the preoperative assessment of patients who have shoulder joint disease.

CT arthrography of the shoulder can be performed as an air-contrast, double-contrast, or single-contrast examination. Older series of CTA for the evaluation of labral pathology promoted a double-contrast technique. The double-contrast plain film arthrogram is reported to be superior for the evaluation of rotator cuff tears [17], possibly explaining the use of double-contrast CTA in the evaluation of labral disease.

Despite meticulous technique, however, it is difficult to perform a double-contrast examination resulting in a uniform modest coating of contrast throughout the shoulder joint. Additionally, the nominal exercise required to coat the joint surfaces often ruptures the capsule, degrading the examination.

Capsule rupture is less likely to occur with single-contrast arthrography, particularly if the total injected volume does not exceed 12 mL. For these reasons, the author's institution advocates the use of a single-contrast technique, which is the same technique used for MRA. In general, two acquisitions are obtained—one in neutral or external rotation positioning and one in internal rotation position—to optimize visualization of both anterior and posterior labra [18]. It is also possible to scan with the patient in the ABER (abduction and external rotation) position. Oblique reformations are created along the long axis of the proximal humerus from the ABER acquisition, detailing the anterior inferior glenoid as well as the undersurface of the supraspinatus tendon.

CT arthrography is a useful tool in the assessment of patients who have rotator cuff disease (Fig. 5). Both conventional plain film arthrography as well as ultrasound can be used to diagnose and stage rotator cuff tears; ultrasound has the added benefit of visualizing partial bursal-sided tears. CT arthrography, however, can provide a detailed preoperative roadmap of the shoulder joint. CT arthrography can accurately size the rotator cuff tear, detail the location of the retracted tendons (see Fig. 5A-C), and assess AC joint osteophytes, cartilage defects (see Fig. 5D), and loose bodies. The CT examination also documents the acromial shape, and can illustrate the presence or absence of rotator cuff muscle atrophy [19] (Fig. 6A).

The diagnosis of a complete rotator cuff tear is established at CTA by observing a contrast-filled gap in the rotator cuff tendon (see Fig. 5A). Partial undersurface tears can be detected by inspecting the contour of the articular margin of the cuff. Recent reports of the accuracy of CTA (single-contrast) in the assessment of rotator cuff tears show sensitivity and specificity of 99% and 100% respectively for the diagnosis of supraspinatus tears, 97% and 100% for infraspinatus tears, and 65% and 99% for the diagnosis of subscapularis tears [20]. Results from an earlier study [21] using double-contrast CTA and direct CT coronal imaging were comparable with sensitivity and specificity of 86% and 98% respectively. In this study, there was good correlation between the extent of tear and the arthroscopic findings, emphasizing the usefulness of CTA for the preoperative assessment of rotator cuff disease [21].

Infraspinatus Tendon Tear

Fig. 5. (A) Coronal oblique reformation, single-contrast shoulder CT arthrogram. Patient has had prior acromioplasty (a) and lateral clavicular (c) resection. Supraspinatus tendon is torn and retracted (arrow); injected contrast media outlines both articular and bursal surfaces of tendon. (B) Sagittal oblique reformation, same patient, anterior to image left. Torn and retracted edges of supraspinatus tendon (arrows) result in a gap in the rotator cuff tendon (dou-ble-headedarroW). (C) Axial plane image, same patient. Subscapularis tendon (curvedarroW) is torn and retracted; long-head biceps tendon (open arroW) is medially dislocated. (D) Coronal oblique reformation, same patient. Focal full-thickness cartilage defect of glenoid (arrowhead) is outlined by contrast media.

The bursal side of the cuff is not evaluated with CTA when the rotator cuff is intact, because contrast remains within the glenohumeral joint. This region of the rotator cuff is best evaluated using ultrasound or conventional MRI. If a bursal sided tear is suspected, the subacromial-subdeltoid bursa can be injected, followed by a CT study [22].

CT arthrography also can be used to evaluate the postoperative cuff (see Fig. 6B,C). To the author's knowledge, there are no series documenting the efficacy of CTA in these patients; however, unlike MRI, artifacts in the tendon from adjacent metal tendon anchors or sutures are minimal (see Fig. 6B). Additionally, a watertight seal of the cuff is not expected following rotator cuff repair. If contrast leaks into the subacromial-subdeltoid bursa, the full extent of the rotator cuff tendon is outlined and the thickness of the repaired cuff tendon can be quantified. Any remaining gaps or tears of the tendon can be assessed

Infraspinatus Tendon TearInfraspinatus Tendon TearShoulder Mra Slap

Fig. 6. Postoperative patient. (A) Sagittal oblique reformation medial to glenoid illustrates how rotator cuff muscle atrophy can be assessed at CT imaging, anterior to image left (c, clavicle; *, coracoid). Fatty infiltration and decreased bulk indicate moderately severe atrophy of supraspinatus (arrow), infraspinatus (open arrow), and upper portion of subscapularis muscle (arrowhead). Compare with more normal-appearing inferior subscapularis (S) and teres minor muscles (T). (B) Same patient. Radiograph taken during single-contrast arthrogram shows four tendon anchors in humeral head from prior rotator cuff repair. Contrast media injected into gle-nohumeral joint space tracks into subacromial bursa because of rotator cuff tear. (C) Coronal oblique reformation from subsequent CT examination clearly illustrates extensive tear of supraspinatus tendon (arrow), which is medially retracted. Presence of metal anchors does not interfere with visualization at CT.

Fig. 6. Postoperative patient. (A) Sagittal oblique reformation medial to glenoid illustrates how rotator cuff muscle atrophy can be assessed at CT imaging, anterior to image left (c, clavicle; *, coracoid). Fatty infiltration and decreased bulk indicate moderately severe atrophy of supraspinatus (arrow), infraspinatus (open arrow), and upper portion of subscapularis muscle (arrowhead). Compare with more normal-appearing inferior subscapularis (S) and teres minor muscles (T). (B) Same patient. Radiograph taken during single-contrast arthrogram shows four tendon anchors in humeral head from prior rotator cuff repair. Contrast media injected into gle-nohumeral joint space tracks into subacromial bursa because of rotator cuff tear. (C) Coronal oblique reformation from subsequent CT examination clearly illustrates extensive tear of supraspinatus tendon (arrow), which is medially retracted. Presence of metal anchors does not interfere with visualization at CT.

accurately, an advantage of the CT examination over conventional arthrography.

In the past, the main indication for a shoulder CTA was the assessment of the glenoid labrum. Initial reports of CTA indicated high accuracy (85%-100%) for the detection of labral pathology [23-27]. MR arthrography now is considered to be the gold standard for nonoperative assessment of the labrum [28-30]. Tears of the labrum can be difficult to assess because of the wide range of normal variants that occur in the shoulder. Fortunately, the majority of normal variants (sublabral recess, sublabral foramen, Buford complex) occur in the anterior superior quadrant of the glenoid labrum.

The most reliable finding of a tear is the presence of contrast extending completely through the labrum; a small amount of undercutting is considered to be a normal finding. Paralabral cysts are nearly always associated with a labral tear, but these cysts are easier to detect at MRI on T2-weighted or fluid-sensitive sequences than on CTA. Delayed imaging at CTA may be helpful because contrast can fill the cyst, but delayed imaging is rarely performed because the patient usually leaves the imaging suite at the completion of the initial scans. Inspection of the surrounding soft tissues using a narrower window setting increases the likelihood of detecting a paralabral cyst at CTA. Tears of the capsule and surrounding structures can be detected if focal contrast leaks into the surrounding soft tissues. Detection of these tears is less reliable using a double-contrast technique because of the higher likelihood of joint rupture; however, capsular and surrounding soft tissues are best visualized at MRI and MRA.

The long head biceps anchor point and, more specifically, SLAP (superior labrum anterior to posterior) tears remain a challenge regardless of the imaging method chosen. Sporadic reports of SLAP tear detection using CTA [31,32] show mixed results, and current consensus is that MRA is best if a SLAP tear is suspected; however, if CTA is the only imaging option available for the patient, it should be considered. Detection of long-head biceps dislocation or disruption is easy to establish at CTA, because the proximal long-head biceps tendon sheath always fills with contrast during an arthrogram, and the tendon is relatively large (see Fig. 5C).

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