MR arthrography of the shoulder: comparison with conventional MR imaging

Twenty-three patients underwent both conventional MR imaging of the shoulder and MR shoulder arthrography for clinically suspected labral or rotator cuff abnormalities. Images obtained before and after contrast administration were studied independently, and without knowledge of clinical findings, by two radiologists for the presence of abnormalities of the glenoid labrum or rotator cuff. Results were correlated with surgical findings in all patients. Nine patients had surgically proved labral tears. MR arthrography detected all nine labral abnormalities, while six of the nine were missed on conventional MR imaging. Fourteen patients had surgically proved rotator cuff tears. MR arthrography detected 11 of the 14 tears and missed three partial tears on the bursal surface. Conventional MR imaging detected nine cuff tears and missed five tears; two of these were complete rotator cuff tears and three were partial tears of the undersurface of the rotator cuff. Our results suggest that MR arthrography enhances the accuracy of MR in the evaluation of the glenoid labrum and rotator cuff tendon.     

Humeral avulsion of the anterior shoulder stabilizing structures after anterior shoulder dislocation: demonstration by MRI and MR arthrography

 Objective. To demonstrate the MRI findings of an anterior shoulder capsular avulsion from the humerus, with or without subscapularis rupture, after anterior dislocation or severe abduction external rotation injury. Design and patients. We retrospectively reviewed the MRI and MR arthrographic examinations of seven patients who were identified at surgery with avulsion of the anterior shoulder stabilizers from the humerus. MRI was correlated with clinical history and surgical results. Results. MRI findings included: inhomogeneity or frank disruption of the anterior capsule at the humeral insertion (all), fluid intensity anterior to the shoulder (six patients), tear of the subscapularis tendon (six patients), dislocation of the biceps tendon (four patients), and a Hill-Sachs deformity (four patients). MR arthrography additionally found extravasation of contrast through the capsular defect (two patients). Conclusions. Our findings suggest that MRI is helpful for diagnosing humeral avulsion of the anterior glenohumeral capsule, especially when a tear of the subscapularis tendon insertion is present. MR arthrography may be of benefit for diagnosing capsular avulsion without associated subscapularis tendon abnormality.     

Unclassified MR arthrography pattern evaluation in patients with episodes of recurrent antero-inferior shoulder dislocation

Purpose

To evaluate prospectively the incidence of unclassifiable MR arthrography patterns of glenoid anterior–inferior labrum lesions, in patients with at least two episodes of recurrent antero-inferior shoulder dislocation.

Materials and methods

The MR shoulder Arthrography images of 36 patients, with at least two episodes of recurrent antero-inferior dislocation, were prospectively evaluated, during a period between November 2015 and Mai 2016. All patients were contacted after 6 months of the MR arthrography to evaluate their course of treatment. The MR arthrography images were analyzed by two radiologists, respectively with 5 and 15 years of experience in musculoskeletal radiology.

Results

36 cases of unclassifiable MR arthrography pattern of the anterior–inferior glenoid labrum were evaluated: in 13 out 36 cases (36.1%), the glenoid labrum has been described as “oedematous and swollen”; in 19 out 36 cases (52.8%), it has been described as “smooth” (not hypoplastic); in 4 out 36 cases (11.1%), it has been described as degenerated.

Conclusion

The unclassifiable MR arthrography patterns of fibrocartilage glenoid lesions after episodes of recurrent antero-inferior dislocation are commons. The unclassifiable MR arthrography patterns require a careful consideration, in order to improve the diagnostic and therapeutic multidisciplinary approach.

     

MR and CT arthrography of the shoulder

The combined use of shoulder arthrography with MR and CT imaging offers distinct advantages over conventional nonarthrographic imaging techniques. The improved contrast and joint distension afforded by direct arthrography optimize evaluation of various intra-articular structures and help to define subtle abnormalities and distinguish normal variants from true shoulder pathology. In this article, we review the rationale and basic approaches to shoulder arthrography as well as the imaging appearance of the normal shoulder, anatomical variants, and pathology highlighted by this technique.     

Comparative study of direct MR arthrography and CT arthrography with arthroscopic correlation in preoperative evaluation of anterior shoulder instability

Purpose

To compare direct MR arthrography and CT arthrography for the preoperative planning of shoulder anterior instability.

Patients and methods

47 patients were included in this study. 43 patients with clinical history of anterior GHI or recurrent shoulder pain had no clinical findings of rotator cuff abnormality. They experienced multiple anterior dislocations of the shoulder. No patient showed evidence of multidirectional instability or generalized ligamentous laxity. The remaining 4 patients complained of anterior shoulder instability after anchor repair. All the patients underwent direct CT and MR arthrography. The results of CTA and MRA were compared with results obtained from arthroscopy in each patient to detect the sensitivity and specificity of each modality.

Results

The sensitivity and specificity of CTA for bankart lesion are 89.4% and 96.4% respectively and of MRA 94.7% and 96.4%, for Perthes lesion the sensitivity and specificity of CTA are 33.3% and 100% respectively and of MRA 66.6% and 100%, for ALPSA the sensitivity and specificity of CTA are 85.7% and 97.5% respectively and of MRA 100% and 97.5%, for GLAD the sensitivity and specificity of CTA are 80% and 97.6% respectively and of MRA 60% and 97.6%, for SLAP lesion the sensitivity and specificity of CTA are 100% and 100% respectively and of MRA 100% and 100%, for absent or degenerated labrum the sensitivity and specificity of CTA are 100% and 100% respectively and of MRA 66.6% and 97.7%, for post operative recurrent Bankart lesion the sensitivity and specificity of CTA are 100% and 100% respectively and of MRA 50% and 100%, for bony glenoid fracture the sensitivity and specificity of CTA are 100% and 100% respectively and of MRA 66.6% and 97.5%.

Conclusion

CTA and MRA were equivalent in demonstrating labro-ligamentous and cartilaginous lesions associated with shoulder instability. CTA was superior in detecting post operative instability and glenoid rim osseous lesions that are known to be a decisional element in the surgical strategy. Hence, CTA may be considered a method of choice in the preoperative evaluation of shoulder anterior instability.     

Imaging findings in the dominant shoulder of throwing athletes: comparison of radiography, arthrography, CT arthrography, and MR arthrography with arthroscopic correlation

OBJECTIVE: Conventional radiography, arthrography, CT arthrography, and MR arthrography--including use of the abduction and external rotation position--were compared, with arthroscopic correlation, to determine the spectrum of abnormalities encountered and the relative benefits of each imaging method in the evaluation of shoulder lesions occurring in 17 throwing athletes. SUBJECTS AND METHODS: Each of 36 athletes with shoulder pain aggravated by abduction and external rotation was examined in a single visit during which conventional radiography, arthrography, CT arthrography, and MR arthrography were performed. In 17 of these athletes, imaging findings were compared with those at arthroscopy. All images were independently evaluated by two groups of musculoskeletal radiologists. RESULTS: Structures found to be affected were, in decreasing order of frequency, the following: the posterosuperior labrum, supraspinatus tendon, infraspinatus tendon, humeral head, glenoid cavity and rim, acromioclavicular joint, anteroinferior capsulolabral complex, biceps tendon, and subscapularis tendon. MR arthrography without and with abduction and external rotation yielded the highest sensitivity and specificity for all lesions with the exceptions of bone sclerosis and enthesophytes (which were best seen with CT arthrography). MR arthrography with abduction and external rotation was most accurate for diagnosis of rotator cuff and anteroinferior capsulolabral complex tears. CONCLUSION: On the basis of these preliminary results, we believe that MR arthrography with abduction and external rotation should be part of the imaging evaluation of shoulder pain in throwing athletes, owing to the high sensitivity of this imaging technique.     

多层螺旋CT评价复发性肩关节前方脱位的前方关节盂骨质缺损的临床意义

目的 在复发性肩关节前方脱位中,利用MSCT评估关节盂前方骨质缺损情况.方法 回顾分析108例复发性肩关节前脱位和12例单次肩关节脱位患者的MSCT检查,对比评价前方关节盂骨质缺损的发生率、程度及位置.利用Fisher精确概率法分析前方关节盂骨质缺损的发生率,利用Wilcoxon秩和检验比较前方关节盂骨质缺损的上下长径、深度及比例.结果 在复发性肩关节前脱位中,91.7％(99/108)存在前方关节盂的骨质缺损,缺损比例为(16.0±6.0)％,缺损中心位置介于时钟分区的2:20～ 4:25点(平均3:20点),62.0％(67/108)前方出现骨性Bankart病变,包括游离型39例(58.2％)及黏附型28例(41.8％).12例单次肩关节脱位中,9例出现前方关节盂骨质缺损,其缺损发生率(9/12;P=0.100)和缺损比例[(15.2±7.1)％;P=0.453]与复发性肩关节脱位比较差异均无统计学意义.结论 前方关节盂骨质缺损为复发性肩关节前方脱位的常见表现.     

MR imaging of subscapularis tendon injury in the setting of anterior shoulder dislocation

Objective

To evaluate the degree and location patterns of subscapularis tendon injury in patients with prior anterior shoulder dislocation (ASD).

Material and methods

Forty-five consecutive MR shoulder examinations in patients with a history of ASD and 20 consecutive MR examinations in patients without prior dislocation were reviewed. Two readers assessed for the presence and location of tendinosis and tearing in the subscapularis tendon, which was divided into three segments: superior, middle, and inferior. The readers also documented the presence of anterior labral tears, osseous Bankart defects and Hill–Sachs lesions. Fisher’s exact tests were performed to analyze the different types of pathology and their locations.

Results

Subscapularis tendinosis, and partial thickness and full thickness tears were more common in patients with a history of ASD. Tendinosis was found in 60-64.4% of the dislocation patients compared with 40% of the non-dislocation group. When stratified by location, the middle and inferior thirds were the most commonly affected with statistical significance (p?p?Conclusion Our study suggests an association between middle and inferior subscapularis tendon pathology and prior anterior shoulder dislocation. Based on our results, careful MR assessment of the subscapularis tendon by the radiologist is indicated in the setting of ASD as injury of this structure can be symptomatic and may be amenable to treatment.     

Cartilage lesions in the ankle joint: comparison of MR arthrography and CT arthrography

OBJECTIVE: To compare MR arthrography and CT arthrography for the evaluation of cartilage lesions in the ankle joint. DESIGN AND PATIENTS: Thirty-six consecutive patients with clinically suspected cartilage lesions were prospectively included in the study. A 1:1 mixture of diluted gadoteridol (4 mmol/l) and iopamidol (300 mg iodine/ml) was injected. The articular cartilages of the talus, tibia, and fibula were analyzed separately by two musculoskeletal radiologists. A review panel consisting of two musculoskeletal radiologists and an orthopedic surgeon represented the standard of reference. RESULTS: For reader 1 accuracy of MR arthrography in the talus/tibia/fibula (88%/88%/94%) was slightly inferior to CT arthrography (90%/94%/92%). For reader 2, the accuracy was 76%/78%/83% for MR arthrography, and 92%/93%/92% for CT arthrography, respectively. Interobserver agreement for MR arthrography was 79%/74%/89% (kappa 0.47/0.34/0.27), while interobserver agreement for CT arthrography was 89%/90%/89% (kappa 0.69/0.54/0.54). CONCLUSION: CT arthrography appears to be more reliable than MR arthrography for the detection of cartilage lesions in the ankle joint.     

Rotator cuff interval: evaluation with MR imaging and MR arthrography of the shoulder in 32 cadavers

PURPOSE: The purpose of this work was to establish the optimal means of evaluation of the rotator cuff interval (RCI) and rotator interval capsule and demonstrate normal anatomy of the RCI using MR imaging and MR arthrography. METHOD: MR arthrography was performed in 32 cadaveric shoulders. In 20 cases, MR imaging was completed prior to arthrography. Pre- and postarthrography studies included standard imaging planes. Images were evaluated by the consensus of two musculoskeletal radiologists with attention to the RCI, rotator interval capsule (measurements on postarthrographic studies), and crossing structures. In five cases, specialized imaging planes were performed after arthrography. RESULTS: The RCI, rotator interval capsule, and crossing structures were best evaluated by MR arthrography. The anteroposterior dimension of the rotator interval capsule could be best depicted on postarthrogram images. CONCLUSION: MR arthrography, with both standard and specialized imaging planes, is a useful way to evaluate the RCI, the rotator interval capsule, and its crossing structures.     

Irreducible posterior dislocation of the shoulder: MR and CT findings

Failure to reduce an acute posterior dislocation of the shoulder is rare and is usually due to the interposition of a structure into the joint. In this paper we report the MR and CT findings of a failed reduction due to interposition of a dislocated biceps tendon between the humeral head and anterior glenoid fossa. This was associated with an avulsed subscapularis tendon with its attachment to the lesser tuberosity and a nondisplaced fracture of the humeral neck, findings which were only evident on MR.     

Interosseous ligament tears of the wrist: comparison of multi-detector row CT arthrography and MR imaging

PURPOSE: To compare the accuracy of multi-detector row computed tomographic (CT) arthrography and magnetic resonance (MR) imaging in depicting tears of dorsal, central, and palmar segments of scapholunate (SL) and lunotriquetral (LT) ligaments in cadavers. MATERIALS AND METHODS: Cadaver wrists were obtained and used according to institutional guidelines and with informed consent of donors prior to death. Nine cadaver wrists of eight subjects were evaluated. MR images were obtained with a 1.5-T MR unit. Imaging protocol included intermediate-weighted coronal and transverse fast spin-echo and coronal three-dimensional gradient-echo sequences. Multi-detector row CT arthrography was performed after tricompartmental injection of 3-6 mL of contrast material with a concentration of 160 mg per milliliter of iodine. Palmar, dorsal, and central segments of both ligaments were analyzed on transverse and coronal MR images and multiplanar multi-detector row CT reconstructions by two musculoskeletal radiologists working independently. Open inspection of the wrists was the reference standard. Sensitivity, specificity, accuracy, and positive and negative predictive values were calculated from the imaging and gross pathologic readings. Statistical significance was calculated with the McNemar test. Weighted kappa values for interobserver agreement were calculated for both imaging modalities. RESULTS: All ligament segments could be visualized in all cases with both imaging modalities. CT arthrography was more sensitive (100%) than MR imaging (60%) in detection of palmar segment tears (P = .62); specificity of both imaging modalities was 77%. Sensitivity (CT arthrography, 86%; MR imaging, 79%) and specificity (CT arthrography, 50%; MR imaging, 25%) for detection of the central segment tears were determined. Dorsal segment tears were detected only with CT arthrography, while all tears were missed with MR imaging (P = .02). Interobserver agreement was better for multi-detector row CT arthrography (kappa = 0.37-0.78) than for MR imaging (kappa = -0.33 to -0.10). CONCLUSION: Performance in depiction of palmar and central segment tears of SL and LT ligaments is almost equal for multi-detector row CT arthrography and MR imaging, with much higher interobserver reliability for CT arthrography. CT arthrography is significantly superior to MR imaging in the detection of dorsal segment tears of SL and LT ligaments.     

Adhesive capsulitis of the shoulder: evaluation with MR arthrography

The purpose of this study was to determine the usefulness of magnetic resonance (MR) arthrography for diagnosing adhesive capsulitis. Shoulder MR images of 28 patients with (n=14) and without (n=14) adhesive capsulitis were retrospectively analyzed. MR images were assessed for capsule and synovium thickness as well as the width of the axillary recess on oblique coronal fat-suppressed T1-weighted images and T2-weighted images, respectively. On oblique sagittal fat-suppressed T1-weighted images, the width of the rotator interval and the presence of abnormal tissue in the interval were evaluated. Significant differences were found between the two groups in capsule and synovium thickness on both sides of the recess on oblique coronal T2-weighted images (P=0.000), whereas thickness on the humeral aspect showed no significant difference on oblique coronal fat-suppressed T1-weighted images (P=0.109). On oblique coronal T2-weighted images, a cut-off value of 3-mm thickness gave the highest diagnostic accuracy for adhesive capsulitis with sensitivity, specificity, and accuracy of 79% (11/14), 100% (14/14), and 89% (25/28) at the humeral side and 93% (13/14), 86% (12/14), and 89% (25/28) at the glenoid side, respectively. There were significant differences in rotator interval width, presence of abnormal tissue in the rotator interval, and axillary recess width between the two groups (P<0.05). Thickness of capsule and synovium of the axillary recess greater than 3 mm is a practical MR criterion for diagnosing adhesive capsulitis when measured on oblique coronal T2-weighted MR arthrography images without fat suppression. The presence of abnormal tissue in the rotator interval showed high sensitivity but rather low specificity.