Prevalence of shoulder enchondromas on routine MR imaging

The objective of this study was to examine the prevalence of incidental shoulder enchondromas on routine magnetic resonance (MR) shoulder imaging. Consecutive routine shoulder MR examinations (N=477) performed for suspected internal derangement were reviewed for the presence of incidental enchondromas. Incidental enchondromas were detected on 2.1% of routine MR shoulder examinations, the vast majority abutting the physeal plate. This prevalence is important to appreciate, in order to form a meaningful differential diagnosis of pathologic proximal humerus lesions.     

Surgical treatment of significant glenoid bone defects and associated humeral avulsions of glenohumeral ligament (HAGL) lesions in anterior shoulder instability

Purpose

Combined occurrence of humeral avulsion of glenohumeral ligament (HAGL) lesion and a significant glenoid bone defect is an unusual and previously undescribed association in traumatic anterior shoulder instability. The purpose of this study was (1) to report a retrospective case series of seven anterior bony instability patients who were diagnosed with this unusual association and (2) to evaluate the results of a modified Latarjet procedure and simultaneous HAGL repair using a new subscapularis-sparing approach.

Methods

A retrospective review of the records of 64 anterior shoulder instability patients who underwent bony stabilization surgery was performed, and patients who underwent a combined reconstruction for significant glenohumeral bone defects (glenoid loss >20 %) and an associated HAGL lesion were identified. Pre- and postoperative follow-up clinical parameters and functional scores were documented (Oxford shoulder instability score [OSIS], Western Ontario shoulder instability index [WOSI]), Rowe score). Radiological assessment included measurement of the glenoid bone defect (CT scan) and evaluation of soft tissue lesions (MR arthrogram).

Results

Radiological and arthroscopic evaluation confirmed the combined lesion complex in 7 (11 %) patients. Follow-up evaluation (mean 20.6 months) suggested an excellent outcome (Rowe score: median 95, range 95–100); a statistically significant improvement was seen in the follow-up OSIS (median 12, range 12–14, p = 0.018) and WOSI score (median 28, range 17–102, p = 0.018) as compared to the preoperative score (median OSIS 50, range 32–53; median WOSI 1,084, range 919–1,195). Clinical tests for subscapularis function revealed a functional subscapularis muscle; no significant differences were detected in pre- versus postoperative internal rotation strength and in the operated versus normal contralateral shoulder (ns). The dual-window subscapularis–sparing approach provided adequate exposure for combined reconstruction of the humeral and glenoid lesions, and no complications were encountered.

Conclusions

Significant glenoid defects are associated with HAGL lesions in approximately 1/10th of patients with bony instability. Combined reconstruction of these lesions via a subscapularis-sparing approach results in an excellent outcome and significant improvement in functional scores at a medium-term follow-up.

Level of evidence

Therapeutic study, Level IV.     

上方盂唇前后向撕裂的肩关节MR造影评价

目的 评价肩关节MR造影对上方盂唇前后向撕裂(SLAP损伤)的诊断价值.方法 由2名影像诊断医师独立回顾分析137例经肩关节镜证实的肩关节造影MR图像,判定有无SLAP损伤,并进行分型.SLAP损伤分4型:Ⅰ型为上盂唇毛糙,Ⅱ型为肱二头肌腱盂唇复合体从关节孟撕裂,Ⅲ型为上盂唇桶柄状撕裂,Ⅳ型为上盂唇桶柄状撕裂并同时累及肱二头肌长头腱.计算肩关节MR造影对SLAP损伤的敏感度、特异度和准确度,以及与肩关节镜分型的符合率.采用Kappa统计计算2名影像诊断医师评价的一致性.结果 137例患者中,肩关节镜证实SLAP损伤59例,包括SLAP损伤Ⅰ型6例(10.2%)、Ⅱ型50例(84.7%)、Ⅲ型3例(5.1%).肩关节MR造影的敏感度、特异度和准确度医师甲分别为86.4%(51/59)、78.2%(61/78)和81.8%(112/137),医师乙分别为88.1%(52/59)、84.6%(66/78)和86.1%(118/137).2名影像诊断医师的评价一致性极好(K=0.796).肩关节MR造影与肩关节镜的分型符合率医师甲为83.1%(49/59),医师乙为79.7%(47/59).结论 肩关节MR造影是评价SLAP损伤比较可靠的影像方法.     

上方盂唇前后向撕裂的肩关节MR造影评价

Objective To evaluate the diagnostic value of shoulder MR arthrography for superior labral anterior-posterior (SLAP) lesions.Methods A retrospective study was conducted in 137 cases of shoulder MR arthrography confirmed by subsequent shoulder arthroscopy.Two radiologists analyzed all MR examinations independently and the results were compared with those of arthrescopy.The superior labrum was described as normal or torn.In addition, each iabral tear was classified as type Ⅰ-Ⅳ.Type Ⅰ lesions were defined as marked fraying of the articulating surface of the superior labrum; type Ⅱ, avulsion of the labral-bicipital complex from the ghnoid; type Ⅲ, displaced bucket handle tear of the superior labrum; and type Ⅳ, bucket handle tear of the superior labrum with extension into the fibers of the biceps tendon.Sensitivity, specificity, and accuracy were calculated.Kappa values were calculated to quantify the level, of inter-observer agreement.Results SLAP lesions were arthroscopically diagnosed in 59 of the 137 patients.Six of the 59 lesions ( 10.2% ) were classified as type Ⅰ , 50 (84.7% ) as type Ⅱ, and 3 (5.1% ) as type Ⅲ.The overall sensitivity, specificity, and accuracy of MR arthrographic detection of SLAP lesions were 86.4% (51/59), 78.2% (61/78), and 81.8% ( 112/137), respectively, for observer A, and 88.1% (52/59), 84.6% (66/78), and 86.1% (118/137), respectively, for observer B.At inter-observer comparison, agreement was very good (Kappa values = 0.796 ).The MR arthrographic classification showed correlation with the arthroscopic classification of SLAP lesions were 83.1% (49/59)and 79.7% (47/59) for two observers, respectively.Conclusion Shoulder MR arthrography is a reliable method for evaluating SLAP lesions.     

上方盂唇前后向撕裂的肩关节MR造影评价

Objective To evaluate the diagnostic value of shoulder MR arthrography for superior labral anterior-posterior (SLAP) lesions.Methods A retrospective study was conducted in 137 cases of shoulder MR arthrography confirmed by subsequent shoulder arthroscopy.Two radiologists analyzed all MR examinations independently and the results were compared with those of arthrescopy.The superior labrum was described as normal or torn.In addition, each iabral tear was classified as type Ⅰ-Ⅳ.Type Ⅰ lesions were defined as marked fraying of the articulating surface of the superior labrum; type Ⅱ, avulsion of the labral-bicipital complex from the ghnoid; type Ⅲ, displaced bucket handle tear of the superior labrum; and type Ⅳ, bucket handle tear of the superior labrum with extension into the fibers of the biceps tendon.Sensitivity, specificity, and accuracy were calculated.Kappa values were calculated to quantify the level, of inter-observer agreement.Results SLAP lesions were arthroscopically diagnosed in 59 of the 137 patients.Six of the 59 lesions ( 10.2% ) were classified as type Ⅰ , 50 (84.7% ) as type Ⅱ, and 3 (5.1% ) as type Ⅲ.The overall sensitivity, specificity, and accuracy of MR arthrographic detection of SLAP lesions were 86.4% (51/59), 78.2% (61/78), and 81.8% ( 112/137), respectively, for observer A, and 88.1% (52/59), 84.6% (66/78), and 86.1% (118/137), respectively, for observer B.At inter-observer comparison, agreement was very good (Kappa values = 0.796 ).The MR arthrographic classification showed correlation with the arthroscopic classification of SLAP lesions were 83.1% (49/59)and 79.7% (47/59) for two observers, respectively.Conclusion Shoulder MR arthrography is a reliable method for evaluating SLAP lesions.     

MR imaging of the shoulder. Impingement and instability-related abnormalities

In addition to the case history and the clinical examination, MR imaging has an important role in the diagnosis and differential diagnosis of numerous shoulder abnormalities and in the investigation of chronic shoulder pain. Important indications for MR imaging are any conditions or symptoms making assessment of the rotator cuff and the labrocapsular complex necessary. Assessment of the rotator cuff muscles, in particular, is crucial. The value of MR arthrography, which is still controversial, is discussed. The greatest potential benefit of MR arthrography is the accurate evaluation of subtle rotator cuff abnormalities and shoulder instability-related lesions, and the assessment of pathologic conditions of the long biceps tendon. This paper describes the most common pathologic findings of the shoulder joint and describes how the relevant findings are reported and quantified for the orthopaedic shoulder surgeon.     

One-shot MR and MDCT arthrography of shoulder lesions with arthroscopic correlation

Although MR imaging and MR arthrography are the first choice modalities for shoulder imaging, CT arthrography (CTA) may be used successfully to address many clinical questions. The advent of sub-millimeter multiple detector CT (MDCT) technology and subsequent excellent three-plane resolution has considerably increased the quality of CTA examinations and has propelled this technique to the forefront in a growing number of indications.     

Capsulo-labro-ligamentous lesions of the shoulder: evaluation with MR arthrography

PURPOSE: The aim of the study was to analyse the accuracy of MR arthrography in the evaluation of capsulo-labro-ligamentous lesions of the shoulder in patients with glenohumeral joint instability. MATERIALS AND METHODS: From 1999 to 2001 fifty-eight patients with glenohumeral joint instability were studied by MR arthrography. Twenty-seven patients underwent surgical repair: 11 by arthroscopic and 16 by arthrotomic approach. All shoulder evaluations were performed with T1 and T2 weighted axial, coronal and sagittal oblique images, before and after intra-articular injection of gadolinium contrast. RESULTS: Forty capsulo-ligamentous lesions (including 14 capsular ruptures with extravasation of the contrast medium) were detected by MR arthrography. Fifty-two labral tears (36 of the anterior, 13 of the superior and 3 of the posterior glenoid labrum) were identified: 11 out of 52 were not recognized before gadolinium contrast injection. Five rotator cuff tears were identified, one of which was not shown in the pre-injection examination. Surgical results confirmed the MR arthrographic findings in 25/27 patients. In one case MR arthrography did not recognize a SLAP lesion; in another case it identified a tear of the capsule but not of the glenoid labrum. CONCLUSIONS: In many cases of subacute glenohumeral joint lesions with intracapsular fluid, MR may accurately evaluate capsulo-labral-ligamentous lesions. Indeed, the examination of lesions is limited by the absence of the natural contrast determined by fluid; in such cases, intra-articular injection of gadolinium contrast is necessary. MR arthrography evaluates the degree of capsulo-labro-ligamentous tears and may guide the surgical approach.     

Demonstration of diastematomyelia and associated abnormalities with MR imaging

Three patients were studied with a 0.3 T superconducting magnet to assess the role of magnetic resonance (MR) imaging in the recognition and evaluation of diastematomyelia and associated abnormalities. Comparison was made with other imaging techniques, including metrizamide computed tomographic (CT) myelography. With MR imaging, the divided spinal cord was well imaged in its entire craniocaudal extent, comparable to CT myelography. The bony septum, when it contained a marrow cavity, was also seen well. In two patients, dural ectasia and low position of the spinal cord with and without associated lipoma were clearly imaged. MR imaging demonstrated associated syringohydromyelia in one patient that was not detected by other radiologic studies. This preliminary experience with MR imaging of diastematomyelia suggests that once the bony details of the abnormality are defined, MR imaging can delineate the presence and extent of the divided spinal cord as well as its associated abnormalities adequately, obviating other studies.     

Normal anatomy and common labral lesions at MR arthrography of the shoulder

MR arthrography of the shoulder is the most accurate imaging modality in demonstrating abnormalities of the glenoid labrum and associated structures. Tears of the labrum, the capsule or the gleno-humeral ligaments can lead to pain, catching, popping or instability. The anatomy of this region is complex. We present the normal anatomy of the glenoid labrum, biceps anchor and gleno-humeral ligaments together with their normal variants and then describe common labral-ligamentous pathologies.     

MR imaging of lipoma arborescens and the associated lesions

Objective To describe the typical features of lipoma arborescens on MR imaging with pathologic correlation and to evaluate the associated lesions within the joints.Design and patients The MR imaging findings of 32 patients with the diagnosis of lipoma arborescens of the knee (n=32) and shoulder (n=1) were reviewed. The diagnosis of lipoma arborescens was confirmed by the histologic findings in 12 cases and the other 21 cases were diagnosed by the characteristic MR imaging features. One patient had bilateral lipoma arborescens of the knee joint.Results MR imaging showed a typical pattern of villous lipomatous proliferation of the synovium in all cases, as a diffuse pattern in 79% (26/33) of cases and as a dominant mass-like lesion in 21% (7/33) of cases. The associated MR pathology in the knee was (n=32): joint effusion (100%), degenerative changes (87%), meniscal tear (72%), synovial cysts (38%), bone erosions (25%), chondromatosis (13%), patellar subluxation (6%) and discoid meniscus (3%). In all cases except two there was associated pathology of the knee. MR imaging showed an associated rotator cuff tear in the lipoma arborescens of the shoulder.Conclusion The characteristic MR features of lipoma arborescens allows an accurate diagnosis of this rare lesion, which is almost always associated with other chronic pathology of the joint in the elderly.     

Frequency of glenoid chondral lesions on MR arthrography in patients with anterior shoulder instability

Purpose

To describe the frequency of glenoid chondral abnormalities in relation to Hill Sachs (HS) lesions in MR arthrograms of patients with anterior shoulder instability versus controls. Such glenoid lesions can directly impact surgical decision-making and approach, and potentially negatively impact outcome if missed.

Materials and methods

Retrospective analysis of direct MR shoulder arthrograms in 165 subjects, (101 with anterior instability/64 controls) was performed independently by 2 blinded musculoskeletal radiologists. Outcome measures were the presence of a HS, anterior labral pathology and glenoid chondral injury. Kappa statistic, Pearson Chi-square and Mann–Whitney analysis were employed for analysis.

Results

Inter-observer variability for the presence of HS, labral and chondral lesions was 0.964, 0.965 and 0.858 respectively, with intra-observer variability of 1.0, 0.985 and 0.861 for the principle reader. 58% of patients and 8% of controls had HS (p < 0.001). 72% of patients and 25% of controls had anterior labral injury (p < 0.001).36% of instability patients and 10% controls had glenoid chondral lesions (p < 0.001). 46% of anterior instability patients with HS defects had chondral injury as opposed to 21% of patients without HS defects (p = 0.009). Depth of the HS lesion did not increase the likelihood of a glenoid chondral lesion (p = 0.7335).

Conclusion

In the clinical anterior instability cohort, we demonstrated a statistically significant higher number of HS and glenoid chondral lesions than in controls. In anterior instability patients, the presence of a HS lesion confers a statistically significant greater likelihood of having a glenoid chondral lesion when compared to patients with instability and no HS.     

Biliary abnormalities associated with portal biliopathy: evaluation on MR cholangiography

OBJECTIVE: The purpose of our study was to evaluate the MRI features of portal biliopathy. CONCLUSION: MR cholangiography coupled with dynamic 3D gradient-echo imaging could not only detect portal vein occlusion, cavernous transformation, and gallbladder varices but is also suitable for delineating associated bile duct abnormalities.     

Superior labrum anterior-posterior lesions: diagnosis with MR arthrography of the shoulder

PURPOSE: To determine the accuracy of magnetic resonance (MR) arthrography in the diagnosis of superior labrum anterior-posterior (SLAP) lesions of the shoulder. MATERIALS AND METHODS: From January 1995 to June 1998, MR arthrography of the shoulder was performed in 159 patients with a history of chronic shoulder pain or instability. Fifty-two patients underwent arthroscopy or open surgery 12 days to 5 months after MR arthrography. Diagnostic criteria for SLAP lesion included marked fraying of the articular aspect of the labrum, biceps anchor avulsion, inferiorly displaced bucket handle fragment, and extension of the tear into the biceps tendon fibers. Surgical findings were correlated with those from MR arthrography. RESULTS: SLAP injuries were diagnosed at surgery in 19 of the 52 patients (37%). Six of the 19 lesions (32%) were classified as type I, nine (47%) as type II, one (5%) as type III, and three (16%) as type IV. MR arthrography had a sensitivity of 89% (17 of 19 patients), a specificity of 91% (30 of 33 patients), and an accuracy of 90% (47 of 52 patients). The MR arthrographic classification showed correlation with the arthroscopic or surgical classification in 13 of 17 patients (76%) in whom SLAP lesions were diagnosed at MR arthrography. CONCLUSION: MR arthrography is a useful and accurate technique in the diagnosis of SLAP lesions of the shoulder. MR arthrography provides pertinent preoperative information with regard to the exact location of tears and grade of involvement of the biceps tendon.     

MRI of HAGL lesions: four arthroscopically confirmed cases of false-positive diagnosis

OBJECTIVE: The purpose of this article is to present the cases of four consecutive patients with preoperative MR diagnosis of humeral avulsion of the glenohumeral ligament (HAGL) who had no evidence of HAGL at arthroscopy. CONCLUSION: These four cases suggest that the diagnosis of HAGL should be reserved for arthroscopy and illustrate the difficulty in distinguishing HAGL from other abnormalities of the inferior glenohumeral ligament complex with MRI. Thus, MRI findings classically associated with HAGL should be more broadly described as defects of the inferior glenohumeral ligament complex. This terminology more accurately describes the abnormalities of the inferior glenohumeral ligament complex that may be depicted by MRI.     

Femoral capital osteonecrosis: MR finding of diffuse marrow abnormalities without focal lesions

Six painful hips in five patients were examined with magnetic resonance (MR) imaging and were found to have diffuse signal abnormalities in the marrow of the femoral head and neck, which extended into the intertrochanteric area in five cases. The abnormal regions were low in signal intensity on images obtained with a short repetition time (TR) and a short echo time (TE) and were isointense or hyperintense on long TR/TE images--findings that have been attributed by others to bone marrow edema. Edema was also seen in marrow just above the acetabulum in two cases. No focal abnormalities characteristic of osteonecrosis were seen. Osteonecrosis was subsequently shown to be present in all six femoral heads at core biopsy (three cases) or by subsequent development of focal MR abnormalities reported to be highly specific for osteonecrosis (three cases). The affected hips had been radiographically normal or subtly osteopenic and had shown intense radionuclide uptake in the femoral head at scintigraphy, with lesser abnormality in the neck and intertrochanteric region. Follow-up MR examinations of five of the six femoral heads showed the diffuse abnormalities to have been transient. Although diffuse MR abnormalities in the proximal femur are not specific, they may indicate the presence of osteonecrosis of the femoral head.     

Open MR imaging of the unstable shoulder in the apprehension test position: description and evaluation of an alternative MR examination position

The aim of this study was to describe and evaluate an alternative MR assessment procedure for analysis of unstable shoulders. Twelve patients with unilateral recurrent anterior shoulder dislocation had both shoulders examined. Magnetic resonance imaging was performed with an open-MR system in the apprehension position with the shoulder in 90 degrees of abduction and maximum tolerable external rotation. Contrast enhancement was achieved with intravenous gadolinium. Correlations were made to the findings at operation. In 10 of 12 unstable shoulders the inferior glenohumeral ligament labral complex (IGHLLC) was detached from the glenoid as seen on MR and later verified during surgery. In one shoulder MR was unable to show a capsulolabral detachment that was verified at surgery, whereas in one shoulder both MR and surgical assessment revealed no soft tissue detachment (accuracy 92 %). A Hill-Sachs lesion was visualized and verified in all unstable shoulders, whereas the stable controls revealed normal IGHLLC and no Hill-Sachs lesion. Open-MRI evaluation of the shoulder in the apprehension test position may become a useful tool for the evaluation of anterior shoulder instability.     

Reversible cerebral lesions associated with tiazofurin usage: MR demonstration

Tiazofurin is an experimental chemotherapeutic agent currently undergoing clinical evaluation. We report our results with magnetic resonance (MR) in demonstrating reversible cerebral abnormalities concurrent with the use of this drug. The abnormalities on MR were correlated with findings on CT as well as with cerebral angiography. The utility of MR in the evaluation of patients receiving this new agent is illustrated.