Evaluation of articular cartilage thickness of the humeral head and the glenoid fossa by MR arthrography: anatomic correlation in cadavers

Objective. To evaluate the accuracy of MR arthrography in determining the thickness of articular cartilage of the humeral head and glenoid fossa. Design and patients. MR arthrography of the glenohumeral joint was performed in 17 cadaveric shoulders. Articular cartilage thickness was measured on the MR arthrographic images and corresponding anatomic sections. Results. The correlation coefficients for MR arthrographic measurement versus anatomic measurement of the cartilage thickness were 0.7324 and 0.8757 for humeral head and glenoid fossa, respectively. With regard to the humeral head, there was a tendency to overestimate regions of thin cartilage and underestimate regions of thick cartilage. This tendency was not found in the assessment of glenoid cartilage. The mean of the absolute value of MR-anatomic differences was similar on the glenoid side (0.27 mm) and the humeral side (0.29 mm). The accuracy of measurement was significantly better on the glenoid side (Fisher’s r-to-Z transformation: Z=5.21, P=0.000001). Conclusion. MR arthrography causes a moderate degree of error in the naked-eye measurement of the cartilage of the glenohumeral joint. The accuracy is higher on the glenoid side than on the humeral side.     

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.     

Internal derangements of the shoulder: decision tree and cost-effectiveness analysis of conventional arthrography, conventional MRI, and MR arthrography

Purpose. In a patient with internal derangement of the shoulder, the diagnostic method of choice is controversial. Conventional arthrography can diagnose most rotator cuff tears accurately; however, in many institutions MR arthrography is usually necessary to diagnose labral tears. We utilized decision tree methodology to compare the cost- effectiveness of conventional arthrography and conventional MRI with a hypothetical algorithm in which a patient underwent arthrography, performed with admixed gadolinium, which if negative, was followed by MRI. Design. The use of double-contrast arthrography alone, conventional MRI alone, and gadolinium-enhanced MRI used as an adjunct to conventional arthrography were modeled for the diagnosis of full-thickness rotator cuff tears (RCT), partial RCTs, labral tears, and the absence of cuff/labral tears using decision analysis methodology. English language medical publications were searched to determine the base probabilities for the accuracy of the diagnostic tests. The outcome utilities ranged from –1 to +1 to reflect the value of correct diagnostic evaluation. Charges for diagnostic tests and appropriate surgical treatments were based on 1997 Medicare reimbursement rates for professional fees and hospital charges in an outpatient setting. Sensitivity analyses were performed to evaluate the effects of uncertainty regarding the prevalence of each disease state and the accuracy of several diagnostic tests. Results. In the base-case analysis, the average effectiveness of double-contrast arthrography alone, MRI alone and arthrography selectively followed by MRI were 0.6610, 0.6715, and 0.7204, respectively. The average costs for each of these strategies were $1090, $2033, and $2339, respectively. Conclusion. Arthrography performed with admixed diluted gadolinium, which if negative is immediately followed by MRI, was somewhat more expensive than conventional MRI. However, because of much greater effectiveness, cost-effectiveness was significantly higher for our proposed algorithm. Conventional arthrography without gadolinium, although less expensive, had severely limited effectiveness. Received: 4 June 1999 Revision requested: 6 August 1999 Revision received: 30 August 1999 Accepted: 1 September 1999     

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.     

Glenohumeral joint instability

Due to the configuration of its bony elements, the glenohumeral joint is the most mobile joint of the body, but also an inherently unstable articulation. Stabilization of the joint is linked to a complex balance between static and dynamic soft tissue stabilizers. Because of complex biomechanics, and the existence of numerous classifications and acronyms to describe shoulder instability lesions, this remains a daunting topic for most radiologists. In this article we provide a brief review of the anatomy of the glenohumeral joint, as well as the classifications and the pathogenesis of shoulder instability. Technical aspects related to the available imaging techniques (including computed tomography [CT] arthrography, magnetic resonance imaging [MRI], and MR arthrography) are reviewed. We then describe the imaging findings related to shoulder instability, focusing on those elements that are important to the clinician.     

Utility of MR arthrography in the diagnosis of adhesive capsulitis

Objective. Arthrographically, adhesive capsulitis is characterized by decreased joint volume; histologically, the capsule and synovium are thickened. We therefore compared using MR arthrography the joint volumes and capsule/synovial thickness of patients with and without adhesive capsulitis in order to assess the utility of MR arthrography in diagnosing adhesive capsulitis. Design and patients. The 1.5 T MR arthrography images of 28 subjects with (n=9) and without (n=19) adhesive capsulitis were compared. Adhe- sive capsulitis was diagnosed when there was an injected glenohumeral joint volume of less than 10 ml. Two masked observers working in consensus assessed the images for the relative amount of fluid in the biceps tendon sheath and axillary recess, corrugation at the margin of the capsule, capsule/synovial thickness, abnormalities of the rotator interval capsule, and for the presence of a cuff tear. Results. There was a trend towards differences in capsular and synovial thickness (P>0.07) between the subjects with and without adhesive capsulitis; however, the controls had thicker synovium/capsules. Surprisingly, the amount of fluid in the axillary recess and biceps tendon sheath was not significantly different between the groups (P>0.25). There were more tears of the rotator cuff in controls than in patients with adhesive capsulitis (6, 3 vs 1, 1: complete, partial). Also, both corrugation (7 vs 0) and interval abnormalities (7 vs 0) were more common in the controls. Conclusion. There appear to be no useful MR arthrographic signs of adhesive capsulitis. Capsular/synovial thickness, static fluid volume, and the presence of corrugation are inconclusive as MR arthrographic signs for distinguishing shoulders with adhesive capsulitis from those without. Received: 1 June 2000 Revision requested: 11 September 2000 Revision received: 13 November 2000 Accepted: 27 November 2000     

Indirect wrist MR arthrography: the effects of passive motion versus active exercise

Purpose.In the wrist, to determine whether passive motion or active exercise yields a better indirect MR arthrographic effect following intravenous gadolinium administration. Design and patients. Twenty-six consecutive patients were studied by indirect wrist MR arthrography. In half active exercise and in half passive motion was performed. Four regions of interest were studied including the distal radioulnar joint, the radiocarpal joint, the midcarpal joint, and the triangular fibrocartilage. Ranges and means of signal intensity were calculated. Surgical follow-up was performed in 22 patients. Results. The joint fluid intensity was greatest in the distal radioulnar joint. Fluid signal intensity was greater and more consistent in the passive motion group although the results did not achieve statistical significance. Imaging accuracy appeared similar in the two groups and was excellent for the triangular fibrocartilage (100%) and scapholunate ligaments (96%). Conclusion. Active exercise and passive motion yield similar degrees of wrist arthrographic effect, but the effect of passive motion is somewhat more consistent. Preliminary data show good accuracy for internal derangements. Received: 4 June 1999 Revision requested: 6 August 1999 Revision received: 14 September 1999 Accepted: 20 September 1999     

Indirect MR arthrography of anterior shoulder instability in the ABER and the apprehension test positions: a prospective comparative study of two different shoulder positions during MRI using intravenous gadodiamide contrast for enhancement of the joint fluid

Objective. The value of MRI for the evaluation of anterior shoulder instability can be enhanced by shoulder positions that stress the stabilising structures. The ABER position is one that has been described in combination with intra-articular gadopentetate dimeglumine arthrography. We believe that MRI in the Apprehension test position with 90° abduction and maximal tolerable external rotation provides maximum tension on the anterior stabilising structures and with this technique it is sufficient to use indirect gadodiamide arthrography following intravenous injection of the contrast medium. The purpose of this study was to make a prospective comparative evaluation of the ABER and Apprehension test positions when using indirect arthrography with intravenous gadodiamide administration in shoulders with anterior instability. Design and patients. Sixteen patients with persistent anterior instability after recurrent shoulder dislocations were examined in an open MRI unit (0.2 T) following 0.1 mmol/kg of intravenous gadodiamide. Oblique axial T1-weighted imaging was used for analysis. Operative findings were used for correlation. Results. Both the ABER and the Apprehension test position were useful techniques in detecting capsulolabral pathology and Hill-Sachs lesions. The Apprehension test position produced significantly better gadodiamide-enhanced joint fluid in the region of pathology in both the capsulolabral lesion and the Hill-Sachs lesion. It also visualised the size of the Hill-Sachs lesion significantly better than did the ABER position. Conclusion. MRI examination of anterior shoulder instability in the Apprehension test position was more beneficial than examination in the ABER position in visualising capsulolabral and Hill-Sachs lesions when using indirect arthrography.     

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.     

Low-field MR arthrography of the shoulder joint: technique,indications, and clinical results

In the age of cost containment and urgent reductions in health care expenditures, new options have to be explored to satisfy both diagnostic requirements and economic limitations. The introduction of low-field MR systems for assessment of joint disorders seemed to be an option for lower costs. The purpose of this article is to summarize available experiences with low-field MR arthrography of the glenohumeral joint with respect to image quality and diagnostic accuracy in detecting labral and rotator cuff lesions. Up to now, there has been only a limited number of studies available dealing with low-field MR arthrography of the glenohumeral joint. They reveal that, despite a minor image quality in comparison with high-field imaging, low-field MR arthrography of the shoulder allows for sufficient evaluation of intra- and extra-articular structures in the detection of major abnormalities such as glenohumeral instability or rotator cuff disease. Furthermore, open-configured MR scanners enable kinematic studies: Besides the analysis of normal motion, pathological findings in patients with instabilities and impingement syndrome can be delineated. They further offer the possibility for performing MR imaging-guided arthrography of the shoulder. This was first described using an open C-arm scanner with a vertically oriented magnetic field so that MR arthrography may be performed in one setting. Electronic Publication     

Non-contrast MR imaging of the glenohumeral joint. Part II. Glenohumeral instability and labrum tears

MR imaging of the shoulder without contrast is frequently used for evaluation of glenohumeral instability in spite of the popularity of MR arthrography. With proper imaging technique, familiarity with normal anatomy and variants as well as knowledge of the expected pathologic findings high diagnostic accuracy may be achieved.Part I of this Review Article Non-contrast MR imaging of the glenohumeral joint: Normal anatomy appeared in the previous issue (Number 10/Oct. 2004). See also:     

Glenohumeral joint injection: a comparative study of ultrasound and fluoroscopically guided techniques before MR arthrography

To assess the variability in accuracy of contrast media introduction, leakage, required time and patient discomfort in four different centres, each using a different image-guided glenohumeral injection technique. Each centre included 25 consecutive patients. The ultrasound-guided anterior (USa) and posterior approach (USp), fluoroscopic-guided anterior (FLa) and posterior (FLp) approach were used. Number of injection attempts, effect of contrast leakage on diagnostic quality, and total room, radiologist and procedure times were measured. Pain was documented with a visual analogue scale (VAS) pain score. Access to the joint was achieved in all patients. A successful first attempt significantly occurred more often with US (94%) than with fluoroscopic guidance (72%). Leakage of contrast medium did not cause interpretative difficulties. With US guidance mean room, procedure and radiologist times were significantly shorter (p < 0.001). The USa approach was rated with the lowest pre- and post-injection VAS scores. The four image-guided injection techniques are successful in injection of contrast material into the glenohumeral joint. US-guided injections and especially the anterior approach are significantly less time consuming, more successful on the first attempt, cause less patient discomfort and obviate the need for radiation and iodine contrast.     

Labral-ligamentous complex of the shoulder. Evaluation with double oblique axial MR arthrography

Purpose: 
To assess the ability of double oblique axial (DOA) MR arthrography in evaluating labral-ligamentous complex compared with conventional axial (CA) MR arthrography. Material and Methods: 
MR arthrography of 51 shoulders, subsequently examined with arthroscopy, were retrospectively reviewed. DOA imaging was performed in all 51 shoulders and both DOA and CA imaging in 37 using a 1.5 T unit with gradient recalled-echo T2*-weighted sequences. DOA imaging was performed using perpendicular planes to the long axis of the glenoid fossa obtained by an oblique sagittal scout image. We compared the ability of DOA with that of CA MR arthrography to assess labral injuries and to demonstrate the whole length of the anterior band of the inferior glenohumeral ligament (AIGHL), which were shown to be intact by arthroscopy. Results: 
For anterior labral injuries, sensitivity and specificity were 87% and 93% with CA, and 94% and 100% with DOA imaging, respectively. For posterior labral injuries, sensitivity and specificity were 47% and 100% with CA, and 79% and 96% with DOA imaging, respectively. There were no statistically significant differences between CA and DOA images, except for the ability to diagnose posterior labral injuries, where DOA imaging had a significant superior sensitivity (p = 0.0327). DOA images also demonstrated the whole length of the intact AIGHL in 10 of 11 shoulders, while CA imaging showed this in only 3 of 11. Conclusion: 
DOA imaging was equal or better than CA imaging for evaluating the labral-ligamentous complex.     

Gradient-recalled echo sequences in direct shoulder MR arthrography for evaluating the labrum

Objective The purpose of this study was to determine the utility of fat-suppressed gradient-recalled echo (GRE) compared with conventional spin echo T1-weighted (T1W) sequences in direct shoulder MR arthrography for evaluating labral tears. Materials and methods Three musculoskeletal radiologists retrospectively reviewed MR arthrograms performed over a 12-month period for which surgical correlation was available. Of 180 serial arthrograms, 31 patients had surgery with a mean of 48 days following imaging. Paired coronal oblique and axial T1W or GRE sequences were analyzed by consensus for labral tear (coronal oblique two-dimensional multi-echo data image combination, 2D MEDIC; and axial three-dimensional double-echo steady-state, 3D DESS; Siemens MAGNETOM Sonata 1.5-T MR system). Interpretations were correlated with operative reports. Results Of 31 shoulders, 25 had labral tears at surgery. The GRE sequences depicted labral tears in 22, while T1W images depicted tears in 16 (sensitivity 88% versus 64%; p < 0.05). Subdividing the labrum, GRE was significantly more sensitive for the posterior labrum (75% versus 25%; p < 0.05) with a trend toward greater sensitivity at the anterior labrum (78% versus 56%; p = 0.157) but not significantly different for the superior labrum (50% versus 57%; p > 0.7). Specificities were somewhat lower for GRE. Conclusion Thin section GRE sequences are more sensitive than T1W for the detection of anterior and posterior labral tears. As the specificity of GRE was lower, it should be considered as an adjunctive imaging sequence that may improve depiction of labral tears, particularly smaller tears, in routine MR arthrography protocols. Preliminary results of this study were presented at the Annual Meeting of the Society of Skeletal Radiology, Orlando, FL, USA, on 21 March 2007.     

MR arthrography of the shoulder: Optimizing pulse sequence protocols for the evaluation of cartilage and labrum

Objectives

To compare axial T1weighted fat-saturated (T1w fs) and T1w non-fs sequences, and coronal T1w-fs and T2w-fs sequences, for evaluation of cartilage and labrum using CT arthrography (CTA) as the reference.

Methods

Patients had MR arthrography (MRA) and CTA of the shoulder on the same day. Cartilage was assessed for superficial and full thickness focal and diffuse damage. Labral lesions were graded for Bankart variants and SLAP lesions. CTA images were read for the same features. The diagnostic performance of MRA including area under the curve (AUC) was evaluated against CTA.

Results

When comparing axial sequences, the diagnostic performance for cartilage lesion detection on T1w non-fs was 61.9% (sensitivity) 93.6% (specificity) and 89.5% (accuracy) with AUC 0.782, while that for T1w fs was 61.9%, 94.0%, 89.8% and 0.783. For labral assessment, it was 89.1%, 93.0%, 91.4% and 0.919 for T1w non-fs, and 89.9%, 94.0%, 92.6% and 0.922 for T1w fs. Comparing coronal sequences, diagnostic performance for cartilage was 42.5%, 97.5%, 89.8% and 0.702 for T1w fs, and 38.4%, 98.7%, 90.2%, and 0.686 for T2w fs. For the labrum it was 85.1%, 87.5%, 86.2%, and 0.868 for T1w fs, and 75.7%, 97.5%, 80.8% and 0.816 for T2w fs.

Conclusions

Axial T1w fs and T1w non-fs sequences are comparable in their ability to diagnose cartilage and labral lesions. Coronal T1w fs sequence offers slightly higher sensitivity but slightly lower specificity than T2w fs sequence for diagnosis of cartilage and labral lesions.     

MR arthrography of the shoulder: comparison of low-field (0,2 T) vs high-field (1.5 T) imaging

The objective of this study was to compare the image quality, sensitivity, specificity, and diagnostic accuracy of an open low-field MR system (0.2 T) with a standard high-field MR system (1.5 T) after arthrography of the shoulder. Thirty-eight patients either with suspected chronic instability (n = 12) or rotator cuff abnormalities (n = 26) were examined. Intra-articular injection of diluted Gd-DTPA was followed in randomized order either first by imaging on an open 0.2-T system or on a 1.5-T system. The image material was evaluated independently by two radiologists in a blinded fashion with respect to overall image quality and the detection of rotator cuff as well as capsular and labral abnormalities. Surgical correlation was available in 27 (71 %) of 38 patients. For both systems, sensitivity and specificity for rotator cuff tears were 100 % each, and for labrum pathologies, these values were 100 and 93 %, respectively. The agreement for detection of labral pathologies between low-field and high-field examinations was good (ϰ = 0.69, ϰ = 0.61). For the detection of full-thickness tears of the rotator cuff, the agreement between the low-field and high-field MR examinations was very good and significant (ϰ = 0.94, ϰ = 1, p < 0.001). Overall image quality was rated good in 17 (45 %) and fair in 21 (55 %) of 38 cases on the 0.2-T MR system, and good in 32 (84 %) and fair in 6 (16 %) of 38 cases on the 1.5-T system. Motion artifacts were considered low in 24 (63 %) and moderate in 14 (37 %) of 38 cases for the 0.2-T system and low in 34 (89 %) and moderate in 4 (11 %) for 1.5-T system. Based on our results, low-field MR compares favorably to high-field MR in the detection of major abnormalities of the glenohumeral joint, at least when MR arthrography is used. Disadvantages are the duration of the examination and thus the risk of reduced image quality caused by motion artifacts. Received: 14 July 1999; Revised: 27 December 1999; Accepted: 27 December 1999     

Indirect MR arthrography of the shoulder in detection of rotator cuff ruptures

The aim of this study was to compare the efficacy of indirect MR arthrography images obtained following intravenous contrast injection and conventional MR imaging in the diagnosis of rotator cuff tears. Twenty-four patients with clinically suspected rotator cuff disease were examined. Conventional MR images and post-contrast indirect MR arthrography images were obtained. All images were evaluated in a blinded fashion by two musculoskeletal radiologist. Results were than analyzed depending on surgical output. The correlation coefficient (Spearman rank correlation test) and the kappa values for agreement between surgery and imaging techniques were calculated. The correlation coefficients between indirect MR arthrography and surgery for reader 1 and reader 2 were 0.9137 and 0.9773, respectively. Whereas the agreement between conventional MR imaging and surgery was moderate (ϰ = 0.383–0.571), the agreement between indirect MR arthrography and surgery was excellent (ϰ = 0.873–0.936). We suggest the use of indirect MR arthrography technique when conventional MR images are equivocal in diagnosis of rotator cuff disease. Received: 12 April 2000/Revised: 22 May 2000/Accepted: 23 May 2000     

MR arthrographic findings in tenosynovitis of the long bicipital tendon of the shoulder

 Purpose. To assess the MR arthrographic findings of bicipital tenosynovitis in correlation with arthroscopy. Design and patients. The shoulder MR arthrographies of 500 consecutive patients were retrospectively analyzed for signs of bicipital tenosynovitis and associated pathologies. Forty patients (8%) had MR evidence of bicipital tenosynovitis, but only 17 (3%) with arthroscopic confirmation were included in the study. The MR findings in these patients were compared with those of 10 patients with rotator cuff lesions but arthroscopically normal long biceps tendons. MR arthrography was performed with 10–15 ml of a 250 mmol/l gadoterate meglumine (Gd-DOTA) solution injected under fluoroscopic guidance, and transaxial, oblique coronal and sagittal MR sequences were obtained. Results. All 17 patients showed one or more abnormal findings: signal increase in the tendon with or without fusiform distension was seen in 12, surface irregularities in six, adhesions in 11 and noncommunicating effusions of the tendon sheath in six. Associated abnormalities of the rotator cuff were present in 16 while the seventeenth patient had glenohumeral synovitis without rotator cuff pathology. MR arthrograms correlated with arthroscopic findings in the joint but comparison was not possible in the intertubercular groove portion of the biceps tendon. None of the 10 patients with an arthroscopically normal biceps tendon showed any of the MR findings of bicipital tenosynovitis. Conclusion. Bicipital tenosynovitis is detectable by MR arthrography. In most cases it is an associated finding of rotator cuff abnormalities and likely to have a similar etiology. When lesions of the anterior rotator cuff are recognized, the biceps tendon should be scrutinized for inflammatory changes.     

Supraspinatus tendon tears: comparison of US and MR arthrography with surgical correlation

The aim of this study was to compare the diagnostic reliability of US with MR arthrography in diagnosing supraspinatus tendon tears. Surgical findings were used as the gold standard in detecting tears. A total of 44 patients were assessed with transverse and longitudinal US scans with respect to the long axis of the rotator cuff tendons and then examined with MR arthrography. This technique involved free-hand injection of contrast medium into the shoulder joint. At surgery 20 incomplete and 24 complete tears were observed. Ultrasound offered good results for the large tears, but its sensitivity decreased proportionally with the size of the tears. Magnetic resonance arthrography correctly diagnosed 43 tears, whereas only one false-negative diagnosis of tendinosis was made for a partial tear on the bursal side. Since it improves the diagnosis of small tears, MR arthrography must be performed on all patients for whom surgical repair is necessary in order to restore normal functions.     

MR imaging in sports-related glenohumeral instability

Sports-related shoulder pain and injuries represent a common problem. In this context, glenohumeral instability is currently believed to play a central role either as a recognized or as an unrecognized condition. Shoulder instabilities can roughly be divided into traumatic, atraumatic, and microtraumatic glenohumeral instabilities. In athletes, atraumatic and microtraumatic instabilities can lead to secondary impingement syndromes and chronic damage to intraarticular structures. Magnetic resonance (MR) arthrography is superior to conventional MR imaging in the diagnosis of labro-ligamentous injuries, intrinsic impingement, and SLAP (superior labral anteroposterior) lesions, and thus represents the most informative imaging modality in the overall assessment of glenohumeral instability. This article reviews the imaging criteria for the detection and classification of instability-related injuries in athletes with special emphasis on the influence of MR findings on therapeutic decisions.