Accuracy of T2-weighted fast spin-echo MR imaging with fat saturation in detecting cartilage defects in the knee: comparison with arthroscopy in 130 patients.

OBJECTIVE: The purpose of this study was to assess the accuracy of routine T2-weighted MR imaging in detecting and grading articular cartilage lesions in the knee compared with arthroscopy. SUBJECTS AND METHODS: We examined 130 consecutive patients who underwent MR imaging and arthroscopy of the knee for suspected internal derangement. MR imaging consisted of axial and coronal T2-weighted fast spin-echo sequences with fat saturation and sagittal T2-weighted spin-echo sequences. Each single plane was evaluated and graded for the presence and appearance of articular cartilage defects using a standard arthroscopic grading scheme adapted to MR imaging. RESULTS: Of the 86 arthroscopically proven abnormalities, 81 were detected on MR imaging. Sensitivity of the T2-weighted fast spin-echo sequence with fat saturation was 61% for the coronal plane alone and 59% for the axial plane alone. Specificity for each plane was 99%. Sensitivity for the sagittal T2-weighted spin-echo sequence was 40%, and specificity was 100%. Sensitivity of the combination of axial and coronal T2-weighted fast spin-echo sequences with fat saturation and sagittal T2-weighted spin-echo sequence compared with arthroscopy for revealing cartilage lesions was 94%, specificity was 99%, and accuracy was 98%. Sensitivity of coronal and axial T2-weighted fast spin-echo sequences with fat saturation was 93%, and specificity was 99%. Fifty-five lesions (64%) were identically graded on MR imaging and arthroscopy. Seventy-eight lesions (90%) were within one grade using MR imaging and arthroscopy, and 84 lesions (97%) were within two grades using MR imaging and arthroscopy. CONCLUSION: T2-weighted fast spin-echo MR imaging with fat saturation is an accurate and fast technique for detecting and grading articular cartilage defects in the knee. The combination of the axial and coronal planes offers sufficient coverage of articular surfaces to provide a high sensitivity and specificity for chondral defects.

Tear of the posterior shoulder stabilizers after posterior dislocation: MR imaging and MR arthrographic findings with arthroscopic correlation.

OBJECTIVE: The purpose of this article is to describe the findings on MR imaging and MR arthrography in posterior capsular tear and teres minor muscle injury after posterior dislocation. We also correlate MR imaging with the arthroscopic findings and present treatment options for these patients. CONCLUSION: MR imaging is helpful in diagnosing abnormalities caused by posterior dislocation injuries and in directing therapy. Teres minor muscle and capsular injuries may occur without the typical reverse Bankart lesion. Isolated teres minor muscle tears seen on MR imaging after posterior dislocation injury may cause pain. However, no consensus exists as to whether the lesions seen on MR images in these patients should be treated surgically or conservatively.

A practical approach to imaging of the shoulder with emphasis on MR imaging.

Our understanding of shoulder disorders has changed considerably as a result of improved diagnostic tools, such as arthroscopy and multiplanar imaging modalities. The diagnosis of the cause of shoulder pain can be difficult because a spectrum of disorders, including cervical spine disease, acromioclavicular arthritis, and shoulder instability. Impingement and denervation syndromes can present with similar clinical findings. Accurate depiction of anatomic abnormalities is important for treatment planning. The purpose of this article is to report on the application of available imaging modalities, with emphasis on MR imaging. A strategy for the appropriate use of these studies and their variations of technique is also provided.

Using abduction and external rotation of the shoulder to increase the sensitivity of MR arthrography in revealing tears of the anterior glenoid labrum.

OBJECTIVE: The purpose of this study was to compare oblique axial MR arthrograms obtained with the patient's shoulder in abduction and external rotation (ABER) position with conventional axial MR arthrograms obtained with the patient's arm in neutral position and the shoulder not rotated in revealing tears of the anterior glenoid labrum (AGL). SUBJECTS AND METHODS: MR arthrography of the shoulder that included an additional oblique axial imaging sequence with the patient in the ABER position was performed in 256 patients. Assessment of AGL integrity with patients in both conventional axial and ABER positions was made before surgery. These assessments were compared with the surgical findings. RESULTS: Of the 92 patients who underwent surgery, AGL tears were found in 27. Conventional axial MR arthrograms revealed 13 tears (sensitivity, 48%; specificity, 91%). A separate review of MR arthrograms obtained with patients in the ABER position revealed 24 tears (sensitivity, 89%; specificity, 95%). Reviewed together, axial MR arthrograms and MR arthrograms obtained with patients in the ABER position revealed 26 tears (sensitivity, 96%; specificity, 97%). CONCLUSION: Oblique axial MR arthrograms obtained with the patient's shoulder in the ABER position were significantly more sensitive in revealing AGL tears (p = .005) than were conventional axial MR arthrograms obtained with the patient's aim in a neutral position and the shoulder not rotated.

Posterosuperior glenoid impingement of the shoulder: findings at MR imaging and MR arthrography with arthroscopic correlation.

PURPOSE: To determine the utility of magnetic resonance (MR) imaging and MR arthrography in the evaluation of arthroscopic findings of posterosuperior glenoid impingement. MATERIALS AND METHODS: The findings at MR imaging, MR arthrography, and physical examination with the patient under anesthesia were retrospectively reviewed in eight patients with arthroscopic evidence of posterosuperior glenoid impingement. RESULTS: All patients had shoulder pain; anterior instability was found in six patients. Other than bone marrow abnormalities, findings at MR imaging were not reliable for the detection of posterosuperior glenoid impingement. MR arthrography was superior to routine MR imaging in all four cases in which it was done; positioning the shoulder in abduction and external rotation was beneficial in three of four patients. CONCLUSION: Impingement of the rotator cuff on the posterior superior glenoid labrum is a cause of posterior shoulder pain in athletes who throw. MR arthrography may allow detection of abnormalities associated with this clinical entity.

MR arthrographic depiction of tears of the rotator cuff: benefit of abduction and external rotation of the arm.

PURPOSE: To show the effectiveness of positioning the arm in abduction and external rotation (ABER) during magnetic resonance (MR) arthrography for depiction of tears of the rotator cuff. MATERIALS AND METHODS: Five throwing athletes with shoulder pain were prospectively imaged with standard MR imaging, MR arthrography, and ABER MR arthrography. The status of the rotator cuff was recorded; arthroscopic correlation was obtained. RESULTS: One partial tear of the distal infraspinatus tendon was detected with ABER MR arthrography only. One full-thickness tear was detected with both MR arthrography and ABER MR arthrography, but the component of the tear that extended into the infraspinatus tendon was depicted with ABER MR arthrography only. One partial tear was detected with both MR arthrography and ABER MR arthrography; no additional information was provided by either technique alone. CONCLUSION: The ABER position may be useful in detection and characterization of tears of the rotator cuff, especially partial tears of the undersurface. This information would be useful in selection of patients for conservative therapy, arthroscopy, or arthrotomy.