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Objective: The purpose of this study was to assess the performance of a near-isotropic 3D turbo spin-echo sequence in comparison with a standard 2D protocol and with arthroscopy in direct 1.5-T MR arthrography of the shoulder., Subjects and Methods: Dilute gadolinium was injected into three cadaver shoulders, and 3D turbo spin-echo and 2D sequences were evaluated with respect to the signal-to-noise and contrast-to-noise ratios of key tissues. In a prospective study, the 3D intermediate-weighted fat-suppressed sequence (reformatted in three planes) was added to shoulder MR arthrography of 43 consecutively registered patients, 13 of whom later underwent arthroscopy. Two radiologists independently graded the 3D and 2D images in separate sessions to visualize normal anatomic features and to detect pathologic changes in the labrum, cartilage, cuff, and glenohumeral ligaments, assigning confidence levels to their readings. One reader repeated the readings of images of 10 patients. Reports of subsequent arthroscopy were available for 13 patients., Results: The sequences performed comparably with respect to signal-to-noise and contrast-to-noise ratios in the cadavers. The 3D images suffered from mildly increased blurring, but the readers were significantly more confident in assessing the proximal biceps tendon and curved portions of the labrum and in their findings of partial tears of the articular side of the supraspinatus tendon and posterior labral tears on the 3D images. A larger number of partial-thickness cartilage defects were found on 2D images., Conclusion: The 3D turbo spin-echo sequence is a promising technique that can be used in shoulder arthrography with image quality and results comparable to those of traditional 2D techniques. Use of the 3D technique may result in greater anatomic detail in evaluating small obliquely oriented structures, including the curved portions of the labrum and the intraarticular portion of the biceps tendon.

Objective: Our purpose was to describe the appearance of the acetabular capsular-labral complex on MR arthrography and to correlate this appearance with surgical findings in adult patients and with gross anatomic findings in cadavers., Subjects and Methods: MR arthrography of the hip joint was performed in 40 patients and six cadavers. All patients underwent subsequent arthrotomy of the hip. MR arthrography consisted of a T1-weighted three-dimensional gradient-echo sequence in both the coronal oblique and sagittal oblique planes after intraarticular injection of a 2 mmol/l solution of gadopentetate dimeglumine. The normal and pathologic appearance of the capsular-labral complex was assessed, and the labra were evaluated on the basis of morphology, signal intensity, presence of a tear, and attachment to the acetabulum. MR arthrography findings were correlated with the surgical results in all patients and with the anatomic sections of the cadaveric hip joint specimens., Results: MR arthrography images of the T-weighted three-dimensional gradient-echo sequences allowed visualization of the anatomic structures. The normal labrum was triangular, without any sublabral sulcus, and of homogeneous low signal intensity. A recess between the labrum and the joint capsule could be identified in instances in which no thickened labrum was present. Labral lesions included labral degeneration, a tear, or a detached labrum either with or without thickening of the labrum. The sensitivity for detection and correct staging of labral lesions with MR arthrography in the patient study was 91%; the specificity, 71%; and the accuracy, 88%., Conclusion: MR arthrography with T1-weighted three-dimensional gradient-echo sequences allows excellent assessment of the normal and pathologic acetabular capsular-labral complex.

Objective: The purpose of this study was to subjectively compare the visibility of normal anatomy of the hands and feet using selenium-based digital radiography versus conventional film-screen (100-speed) radiography., Subjects and Methods: Digital and film-screen images of the hands and feet of 24 patients were obtained without an antiscatter grid using identical X-ray exposure. Each pair of images was evaluated independently by five experienced radiologists for visibility of normal anatomy using a six-point rating scale. Soft tissues, cortical bone, and trabeculae were evaluated. For each observer, "equivalence" was defined as a mean difference in image quality of less than 1 unit on the 0-5 scale used in the study. Paired t tests were also performed to determine whether the average visibility rating of one technique was statistically superior to that of the other at a .05 level of significance for each observer and at each anatomic landmark., Results: In all categories, selenium-based digital images were rated equivalent to film-screen images by the five observers. Using the sum of the nine landmarks, four of the five observers rated the quality of selenium-based digital images superior to that of film-screen images., Conclusion: Subjective visibility of normal anatomy of the hands and feet using selenium-based digital radiography was similar to that achieved using conventional film-screen radiography.

Objective: MR imaging is not routinely used for evaluation of tophaceous gout. However, gout may present clinically in an atypical, unusual, or confusing manner. A gouty tophus occasionally mimics an infectious or neoplastic process, and MR imaging may be obtained under these circumstances. The purpose of this study was to determine the MR imaging characteristics of intraosseous and soft-tissue tophi., Materials and Methods: We identified 13 MR imaging examinations performed during a 27-month period on nine patients with gouty arthritis. All were men 42-70 years old. T1-, proton density-, and T2-weighted spin-echo MR images were obtained for all the examinations. Nine examinations included contrast-enhanced MR images. The findings were then evaluated, as were the corresponding radiographs., Results: Five patients presented with articular involvement, three patients with an isolated soft-tissue mass, and one patient with persistent soft-tissue swelling. The duration of symptoms ranged from 3 months to more than 20 years. Nearly all the tophi were of intermediate signal intensity on T1-weighted images. On T2-weighted images, three sites revealed an overall increase in the signal intensity of the tophi, whereas 10 studies showed a heterogeneous decrease in signal intensity. All but one tophus showed homogeneous enhancement. Erosion of adjacent bone, synovial pannus, joint effusion, soft-tissue edema, and bone marrow edema were common associated findings., Conclusion: The MR appearance of tophi in patients with tophaceous gout is constant on T1- but quite variable on T2-weighted images. This variability in signal intensity could be related to calcium within a tophus. Tophaceous gout should be considered in the differential diagnosis when a mass reveals heterogeneously low to intermediate signal intensity, particularly if the adjacent bone shows typical erosive changes or if other joints are involved. When faced with this situation, radiologists may find it helpful to obtain a further clinical history and recommend evaluating the patient's serum urate level.

Objective: A localized form of anterior arthrofibrosis, the so-called cyclops lesion, has recently been reported to be a significant cause of loss of knee extension after reconstruction of the anterior cruciate ligament (ACL) of the knee. The purpose of this study was to characterize the MR appearance of this lesion., Subjects and Methods: Five patients who had arthroscopic verification of a focal nodule of fibrous tissue in the intercondylar notch anterior to the reconstructed ACL (the cyclops lesion) and who had an MR examination after ACL reconstruction but before repeat arthroscopy and excision of the cyclops lesion were included in this study. The MR images were evaluated for the presence of soft tissue in the intercondylar notch anterior to the reconstructed ACL. If present, this tissue was graded as 1, 2, or 3, depending on its anterior extent along the femoral condyle., Results: MR images of all five patients showed abnormal soft tissue with signal characteristics consistent with fibrous tissue anterior to the reconstructed ACL in the intercondylar notch. The abnormal tissue was grade 2 or 3 in all patients., Conclusion: MR imaging shows soft tissue with signal characteristics consistent with fibrous tissue anterior to the reconstructed ACL in the intercondylar notch in patients with localized anterior arthrofibrosis. Although the sensitivity and specificity of MR imaging for the cyclops lesion are yet to be determined, visualization of such fibrous tissue on MR images in a patient with clinical symptoms suggestive of localized anterior arthrofibrosis may be helpful in confirming the diagnosis.

Advances in surgical and pharmacologic techniques for treating and preventing chondral abnormalities are creating a demand for an accurate, noninvasive imaging method to evaluate articular cartilage. The most promising technique is MR imaging, but its exact role in this evaluation remains undefined. This article reviews the MR appearance of normal and abnormal articular cartilage and the various pulse sequences that can be used to evaluate chondral lesions. It also briefly discusses possible future directions for MR imaging of articular cartilage.