Iliotibial band friction syndrome: MR imaging findings.

Six patients with clinical histories and physical examination results consistent with iliotibial band friction syndrome (ITBFS) were examined with magnetic resonance (MR) imaging. Ill-defined decreased signal intensity on T1-weighted images and increased signal intensity on T2-weighted images was present deep to the iliotibial band, adjacent to the lateral femoral epicondyle. Axial fast imaging with steady-state precession (FISP) gradient-echo sequences were essential in differentiating the ill-defined signal intensity abnormality associated with ITBFS from fluid in the lateral knee joint. None of these patients were found to have lateral meniscal tears, and all responded to conservative measures directed at treating ITBFS. The authors conclude that MR imaging may be useful in confirming or establishing the diagnosis of ITBFS in patients with the appropriate clinical history and distal lateral thigh or lateral knee pain.     

Comparison of conventional and computed arthrotomography with MR imaging in the evaluation of the shoulder

To compare conventional arthrography and computed arthrotomography (CAT) with magnetic resonance (MR) imaging in the evaluation of the shoulder, we studied 18 patients who underwent conventional double contrast arthrography and CAT, and T1-, balanced, and T2-weighted MR imaging. The arthrograms were independently reviewed by two of the authors and the MR images were independently reviewed by three other authors in a systematic fashion with the aid of a prewritten evaluation form. The findings were compared among reviewers and between imaging methods. We found MR comparable to conventional arthrography in the evaluation of the rotator cuff; however, MR also enabled evaluation of tendonitis, which could not be accomplished with conventional arthrography. Because of MR's superior soft tissue imaging capability, we were able to stage the impingement syndrome. Magnetic resonance also allowed evaluation of the glenoid labrum and capsuloligamentous structures and assessment of instability in a fashion similar to CAT. In most cases, information obtained from MR equaled or exceeded that obtained from conventional arthrography and CAT. With refinement in technique and increased experience, we believe that MR may replace arthrography in the evaluation of the shoulder.     

Normal and degenerated intervertebral disk: in vivo and in vitro MR imaging with histopathologic correlation

The components of the intervertebral disk serve two purposes. The hydrophilic matrix is contained by circumferential rings of fibrocartilage (outer anulus) and Sharpey's fibers. The gellike hydrophilic matrix acts as a cushion between the vertebral body endplates by providing an even distribution of axial and rotational compressive forces. The construction and integrity of the intervertebral disk are assessed well by MR. The purpose of this pictorial essay is to show the in vitro and in vivo MR appearances of the normal and degenerated disk, and to correlate these MR changes with their respective histopathologic findings.     

Magnetic resonance imaging of the shoulder. Sensitivity, specificity, and predictive value

The sensitivity, specificity, and predictive value of magnetic resonance imaging in the diagnosis of lesions of the rotator cuff, glenohumeral capsule, and glenoid labrum were evaluated in ninety-one patients and fifteen asymptomatic volunteers. Magnetic resonance imaging demonstrated 100 per cent sensitivity and 95 per cent specificity in the diagnosis of complete tears, and it consistently predicted the size of the tear of the rotator cuff. There was a definite correlation between atrophy of the supraspinatus muscle and the size of a complete, chronic tear of the rotator cuff. The sensitivity and specificity of magnetic resonance imaging in the differentiation of tendinitis from degeneration of the cuff were 82 and 85 per cent, and in the differentiation of a normal tendon from one affected by tendinitis with signs of impingement the sensitivity and specificity were 93 and 87 per cent. The formation of spurs around the acromion and acromiocalvicular joint correlated highly with increased age of the patient and with chronic disease of the rotator cuff. The sensitivity and specificity of magnetic resonance imaging in the diagnosis of labral tears associated with glenohumeral instability were 88 and 93 per cent. The study showed that high-resolution magnetic-resonance imaging is an excellent non-invasive tool in the diagnosis of lesions of the rotator cuff and glenohumeral instability.     

The use of magnetic resonance imaging in the evaluation of bone and soft-tissue tumors

We believe that MR imaging should follow plain films in the imaging analysis of soft-tissue tumors and bone tumors suspected of malignancy. MR imaging is primarily useful in tumor staging, although it may aid in diagnosis and the detection of recurrent or residual disease. Gd-DTPA and MR spectroscopy are currently being evaluated in many medical centers; their utility in the work-up and management of tumors of bone and soft tissue has yet to be determined.     

Combined MR imaging and spectroscopy of bone and soft tissue tumors

Twenty-three patients with bone and soft tissue tumors were studied with combined magnetic resonance (MR) imaging and spectroscopy. The MR examinations were utilized to determine the size, internal characteristics, and relationships of the tumor to the surrounding tissues. They also determined the optimal placement of the surface coil. The surface coil profile was the localization technique utilized. Four patients were also studied with one-dimensional chemical shift localization. Tumors were grouped according to histologic type, degree of muscle contamination, size, and extent of necrosis. Quantitative comparison among the groups was carried out by comparing the mean ratios of the low-energy phosphate portion of the spectra [phosphomonoester (PME), Pi, phosphodiester (PDE)] to beta-nucleotide triphosphate (NTP). Tumor spectra typically showed a relative elevation in PME, Pi, and PDE and a relative decrease in phosphocreatinine. No characteristic spectra were observed for individual tumor types. Contamination of the tumor spectra from surrounding muscle impaired interpretation of the spectral data. Tumor size and extent of necrosis were important determinants of the relative degree of abnormally elevated metabolite peaks (PME, Pi, PDE). A trend toward a higher mean PME/beta-NTP ratio was observed among high-grade lesions. Combined MR imaging and spectroscopy is a useful way to study tumor metabolism. Muscle contamination is a significant problem in analysis of the spectra. Better localization techniques are required.     

Patterns of femoral head migration in osteoarthritis of the hip: a reappraisal with CT and pathologic correlation

Although medial, superior, and axial patterns of migration of the femoral head in osteoarthritis of the hip have been well described, it is not clear what anatomic and biomechanical factors determine the direction of migration. The authors studied 22 patients with bilateral (11 patients) or unilateral (11 patients) osteoarthritis by means of conventional radiography and computed tomography (CT) to define any relationships between migration in the coronal plane and that in the transverse plane and to determine whether femoral anteversion, acetabular anteversion, femoral neck-shaft angle, or acetabular inclination were related to particular migration patterns. Anterior migration was evident in 14 of the 19 hips with a superior migration pattern, whereas posterior migration was present in five of the seven hips with a medial migration pattern. In the remainder of cases, no migration in the transverse plane was present. Femoral anteversion as determined with CT, femoral neck-shaft angle, angle of acetabular inclination, and acetabular anteversion angle in this relatively small sample were all found to be within normal limits and appeared to have no influence on the occurrence of a specific pattern of femoral head migration.