MRI criteria of developmental lumbar spinal stenosis revisited.

PURPOSE: It is somewhat surprising that radiographic criteria for lumbar stenosis have been transposed from radiography and CT to MR without scientific validation. As these radiographic criteria were developed via population studies with criteria defined by two standard deviations from the mean, we sought to perform the same methodology via MR. METHODS: The study was approved by the institutional review board; the requirement for informed consent was waived. One-hundred patients referred for possible metastatic disease, aged 4 to 94 were studied. Measurements were obtained on a midline sagittal T2-weighted (6000/120) image at each disc level, as well as at the mid-vertebral level. The distributive mean, and standard deviations were calculated and -2 SD was used as a "cutoff" for spinal stenosis. To assess for interobserver variation, 20% of the measurements were repeated by a second observer. To assess for intraobserver variation, another 20% of the measurements were repeated a second time at a minimum of a two month interval. RESULTS: The spinal canal was narrowest at L5-S1 (mean: 1.16 cm), and widest at L1-L2 (mean: 1.56 cm). Overall the narrowest measurements were at the intervertebral disc space and were narrower at the lower disc spaces. In our population, the lowest cutoff limit (two standard deviations below the mean) had a range between 0.38 cm at the L3-L4 disc space and 0.9 cm at the L1 vertebral level. Notably at the L3 level the size range was from 0.77 to 1.75 CONCLUSION: Traditional measurements of canal diameters may be too large when applied to soft tissue analysis on MR. We suggest using a cutoff of smaller than 0.90 cm for developmental stenosis.

The appearance of Mazabraud's syndrome on 18F-FDG PET/CT.

Mazabraud's syndrome is a rare disorder, the main characteristics of which are fibrous dysplasia of bone associated with intramuscular myxomas. The metabolic characteristics of intramuscular myxomas, associated with fibrous dysplasia, have not previously been described with 18F-FDG-PET. Our case demonstrates that there is low, but not insignificant uptake associated with these intramuscular myxomas, with a standardized uptake value (SUV) range between 1.3 and 2.6. As such, this entity merits consideration when evaluating hypoattenuating intramuscular masses, particularly in the context of fibrous dysplasia.

MR imaging of the normal hip.

This article reviews the complex normal anatomy of the hip joint and its surrounding structures on MR imaging, including MR arthrography.Thorough knowledge of the normal appearance of the marrow and osseous and articular anatomy as well as the ligaments, tendons, and surrounding muscles of the hip is essential for imaging diagnosis.

MR imaging of the diabetic foot: diagnostic challenges.

Pedal complications of diabetes have long presented a challenge for the clinician and radiologist predominately related to the difficulty in distinguishing infection from neuroarthropathy. The spectrum of diabetic foot infections is broad, ranging from callous and ulcer formation, to septic arthritis, abscess formation, and osteomyelitis. This article summarizes the MR imaging findings in the diabetic foot and the optimal pulse sequences. Focus is placed on aids in differentiating diabetic infection from other entities and increasing the specificity of diagnosing diabetic foot complications.

MR imaging findings in African trypansomiasis.

We report the initial and follow-up brain findings in a 42-year-old male patient with CNS involvement with African trypansomiasis. Initial MR imaging demonstrated diffuse hyperintensity in the basal ganglia bilaterally as well as involvement of the internal capsule, external capsule, and extreme capsule. Follow-up examination at 1 year revealed decreased signal intensity in the previously affected areas; however, ventricular enlargement indicative of atrophy was readily apparent.