Diagnosing intracranial vasculitis: the roles of MR and angiography.

PURPOSE: To describe our experience with MR and angiography in diagnosing intracranial vasculitis and to test the hypothesis that MR can be used to screen for patients unlikely to have vasculitis. METHODS: Ninety-two patients who had angiography with "exclude vasculitis" as the indication or who had angiography and a clinical diagnosis of vasculitis were identified. Angiograms of all 92 patients and the MRs of the 70 patients who had both studies were reviewed. RESULTS: Eleven patients had intracranial vasculitis. Angiography showed characteristic changes in 8. MR, performed in 9 of 11 vasculitis cases, was significantly abnormal in all 9. Among 70 patients who had both studies, 19 had MR that was completely normal or showed only incidental findings. None of these 19 was diagnosed with vasculitis. The diagnostic yield of angiography performed to exclude vasculitis was only 6%. CONCLUSIONS: Evaluation for intracranial vasculitis should include MR. A negative MR excludes intracranial vasculitis more definitively than does a negative angiogram and makes the likelihood of finding vasculitis with angiography negligible.

Vertebral compression fractures: distinction between benign and malignant causes with MR imaging.

Magnetic resonance (MR) imaging was performed on 64 patients with 109 vertebral compression fractures, the cause of which could not be determined from plain radiographs. Twenty-five fractures were due to malignancy; 84 were caused by a benign process. In 22 of the 25 fractures caused by malignancy, MR images showed complete replacement of normal bone marrow, whereas 47 of the 61 benign fractures without history of trauma had complete preservation of normal bone marrow. The remaining 14 benign fractures had incompletely preserved bone marrow in a regular pattern. In two of the three remaining malignant fractures, the bone marrow replacement also was incomplete but with an irregular pattern. In cases of recent trauma or primary bone marrow abnormalities, the configuration and signal of remaining bone marrow were not useful in differentiating among malignancy, osteoporosis, and other benign processes. When criteria based on complete loss or preservation of marrow and marrow configuration in cases of incomplete loss were used, the accuracy in differentiating benign from malignant fractures was 94%. MR imaging may be a useful adjunct in differentiating benign from metastatic fractures and may provide information not available with other imaging methods.

Magnetic resonance imaging in the diagnosis and followup of idiopathic retroperitoneal fibrosis.

Four cases of idiopathic retroperitoneal fibrosis are reported. Magnetic resonance and computerized tomographic images were obtained for diagnosis in each case, and followup scans were obtained at various intervals after therapy. In all 4 cases magnetic resonance imaging was equal or superior to computerized tomography in the diagnosis of retroperitoneal fibrosis, outlining the extent of involvement, preoperative planning and assessing response to medical or surgical therapy.

Partial lipodystrophy. Magnetic resonance findings in one case.

The magnetic resonance findings in a patient with acquired partial lipodystrophy are described. Adipose tissue in a variety of locations, including the retroperitoneum and bone marrow, is well demonstrated by magnetic resonance in several anatomic planes. Magnetic resonance may provide complementary information to clinical findings in evaluation of patients with partial lipodystrophy.