FIG 1. Three serial MR imaging studies obtained during a period of 18 days. Images were obtained by the fluid-attenuated inversion recovery (FLAIR) sequences, with the exception of columns 4 and 6, which were obtained by the postgadolinium T1-weighted sequence. The initial study (top row) revealed a few nonspecific white matter lesions that were thought to be related to cyclosporine toxicity.

The lesions were not seen on noncontrast T1-weighted images or diffusion-weighted images (not shown). After gadolinium administration, lesions were nonenhancing, except for the left parietal-occipital lesion, which shows faint, questionable enhancement. Because of neurologic deterioration, brain MR imaging was repeated (middle row) 6 days after the initial study, revealing worsening lesions in the subcortical white matter, cerebellum, bilateral thalamus, and basal ganglia, with no mass effect or abnormal parenchymal enhancement; there was possibly some increased leptomeningeal enhancement. During the following week, the patient became progressively obtunded and comatose. A third MR imaging study obtained 18 days after the initial study (bottom row) showed continuous progression of lesions in size and distribution, which at this time involved much of the brain. There was a remarkable lack of mass effect and lack of parenchymal enhancement of most lesions; irregular meningeal enhancement with secondary involvement (perhaps by meningeal spread) of the cortex and subcortical areas was suggested. A few lesions were hyperintense on diffusion-weighted images. Apparent diffusion coefficient maps were not obtained to distinguish restricted diffusion versus T2 shine-through (not shown). MR imaging was performed at 1.5 T with the following parameters on each day. Fast spin-echo FLAIR: 5-mm axial sequences with 1-mm section gaps, TR/TE/TI of 10,002/145/2200, matrix of 192 x 256, one signal averaged, and 22-cm field of view. T1-weighted images: 5-mm axial sequences with 1-mm section gaps, TR/TE of 500/20, matrix of 192 x 256, one signal averaged, 22-cm field of view.