PRES
Findings:
Abnormal T2 hyperintensity is present in the bilateral
parietooccipital regions and frontal lobes involving cortex and white matter,
associated with mild mass effect.
Differential Diagnosis:
hypertensive encephalopathy, cyclosporine toxicity, dural
sinus thrombosis
Discussion:
The characteristic lesions of hypertensive encephalopathy
may be seen in preeclampsia/eclampsia, chronic renal failure, TTP, hemolytic
uremic syndrome, SLE, and cyclosporin toxicity. The characteristic distribution
is posterior, thought to be due to deficient autoregulation, but frontal
lobe involvement may also be seen as in this case. The changes are reversible
and may enhance. Diffusion imaging may show hypointensity in the affected
areas, to distinguiish this process from infarction. This distribution
could also be seen with dural sinus thrombosis, and the dural sinuses should
be closely inspected for normal flow voids.