Diffusion-Weighted Imaging Discriminates Between Cytotoxic and Vasogenic Edema in a Patient With Eclampsia

TLDR

Eclampsia’s pathophysiology is unclear, and while most patients exhibit reversible MRI T2 hyperintensities and neurological deficits, a subset develops permanent infarctions that routine MRI cannot prospectively differentiate. The study proposes that diffusion‑weighted imaging be performed in all eclamptic patients to guide management. Echo‑planar diffusion‑weighted imaging was applied to a 30‑year‑old eclamptic patient to distinguish cytotoxic from vasogenic edema. Diffusion‑weighted imaging revealed increased diffusion indicative of vasogenic edema, allowing clear differentiation between hypertensive ischemic encephalopathy and infarction, which have distinct treatment protocols.

Abstract

Background The pathophysiology of eclampsia remains unclear. While the majority of patients develop reversible T2 hyperintense signal abnormalities on MR scans and reversible neurological deficits, some patients do develop infarctions (permanent T2 hyperintense abnormalities) and permanent neurological impairment. Routine MRI cannot prospectively differentiate between these two patient groups. Echo-planar diffusion-weighted imaging, however, is a new technique that clearly differentiates between cytotoxic and vasogenic edema. Case Description A 30-year-old woman developed symptoms consistent with eclampsia 24 hours after delivering premature twins. An MRI demonstrated extensive, diffuse T2 hyperintense signal abnormalities involving subcortical white matter and adjacent gray matter with a posterior predominance, consistent with either infarction or hypertensive ischemic encephalopathy. Diffusion-weighted images demonstrated increased diffusion, consistent with vasogenic edema and hypertensive ischemic encephalopathy. Conclusions Unlike routine MRI, diffusion-weighted imaging reliably differentiates between vasogenic edema and cytotoxic edema. Consequently, in eclamptic patients diffusion-weighted imaging can afford clear differentiation between hypertensive ischemic encephalopathy and infarction, two very different entities with very different treatment protocols. Diffusion-weighted imaging should be performed in all eclamptic patients and should greatly affect their management.