Assessment of vasogenic edema in eclampsia using diffusion imaging.

We qualitatively assessed the regional distribution of vasogenic edema in a case of postpartum eclampsia. Although diffusion-weighted imaging showed no abnormalities, bilateral high signal was seen on T2-weighted images and apparent diffusion coefficient (ADC) maps. ADC of 1.45 +/- 0.10 mm2/s x 10(-3) for the posterior cerebral artery (PCA) territory and 1.22 +/- 0.12 mm2/s x 10(-3) for the watershed areas were significantly higher than those in the territories of the anterior (0.85 +/- 0.07 mm2/s x 10(-3) and middle cerebral (0.79 +/- 0.06 mm2/s x 10(-3)) arteries (P < 0.05). The predilection of ADC changes within the PCA territory and in a previously undescribed watershed distribution supports the hypothesis that vasogenic edema in eclampsia is due to hypertension-induced failure of vascular autoregulation.