Susceptibility-weighted angiography and diffusion-weighted imaging in posterior reversible encephalopathy syndrome - Is there an association between hemorrhage, cytotoxic edema, blood pressure and imaging severity?

Purpose: To assess the significance of association and possible correlation between hemorrhage, cytotoxic edema, blood pressure and imaging severity in posterior reversible encephalopathy syndrome (PRES).

Materials And Methods: This retrospective study included the medical and imaging records of 35 consecutive patients with PRES. The clinical data analysis included the highest recorded blood pressure (BP) on the day of the ictus, MRI including spin-echo echo planar diffusion-weighted imaging (DWI), susceptibility weighted angiography (SWAN) and conventional sequences. The presence of hemorrhage and cytotoxic edema was evaluated for the significance of correlation and association with each other and with blood pressure and imaging severity.

Results: On MR imaging, hemorrhage was found in 25.7%, and cytotoxic edema in 20% of patients. There was no statistically significant association of hemorrhage (P=0.403) and cytotoxic edema (P=0.162) with BP in contrast to significant association of hemorrhage (P<0.001) and cytotoxic edema (P=0.011) with imaging severity and with each other (P=0.002). There was a significant correlation of hemorrhage (Cramer's V - 0.672) and cytotoxic edema (Cramer's V - 0.506) with imaging severity and with each other (Cramer's V - 0.523).

Conclusion: The extent of imaging severity in PRES showed significant association and correlation with hemorrhage and cytotoxic edema. There was no statistically significant association of blood pressure with imaging severity, hemorrhage, and cytotoxic edema. Further prospective studies are needed to elucidate the pathophysiological mechanisms and their correlation with imaging findings in PRES.