Decline in total cerebral blood flow is linked with increase in periventricular but not deep white matter hyperintensities.

Purpose: To retrospectively investigate the association between changes in total cerebral blood flow and progression of total, periventricular, and deep white matter hyperintensities over time.
Materials and Methods: The institutional ethics review board approved the protocol for the prospective magnetic resonance (MR) imaging study, and all participants gave written informed consent. Participants also agreed to future retrospective analysis of their MR data for research purposes. In this substudy of the Prospective Study of Pravastatin in the Elderly at Risk, investigators performed a repeated MR imaging examination after an average interval of 33 months (standard deviation, 1.4) in 390 elderly men and women (ages 70-82 years at baseline) without dementia who were at high vascular risk. White matter hyperintensities were quantified with a semiautomatic method, and total cerebral blood flow was measured with a gradient-echo phase-contrast MR imaging technique. The association between total cerebral blood flow and volume of white matter hyperintensities was analyzed with logistic regression.
Results: There was no association between baseline cerebral blood flow and prevalence of total, periventricular, or deep white matter hyperintensities at baseline MR imaging. Moreover, decline in cerebral blood flow was not associated with increase in total load of white matter hyperintensities. When the total volume of white matter hyperintensities was separated into periventricular and deep hyperintensities, for every 50 mL/min decrease in total cerebral blood flow there was a 1.32 (95% confidence interval: 1.06, 1.66; P = .015) increase in risk for developing periventricular white matter hyperintensities; there was no association, however, between decrease in total cerebral blood flow and risk of developing deep white matter hyperintensities (odds ratio, 1.00 [95% confidence interval: 0.79, 1.25]; P = .98).
Conclusion: Decline in total cerebral blood flow is associated with increase in volume of periventricular but not deep white matter hyperintensities.