In vivo vascular hallmarks of diffuse leukoaraiosis.

PURPOSE To characterize multiple patterns of vascular changes in leukoaraiosis using in vivo magnetic resonance imaging (MRI) techniques. MATERIALS AND METHODS We measured cerebral blood flow (CBF), cerebrovascular reactivity (CVR), and blood-brain-barrier (BBB) leakage in a group of 33 elderly subjects (age: 72.3 +/- 6.8 years, 17 males, 16 females). Leukoaraiosis brain regions were identified in each subject using fluid-attenuated inversion-recovery (FLAIR) MRI. Vascular parameters in the leukoaraiosis regions were compared to those in the normal-appearing white matter (NAWM) regions. Vascular changes in leukoaraiosis were also compared to structural damage as assessed by diffusion tensor imaging. RESULTS CBF and CVR in leukoaraiosis regions were found to be 39.7 +/- 5.2% (P < 0.001) and 52.5 +/- 11.6% (P = 0.005), respectively, of those in NAWM. In subjects who did not have significant leukoaraiosis, CBF and CVR in regions with high risk for leukoaraiosis showed a slight reduction compared to the other white matter regions. Significant BBB leakage was also detected (P = 0.003) in leukoaraiosis and the extent of BBB leakage was positively correlated with mean diffusivity. In addition, CVR in NAWM was lower than that in white matter of subjects without significant leukoaraiosis. CONCLUSION Leukoaraiosis was characterized by reduced CBF, CVR, and a leakage in the BBB.