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Background and Purpose: Low wall shear stress (WSS) is an early marker in the development of vascular lesions. The present study aims to assess the relationship between diastolic and systolic WSS in the internal carotid artery and periventricular (PWML), deep white matter lesions, and cerebral infarcts (CI)., Methods: Early, mid, and late diastolic and peak systolic WSS were derived from shear rate obtained by gradient echo phase contrast magnetic resonance sequences multiplied by individually modeled viscosity. PWML, deep white matter lesions, and CI were derived from proton density (PD), T2, and fluid attenuated inversion recovery (FLAIR) MRI in 329 participants (70-82 years; PROSPER baseline). Analyses were adjusted, if appropriate, for age, gender, intracranial volume, and multiple cardiovascular risk factors., Results: Mid-diastolic WSS was significantly correlated with the presence of PWML (B=-10.15; P=0.006) and CI (B=-2.06; P=0.044), but not with deep white matter lesions (B=-1.30; P=0.050; adjusted for age, gender, WML, and intracranial volume). After adjustment for cardiovascular risk factors, these correlations weakened but remained significant. Systolic WSS was not correlated with any of the cerebrovascular parameters., Conclusions: This study is the first to our knowledge to present a cross-sectional correlation between carotid artery WSS and cerebrovascular pathology such as PWML and CI in a large population. Furthermore, it shows that diastolic hemodynamics may be more important than systolic or mean hemodynamics. Future studies exploring vascular hemodynamic damage should focus on diastolic WSS.

Background and Purpose: Hypoxic-ischemic cerebral changes can be difficult to distinguish from normal myelination on T1-weighted images. We hypothesized that comparing signal intensity (SI) of brain structures on T1-weighted images enables differentiation of myelination from hypoxic-ischemic brain damage., Materials and Methods: T1-weighted images, obtained in 57 infants aged 1-104 days and born after a gestational age of 35 weeks or older, were retrospectively evaluated. Subjects were assigned to a patient (n = 23, with perinatal hypoxic-ischemic encephalopathy [HIE] stage 2/3) or a control group (n = 34). In each subject, an SI score was assigned to 19 brain structures on the basis of pairwise comparisons with the other 18 structures. In both groups, mean total SI scores were calculated for the 19 structures. Independent samples t tests assessed whether the mean total score of a structure differed significantly between the 2 groups. Logistic regression assessed which comparison was best to distinguish between the groups and to predict the presence of hypoxic-ischemic injury., Results: In patients, mean total SI scores for posterolateral putamen (PP) and peri-Rolandic cortex (PC) were significantly higher (P = .000 for both). Mean total SI scores of the posterior limb of internal capsule (PLIC) and the corona radiata (CR) were significantly lower in patients (P = .000 and 0.005, respectively). Two comparisons (PLIC versus CR, PP versus PC) were best to distinguish patients and controls and to predict absence or presence of HIE (P < .0001)., Conclusion: SI changes due to hypoxia-ischemia can be differentiated from normal myelination by comparing SI of 4 brain structures on T1-weighted images.