Reduced perfusion in normal‐appearing white matter in mild to moderate hypertension as revealed by 3D pseudocontinuous arterial spin labeling

Abstract

Purpose To investigate the hemodynamic changes of normal‐appearing white matter (NAWM) in hypertension using the 3D pseudocontinuous arterial spin labeling (pCASL) technique. Materials and Methods Seventy‐three subjects, including a patient group (n = 41; 30 males; age = 47.7 ± 8.3 years; test‐time blood pressure [BP] = 155 ± 23/98 ± 11 mmHg) and an age‐matched control group (n = 32; 14 males; age = 46 ± 8.3 years; test‐time BP = 117 ± 8/76 ± 10 mmHg), were recruited and scanned on a 3.0T magnetic resonance imaging (MRI) system using routine MRI sequences and 3D pCASL sequence. The routine MRI sequences were used to further define the NAWM. The cerebral blood flow (CBF) values in various regions of interest (ROIs) were extracted. One‐way analysis of variance (ANOVA) and unpaired t‐test were performed to evaluate the significance of the intergroup difference in CBF modifications. Results Compared to healthy volunteers, CBF values in global gray matter (GM) and various NAWM regions were found to be lower (P < 0.05) in hypertensive patients, except for genu of corpus callosum (CC), cingulate gyrus, amygdala, pallidum, putamen, and thalamus (P > 0.05). Furthermore, compared to the control group, mild hypertension showed significantly reduced CBF in various ROIs (P < 0.05), but no intergroup differences in GM, R anterior horn of periventricular WM, and genu of CC (P > 0.05), while moderate hypertension showed reduced CBF in all ROIs (P < 0.05). However, it was observed that, between mild and moderate hypertensive patients, there were no statistically significant difference in CBF values except for genu of CC (P < 0.05). Conclusion 3D pCASL has the ability to detect subtle hemodynamic abnormalities in NAWM regions at relatively early stages of hypertension. The observed decreases in CBF in these regions may suggest an increased risk of cerebral small vessel diseases. J. MAGN. RESON. IMAGING 2016;43:635–643.

Defining the Relationship Between Hypertension, Cognitive Decline, and Dementia: a Review

“…Hypertension is believed to alter cerebral autoregulation by inducing changes in arteriole endothelial and vascular smooth muscle cells that diminish cerebrovascular reactivity [150] and increase myogenic tone, respectively [151]. Not only do these vascular changes shift the cerebral autoregulatory curve in a manner which reduces resting cerebral blood flow, but the brain also becomes more susceptible to hypoperfusion during periods of low systemic BP [152] or during periods of normal BP in chronically hypertensive individuals [153]. These hypertension-induced changes to cerebral autoregulation and perfusion may explain why individuals with chronic hypertension in midlife and low BP in late-life show significant reductions in brain volume [34,121] and greater levels of cognitive deficits [101].…”

Microvascular Dysfunction and Cognitive Impairment

“…Reductions in local PO 2 , and cellular injury occurs in white matter in a genetic model of hypertension (Weaver et al, 2014). Wang et al described reduced blood flow in deep white matter in the early stages of hypertension in humans (Wang et al, 2015). Changes in blood-brain barrier permeability, such as loss of tight junction protein expression and integrity in white matter, occur progressively during hypertension (Fan et al, 2015a; Fan et al, 2015b).…”

Analysis of Cerebral Hemodynamics in Healthy Adult Rhesus with Dynamic Susceptibility Contrast Perfusion (DSC-MR) Imaging

“…However, ASL methods can lose some perfusion defect lesions when compared with DSC methods [13]. In addition, the reliability of ASL measurement of white matter perfusion is controversial [14][15][16][17][18]. Therefore, DSC method was used in this study.…”