The relationship between microvasculature in white matter hyperintensities and cognitive function

Abstract

White matter hyperintensities (WMHs) are associated with cognitive decline, but less is known about pathophysiology of cognitive decline in patients with WMHs. We investigated microvasculature and microstructure in WMHs using intravoxel incoherent motion (IVIM) and their associations with cognitive function. Thirty-two subjects with WMHs were enrolled in our study. Fast diffusion coefficient (D*), perfusion fraction (f) and slow diffusion coefficient (D) from IVIM model were compared between regions of WMHs (periventricular WMHs, PWMHs and deep WMHs, DWMHs) and surrounding normal white matter. Multivariate linear model was used to determine the independent factors associated with cognitive function assessed by the Mini Mental State Examination (MMSE) and the standardized coefficient (β) of factors was estimated. D* was significantly lower (4.95 × 10 mm/s versus 8.36 × 10 mm/s in PWMHs and 5.04 × 10 mm/s versus 8.67 × 10 mm/s in DWMHs, both P < 0.001), and f (14.64 % versus 12.01 % in PWMHs and 14.26 % versus 11.31 % in DWMHs, both P < 0.001) and D (1.02 × 10 mm/s versus 0.73 × 10 mm/s in PWMHs and 0.86 × 10 mm/s versus 0.70 × 10 mm/s in DWMHs, both P < 0.001) were significantly higher in WMHs. Only f in PWMHs was independently associated with MMSE (β = 0.443, P = 0.016). The decreased D* and increased D in WMHs were similar to previous findings. The increased f in PWMHs relating with better cognition provides the pathophysiological basis in understanding cognitive decline in patients with WMHs.

Intravoxel Incoherent Motion Imaging in Small Vessel Disease

“…Recently, a study using IVIM imaging examined the microstructural integrity in patients with WMH, and similarly, no significant association was found between microstructural integrity and cognitive function. 35 However, our finding is partly dissimilar to earlier diffusion tensor imaging studies showing an association between cognitive function and microstructural integrity in the WMH and in the NAWM. 4,6 The difference is that the patients of these aforementioned studies were selected on extensive WMH on brain imaging, whereas ours was primarily based on clinical symptoms of SVD (ie, including lacunar stroke patients without any WMH).…”

Lung Cancer: Short‐Term Reproducibility of Intravoxel Incoherent Motion Parameters and Apparent Diffusion Coefficient at 3T

“…In the second step (using Eq. ), the curve was fitted for f and D* for all the b values, while keeping D constant . The ROI was drawn using the same method as DWI, which was also manually outlined on the largest cross‐section of the tumor, and the ROI was kept as similar as possible to those on the ADC map, then the f, D, and D* values were automatically calculated.…”

Can the low and high b-value distribution influence the pseudodiffusion parameter derived from IVIM DWI in normal brain?

“…Between November and December 2014, 22 male healthy volunteers were recruited (mean age, 28 years; range, [25][26][27][28][29][30][31][32][33][34] with inclusion standard as follows: no potential vascular risk factors or diseases affecting brain microvascular perfusion including hypertension or cerebral vascular diseases, systemic metabolic disease, such as diabetes, obesity or cirrhosis; no infection or fever, and use of corticosteroid drugs; no MRI contraindication and appearing normal on conventional brain MR image (as shown in Fig. 1).…”

“…Previous studies have supported that IVIM DWI could be potentially useful in measuring brain perfusion [22][23][24][25][26][27][28][29][30]. However, the calculated perfusion-related IVIM maps usually suffer from low image quality and high parametric variance [31].…”