Peak width of skeletonized mean diffusivity and its association with age‐related cognitive alterations and vascular risk factors

Abstract

Introduction Only two studies investigated the associations between peak width of skeletonized mean diffusivity (PSMD) and age‐related cognitive alterations, whereas none of the studies investigated the association with vascular risk factors. Methods We evaluated 801 stroke‐ and dementia‐free elderlies with baseline and 3‐year follow‐up assessments. Regression analyses were used to assess the association between age‐related cognitive functions and PSMD. Simple mediation models were used to study the mediation effect of PSMD between vascular risk factors and age‐related cognitive outcomes. Results PSMD was negatively associated with processing speed at baseline and negatively associated with processing and memory scores at 3‐year follow‐up. The association between vascular risk factors and age‐related cognition was mediated by PSMD, as well as other diffusion tensor imaging markers. Discussion PSMD is preferred over other diffusion tensor imaging markers as it is sensitive to age‐related cognitive alterations and calculation is fully automated. PSMD is proposed as a research tool to monitor age‐related cognitive alterations.

Pandemic of the aging society — sporadic cerebral small vessel disease

“…[ 6 , 17 ] Interestingly, our group further found that the expression changes of AD susceptibility genes appear especially prominent at the capillary endothelium, suggesting a possible etiological role of capillary endothelial dysfunction in AD. [ 4 ]…”

“…There are certain brain changes that are associated with CSVD but may not be captured by pathological studies or conventional MRI sequences or CT, these include diffusion tensor imaging (DTI) (fractional anisotropy, mean diffusivity, peak weak of skeletonized mean diffusivity) and functional MRI, which reflect white matter microstructural changes and brain network connectivity changes, respectively. [ 4 , 34 ] In addition, the BBB leakage and neuroinflammation can also be captured by dynamic contrast-enhanced MRI [ 35 ] and translocator protein positron emission tomography (PET) imaging, respectively. [ 36 ]…”

“…Using DTI MRI, the CU-RISK (The Chinese University of Hong Kong — Risk Index for Subclinical Brain Lesions in Hong Kong) community study showed that CSVD probably accounts for at least partially to the subtle cognitive decline that is related to aging. [ 4 ] The cognitive impairment associated with CSVD is typically of the “subcortical” type, which is characterized by slow processing speed, executive dysfunction, and reduced attention span (often mixed with some degree of apathy, depression, or slow motion), as the frontal-subcortical circuits that are responsible for these cognitive domains are disrupted by the subcortically located CSVD lesions. [ 4 , 48 ] Of further note is that the memory or recall problem associated with CSVD commonly shows an improvement with cueing and the subject performs better on recognition task than on free recall.…”

“…Such subtle changes are often accepted as part of the normal aging process. [ 4 ] CSVD may progress slowly (eg, over years to decades) and when a certain threshold has been reached or when some precipitating events (eg, pneumonia, hypotension) happen, [ 5 ] the CSVD may become “malignant” and manifest clinically in a more rapid manner, commonly presenting as stroke or stroke-like episodes, affecting single or multiple mental and bodily functions, resulting in dementia and disability. The first clinical manifestation of CSVD can even be a fatal event if it is an intracerebral hemorrhage (ICH).…”

Magnetic resonance imaging manifestations of cerebral small vessel disease: automated quantification and clinical application

“…Of note, this review focused on the CSVD imaging features that are visible on conventional structural MRI as detailed in STRIVE criteria. Although, some CSVD features from advanced MRI modalities [ 2 ] (eg, diffusion tensor imaging) have been validated for their robustness for clinical studies [ 3 , 4 ] or even as secondary outcomes in clinical trials [ 5 ] (eg, peak width of skeletonized mean diffusivity that could sensitively capture CSVD progression), they would not be discussed in the following sections.…”