Cortical microinfarcts in memory clinic patients are associated with reduced cerebral perfusion

Abstract

Cerebral cortical microinfarcts (CMIs) are small ischemic lesions associated with cognitive impairment and dementia. CMIs are frequently observed in cortical watershed areas suggesting that hypoperfusion contributes to their development. We investigated if presence of CMIs was related to a decrease in cerebral perfusion, globally or specifically in cortex surrounding CMIs. In 181 memory clinic patients (mean age 72 ± 9 years, 51% male), CMI presence was rated on 3-T magnetic resonance imaging (MRI). Cerebral perfusion was assessed from cortical gray matter of the anterior circulation using pseudo-continuous arterial spin labeling parameters cerebral blood flow (CBF) (perfusion in mL blood/100 g tissue/min) and spatial coefficient of variation (CoV) (reflecting arterial transit time (ATT)). Patients with CMIs had a 12% lower CBF (beta = −.20) and 22% higher spatial CoV (beta = .20) (both p < .05) without a specific regional pattern on voxel-based CBF analysis. CBF in a 2 cm region-of-interest around the CMIs did not differ from CBF in a reference zone in the contralateral hemisphere. These findings show that CMIs in memory clinic patients are primarily related to global reductions in cerebral perfusion, thus shedding new light on the etiology of vascular brain injury in dementia.

Alterations of the Whole Cerebral Blood Flow in Patients With Different Total Cerebral Small Vessel Disease Burden

“…Small vessel disease was regarded as a dynamic, whole-brain disorder (Wardlaw et al, 2019). Previous research showed that there was a correlation between microinfarction of CSVD and global CBF, and found microinfarction could lead to decreased CBF throughout the anterior circulation rather than being confined to the area around them (Ferro et al, 2019). The presence of microbleeds was also reported to be related to reduced brain perfusion (Gregg et al, 2015).…”

“…A systematic review showed that CBF was negatively correlated with the severity of WMH, and white matter lesions led to a decreased perfusion in global brain and cortical structure rather than reverse (Shi et al, 2016(Shi et al, , 2020. Although perfusion may decrease at the lesion sites, particular for WMH, the consistent finding for the different manifestations of CSVD is that they predominantly associate with reduced CBF in the whole brain (Ferro et al, 2019).…”

Histological correlates of postmortem ultra-high-resolution single-section MRI in cortical cerebral microinfarcts

“…Thus, the presence of string vessels pointed to disturbances in the microcirculation in and around cortical cerebral microinfarcts, which may explain the comparatively strong MRI signals obtained from relatively small cortical microinfarcts in vivo [27,28,32]. Thus, advanced techniques that detect changes in cerebral perfusion [20] and/ or axonal disorganization [14] may further enhance the visualization of chronic cortical cerebral microinfarcts with in vivo MRI, especially when combined with techniques that use local perturbations of the MR phase to enhance T2* contrast, e.g., 3D T2*-weighted imaging with postprocessing susceptibility-weighted imaging [25], to distinguish microbleeds from calcifications.…”

Spatial coefficient of variation of arterial spin labeling MRI as a cerebrovascular correlate of carotid occlusive disease

“…Another potential explanation for our findings is an indirect association between the spatial CoV and the side of occlusion. Patients with internal carotid disease are likely to have a degree of both large and small vessel disease [27], which have shown to be associated with the spatial CoV [28][29][30][31]. It is likely that these factors have contributed to the sCoV and CBF measures in our cohort.…”