Associations between Total Cerebral Blood Flow and Age Related Changes of the Brain

Abstract

Background and PurposeAlthough total cerebral blood flow (tCBF) is known to be related to age, less is known regarding the associations between tCBF and the morphologic changes of the brain accompanying cerebral aging. The purpose of this study was to investigate whether total cerebral blood flow (tCBF) is related to white matter hyperintensity (WMH) volume and/or cerebral atrophy. Furthermore, we investigate whether tCBF should be expressed in mL/min, as was done in all previous MR studies, or in mL/100 mL/min, which yielded good results in precious SPECT, PET and perfusion MRI studies investigating regional cerebral blood flow.Materials and MethodsPatients were included from the nested MRI sub-study of the PROSPER study. Dual fast spin echo and FLAIR images were obtained in all patients. In addition, single slice phase contrast MR angiography was used for flow measurements in the internal carotids and vertebral arteries. tCBF was expressed in both mL/min and mL/100 mL/min.ResultsWe found a significant correlation between tCBF in mL/min and both age (r = −.124; p = p≤.001) and parenchymal volume (r = 0.430; p≤.001). We found no association between tCBF in mL/min and %-atrophy (r = −.077; p = .103) or total WMH volume (r = −.069; p = .148). When tCBF was expressed in mL/100 mL/min the correlation between tCBF and age was no longer found (r = −.001; p = .985). Multivariate regression analyses corrected for age showed a significant correlation between tCBF in mL/100 mL/min and WMH volume (r = −.106; p = .044). No significant association between tCBF in mL/100 mL/min and %-atrophy was found.ConclusionFrom this study we conclude that, when evaluating tCBF alterations due to various pathologies, tCBF should in mL/100 mL/min instead of mL/min. Furthermore, changes or differences in WMH volume should be accounted for.

Blood Flow Distribution in Cerebral Arteries

“…This has previously been reported in elderly but not in HY. 23 Cerebral autoregulation is defined as the relationship between blood flow and perfusion pressure 24 and should guarantee a stable cerebral blood flow. Each PCMRI flow measurement in this study represents mean values of BFR sampled during a couple of minutes.…”

Temporal and Spatial Variances in Arterial Spin-Labeling Are Inversely Related to Large-Artery Blood Velocity

“…29 Older adults with WMH, however, exhibited lower GM-CBF than previously reported. 30 Calibration of the GM-CBF to individual labeling efficiency on the basis of PC altered the sensitivity to distinguish clinical groups. With PC-based calibration, we noted GM-CBF differences between healthy young and older adults and between healthy older adults and those with stroke, which were not apparent with a constant labeling efficiency for all participants.…”

Longitudinal Relationship Between Cerebral Small-Vessel Disease and Cerebral Blood Flow

“…This ischemic mechanism has been demonstrated in animals 2,3 ; however, human studies studying the effect of lower CBF on development of WMHs and lacunes are scarce and cross-sectional. [4][5][6][7][8] A possible explanation for the lack of an association between baseline pCBF and progression of WMHs and lacunes could be that they represent different pathological processes. The development of WMHs and lacunes could be the result of mechanisms unrelated to hemodynamic processes, such as neurodegeneration and genetic predisposition.…”

“…1 Evidence supporting this mechanism comes from animal studies and cross-sectional studies in humans. [2][3][4][5][6][7][8] These studies showed that lower cerebral blood flow (CBF) is related to more WMHs and lacunes in the general population and in patients with cardiovascular disease. Also, patients with cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) have significantly lower baseline CBF than controls.…”