Table 1.
Blood flow changes in aging and dementias.
| Aging/cognitive disorders | Blood flow changes and brain regions | Other findings | Measurement techniques | |
|---|---|---|---|---|
| Aging | Reduced CBF in the cortex of lateral occipital, cingulate, precuneus,32 temporal,32,34 parietal,32,34 insular and frontal lobes32,33 | No CBF change in subcortical areas32 | ASL-MRI;32 PET;33 SPECT34 | |
| Vascular cognitive impairment | Multiple regional CBF reduction with a posterior–anterior gradient, sparing occipital lobe;63–66 extensive white matter involvement with a tendency toward subcortical circuit44 | NVU dysregulation due to a combination of hypoperfusion and BBB permeability44 | SPECT;63,64 ASL-MRI;65 PET;66 DCE/DSC-MRI44 | |
| Alzheimer’s disease | Asymptomatic phase | Regional blood flow changes in asymptomatic middle-aged adults with a maternal history of AD53 and APOε4 carriers67 | CBF difference between older and younger APOε4 carriers67 | ASL-MRI53,59,67 |
| MCI | Intra-brain vascular dysregulation as early pathological findings with disease development.43 Reduced CBF in the occipital,68 angular gyrus, temporal,62,68 posterior cingulate gyrus, cuneus,69 parietal62,70 and frontal lobes62 | Compensatory CBF increment in hippocampus, amygdala, caudate, putamen and globus pallidus;69 CMBs in 25% of cases71 | ASL-MRI;68–70 GE-MRI;62 2D phase-contrast MRI;54 SW-MRI71 | |
| Dementia | Regional CBF reduction beyond the MCI regions with a prominent decline in the medial temporal lobe,72 posterior cingulate gyrus,69,70 and inferior parietal cortex69 | Limited compensatory CBF increment in the anterior cingulate gyrus;69 lobar CMBs (78% of cases) | ASL-MRI;57,58,68–70,73 GE-MRI;62 SPECT;72,74 PET;58,66 7-tesla MRI75 | |
| Amyotrophic lateral sclerosis | Generalized CBF reduction (whole cortex and subcortical areas);76 regional CBF reduction in the frontal and parietal lobes77 | CMBs in motor cortex78 | ASL-MRI;77 CT;76 MRI78 | |
| Frontotemporal dementia | Reduced CBF in the frontal lobe73 | Increased CBF in medial parietal, posterior cingulate and precuneus73 | ASL-MRI | |
| Huntington's disease | Reduced CBF in the sensorimotor paracentral, temporal, occipital, postcentral gyrus and insula79 | ASL-MRI | ||
| Lewy body dementia | Reduced CBF in the parietal, temporal and occipital lobes;74 occipital hypoperfusion74,80 | SPECT;74 Radio pharmacological techniques74,80 | ||
| Multiple sclerosis | Reduced CBF in both white81,82 and gray matter82 | Increased BBB permeability;81 impaired cerebrovascular reactivity83 | DCE-MRI;81 DSC-MRI;82 ASL-MRI83 | |
| Parkinson’s disease | Reduced CBF in the parietal, occipital, frontal, cuneus,84 supramarginal gyrus,85 precuneus, temporal, cingulate84,85 and subcortical areas (thalamus and caudate)84 | CMBs in both white and gray matter;86,87 impaired whole brain cerebrovascular reactivity88 | T2-MRI and SWI-MRI;86,87 ASL-MRI84,85,88 | |
| Progressive supranuclear palsy | Reduced CBF in the frontal lobe89 | SPECT | ||
Abbreviations: 2D: two-dimensional; ASL-MRI: arterial spin labeling magnetic resonance imaging; BBB: blood–brain barrier; CBF: cerebral blood flow; CMBs: cerebral microbleeds; CT: computed tomography; DCE-MRI: dynamic contrast-enhanced magnetic resonance imaging; DSC-MRI: dynamic susceptibility contrast magnetic resonance imaging; GM: gray matter; MCI: mild cognitive impairment; MRI: magnetic resonance imaging; NVU: neurovascular unit; PET: positron emission tomography; rCBF: regional cerebral blood flow; SPECT: single photon emission computed tomography; SWI: susceptibility-weighted imaging; WM: white matter.