Analysis of Cerebral Lobar Microbleeds and a Decreased Cerebral Blood Flow in a Memory Clinic Setting

Abstract

Objective Cerebral microbleeds (MBs) have been previously associated with cognitive dysfunction, including Alzheimer's disease. In the present study, we aimed to clarify the relationship between cerebral lobar MBs and the regional cerebral blood flow (CBF). Methods We investigated the data obtained from 122 patients in our memory clinic who were examined by both MRI and 99m Tc-ethyl cysteinate dimer (ECD)-single photon emission computed tomography (SPECT). Patient brain scans were superimposed and brain regions containing both decreased CBF and MBs were visually identified. For each patient eight brain regions were evaluated, comprising the right and left frontal, temporal, parietal, and occipital lobes. Results Cerebral MBs were detected in 36 of the 122 (29.5%) patients. Of these 36 patients, 23 had detectable lobar MBs, which were primarily distributed in the occipital lobe in 19 of the 46 (41.3%) regions with lobar MBs. The frequency of MBs accompanied by a decreased CBF in the parietal and occipital lobes was significantly higher than that observed in the frontal lobe (73.3% vs. 27.3%, p<0.05, and 73.7% vs. 27.3%, p <0.05, respectively). Additionally, a decreased CBF was observed significantly more frequently in the brain regions with 5 or more MBs compared to the regions with one microbleed (83.3 vs. 25.0%, p<0.0005). Among the 17 patients with observable MBs accompanied by a decreased CBF, none were initially diagnosed with either subjective complaints or mild cognitive impairment. Conclusion We determined that the cerebral lobar MBs located in the parietal and occipital lobes, and the lobar regions with a large number of MBs, were significantly more likely to be accompanied by a decreased CBF.

Invited Review: The spectrum of age‐related small vessel diseases: potential overlap and interactions of amyloid and nonamyloid vasculopathies

“…In DPA, cerebral CMB are commonly found in the deep grey (Bg, thalami) and white matter, and infratentorially (brainstem, cerebellum) (Figure B ) . A strictly lobar (cortico‐subcortical) pattern of CMB (typically located most often in the occipital and temporal cortical grey matter) has high specificity for CAA (Figure B ) . The burden of CAA‐related lobar CMB seems to be associated with cortical position emission tomography (PET) Aβ load , but a recent analysis questioned the common expectation that in CAA, the ruptured vessel displays significant Aβ load, as microhaemorrhages were preferentially found surrounding the Aβ negative small vasculature .…”

Apolipoprotein E and Sex Bias in Cerebrovascular Aging of Men and Mice

“…Similarly, in patients with ischemic stroke and/or transient ischemic attacks, lobar CMBs are associated with executive dysfunction[25]. Lobar CMBs are also associated with lower cerebral blood flow and hypoperfusion in both healthy elderly and in a memory clinic setting [26,27], which highlights the complex interaction of SVD with healthy ageing. Again, ApoE ε4 is associated with lobar CMBs in patients with cognitive impairment[28].…”

Mixed-location cerebral microbleeds as a biomarker of neurodegeneration in a memory clinic population

“…It is further reported that lobar CMBs may alter cerebral white matter perfusion leading to brain volume reduction [11, 12]. However, previous studies have shown conflicting results.…”