Cerebral microhemorrhage in middle-aged and elderly people is 7%

Cerebral microbleeds (CMBs) are small (<10mm), low signal, oval or circular imaging findings found on T2*-weighted GRE or sensitivity-weighted imaging (SWI). 

Pathologically, it mainly corresponds to the deposits rich in hemosiderin near the arterioles, which is considered to be the bleeding under the microscope reported in the past. 

They are increasingly recognized that it has common pathophysiological process with one of a series of imaging features related to small vessel disease (SVD) and  small vessel arterial diseases related to ischemic lacunar stroke and cerebral hemorrhage.

Pathology suggests that CMBs in the lobe correspond to cerebral amyloid angiopathy (CAA), while deep CMBs may indicate arteriolar sclerosis.

Many studies have analyzed the risk factors of CMBs. They believe that CMBs are related to a series of risk factors such as age, hypertension, obesity and diabetes. The use of drugs such as clopidogrel or anticoagulants has also been shown to be associated with a higher prevalence of CMB.

 However, whether these risk factors are equally important for CMBs in different locations, and whether there are differences in the relationship between them and the lobes, deep, and subtentorial CMBs, these questions still exist.

The sensitivity of MRI to CMBs is a complex issue, depending on many factors, including the scanner field strength, acquisition sequence, and whether to use gradient echo or more sensitive sensitivity weighting sequence (SWI), etc. Many studies have adopted multiple Different scanners.

In October 2021, Dongwei Lu from the University of Cambridge, UK, and others announced their research results on Neurology. They used data from the UK Biobank to determine the relationship between the risk factors and CMBs of more than 8,000 healthy middle-aged and elderly people. The relationship was studied.

The MRI scans of the 8159 participants in the UK Biobank study were suitable for CMB analysis. Obtain brain SWI imaging data on two identical 3.0T scanners.

The average age at the time of the scan was 62.1±7.4 years. One or more clear CMBs were detected in 572 (7.0%) participants. Among CMBs patients, 439 cases (76.7%) were lobar CMBs, 103 cases (18.0%) were deep CMBs, and 83 cases (14.5%) were subtentorial CMBs.

Age is an independent risk factor for CMBs in all regions. APOE4 is positively correlated with males and lobar CMBs, while higher body mass index is negatively correlated with lobar CMBs. Hypertension, smoking and drinking are related to deep CMBs, but not related to lobar CMBs. Only age is related to CMBs under the curtain. After controlling the volume of white matter hyperintensity lesions (as a marker of the severity of small vessel disease), the correlation did not change.

In the end, the author believes that in this large-scale population study, the prevalence of CMB detected by a low-sensitivity and high-specificity detection system was 7%. The risk factors of lobes and deep CMBs are different, suggesting that there are different pathophysiological processes.

Reference:

Neurology. 2021 Aug 18; 10.1212/WNL.0000000000012673. doi: 10.1212/WNL.0000000000012673. Online ahead of print.