[Neuroradiological study of cerebral microlesions (2): changes in elderly].

BACKGROUND

Some of the cerebral microlesions less than 3 mm in diameter observed on magnetic resonance imaging (MRI) are considered to represent pathological processes. The present study investigated changes due to aging in microlesions according to anatomical regions and phenotypes.

PATIENTS

A total of 390 cases without localized lesions other than lacune less than 15 mm in diameter were studied.

METHOD

Microlesion type on MRI was categorized into hypo-, iso-, and hyper-intensities on T1-weighted (T1WI), T 2-weighted (T2WI), and proton-weighted or fluid-attenuated inversion recovery (proton/FLAIR) images. Correlations between unidentified bright objects (UBO) in white matter and vascular risk factors were analyzed using logistic regression analysis.

RESULTS

Microlesions of the upper basal ganglia showing low intensity on T1WI, high intensity on T2WI and iso intensity on proton/FLAIR, and showing low intensity on T1WI, high intensity on T2WI and low intensity on proton/FLAIR increased with age, whereas those showing low intensity on T1WI, iso intensity on T2WI, and low intensity on proton/FLAIR of the upper basal ganglia decreased. In subcortical white matter, microlesions of the first two types: and those showing iso intensity on T1WI, high intensity on T2WI and iso intensity on proton/FLAIR decreased with age. Conversely, UBO increased with age, and significantly correlated with hypertension.

CONCLUSION

Although microlesions in the upper basal ganglia increase with age, those in the subcortical white matter decrease with age. These observations suggest pathological changes surrounding small arteries with aging in the brain.