Reduced cerebral glucose metabolism in subjects with incidental hyperintensities on magnetic resonance imaging

Abstract

Objective: To clarify the significance of incidental and asymptomatic hyperintensities on T 2-weighted magnetic resonance images (MRI) in adults, we examined the relationship between a variety of these lesions and cerebral metabolism evaluated by positron emission tomography (PET) with 18F-labeled fluorodeoxyglucose ([ 18F]FDG). Subjects and methods: Two hundred and thirty-one persons with hyperintensities on T 2-weighted MRI but without overt neurological disease (mean age 60±9 years) were studied. MR hyperintensities were classified into deep and/or subcortical white matter hyperintensities (DSWMHs), periventricular hyperintensities (PVHs) and hyperintensities in the basal ganglia and/or thalamus (HBGTs). The relationship between these lesions and cerebral metabolic rate of glucose (CMRgl) measured by [ 18F]FDG-PET was investigated. Results: The CMRgl values in white matter and cerebral cortex in the group with severe PVHs were lower than those in the group with mild PVHs ( P<0.0001 and P<0.005). Although the severity of PVHs was associated with the numbers of DSWMHs and HBGTs, the results of multivariate analysis showed a significant relationship of PVHs to glucose metabolism in cerebral cortex and white matter. Conclusions: We conclude that increasing severity of MRI hyperintensities in adults is associated with a deterioration of cerebral metabolism. In particular, involvement of PVHs may be a marker of widespread deterioration of cortical metabolism.