P8.16 WHITE MATTER LESIONS ARE ASSOCIATED WITH A SIGNIFICANT DECREASE IN THE METABOLISM OF THE BRAIN GREY-MATTER FROM OLDER HYPERTENSIVE PATIENTS

Abstract

White matter lesions, described as leukoaraiosis, are frequently documented in older hypertensive patients, but their consequence on brain metabolism remains debated. This study aimed at characterizing the changes in brain metabolism, assessed by [18F]-fluorodesoxyglucose Positron Emission Tomography (FDG-PET) imaging in relation to the severity of leukoaraiosis in older hypertensive patients. Methods: Sixty-six older hypertensive patients (75±5 years, 37 women) presenting memory complaint or mild cognitive impairment were prospectively referred to FDG-PET and MRI brain imaging and to neuropsychological tests. FDG-PET images were quantified with the Statistical Parametric Mapping software and a population-specific template, and they were correlated to the severity of leukoaraiosis, assessed by Fazekas score on MRI-Flair images, while considering the additional influences of age and of the grey-matter volume expressed in % of intracranial volume. Results: The severity of leukoaraiosis was low (Fazekas scores 1 or 2) in 27 patients (41%), mild to moderate (scores 3 or 4) in 21 (32%) and high (score 5 or 6) in 18 (27%). This severity inversely related to FDG-PET metabolism within 14 Brodmann areas, corresponding to 17% of the total grey-matter volume and mainly located with the frontal lobe (14% of the total grey-matter volume). The global frontal uptake of FDG, was inversely related to the Fazekas score (p=0.005), independently of the additional influences of age and grey-matter volume. No association was found in this population between Fazekas score and the neuropsychological state. Conclusions: White matter lesions are associated with a significant decrease in the metabolism of brain grey-matter, mainly within frontal areas and independently of the concomitant effects of age and atrophy.