Imaging Biomarkers of Neurodegeneration in Alzheimer’s Disease: Distinct Contributions of Cortical MRI Atrophy and FDG-PET Hypometabolism

Article type: Research Article

Authors: Benvenutto, Agnès^{a; *} | Giusiano, Bernard^{b; c} | Koric, Lejla^{a; d} | Gueriot, Claude^a | Didic, Mira^{a; c} | Felician, Olivier^{a; c} | Guye, Maxime^{e; f} | Guedj, Eric^{d; g; h} | Ceccaldi, Mathieu^{a; c}

Affiliations: [a] Neurology and Neuropsychology Department and CMMR PACA Ouest, Assistance Publique-Hôpitaux de Marseille, Marseille, France | [b] Department of Public Health, Assistance Publique-Hôpitaux de Marseille, Marseille, France | [c] Institut de Neurosciences des Systèmes, Aix-Marseille Univ, INSERM UMR 1106, Marseille, France | [d] Aix Marseille Univ, CNRS, Centrale Marseille, Institut Fresnel, Marseille, France | [e] Aix Marseille Univ, CNRS, CRMBM, Marseille, France | [f] AP-HM, Timone University Hospital, CEMEREM, Marseille, France | [g] Department of Nuclear Medecine, Assistance Publique-Hôpitaux de Marseille, Marseille, France | [h] CERIMED, Aix-Marseille Univ, Marseille, France

Correspondence: [*] Correspondence to: Agnès Benvenutto, Service de neurologie et neuropsychologie, CMRR PACA Ouest, Hôpital de la Timone, 264 Rue Saint Pierre, 13385 Marseille Cedex05, France. Tel.: +33 491385928; E-mail: agnesbenvenutto@outlook.com.

Abstract: Background:Neurodegeneration biomarkers are routinely used in the diagnosis of Alzheimer’s disease (AD). Objective:To evaluate the respective contributions of two neuroimaging biomarkers, structural MRI and 18FDG-PET, in the assessment of neurodegeneration in AD dementia. Methods:Patients with mild AD dementia diagnosed based on clinical and cerebrospinal fluid criteria and cognitively healthy subjects, from the Marseille cohort ADAge with cognitive, structural MRI and 18FDG-PET assessments, were included. Extent of atrophy on MRI and of hypometabolism on 18FDG-PET were individually evaluated in each patient using a voxel-based analysis on whole-brain approach and compared to healthy subjects. Patients were divided in distinct groups according to their atrophy extent on the one hand and to their hypometabolism extent on the other, then, to their imaging profile combining the extent of the two biomarkers. Results:Fifty-two patients were included. The MMSE score was significantly lower in the “Extensive hypometabolism” group than in the “Limited hypometabolism” group (respectively 19.5/30 versus 23/30). A lower Innotest Amyloid Tau Index was associated with an extensive hypometabolism (p = 0.04). There were more patients with low educational level in the “Extensive atrophy” group, while a higher educational level was more found in the “Limited atrophy” group (p = 0.005). Conclusion:18FDG-PET hypometabolism extent is associated with the pathological processes and clinical severity of AD, while MRI atrophy seems to be influenced by the cognitive reserve. In the context of mild AD dementia, these two biomarkers of neurodegeneration are thus not interchangeable and require to be considered in combination rather than in isolation.

Keywords: Alzheimer’s disease, dementia, magnetic resonance imaging, neuroimaging biomarkers, positron emission tomography imaging

DOI: 10.3233/JAD-180292

Journal: Journal of Alzheimer's Disease, vol. 65, no. 4, pp. 1147-1157, 2018