Metabolic patterns associated with survival in PSP/CBS: An 18FDG PET voxel-based analysis

Abstract

The four-repeat (4R) tauopathies progressive supranuclear palsy (PSP) and corticobasal degeneration (CBD) as atypical parkinsonian syndromes are characterized by rapid disease progression and short survival times. We investigated metabolic patterns depicted by positron emission tomography with [18F] fluorodeoxyglucose (18FDG PET) that may predict overall survival in 4R tauopathies. Thirty-one patients with a clinically diagnosed PSP (n=23) or corticobasal syndrome (CBS; n=8) underwent an extended follow-up up to 5.4 years after prospective 18FDG PET imaging. On the basis of follow-up data, patients were allocated to the following subgroups: deceased patients with survival time after imaging up to 2.5 years; 2.51–3.5 years;>3.5 years; and patients still alive at follow up (≥3.49 years). Associations between survival and regional cerebral glucose metabolism were analyzed by statistical parametric mapping (SPM), including patient age at PET as covariate. Twenty patients deceased during follow-up (n=7, 8 and 5 at ≤2.5, 2.51–3.5 and >3.5 years after PET imaging, respectively); 11 patients were still alive at follow-up (3.49–4.89 years). Analysis of covariance revealed that reduced regional glucose metabolism in left sided sensorimotor area and adjacent parietal and frontal regions areas were significantly associated with shorter survival times. A regression analysis including data of all patients deceased showed additional clusters of hypometablism in left anterior cingulate gyrus and midbrain. 4R tauopathies show distinct metabolic patterns associated with survival, which resemble post mortem stages of disease-specific spreading of tau pathology.