FDG-PET patterns associated with underlying pathology in corticobasal syndrome

Abstract

ObjectiveTo evaluate brain 18Fluorodeoxyglucose PET (FDG-PET) differences among patients with a clinical diagnosis of corticobasal syndrome (CBS) and distinct underling primary pathologies.MethodsWe studied 29 patients with a diagnosis of CBS who underwent FDG-PET scan and postmortem neuropathologic examination. Patients were divided into subgroups on the basis of primary pathologic diagnosis: CBS-corticobasal degeneration (CBS-CBD) (14 patients), CBS-Alzheimer disease (CBS-AD) (10 patients), and CBS–progressive supranuclear palsy (CBS-PSP) (5 patients). Thirteen age-matched healthy patients who underwent FDG-PET were the control group (HC). FDG-PET scans were compared between the subgroups and the HC using SPM-12, with a threshold of pFWE < 0.05.ResultsThere were no differences in Mattis Dementia Rating Scale or finger tapping scores between CBS groups. Compared to HC, the patients with CBS presented significant hypometabolism in frontoparietal regions, including the perirolandic area, basal ganglia, and thalamus of the clinically more affected hemisphere. Patients with CBS-CBD showed a similar pattern with a more marked, bilateral involvement of the basal ganglia. Patients with CBS-AD presented with posterior, asymmetric hypometabolism, including the lateral parietal and temporal lobes and the posterior cingulate. Finally, patients with CBS-PSP disclosed a more anterior hypometabolic pattern, including the medial frontal regions and the anterior cingulate. A conjunction analysis revealed that the primary motor cortex was the only common area of hypometabolism in all groups, irrespective of pathologic diagnosis.Discussion and conclusionsIn patients with CBS, different underling pathologies are associated with different patterns of hypometabolism. Our data suggest that FDG-PET scans could help in the etiologic diagnosis of CBS.

FDG‐PET Patterns Predict Amyloid Deposition and Clinical Profile in Corticobasal Syndrome

“…Moreover, a recent study with neuropathologic examination showed that CBS underlying pathologies are associated with different metabolic degeneration patterns and described hypometabolism for CBS-CBD, CBS-AD, and CBS-PSP 26 . The CBS-AD metabolic pattern described was similar to what we observed comparing patients with positive and negative PIB-PET.…”

“…Based on the FDG-PET findings, the patients were split into two groups, namely "CBS likely related to AD" (CBS FDG-AD), or "CBS likely not related to AD" (CBS FDG-nonAD), according to patterns of hypometabolism previously described for neurodegenerative diseases. 18,19,21,[23][24][25][26] Hypometabolic pattern suggestive of AD included decreased regional brain glucose metabolism (rBGM) in the posterior temporoparietal, inferior temporal regions, precuneus, and posterior cingulate gyrus. 38,39 We considered the remaining patterns as non-AD group and performed a subclassification regarding these different patterns into CBD, PSP, frontotemporal dementia (FTD), Lewy Body dementia (LBD), and indeterminate (closely related to tauopathies), also according to patterns previously described.…”

“…Statistical results were considered valid when survived correction for multiple comparisons with the familywise error (FWE) or false discovery rate (FDR) methods, (pFWE/FDR ≤0.05), or without correction for multiple comparisons with p unc <0.001, when a priori regions were observed, according to established patterns of neurodegeneration. 18,19,21,[23][24][25][26] Relevant peak voxels from the statistical parametric maps were identified in the Montreal Neurologic Institute (MNI) coordinates system. Numeric values representing the mean FDG uptake in the clusters of rGBM and PIB uptake for each individual were obtained with the toolbox MarsBar for SPM (http://marsbar.sourceforge.…”

“…[23][24][25] A postmortem study recently demonstrated that neuropathology modulates metabolism and established CBS patterns related to CBD, PSP, and AD. 26 There is, however, a lack of evidence supporting FDG-PET in the diagnostic workup depicting pathologies antemortem. 24,25 The present study aimed to use pre-established FDG-PET patterns to distinguish CBS due to AD from other possible pathologies, comparing the dichotomized groups regarding neurological assessment and amyloid PET status.…”

Positron emission computed tomography/single photon emission computed tomography in Parkinson disease

“…[ 6 , 39 ] In another 18 F-FDG PET imaging, the metabolism and perfusion of glucose in the asymmetric frontotemporal lobe and basal ganglia also decrease. [ 49 ]…”