Aims

To identify a characteristic metabolic pattern of Dementia with Lewy Bodies (DLB), to study its expression in Alzheimer’s disease dementia (AD) and to test its ability to differentiate between DLB and AD.

Methods

We applied scaled subprofile model/principal component analysis (SSM/PCA) on FDG-PET scans from 20 DLB1 and 20 normal controls (NC1) from which we removed previously identified Alzheimer's disease related pattern (ADRP) by an orthogonalization procedure. Expressions of newly identified DLB-related pattern (DLBRP) and ADRP were calculated on a validation group of 60 DLB2, 21 NC2 and 63 biomarker-confirmed AD patients.

Results

DLBRP was formed by a linear combination of first and third principal components, accounting for 19,1% and 7.1% variance, respectively. It was characterized by relative hypometabolism in occipital and relative hypermetabolism in temporal lobes and posterior cingulate cortex.

DLBRP expression was significantly higher in DLB1 than NC1, in DLB2 than NC2 and in DLB2 than AD groups (p < 0.001). No significant difference in DLBRP expression was found between AD and NC2 groups. ADRP expression was significantly higher in AD group in comparison to both NC groups (p < 0.001), but no significant difference was found between AD and DLB groups. ROC curves yielded high AUC values for DLBRP: DLB1 vs. AD (AUC = 0.979) and DLB2 vs. AD (0.898) and low AUC values for ADRP: DLB1 vs. AD (0.674) and DLB2 vs. AD (0.574).

Conclusions

DLBRP is a promising imaging biomarker of DLB with ability to distinguish not only between DLB from NC but also between DLB and AD.