Can FDG PET spot prodromal DLB vs AD?

Open paper intelligence

In MCI converters, DLB-like hypometabolism (including substantia nigra) with preserved medial temporal/posterior cingulate metabolism, and a medial temporal/SN ratio (94% sens / 83% spec), distinguished future DLB from AD.

Source

FDG PET metabolic signatures distinguishing prodromal DLB and prodromal AD

Kantarci K, Boeve BF, Przybelski SA, et al. · NeuroImage. Clinical · 2021

doi.org/10.1016/j.nicl.2021.102754 Read the full paper ↗51 citationscc by

Study at a glance

Design: Cohort — Baseline FDG PET in MCI converters to DLB vs AD vs CU controls
N: N=158 · MCI-DLB n=17; MCI-AD n=41; CU controls n=100
Population: Mayo ADRC MCI patients who later met probable DLB or AD, plus CU controls
Outcome: FDG PET hypometabolism patterns and CIS / medial temporal–SN ratios distinguishing prodromal DLB vs AD

Structured fields used in claim comparison tables when every cited study has a complete layer.

What they did

Compared baseline FDG PET in Mayo ADRC MCI patients who progressed to probable DLB (n=17) or AD dementia (n=41) versus CU controls (n=100), evaluating CIS and regional metabolic ratios.

What they found

MCI-DLB showed parieto-occipital hypometabolism extending to temporal lobes, SN, and thalamus, with relatively preserved medial temporal and posterior cingulate metabolism vs MCI-AD. CIS was specific (90%) but not sensitive (59%); medial temporal/SN ratio was both sensitive (94%) and specific (83%).

The limits

What it doesn't show

Small MCI-DLB n and single-center Mayo sample limit generalizability; PET patterns are biomarkers, not definitive pathologic diagnoses at the MCI stage.

Key terms

DLB: Dementia with Lewy bodies.
FDG PET: Fluorodeoxyglucose PET mapping regional glucose metabolism.
Cingulate island sign (CIS): Relatively preserved posterior cingulate metabolism vs precuneus/cuneus in DLB.
Prodromal / MCI: Mild cognitive impairment stage before dementia diagnosis.
Substantia nigra: Midbrain region with greater hypometabolism in MCI-DLB vs MCI-AD.

Flashcards

1 / 8

Research intelligence for this paper

See its role on concept claims, tensions it is part of, placement history, and related discoveries.

Open paper intelligence

Quiz yourself

1 / 5

MCI-DLB sample size was:

Common questions

Group sizes?

MCI-DLB 17; MCI-AD 41; CU 100.

CIS performance?

90% specific but 59% sensitive.

Best ratio?

Medial temporal / substantia nigra (94% sens, 83% spec).

DLB pattern early?

Yes — hypometabolism topography resembled DLB.