Quantitative analysis of early-phase 18F-flutemetamol PET brain images

Resumen

PET imaging techniques can be used to visualise the two major biomarkers of Alzheimer’s disease(AD).A series of radiotracers bind to amyloid-beta (Aβ) plaques in the brain while cerebral metabolism is assessed on18F-fluorodeoxyglucose (FDG)PET images.It is demonstrated that acquiring a PET image up to 10 minutes after the injection of anAβ-binding tracer yieldsimages that resemble PET images acquired with FDG. Therefore, these early-phase PET-amyloid images are suggested to be a surrogate to PET-FDG images and offer information about the cerebral perfusion, which is closely linked to the cerebral metabolism.In this work, early-phase PET images acquired with 18F-flutemetamol (FMM)are analysed and the correlation with FDG images is quantitatively assessed. Moreover, the results are compared to studies that used two different Aβ-binding tracers, namely 18F-florbetapir (FBP) and 18F-florbetaben (FBB).The Pearson’s correlation coefficient(r)is used to analyse how the standard uptake value ratios (SUVR)of different regions of interest of early-phase FMM and FDG images are related.An average correlation(± standard deviation)of r = 0.76 ±0.07 is obtained.ROI-based analysis showed that the highest correlation between both images is present in the right temporal lobe (r = 0.85).These values are comparable to the two selected studies that are based on early-phase FBP and FBB images. Therefore, the results suggest that early-phase PET-FMM acquisitions offer similar information to PET-FDG images.