Amyloid Imaging Using 18F-FIBT PET: a Pilot Study

Objectives 2-(p-Methylaminophenyl)-7-(2-[18F]fluoroethoxy)imidazo[2,1-b]benzothiazole (18F-FIBT) has been fully characterized and reported as a promising selective tracer for imaging cerebral amyloid deposition using PET[1]. For further clinical investigation, the imaging protocol and corresponding evaluation method are optimized in this pilot study.

Methods Six patients with different severity of cognitive impairment and underlying etiologies underwent dynamic PET imaging for 90 min on Siemens Biograph mMR. The image data was spatially normalized based on MRI using PMOD. Images were analyzed by comparing standardized uptake value ratios (SUVR), binding potentials (BP) obtained using reference tissue model, and distribution volume ratio (DVR). Cerebellum and subcortical white matter was selected as reference tissue region. The effect of MRI-based partial volume correction (PVC) on interpretation was also compared.

Results Specific binding was detected in the cases with underlying AD pathology, the intensities of BP and SUVR were associated with clinical severity. Cases with non-AD pathology did not show specific binding. BP has higher contrast than SUVR. However, SUVR is more consistent with the clinical interpretations. No PVC correction is preferred for the imaging evaluation.

Conclusions SUVRs without PVC correction seemed to be an easy and robust analyzing technique, making FIBT a favorable amyloid marker for clinical routine. [1]1. Yousefi BH, Manook A, Grimmer T, Arzberger T, von Reutern B, Henriksen G, Drzezga A, Förster S, Schwaiger M, and Wester HJ Characterization and First Human Investigation of FIBT, a Novel Fluorinated Aβ Plaque Neuroimaging PET Radioligand ACS Chemical Neuroscience 2015, 18;6(3): 428-437. $$graphic_B87D83C1-1B12-4ED5-AA91-2A9034B5C43C$$