[ ¹⁸ F]-PM-PBB3-PET Tau Imaging in Alzheimer’s Dementia and PSP

Ziel/Aim [¹⁸F]Pyridinyl-butadienyl-benzothiazole 3 (¹⁸F-PM-PBB3) is a novel PET imaging agent designed to capture tau pathology in neurodegenerative diseases. We report here our initial clinical experience in Alzheimer`s disease (AD) and progressive supranuclear palsy (PSP) patients with this novel ¹⁸F-labelled PET tracer.

Methodik/Methods 16 clinically confirmed AD patients, 3 clinically confirmed PSP patients and ten age-matched healthy controls (HC) underwent clinical assessment, MRI and ¹⁸F-PM-PBB3-PET imaging. Late emission images recorded at 90 min post injection were pre-processed, spatially normalized in SPM. We then calculated standardized uptake value ratios (SUVR) using cerebellar cortex as reference region. Differences in tracer binding in various brain regions were compared using the two-tailed independent Student’s t-test, and correlations between SUVR and clinical dementia scores (MMSE) were interrogated by Pearson’s correlation.

Ergebnisse/Results Significant differences in SUVR between HC and AD groups (p < 0.05) were noted in the frontal (Cohen’s d =1.95), temporal (d = 1.78), occipital (d = 1.70) and parietal lobes (d = 1.76), as well as in the insula (d = 1.50), cingulum (d = 1.80), putamen (d = 1.42), midbrain (d = 1.07) and pons (d = 1.36). Post hoc regression analysis revealed significant correlations between SUVR and MMSE in the AD patients for the superior right frontal gyrus (r = −0.670; p = 0.005), inferior left temporal gyrus (r = −0.686; p = 0.014) and left hippocampus (r = −0.601; p = 0.014). For the preliminary investigation on PSP patients, increased uptake was observed in mid brain, pallidum, pons, thalamus and putamen (means: 35.0 %, 23.9 %, 9.4 %, 8.8 % and 7.3 % respectively).

Schlussfolgerungen/Conclusions ¹⁸F-PM-PBB3-PET imaging discriminates well between HC and AD groups with a large effect size. Areas of increased uptake correlated with the known distribution pattern of tauopathy in post mortem brain of AD patients. Increased uptake was also observed in PSP patients in brain regions known to accumulate tau. This ¹⁸F-based tau tracer is a promising second-generation tau-tracer suitable for further clinical studies in 3R- and 4R-tauopathies. Acknowledgement: We thank APRINOIA Therapeutics for providing the precursor used in the study.