Comparison between ¹¹C-CFT and ¹⁸F-FP-(+)-DTBZ positron emission tomography-computed tomography in the evaluation of...

Parkinson's disease (PD) is a progressive neurodegenerative disorder. Two positron emission tomography (PET) tracers, carbon-11-labeled 2β-carbomethoxy-3β-(4-fluorophenyl) tropane (¹¹C-CFT) and fluorine-18-labeled fluoropropyl-(+)-dihydrotetrabenazine [¹⁸F-FP-(+)-DTBZ], have emerged as key tools for PD imaging studies. However, the clinical utility of both ¹¹C-CFT and ¹⁸F-FP-(+)-DTBZ in the diagnosis of PD, as well as their relative ability to detect early-stage disease, has not been clarified. This study aimed to evaluate the similarities and differences between ¹⁸F-FP-(+)-DTBZ and ¹¹C-CFT PET/magnetic resonance (MR) in assessing idiopathic PD.

A total of 28 patients with PD (10 with mild PD, 11 with moderate PD, and 7 with advanced PD) and 12 healthy controls (HCs) underwent both ¹¹C-CFT and ¹⁸F-FP-(+)-DTBZ hybrid PET/MR imaging scans within a week of one another. Visual and semiquantitative analyses were applied to interpret the results. The mean standardized uptake value ratio (SUVR) of both tracers was measured in six brain regions and then compared for analysis.

Analysis of variance indicated significant differences in the SUVR between HC status, mild PD, moderate PD, and advanced PD across various brain regions with both tracers (all P values <0.05), except for the ipsilateral substantia nigra (SN) under ¹¹C-CFT. Strong positive correlations between ¹⁸F-FP-(+)-DTBZ and ¹¹C-CFT were observed in certain brain regions, including the bilateral caudate body, caudate head, anterior putamen, posterior putamen, and contralateral SN (all P values <0.05). Both tracers exhibited good performance in diagnosing and distinguishing patients with PD at different stages (all areas under the curve >0.7). Notably, the DeLong test revealed that ¹¹C-CFT was more effective than ¹⁸F-FP-(+)-DTBZ in distinguishing HC status, mild PD, and moderate PD (P<0.05).

Our findings suggest that ¹⁸F-FP-(+)-DTBZ PET/MR provides comparable results to those of ¹¹C-CFT PET/MR in most brain regions in the evaluation of early, moderate, and advanced PD. Future studies with larger sample sizes are warranted to explore discrepancies between the two tracers in the SN of mild PD patients.