Single-site I-FP-CIT Reference Values from Individuals with Non-degenerative Parkinsonism-comparison with Values from Healthy Volunteers
Overview
Authors
Affiliations
Purpose: Iodine 123-radiolabeled 2β-carbomethoxy-3β-(4-iodophenyl)-N-(3-fluoropropyl) nortropane (I-FP-CIT) SPECT can be performed to distinguish degenerative forms of movement disorders/parkinsonism/tremor from other entities such as idiopathic tremor or drug-induced parkinsonism. For equivocal cases, semi-quantification and comparison to reference values are a necessary addition to visual interpretation of I-FP-CIT scans. To overcome the challenges of multi-center recruitment and scanning of healthy volunteers, we generated I-FP-CIT reference values from individuals with various neurological conditions but without dopaminergic degeneration, scanned at a single center on the same SPECT-CT system following the same protocol, and compared them to references from a multi-center database built using healthy volunteers' data.
Methods: From a cohort of 1884 patients, we identified 237 subjects (120 men, 117 women, age range 16-88 years) through a two-stage selection process. Every patient had a final clinical diagnosis after a mean follow-up of 4.8 ± 1.3 years. Images were reconstructed using (1) Flash3D with scatter and CT-based attenuation corrections (AC) and (2) filtered back projection with Chang AC. Volume-of-interest analysis was performed using a commercial software to calculate specific binding ratios (SBRs), caudate-to-putamen ratios, and asymmetry values on different striatal regions. Generated reference values were assessed according to age and gender and compared with those from the ENC-DAT study, and their robustness was tested against a cohort of patients with different diagnoses.
Results: Age had a significant negative linear effect on all SBRs. Overall, the reduction rate per decade in SBR was between 3.80 and 5.70%. Women had greater SBRs than men, but this gender difference was only statistically significant for the Flash3D database. Linear regression was used to correct for age-dependency of SBRs and to allow comparisons to age-matched reference values and "normality" limits. Generated regression parameters and their 95% confidence intervals (CIs) were comparable to corresponding European Normal Control Database of DaTscan (ENC-DAT) results. For example, 95% CI mean slope for the striatum in women is - 0.015 ([- 0.019, - 0.011]) for the Flash3D database versus - 0.015 ([- 0.021, - 0.009]) for ENC-DAT. Caudate-to-putamen ratios and asymmetries were not influenced by age or gender.
Conclusion: The generated I-FP-CIT references values have similar age-related distribution, with no increase in variance due to comorbidities when compared to values from a multi-center study with healthy volunteers. This makes it possible for sites to build their I-FP-CIT references from scans acquired during routine clinical practice.
Dopaminergic PET to SPECT domain adaptation: a cycle GAN translation approach.
Lopes L, Jiao F, Xue S, Pyka T, Krieger K, Ge J Eur J Nucl Med Mol Imaging. 2024; 52(3):851-863.
PMID: 39557690 PMC: 11754385. DOI: 10.1007/s00259-024-06961-x.
Kim J, Kang S, Moon B, Kim B, Jeong J, Yoon H EJNMMI Res. 2024; 14(1):65.
PMID: 39017925 PMC: 11254898. DOI: 10.1186/s13550-024-01126-1.
Investigating the aspect of asymmetry in brain-first versus body-first Parkinson's disease.
Lovdal S, Carli G, Orso B, Biehl M, Arnaldi D, Mattioli P NPJ Parkinsons Dis. 2024; 10(1):74.
PMID: 38555343 PMC: 10981719. DOI: 10.1038/s41531-024-00685-3.
Flaus A, Philippe R, Thobois S, Janier M, Scheiber C EJNMMI Res. 2023; 13(1):37.
PMID: 37117951 PMC: 10147889. DOI: 10.1186/s13550-023-00983-6.
Jeong E, Sunwoo M, Lee J, Han S, Hyung S, Song Y Front Neurol. 2022; 13:976101.
PMID: 36119683 PMC: 9474999. DOI: 10.3389/fneur.2022.976101.