Single-site 123I-FP-CIT reference values from individuals with non-degenerative parkinsonism—comparison with values from healthy volunteers

• Published in: European journal of hybrid imaging Vol. 4; no. 1; p. 5
• Main Authors: Fahmi, Rachid, Platsch, Günther, Sadr, Alexandre Bani, Gouttard, Sylvain, Thobois, Stephane, Zuehlsdorff, Sven, Scheiber, Christian
• Format: Journal Article
• Language: English
• Published: Cham Springer International Publishing 13.03.2020; Springer Nature B.V; SpringerOpen
• Subjects: 123I-FP-CIT SPECT,·Age effect; Age; Age composition; Asymmetry; Attenuation; Basal ganglia; Brain diseases; Central nervous system diseases; Confidence intervals; Degeneration; Dopamine receptors; Dopamine transporter; Gender; Gender difference; Identification methods; Image reconstruction; Imaging; Iodine; Iodine isotopes; Iodine radioisotopes; Medicine; Medicine & Public Health; Movement disorders; Neostriatum; Neurodegeneration; Normality; Nuclear Medicine; Original; Original Article; Putamen; Radiology; Reference values; Regression analysis; Single photon emission computed tomography; Statistical analysis; Tremor; Tremors; I-FP-CIT SPECT,·Age effect; Dopamine transporter; Reference values; Gender difference
• ISSN: 2510-3636; 2510-3636
• DOI: 10.1186/s41824-020-0074-2

Purpose Iodine 123-radiolabeled 2β-carbomethoxy-3β-(4-iodophenyl)- N -(3-fluoropropyl) nortropane ( 123 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 123 I-FP-CIT scans. To overcome the challenges of multi-center recruitment and scanning of healthy volunteers, we generated 123 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 123 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 123 I-FP-CIT references from scans acquired during routine clinical practice.