Effects of medication on dopamine transporter imaging using [123I]I-FP-CIT SPECT in routine practice.

PURPOSE: Dopamine transporter (DAT) imaging is used to support the diagnosis of neurodegenerative parkinsonian disorders. Specific medications have been reported to confound the interpretation of [123I]I-FP-CIT SPECT scans, but there is limited data. The aim of the current study is to identify potential medication effects on the interpretation of [123I]I-FP-CIT SPECT scans in routine practice. MATERIALS AND METHODS: Consecutive patients undergoing a [123I]I-FP-CIT SPECT/CT scan on a 360° CZT camera between September 2019 and December 2022 were included. An exhaustive review of patient medications (antidepressants, antipsychotics, anti-epileptics, anti-parkinsonians, benzodiazepines, lithium, opioids, and stimulants) was performed. Two experienced nuclear physicians, blinded to the medication reports, interpreted the [123I]I-FP-CIT SPECT scans visually and a semi-quantitative analysis was performed using a local normal database. RESULTS: The study included 305 patients (71.0 ± 10.4, 135 women) and 145 (47.5%) visually interpreted normal scans. In normal scans, the striatum/occiput radioligand uptake ratio was decreased by noradrenergic and specific serotonergic antidepressants (NASSAs) (n = 15, z-score of - 0.93) and opioid medication (tramadol, n = 6, z-score of - 0.85) and was associated with a younger age in the multivariate analysis. In the overall population, the striatum/occiput ratio was influenced by NASSAs and associated with consensual visual analysis, age, sex, and anti-parkinsonian medications related to the status of the disease. CONCLUSION: Our study confirms the potential impact of antidepressant (NASSA) and opioid (tramadol) medications on the semi-quantitative analysis of [123I]I-FP-CIT SPECT scans. However, when performing a visual analysis, only NASSAs significantly impacted the interpretation of [123I]I-FP-CIT SPECT scans.

Prospective Paired Comparison of 123I-FP-CIT SPECT Images Obtained With a 360°-CZT and a Conventional Camera.

PURPOSE: This study aimed to compare 123I-FP-CIT SPECT imaging obtained from a 360° cadmium-zinc-telluride (CZT) camera with different focus configurations and from a conventional Anger camera. METHODS: This prospective study (NCT03980418) included patients referred to 123I-FP-CIT SPECT imaging who consecutively underwent a 30-minute acquisition on a conventional camera immediately followed by two 15-minute acquisitions on the 360°-CZT camera with, respectively, striatum and brain focus and reconstruction parameters to give equivalent contrast ratios, albeit with higher spatial resolution for the CZT camera. Tomographic count sensitivities were calculated. The images were analyzed through visual, according to 5 independent physicians, and automatic semiquantitative analyses. RESULTS: Ninety-two patients were included in this study. The 360°-CZT camera tomographic count sensitivities showed increases of +25% and +18% for striatum and brain focus, respectively, as well as significantly higher quality scores (P ≤ 0.04) in comparison to the conventional camera. The κ scores of consensual visual analysis were 0.80 and 0.85, and correlation coefficients of semiquantitative analysis for striatum uptakes were 0.75 and 0.76 for the comparisons of images obtained with the 2 cameras, with striatum and brain focus, respectively, for the CZT camera. Advanced age was the single predictor of discordant cases (10/92 [11%]) showing systematically abnormal scans with the conventional camera, potentially as a result of partial volume effect. CONCLUSIONS: Irrespective of focus mode, this high-sensitivity 360°-CZT camera provides concordant 123I-FP-CIT SPECT results when compared with a conventional camera, but with shorter acquisition times, higher image quality, and few discordant cases possibly explained by its higher spatial resolution.