Dopamine Transporter SPECT with 12-Minute Scan Duration Using Multiple-Pinhole Collimators
Ralph Buchert, Balazs Szabo, Ákos Kovács, Thomas Buddenkotte, Franziska Mathies, Amir Karimzadeh, Wencke Lehnert, Susanne Klutmann, Attila Forgács, Ivayla Apostolova
Abstract
This study evaluated the potential to reduce the scan duration in dopamine transporter (DAT) SPECT when using a second-generation multiple-pinhole (MPH) collimator designed for brain SPECT with improved count sensitivity and improved spatial resolution compared with parallel-hole and fanbeam collimators. <b>Methods:</b> The retrospective study included 640 consecutive clinical DAT SPECT studies that had been acquired in list mode with a triple-head SPECT system with MPH collimators and a 30-min net scan duration after injection of 181 ± 10 MBq of [<sup>123</sup>I]FP-CIT. Raw data corresponding to scan durations of 20, 15, 12, 8, 6, and 4 min were obtained by restricting the events to a proportionally reduced time interval of the list-mode data for each projection angle. SPECT images were reconstructed iteratively with the same parameter settings irrespective of scan duration. The resulting 5,120 SPECT images were assessed for a neurodegeneration-typical reduction in striatal signal by visual assessment, conventional specific binding ratio analysis, and a deep convolutional neural network trained on 30-min scans. <b>Results:</b> Regarding visual interpretation, image quality was considered diagnostic for all 640 patients down to a 12-min scan duration. The proportion of discrepant visual interpretations between 30 and 12 min (1.2%) was not larger than the proportion of discrepant visual interpretations between 2 reading sessions of the same reader at a 30-min scan duration (1.5%). Agreement with the putamen specific binding ratio from the 30-min images was better than expected for 5% test–retest variability down to a 10-min scan duration. A relevant change in convolutional neural network–based automatic classification was observed at a 6-min scan duration or less. <b>Conclusion:</b> The triple-head SPECT system with MPH collimators allows reliable DAT SPECT after administration of about 180 MBq of [<sup>123</sup>I]FP-CIT with a 12-min scan duration.