Ultrafast [123Iode]FP-CIT SPECT imaging on new gamma camera with semiconductor detector technique: First clinical validation

Objectives To assess the feasability and diagnostic performance of a novel ultrafast gamma camera with cadmium-zinc-telluride (CZT) solid-state semiconductor detectors for striatal dopamine transporter uptake SPECT imaging (DaTSCAN).

Methods We first performed two phantoms studies (one normal and one pathological) to examine the feasability and the quantification of this method. Afterwards, our observationnal case-only prospective study comprised 50 consecutive patients who underwent a [123Iode]FP-CIT SPECT standard imaging protocol (EANM Guidelines). Scanning was performed first on a conventional dual-detector SPECT gamma camera (Hawkeye HD, GE Healthcare) with a 35-min acquisition time. All scans were immediately repeated on an ultrafast CZT camera (Discovery NM530c Alcyone, GE Healthcare) with a 10-min scan time and reconstructed from list-mode raw data to obtain scan durations of 1 min, 2 min, etc., up to a maximum of 10 min. For each of the scan durations, image quality was graded visually and clinical agreement (normal, abnormal, equivocal) between CZT and SPECT was assessed for each patient and each nigrostriatal subregion by 3 experimented independents nuclear physicians. Semi-quantitative subregional nigrostriatal tracer uptake values obtained using CZT were compared with those obtained using conventional SPECT by intraclass correlation and by Bland-Altman limits of agreement results.

Results The total counts were four to fivefold upper on CZT camera and no motion artifacts were observed. There was excellent clinical agreement between CZT and conventionnal SPECT on a per-patient basis (87 %) and a per-striatal uptake basis (89 %) as shown by highly significant correlation between subregional striatal tracer uptake values (r=0.89, p<0.001).

Conclusions This CZT solid-state detector system allows a substantially reduction in scan time and provides clinical information equivalent to conventional standard [123Iode]FP-CIT SPECT