Impact of multi-pinhole collimators on reader confidence in DAT SPECT

Ziel/Aim Multi-pinhole (MPH) collimators improve both spatial resolution and count sensitivity in brain SPECT. Aim of this prospective study was to evaluate the impact of MPH collimators on the reader confidence in the interpretation of dopamine transporter (DAT) SPECT with ¹²³I-ioflupane.

Methodik/Methods Two SPECT acquisitions, one with MPH the other with LEHRHS collimators, were performed in randomized order with a triple-head SPECT system (Mediso Anyscan Trio) after a single dose of ≥170 MBq ¹²³I-ioflupane in 24 patients (54 % females, 65 ± 13y). Reconstructed SPECT images were mapped into MNI space. Categorization as ‘non-neurodegenerative’ or ‘neurodegenerative’ was performed twice by each of two independent readers (experienced vs less experienced) based on visual inspection of 12mm thick slab images displayed in randomized order. The readers rated their confidence from 0 (very uncertain) to 10 (very certain). Hottest voxels analysis was used to estimate the specific binding ratio (SBR) of ¹²³I-ioflupane in the putamen.

Ergebnisse/Results The experienced reader categorized 11 of the 24 patients as ‘neurodegenerative’, independent of the collimator and of the reading session. Categorization by the less experienced reader was discrepant between first and second reading session in two of the 48 images, both with LEHRHS. The confidence score was 1.5 points (less experienced reader) to 2.2 points (experienced reader) higher for MPH SPECT compared to LEHRHS SPECT (both p < 0.0005). The putamen SBR (minimum of both hemispheres) was significantly lower in the neurodegenerative cases than in the non-neurodegenerative cases for MPH and LEHRHS SPECT (both p < 0.0005). The effect size was slightly larger with MPH SPECT (Cohen’s d = 3.8 vs 3.4).

Schlussfolgerungen/Conclusions These findings suggest that better image quality by MPH collimators results in improved reader confidence in the visual interpretation of DAT SPECT.

Publikationsverlauf

Artikel online veröffentlicht:
08. April 2021