A multi-center phantom study comparing image resolution from three state-of-the-art SPECT-CT systems

Ongoing advancements in SPECT-CT technology raise important questions regarding the differences in performance between various cameras and their respective image-processing algorithms. Our study seeks the answer to this question via measurement of phantom myocardial wall thickness (MWT) on images obtained from three state-of-the-art cameras.

A thorax phantom with an insert modeling a healthy heart was scanned using cardiac acquisition protocols with Philips' Precedence (PP), GE's Infinia Hawkeye (IH), and Siemens' Symbia-T6 (SS). Processing was performed using advanced reconstruction techniques available on the cameras and our own independent software. The MWT measurement was used as a figure of merit in performance evaluation.

When using 50% threshold, MWTs measured for the data acquired using PP, IH, and SS and reconstructed with independent standardized software were 8.5 +/- 1.2 mm, 7.7 +/- 1.2 mm, and 9.3 +/- 0.9 mm, respectively; and 9.3 +/- 0.5 mm, 19.2 +/- 0.8 mm and 18.4 +/- 1.1 mm when using the manufacturers' own reconstructions, respectively. Thresholds optimized for each image (ranging from 32% to 68%) produced much more uniform results.

No significant differences were observed between image resolutions when data acquired from different cameras were reconstructed with an independent algorithm. However, different manufacturers' reconstruction algorithms produced MWTs that differed by up to about 110% when using a set threshold of 50%.