First performance test of a dual wide-coverage CT system.

Abstract

This study presents a comprehensive performance test of a dual-source wide-coverage CT system, which integrates two 16-cm detectors and two corresponding X-ray tubes on a single gantry. The architecture of the CT system and a dedicated cross-scatter correction algorithm are described, the latter of which is developed for this particular dual wide-coverage geometry and combines physical modeling with empirical calibration. The implemented correction was demonstrated to be effective in reducing cross-scatter artifacts, with preserved spatial resolution (difference < 0.5% at 10% MTF) and low-contrast detectability (3 mm at 0.3% contrast, at a volume CT dose index of 47.6 mGy and a slice thickness of 1.0 mm) after correction. Temporal resolution was assessed using an ECG-signal-driven dynamic phantom, tested with the dual wide-coverage acquisition mode. It provided motion-artifact-free images under simulated sinus rhythm at 100 bpm and arrhythmic conditions varying between 75 and 100 bpm. Clinical performance was further illustrated in a patient with a mean heart rate of 197 bpm, in whom CCTA acquired with this mode showed clear and sharp coronary arteries with minimal motion artifact at a radiation dose of 1.48 mSv. The dual wide-coverage CT system successfully integrates 16-cm wide z-axis coverage with high temporal resolution of the dual-source system, demonstrating potential for advanced dynamic cardiac imaging. KEY POINTS: Question Current CT systems require a compromise between wide z-axis coverage and high temporal resolution, limiting optimal performance in patients with high or irregular heart rates. Findings A novel dual wide-coverage CT system achieved high temporal resolution and motion-artifact-free images across high and irregular heart rates, with effective cross-scatter correction preserving spatial and low-contrast resolution. Clinical relevance The dual wide-coverage CT system enables high-quality coronary CT angiography with high or irregular heart rates, expanding the clinical utility of cardiac CT.