Modulation transfer function-based assessment of temporal resolution:: Validation for single-and dual-source CT

The purpose of this study was to determine a manufacturer-independent quality assurance measurement for temporal resolution with a three-dimensional cardiac motion robot; validation was with single-source (SS) and dual-source (DS) computed tomography (CT). Image acquisition was performed by using standard cardiac protocols. Image contrast-based modulation transfer function (MTF) was assessed as function of time. For motion frequency of 60 beats per minute, MTF slightly decreased by 14% and 6% for SS CT and DS CT, respectively. For higher frequencies, a stronger decrease of MTF (eg, by 50% [SS CT] and 18% [DS CT] at 120 beats per minute) was detected. Effect of manufacturer's adaptive bisegment algorithm for SS CT and corresponding resonance effects of rotation time and heart rate were quantified. The robot-based approach is a reproducible, objective way to assess temporal resolution; it allows practical measurement of temporal resolution and comparison of CT scanners and protocols. (C) RSNA, 2008.