Effects of using Different Reconstruction Algorithms on Coronary Motion Artifacts at Various Heart Rates during Coronary CT Angiography

Abstract

Since the introduction of 64-detector computed tomography (CT), coronary CT angiography (CCTA) has been used increasingly for the noninvasive detection of coronary artery disease with a high diagnostic accuracy 1, 2). However, arterial motion, which is one of the most common limitations in CCTA examination, renders many arterial segments "non-interpretable" 3-6). Coronary motion artifacts tend to be most pronounced at higher heart rates (HRs), and several studies have recommended an average HR no greater than 65 beats per minute (bpm) to obtain reliable image quality in CCTA and recommend the use of medications, if necessary, to control the HR 7-10). The Society of Cardiovascular Computed Tomography (SCCT) guidelines for the performance and acquisition of CCTA has reported that HR control has tangible benefits including not only image quality, but also the ability to use dose-reduction scan acquisitions. Dose-reduction scan acquisitions are not possible at higher HRs, and a target HR for a CCTA set at 60 bpm or less is usually appropriate 11). The multi-sector reconstruction algorithm (MSRA) retrospectively reconstructs images from different cardiac cycles (two to five), and this method can theoretically improve the effective temporal resolution. Meanwhile, the half-scan reconstruction algorithm (HSRA) reconstructs images from a single cardiac cycle. MSRA usually achieves a better temporal resolution than HSRA 12). On the other hand, a novel motion correction algorithm (MCA) has been recently introduced that compensates for coronary arterial motion using image sets reconstructed with HSRA at adjacent cardiac phases within a single cardiac cycle obtained using electrocardiographic (ECG)-gated CCTA scans 6). The use of MCA improves image quality, interpretability, and diagnostic accuracy in CCTA without the use of medications to control HR 6) .