Research on image quality optimization of coronary computed tomography angiography with Snapshot freeze technique

HAN Wei; HU Gang; LU Jun-liang; GUO Ning; CHEN Hua; LIU Geng-huai; ZHOU Yan; FENG Meng; WANG Li; LI Hong-min; WU Xin-huai

doi:10.3969/j.issn.1674-4055.2016.04.20

Abstract：Objective To explore the value of Snapshot Freeze (SSF) technique in image quality optimization of coronary computed tomography angiography (CCTA).Methods Retrospective analysis was conducted on CCTA results of 85 patients (without taking medications to control heart rate) from general hospital of Beijing military between March and May 2013, in order to investigate differences of image quality before and after application of SSF technique. Patients were divided into two groups: group A (26 patients with heart rate≤65 bpm) and group B (59 patients with heart rate>65 bpm). Motion artifact index (MAI) of left anterior descending artery (LAD), left circumflex artery(LCX) and right coronary artery (RCA) were calculated before and after applied SSF technique. Image quality of CCTA was independently assessed by two radiologists using a 5-point scale and then analyzed quantitatively.Results The mean heart rates was 63.5±5.69 for group A and 77.73±6.67 for group B respectively. For group A, MAI of image quality of SSF images(12.65±5.96) was lower than those of non-SSF images(24.10 ±8.62,P<0.05), and subjective score of image quality of SSF images(4.15±0.45) were higher than those of non-SSF images(3.00±1.04,P<0.05). For group B, MAI of image quality of SSF images(18.09±9.00) was lower than those of non-SSF images(66.99±17.49,P<0.01), and subjective score of image quality of SSF image (3.82±0.78) were higher than those of non-SSF images(1.96±0.67,P<0.01). The MAI decrease rate of SSF image in group B (73%) was better than group A (48%).Conclusions SSF algorithm could improve image quality of CCTA, especially in patients with heart rate higher than 65bpm.