High pitch CT in triple rule-out studies: Radiation dose and image quality compared to multidetector CT

Abstract

ObjectiveTo compare the image quality and radiation dose from high pitch dual source CT (128-DSCT) vs. those from retrospective acquisition with 64-row multidetector CT (64-MDCT) in triple rule-out studies. Material and methodsWe retrospectively studied 60 patients with acute chest pain: 30 with a retrospective EKG acquisition with 64-MDCT and 30 with high pitch 128-DSCT. We quantitatively analyzed the image quality by calculating the vascular density, muscular density (DM), noise, vascular density/noise ratio (VDNR), and contrast/noise ratio (CNR). We qualitatively evaluated the artifacts in the vena cava, aorta, and coronary arteries. We estimated the effective dose (ED) of radiation by means of the dose-length product. ResultsThere were no significant differences between 128-DSCT and 64-MDCT in the vascular density. The VDNR and CNR were higher on 128-DSCT than on 64-MDCT in the aorta (VDNR: 28.9±11.7 vs. 20±5.5; CNR: 24.4±10.9 vs. 16.8±5.4; P<.01), in the pulmonary arteries (VDNR: 25.5±10 vs. 20.6±6.5; CNR: 24.5±5.4 vs. 17.4±6.4; P<.01), and in the coronary arteries (VDNR: 25.9±8.2 vs. 18.9±4.9; CNR: 24.9±8.2 vs. 15.6±4.6; P<.01). There were fewer artifacts in the coronary arteries on 128-DSCT than on 64-MDCT (3 vs. 34 nondiagnostic segments; P<.001), and the ED in 128-DSCT was lower than in 64-MDCT (13.77±4 vs. 2.77±0.6mSv; P<.001). ConclusionIn triple rule-out studies, high pitch 128-DSCT delivers a lower dose of radiation and provides better image quality than retrospective acquisition with 64-MDCT.