Low-concentration contrast material for dual-source computed tomography coronary angiography by a combination of iterative reconstruction and low-tube-voltage technique: feasibility study]

To assess the impact of low concentration contrast media on the degree of vascular enhancement, image quality and radiation dose in coronary CT angiography (cCTA) studies when using a combination of iterative reconstruction and low tube voltage.120 patients who underwent cCTA were randomly divided into two groups. The patients in group A received iopromide 370 were scanned using the conventional tube output, and images were reconstructed using filtered back projection (FBP). The patients in group B received iodixanol 270 were scanned using the low tube output, and images were reconstructed using iterative reconstruction technique (SAFIRE, Siemens Healthcare). CT attenuation was measured in the coronary arteries, great arteries, interventricular septum and left ventricular cavity. Noise, subjective image quality scores and effective radiation dose were compared between the two groups.There was no significant difference in the mean CT attenuation achieved, image noise and mean image quality score at each anatomic site between iomeprol 270 group and iopromide 370 group. The effective radiation dose were 0.44 ± 0.25 mSv and 0.94 ± 0.42 mSv for iomeprol 270 and iopromide 370 in low weight subgroups, and 1.17 ± 0.30 mSv and 2.37 ± 0.66 mSv in high weight subgroups, respectively, reflecting dose savings of 53.2% (P < 0.01) and 50.6% (P < 0.01), respectively.The results demonstrate that with a combination of iterative reconstruction and a low tube voltage , a low iodine concentration of 270 mgI/ml still improves the contrast enhancement without impairing image quality, as well as significantly lowers effective radiation dose.