Objective To evaluate the feasibility of dual-source CT (DSCT) under low tube voltage of 80 kV in the patients receiving coronary CT angiography (CCTA).Methods From Dec 2014 to Nov 2015, 56 cases of patients with body mass index(BMI) ≤ 30 kg/m2 underwent CCTA in our hospital were selected,and then divided into group A (100 kV, 320 mgI/mL iodixanol)and group B (80 kV, 320 mgI/mL iodixanol)according to their examination order, 28 cases in each group.The radiation dosages between the two groups were compared, and the CT values and signal-to-noise ratios (SNR)at root of ascending aorta (AO) were measured.Then the CT values of left main coronary artery (LM), proximal segments of left anterior descending (LAD)and left circumflex(LCX)coronary arteries, proximal segment of right coronary artery (RCA) and adjacent tissues were also measured,and the contrast-to-noise ratios (CNR)of LM, proximal segments of LAD, LCX and RCA were further calculated.Statistical analysis was carried out after double-blind subjective grading of the patients'images of volume rendering (VR) and maximum intensity projection(MIP) by means of Likert four-point scale.Results The radiation dose in group A (4.36±0.71) mSv was significantly higher than that ingroup B (1.75±0.40) mSv(P<0.05). The CT values of AO, LM, and proximal segments of RCA, LAD and LCX in group B were higher than those in group A, with significant differences (P<0.05).The image noise in group B(47.17±7.76) HU was significantly higher than that in group A (29.73±4.21) HU (P<0.05). But there was no significant difference in the SNR of root of AO and the CNR of LM and proximal segments of RCA, LAD and LCX between the images of two groups (P>0.05). No significant difference was found in the subjective grades of image quality and the coronary segments for diagnosis between the two groups (P>0.05).Conclusion For patients with BMI ≤ 30kg/m2,operation of CCTA under low tube voltage of 80 kV could largely reduce the X-ray radiation dosage for the mand obtain images meeting the quality requirement of clinical diagnosis. |