【Objective】 To evaluate the effect of one-beat acquisition with wide detector CT on the image quality and diagnostic efficiency of coronary CT angiography (CCTA) in patients with atrial fibrillation. 【Methods】 A total of 52 consecutive patients with atrial fibrillation, including 31 males, (67.32±11.45) years old, who underwent CCTA from July 2022 to February 2023, were analyzed retrospectively. All patients underwent one-beat acquisition CCTA. The subjective and objective image quality of the coronary arteries was evaluated, and using invasive coronary catheter angiography as the gold standard, the diagnostic efficacy of stenosis degrees above moderate and severe degrees was calculated, respectively. 【Results】 Subjective evaluation results: 92.31% (384/416) of the vascular segments were rated as excellent or good, and the diagnosable rate reached 98.08% (408/416, subjective score ≥3 points). Objective evaluation results: The CT value of the right coronary artery, anterior descending branch, and circumflex branch was (433.41±95.17)HU, (422.69±92.81)HU and (420.27±95.43)HU, respectively; the contrast-to-noise ratio was 38.46±7.54, 32.46±13.78 and 37.74±8.89, respectively. The total diagnostic accuracy, sensitivity, and specificity was 94.71%, 87.9% and 96.62%, respectively, for moderate stenosis and 96.15%, 83.64% and 98.06% for severe stenosis. 【Conclusion】 One-beat acquisition with wide detector CT can obtain high-quality coronary artery images and high diagnostic accuracy for patients with atrial fibrillation without radiation dose increase to patients. It has good clinical application value for patients with atrial fibrillation.

【Objective】 To compare the enhancement effects of lean body weight （LBW） and total body weight （TBW） as indexes to calculate the contrast agent dosage under the condition of energy spectrum CT scanning. 【Methods】 A total of 218 patients who received liver enhancement CT from November 2018 to January 2019 were enrolled in this study. There were 101 patients in LBW group and 117 patients in TBW group. Both groups were scanned by energy spectrum CT， and the parameters of scanning and reconstruction were identical. The contrast agent dose was 500 mgI/kg （LBW） in LBW group and 450 mgI/kg （TBW） in TBW group， and the injection rate was 2.8 mL/s. Images were transferred to a GE AW4.7 workstation and the 50 keV monochromatic images were analyzed. We compared the dosage of contrast medium， CT value of aorta in arterial phase （HU-aorta）， hepatic enhancement CT value in venous phase （-liver）， the rate of reaching the enhancement standard and variability in the two groups. 【Results】 Compared with TBW group， LBW group had lower contrast agent dosage， HU-aorta and ∆-liver （P<0.05）， LBW and TBW group had no statistically different enhanced rate of HU-aorta as （91.09% vs. 90.60%） or ∆-liver （92.08% vs. 88.89%） （P>0.05）. The variation rate of HU-aorta and ∆-liver in LBW group was lower than that in TBW group. Using LBW as an index to calculate the dosage of liver enhanced CT also made the enhancement of liver parenchyma more consistent in different patients. 【Conclusion】 Even on the premise of energy spectrum CT scanning， using LBW-based contrast injection in liver enhanced CT can not only reduce contrast dose， but also make the enhancement in liver parenchyma more consistent among different patients.

【Objective】 To investigate the effects of 80 kVp combined with multi-model adaptive statistical iterative reconstruction algorithm （ASiR-V） on the image quality of CT angiography （CTA） of iliac artery in kidney transplantation candidates before operation. 【Methods】 Totally 50 kidney transplantation candidates underwent “one-stop” scanning combined CTA for coronary and iliac arteries were recruited consecutively. After the scanning， images were reconstructed with different ASiR-V levels on the iliac artery from 50% to 100% at a 10% interval， and 6 groups of images were obtained. We evaluated and compared all image qualities， DLP and CTDI in the patients’ examination were recorded， and the effective dose （ED） was calculated. 【Results】 All of the image quality objective scores of different ASiR-V levels on the iliac artery were above 3 points （3.32±0.24）， and the average CT value was （344.30±74.53）HU. The ED received by the patient throughout the examination was （2.71±0.42)mSv. The image noise decreased while SNR and CNR increased monotonically as the ASiR-V levels increased， among which 80% ASiR-V image quality score was the highest with 3.41±0.26. 【Conclusion】 For patients who need to have both coronary and iliac arteries evaluated before kidney transplantation operation， low tube voltage （80 kVp） combined with 80% ASiR-V can obtain high-quality iliac artery images under the premise of reducing the ED dose， which can provide practical basis for further reducing the dose in personalized scanning scheme for such patients. It has good feasibility and clinical application value.