320排CT容积扫描法与螺旋扫描法在低心率冠状动脉成像中的对比研究

目的 比较320排CT 容积扫描法（volume法）与螺旋扫描法（helical法）在低心率冠状动脉成像中的应用价值。 方法 128例患者分为两组：容积扫描组（n=72）和螺旋扫描组（n=56），分别采用CT容积扫描法及螺旋扫描法进行冠状动脉成像扫描（检查时患者心率均低于65次/min），对比分析两组患者的图像质量、辐射剂量及对比剂用量。 结果 容积扫描组和螺旋扫描组患者升主动脉根部CT值分别为（492.08±58.51）HU、（522.72±56.91）HU，图像噪声分别为（19.64±3.51） HU、（22.66±5.33）HU，差异无统计学意义；两组冠状动脉节段优秀率分别为97.5%（632/648）、96.8%（488/504），合格率分别为99.7%（646/648）、99.2%（500/504），差异无统计学意义。容积扫描组、螺旋扫描组有效辐射剂量分别为 （3.21±0.23） mSv、（13.27±2.39） mSv，差异有统计学意义（P<0.001）；对比剂用量分别为50～60 mL、80～90 mL。 结论 低心率时320排CT容积扫描法与螺旋扫描法均可获得满意的冠脉图像，但容积扫描法辐射剂量更低、造影剂用量更少，具有一定优势。

Comparison of volume scan and helical scan in low heart rate coronary CT angiography at 320-row CT

Objective To compare the values of volume scan and helical scan in low heart rate coronary CT angiography. Methods Coronary CT angiography was done with 320-row detector in 128 patients. The patients were assigned to two groups: Group 1 (n=72) undergoing volume scan and Group 2 (n=56) undergoing helical scan. The heart rates of patients were lower than 65/min during examination. The image quality, radiation dose, and amount of contrast were compared between two groups. Results The ascending aorta root CT values of group 1 and group 2 were (492.08±58.51) HU and (522.72±56.91) HU, and the image noise of the two groups were (19.64±3.51)HU and (22.66±5.33)HU, respectively. The excellent rates of coronary artery image quality in group 1 and group 2 were 97.5% (632/648) and 96.8% (488/504), and the pass rates were 99.7% (646/648) and 99.2% (500/504), respectively. There were no significant differences concerning image noise, excellent rates of image, or pass rates of image between the two groups (P>0.05). The effective radiation doses were significantly lower in group 1 compared with group 2 ([3.21±0.23] mSv vs [13.27±2.39] mSv, P<0.001). The amounts of contrast in group 1 and group 2 were 50-60 mL and 80-90 mL, respectively. Conclusion Image quality of coronary CT angiography obtained with volume scan and helical scan can both meet the requirement for clinical diagnosis, but compared with the helical scan, volume scan shows an advantage as it needs lower radiation dose and less contrast.