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目的探讨不同心率在640层螺旋CT冠状动脉CTCA中对血管图像质量的影响以及辐射剂量变化。方法选取91例患者,男性51例,女性40例,平均年龄58岁。分成三组,A组30例,心率≤65次/分;B组30例,65次/分<心率≤80次/分;C组31例,心率>80次/分。扫描完成后选取最佳时相进行容积再现(VR)、最大密度投影(MIP)、多平面重建(MPR)及曲面重建(CPR)进行血管重建,根据4分法对血管图像质量分级并进行统计学分析,记录各组的辐射剂量程度乘积(DLP)。结果三组的血管图像质量在可评价比例及优良率无统计学意义,心率与血管图像质量等级呈负相关。A组DLP为(3.37±2.12)m Gy.cm,B组为(4.78±1.92)m Gy.cm,C组为(6.11±2.79)m Gy.cm,三组的辐射剂量有差异,经检验,有统计学意义,心率与辐射剂量呈正相关。结论 640层螺旋CT冠状动脉CTCA在高心率患者能较好的显示图像,同时辐射剂量也增加,应该在情况允许的条件下尽可能降低心率至65次/分以下,在获得优良血管图像质量的同时降低辐射剂量,有利于冠状动脉CTCA的可持续发展,以便让更多患者从中获益。
Objective To investigate the effect of different heart rates on the quality of vascular images and the change of radiation dose in coronary CTCA with 640-slice spiral CT. Methods 91 patients were selected, 51 males and 40 females, mean age 58 years. Divided into three groups, A group of 30 patients, heart rate ≤ 65 beats / min; B group of 30 patients, 65 beats / min 80 beats / min. After the scan was completed, the optimal phase was selected for volume reconstruction (VR), maximum density projection (MIP), multiplanar reconstruction (MPR) and surface reconstruction (CPR) for vascular reconstruction, and the blood vessel images were graded according to the four- Analyze and record the radiation dose degree product (DLP) of each group. Results The image quality of the three groups showed no significant difference between the evaluable rate and the excellent and good rate, and the heart rate was negatively correlated with the grade of the vascular image. The DLP in group A was (3.37 ± 2.12) m Gy.cm, in group B was (4.78 ± 1.92) m Gy.cm, in group C was (6.11 ± 2.79) m Gy.cm. There was a difference in radiation dose between the three groups , With statistical significance, heart rate and radiation dose was positively correlated. Conclusion The CTCA of coronary artery in 640-slice spiral CT can display the image better in patients with high heart rate and the dose of radiation is also increased. Heart rate should be reduced to 65 beats / min as much as possible under the circumstances, At the same time reduce the radiation dose, is conducive to the sustainable development of coronary CTCA, so that more patients benefit from it.