Flash CT低管电压结合迭代重建技术在超重患者冠状动脉成像中的应用

Application of low kilovoltage and iterative reconstruction in image space of Flash CT coronary angiography of overweight patients

目的探讨Flash CT低管电压结合迭代重建(IRIS)技术对改善超重患者冠状动脉成像图像质量及降低辐射剂量的价值。方法对100例体质量指数(BMI)为25～30kg/m2的患者行Flash CT检查,按扫描管电压随机化分成A(120kV)、B(100kV)两组,对B组图像经IRIS重建获得数据作为C组。测量主动脉根部、左冠状动脉及右冠状动脉起始部血管腔内CT值、噪声(SD),并计算SNR、CNR,记录有效辐射剂量(ED)。结果 3组图像优良率比较差异有统计学意义(χ2=7.604,P<0.05);3组血管腔强化CT值、噪声、SNR、CNR差异均有统计学意义(P均<0.05)。两两比较,血管腔内CT值B、C两组高于A组;B组噪声最大,CNR最低;C组SNR最高。A、C组ED分别为(8.6±1.3)mSv和(3.5±0.7)mSv,差异有统计学意义(t=-16.91,P<0.05)。结论对于超重患者运用低管电压结合IRIS技术进行Flash CT冠状动脉检查能够获得较好的图像质量,显著降低辐射剂量。

Objective To observe the value of low kilovoltage and iterative reconstruction in image space （IRIS） to improve image quality and reduce radiation dose in Flash CT coronary angiography of overweight patients. Methods One hundred patients with body mass index （BMI） of 25-30 kg/m2 underwent Flash CT with tube voltage of 120 kV （group A, n=50） and 100 kV （group B, n=50）, while the images of group B were rebuilt with IRIS and taken as group C. The difference of coronary CT value and image noise （SD） were measured in aorta, left coronary and right coronary, while the SNR and CNR were calculated ,and the radiation dose was recorded. Results There was significant difference in excellent images among 3 groups （X^2=7. 604, P〈0.05）. There was significant difference in the mean intraluminal attenuation, im- age noise, SNR, and CNR among 3 groups （all P〈0.05）. The mean intraluminal attenuation of group 13 and group C were significantly higher than that of group A. Image noise was the greatest and CNR was the lowest in group B, while SNR of group C was the highest. The effective dose was （3.5±0.7）mSv in group C and （8.6±1.3）mSv in group A （t= -16.91, P〈0. 05）. Conclusion Using low kilovoltage and IRIS of Flash CT coronary angiography can get better image quality and low radiation dose for overweight patients.