探讨超低剂量前瞻性冠脉CTA成像技术在低体重指数患者中的应用价值

目的:探讨在低体重指数患者中使用80kVp管电压的前瞻性心脏冠脉CTA成像的可行性。方法:对84例临床上怀疑冠心病的患者应用80kVp管电压的前瞻性心脏冠脉CTA检查。按BMI分为80kVp（BMI≤22kg/m2）和100kVp（2265次/分）。分析直径≥1.5mm的冠脉节段的图像质量（1～4分），比较各组的图像质量及辐射剂量。结果:两组患者的年龄、身高、心率的一致性较好（P>0.05）。80kVp、100kVp组的ED分别为(0.56±0.21)mSv、(1.43±0.58)mSv。两组的CT容积剂量指数（CT dose index volume，CTDIvol）、剂量长度乘积（dose length product，DLP）、ED存在显著的统计学差异（（P=0.000）。80kVp、100kVp组的合格图像分别为92.2％、91.8％。两组的图像质量评分、主动脉SNR及左、右冠主干CNR无统计学差异(P>0.05)。结论:80kVp的超低剂量前瞻性冠脉CTA可以应用于低体重指数患者，图像质量足以满足诊断需要，辐射剂量显著降低。 

Feasibility of 80 kVp Ultra-low Dose Scan Protocol in Prospective Coronary CT Angiography

Objective: To investigate the feasibility of prospective coronary computed tomography angiography (CTA) using tube voltage of 80 kVp in patients with low body mass index (BMI). Methods: Eighty-four patients with suspected coronary artery disease (CAD) underwent prospective ECG-gate coronary CTA. The cases were divided into two groups based on BMI: One group (BMI ≤22 kg/m2) was examined with 80 kVp, and the other group (22 < BMI ≤ 25) with 100 kVp. If heart rates < 65beats/min, pulse exposure time was set at 200 ms, otherwise 380ms. The imaging qualities of coronary artery segments with diameter ≥ 1.5 mm were evaluated. Image quality and radiation dose were compared between groups. Results: The age, height, and heart rate were insignificantly different between groups. In the 80 kVp and 100 kV groups, the EDs were 0.56 ±0.21 and (1.43 ±0.58) mSv, respectively. There were significant differences in CT dose index volume (CTDIvol), dose length product (DLP) and ED between groups. The image quality rates (score of 3 or 4) were 92.2% and 91.8% in the 80 kVp and 100 kVp groups, respectively. In image quality scores, aortic SNR and coronary trunk CNR had no significant differences between two groups. Conclusion: Prospective coronary CTA using tube voltage of 80 kVp in low-BMI patients can provide adequate coronary diagnostic information; while significantly reduce the radiation dose.