前瞻性心电门控技术80kV-CT冠脉造影的临床应用研究

目的:评价80kV-CT冠脉造影图像质量与辐射剂量,明确其临床应用价值。方法:选取拟行CT冠状动脉造影的患者61例,随机分为两组。A组管电压设置为80kV,管电流300~450mA;B组管电压设置为120kV,管电流200~350mA。比较A和B两组的主观图像质量、客观图像质量(CT值、噪声值、SNR、CNR)及辐射剂量。P〈0.05认为差异有统计学意义。结果:A组平均得分3.36±0.68,B组平均得分4.58±0.67,A组与B组(t=-25.859,P=0.000)差异有统计学意义。A组可评估率为97.32%,B组可评估率为99.02%,A组与B组(χ²=3.276,P=0.070)差异无统计学意义。主动脉根部CT值,A组为(573.11±150.42)HU,B组为(428.41±95.32)HU,A组与B组(t=4.434,P=0.000)差异具有统计学意义;主动脉根部噪声值,A组为(43.32±12.25)HU,B组为(28.79±7.61)HU,A组与B组(t=5.488,P=0.000)差异具有统计学意义;主动脉根部SNR,A组为13.99±4.80,B组为14.78±3.50,A组与B组(t=-0.725,P=0.471)差异无统计学意义;主动脉根部CNR,A组为16.25±5.18,B组为18.82±4.65,A组与B组(t=-2.031,P=0.047)差异具有统计学意义;A组ED为(0.95±0.09)mSv,B组ED为(2.07±0.21)mSv,A组与B组(t=-28.052,P=0.000)差异有统计学意义。结论:通过适当提高管电流的80kV-CTCA可以大幅减低辐射剂量,而图像质量可满足诊断。

Clinical Research of 80 kV-CT Coronary Angiography for Prospectively Gated Axial Technique

Objective: To evaluate image quality and radiation dose for coronary artery computed tomographic angiography(CTA) obtained with 80 kV. Methods: 61 patients enrolled in this study were randomly divided into two groups. The group A was 32 patients with tube voltage 80 kV and tube current(200-350)mA. The group B was 29 patients with tube voltage 120 kV and tube current(300-450)m A. Two groups were evaluated for the image quality score, mean attenuation, noise, signal-to-noise ratio(SNR) and contrast-to-noise(CNR) in aortic root and radiation dose. The image quality and radiation dose was compared by Chi-square test and unpaired t-test. A P value below 0.05 was considered to be statistically significant. Results: The aortic root showed significantly higher mean image quality score, mean attenuation, noise and CNR in group A than in group B(P = 0.000, P = 0.000, P = 0.000, P = 0.047, respectively). The SNR was not statistically significant for group A versus group B(P = 0.471). The percentage of assessable coronary artery segments was no statistically significant for group B versus group A(χ2= 3.276, P = 0.070). The mean effective dose was statistically significant for the group A was 0.95 mSv versus 2.07 mSv for the group B(t =-28.052, P = 0.000). Conclusion: 80 kV-CTCA with higher tube current could offer assessable image quality and substantially reduced effective radiation dose.