改良的两次屏气扫描方案联合100 kV管电压行减影CCTA的临床可行性

 目的  探讨一种改良的两次屏气减影扫描方案行减影冠状动脉CT血管造影(coronary CT angiography,CCTA)以及联合使用100 kV管电压行低剂量扫描在屏气受限的患者中的临床可行性。方法  对于钙化积分＞400且体重指数＜25 kg/m2,同时伴有屏气受限的患者纳入本研究;本研究共纳入17人。心脏平扫容积数据及增强容积数据在两次屏气中采集完成;且两次扫描保持相同的时间窗,即位于R-R间期的65%～80%。采用4分法对目标钙化节段行图像质量评估。结果  共53个目标钙化节段纳入本研究。较常规CCTA相比,减影CCTA的目标钙化节段的图像质量明显改善(3.36±0.92 vs.2.51±0.95,P<0.01)。不可评估冠脉节段数在常规CCTA中共23(43.4%)个节段,在减影CCTA中,共6个冠脉节段(11.3%);行减影CCTA扫描后,严重钙化节段的可评估性明显提高(P=0.02)。行减影CCTA扫描总的有效辐射剂量为(2.80±0.64)mSv。结论  这种改良的两次屏气扫描方案在屏气受限患者中行减影CCTA的临床可行性,即通过降低甚至消除钙化斑块伪影的不良影响,提高严重钙化冠脉节段的图像质量以及临床可评估性。通过联合使用100 kV扫描管电压,对于体重指数＜25 kg/m2的患者,可以显著降低扫描的总的有效辐射剂量。

Modified two breath-hold method in subtraction coronary CT angiography with 100 kV tube voltage:a preliminary study

Objective  To explore the feasibility of a modified two breath-hold method with radiation dose reduction technique using lower voltage of 100 kV in subtraction coronary CT angiography (CCTA) for patients with limited breath-hold (<15 s).Methods  A total of 17 patients with Agatston score >400,and body mass index less than 25 kg/m2 were enrolled in this study.The pre-contrast and post-contrast volume data was acquired during two breath-holds with the same time window period in 65%-80% of the R-R interval.A 4-point scale was used for the evaluation of subjective image quality.Results  A total of 53 calcified coronary segments were evaluated.There was an improvement in the image quality from 2.51±0.95 with conventional CCTA to 3.36±0.92 with subtraction CCTA (P<0.01).The non-diagnostic segments significantly reduced from 23(43.4%) to 6 (11.3%) using subtraction CCTA (P=0.02).The average total effective radiation dose was (2.80±0.64) mSv.Conclusions  This preliminary study has shown that our modified method in subtraction CCTA could significantly reduce the non-assessable segments and improve the accessibility of severe calcified segments by reducing or eliminating artifacts.Using 100 kV tube voltage,the total radiation dose was distinctly reduced with maintained image quality in BMI＜25 kg/m2 patients.