应用低剂量造影剂行双源CT肺动脉血管造影价值

Value of low-dose contrast agent to dual energy CT pulmonary angiography

目的探讨低剂量造影剂在双源CT肺动脉血管造影中的应用价值。方法疑诊肺动脉栓塞行CTPA检查患者40例,随机分为常规剂量组和小剂量组各20例,分别应用优维显(300mgI/mL)80mL和40mL行双源CT双能量扫描,获得140kV和80kV能量CT数据,由2名高年资医师进行图像质量评价,Kappa分析行一致性检验,并比较2组相同能量扫描时肺动脉主干、左肺动脉干、右肺动脉干、左肺上叶前段、左肺上舌段、左肺下叶前基底段、右肺上叶前段、右肺中叶内侧支、右肺下叶前基底段的血管信噪比(signal noise ratio,SNR)。结果 2名医师主观图像质量评价结果一致性良好(Kappa=0.77,P=0.000),常规剂量组图像质量评分(4.43±0.23)与小剂量组(4.32±0.23)比较差异无统计学意义(P>0.05);80kV能量扫描时,常规剂量组和小剂量组肺动脉主干SNR(4.79(3.67,5.11)、5.18(4.81,7.59))、左肺动脉干SNR(4.48(3.35,5.12)、5.10(4.46,7.40))比较差异有统计学意义(P<0.05);140kV能量扫描时,常规剂量组和小剂量组肺动脉主干SNR(2.60(2.33,2.71)、3.16(2.73,3.64)),左肺动脉干SNR(2.63(2.17,2.78)、3.09(2.56,3.43)),左肺下叶前基底段SNR(1.96(1.28,2.13)、2.42(1.88,3.11)),右肺上叶前段SNR(2.09(1.66,2.68)、2.84(2.18,3.35)),右肺下叶前基底段SNR(2.18(1.70,2.74)、2.90(2.27,3.21))比较差异有统计学意义(P<0.05),余相同能量扫描时2组血管SNR比较差异无统计学意义(P>0.05)。结论双源CTPA检查时应用小剂量造影剂可获得与常规剂量造影剂相同的清晰图像。

Objective To evaluate the application value of low-dose contrast agent to dual energy CT pulmonary angiography（CTPA）. Methods Forty patients with suspected pulmonary embolism were randomly divided into conventional-dose and low-dose groups,with 20 patients in each group,receiving CTPA with Ultravist（300mgI/mL）in dose of 80 mL and 40 mL respectively to obtain 140 kV and 80 kV energy imaging data.The imaging quality was evaluated by two experienced doctors.The consistency check was done by Kappaanalysis,and the signal noise ratio（SNR）values of same energy scanning were compared between two groups in the main pulmonary artery,the left and right pulmonary trunks,the anterior segments of superior lobe of the left and right lungs,the superior lingular segment of the left lung,the anterior basal segments of inferior lobe of left and right lungs,and the medial branch of middle lobe of the right lung.Results The Kappavalue of diagnosis acceptance ratio was 0.77（P=0.000）,showing no significant difference between conventional-dose group（4.43±0.23）and low-dose group（4.32±0.23）（P〉0.05）.There were significant differences in SNRs of 80 kV between conventional-dose group and low-dose group in the main pulmonary artery（4.79（3.67,5.11）,5.18（4.81,7.59））and the left pulmonary trunk（4.48（3.35,5.12）,5.10（4.46,7.40））（P〈0.05）.There were significant differences in the SNR values of 140 kV energy scanning between two groups in the main pulmonary artery（2.60（2.33,2.71）,3.16（2.73,3.64））,the left pulmonary artery（2.63（2.17,2.78）,3.09（2.56,3.43））,the anterior basal segment of inferior lobe of the left lung（1.96（1.28,2.13）,2.42（1.88,3.11））,the anterior segments of superior lobe of the right lung（2.09（1.66,2.68）,2.84（2.18,3.35））,and the anterior segment of superior lobe of the right lung（2.18（1.70,2.74）,2.90（2.27,3.21））（P〈0.05）.There were no significant differences in the other SNR values of same energy between two groups（P〉0.05）.Conclusion Low-dose contrast agent could obtain the same quality of image in dual energy CTPA as conventional dose contrast agent.