64排螺旋CT肺动脉联合支气管动脉双期增强扫描方案研究

目的:探讨肺动脉（PA）联合支气管动脉（BA）双期增强扫描的成像技术。方法:收集苏州大学第二附属医院行64排螺旋CT胸部增强扫描120名病人，设置固定延迟法和团注示踪法两种扫描方案。固定延迟法设置3组实验。A组:注入对比剂80mL，PA期延迟14s扫描，BA期延迟20s扫描；B组:注入对比剂80mL，PA期延迟14s扫描，BA期延迟22 s扫描；C组:注入对比剂70mL，PA期延迟12s扫描，BA期延迟22s扫描。团注示踪法:对比剂注入量70mL，在注射开始后延迟3s行同层跟踪扫描，感兴趣区放置在主肺动脉干分叉处，当感兴趣区CT值超过100Hu后开始扫描。评价靶血管强化值，比较各组间差异。结果:固定延迟法C组PA期及BA期PA/降主动脉（DA）强化差值分别为（243±111）Hu、（248±73）Hu，密度差异明显高于A组和B组；PA期:C组PA/DA的差值高于A组和B组（P<0.05和P<0.01），B、C组上腔静脉（SCV）的CT值高于A组（P<0.05和P<0.01），C组升主动脉（AA）和DA的CT值低于A组和B组（P<0.05~P<0.01），C组左心房（LV）的CT值低于A组和B组（P<0.05）；BA期:SCV、PA、LV、AA的CT值与A组和B组差异均有统计学意义（P<0.05），其中C组SCV、LV和AA的CT值均低于A、B组（P<0.05~P<0.01），A、B组间差异无统计学意义（P>0.05），且C组减少了对比剂用量。团注示踪法PA期及BA期PA/DA强化差值分别为（241±97）Hu、（234±60）Hu，与固定延迟法C组差异无统计学意义（P>0.05）。结论:合理利用经验延迟法及团注示踪法均可在一次检查中获得良好的CTPA及CTBA图像，能够提供一种辨识PA和BA密度差异的双期成像技术。在精确个体化差异中，团注示踪法比固定延迟法更有优势。

Study on the dual-phase enhanced scanning scheme of 64-slice spiral CT for pulmonary artery and bronchial artery

Objective:To investigate the of dual-phase enhanced scanning technology in pulmonary angiography(PA)and bronchial angiography(BA).Methods:One hundred and twenty scanned by chest enhanced 64-slice spiral CT from the Second Affiliated Hospital of Suzhou University were selected.The fixed delay method and bolus tracking(BT)method were employed.The patients treated with fixed delay method were divided into the group A(injected with 80mL contrast agent,delay scanning for 14 s in PA phase and delay scanning for 20 s in BA phase),group B(injected with 80 mL contrast agent,delay scanning for 14 s in PA phase and delay scanning for 22 s in BA phase),and group C(injected with 70 mL contrast agent,delay scanning for 12 s in PA phase and delay scanning for 22 s in BA phase).Among the patients treated with Bolus Tracking(BT),the same slice was tracked and scanned after 3 s of 70 mL contrast agent injecting.The crotch of the pulmonary artery trunk was the interest region,the scan was launched after the CT value achieved 100 Hu threshold.The target vascular enhancement value was evaluated,and the difference of which was compared.Results:Among the patients treated with fixed delay method,the reinforced difference values of PA/DA in PA phase and BA phase in group C were(243 ± 111)Hu and(248 ± 73)Hu,respectively,and the difference of the density in group C was significantly higher than that in group A and group B.In PA phase,the difference value of PA/DA in group C was higher than that in group A and group B(P<0.05 and P<0.01),the CT values of superior vena cava(SVC)in group B and group C were higher than that in group A(P<0.05 and P < 0.01),the CT values of ascending aorta(AA)and descending aorta(DA)in group C were significantly lower than those in group A and group B(P<0.05 to P<0.01),and the CT value of left atrium(LV)was lower than that in group A and group B(P<0.05).In BA phase,the differences of the CT values of SVC,PA,LV and AA between group A and group B were statistically significant(P<0.05),the CT values of SVC,LV and AA in group C were significantly lower than those in group A and group B(P<0.05 to P<0.01),the differences of the CT values of SVC,LV and AA between groups A and B were not statistically signficant(P >0.05),and the contrast agent in group C decreased.Among the patients treated with bolus tracking(BT)method,the reinforced difference values of PA/DA in PA phase and BA phase in group C were(241 ± 97)Hu and(234 ± 60)Hu,respectively,and the difference of which between two methods was not statistically significant(P>0.05).Conclusions:The good images of CTPA and CTBA can be acquired using the fixed delay method or bolus tracking method at one check,and the fixed delay method or bolus tracking method is a two-phase imaging technology,which can identify the density difference of PA and BA.The bolus tracking method has advantage over the fixed delay method in individualized examination.