kV assist技术联合自动管电流调制技术及ASIR重组算法在主动脉CTA成像的可行性研究

Feasibility Study of CT aortography using KV Assist Combined with Auto Modulation Tube Current Technique and ASIR Reconstruction Algorithm

目的探讨k V assist技术联合自动管电流调制技术及自适应统计迭代重组(ASIR)算法在降低主动脉CT血管成像(CTA)检查辐射剂量的应用价值。方法将临床疑诊主动脉病变而行主动脉CTA检查的60例患者分为两组,A组(30例),采用常规扫描方案:管电压120 k Vp,250 m A,采用30%ASIR;B组(30例)k V assist技术联合自动管电流调制技术,采用50%ASIR;两组对比剂均为碘比醇(350 mg I/ml)。采用两独立样本t检验(非正态分布采用Mann-Whitney U检验)比较两组的临床资料、CT辐射剂量以及图像质量主、客观评价指标。结果两组患者的年龄、身高、体重、体质指数(BMI)和Z轴扫描范围的差异均无统计学意义(P=0.360、0.639、0.611、0.528、0.091)。A、B两组的CT有效辐射剂量(ED)差异具有显著统计学意义(P<0.05),B组[(9.72±2.62)m Sv]较A组[(14.64±2.62)m Sv]减少约33.6%。两组图像主观评分的差异无统计学意义(P=0.898)。图像的客观评价:两组的主动脉主干及其主要分支的CT值均>300 HU,差异无统计学意义(P>0.05),信噪比(SNR)、对比噪声比(CNR)差异无统计学意义(P=0.063、0.620),噪声SD差异有统计学意义(P<0.05),B组低于A组。结论 k V assist技术联合自动管电流调制技术及ASIR算法行主动脉CTA检查,在保证图像质量的同时,可以有效减低辐射剂量。

Objective To explore the feasibility of CT aortography using KV assist combined with auto modulation tube current technique and ASIR reconstruction algorithm in reducing the radiation dose. Methods 60 patients with clinically suspected aortic lesions who underwent CT aortography were divided into two groups（ group A and B）. On Group A（ n =30 cases） was applied with 120 k Vp,250 m A and 30% ASIR. On Group B（ n = 30 cases） was applied with KV assist combined with automodulation tube current technique and 50% ASIR. Xenetix（ 350 mg I/ml） was used in the two groups as contrast medium. The clinical information,CT radiation dose,objective and subjective assessment of image quality between the two groups were retrospectively analyzed by independent test or Mann-Whitney U test. Results The difference of sex,age,height,weight,body mass index（ BMI） and Z axis scanning range of the two groups were not statistically significant（ P= 0. 360、0. 639、0. 611、0. 528 and 0. 091,respectively）. The difference of radiation dose between the two groups was statistically significant（ P〈 0. 05）. ED of group B was less than that of group A by around 33. 6%. The difference of CT subjective assessment score of image quality between the two groups was not statistically significant（ P = 0. 895）. The average CT values of the aorta trunk and its major branches in the two groups were higher than 300 HU（ P 〉0. 05）. There is no statistical difference between the two groups in average CT values,SNR and CNR（ P = 0. 063、0. 620）. There is statistical difference between two groups in SD（ P〈 0. 05）,SD of group B was lower than that of group A. Conclusion On the premise of obtaining good quality of image for diagnosis,KV assist combined with auto modulation tube current technique and ASIR reconstruction algorithm in CT aortography will reduce radiation dose effectively.