CT低剂量扫描小肠造影诊断小肠间质瘤的应用价值

Value of low-dose CT enterography in diagnosis of small intestinal stromal tumors

目的探讨模型迭代重组技术(IMR)在低剂量CT小肠造影增强扫描中的应用价值。方法收集小肠间质瘤患者40例,随机分为常规剂量A组和低剂量B组,将门静脉期数据作为观察对象。A组门静脉期管电压固定为120kV,B组为80kV。重组得到A1(120kV,FBP),A2(120kV,iDose4),A3(120kV,IMR),B1(80kV,FBP),B2(80kV,iDose4),B3(80kV,IMR)。测算病灶的CT值及标准差(SD)、信噪比(SNR)、对比噪声比(CNR);采用五分法进行图像主观质量评分;并计算有效剂量(ED)。结果A3组图像噪声明显低于A1、A2组,SNR和CNR均明显高于A1、A2组;B组评价同A组。A3、B3组评分均优于同组的FBP、iDose4组;除A1与A2组之间的评分无统计学差异外,余各组之间均有统计学差异。B组ED较A组降低68%。结论基于IMR技术的低剂量CT小肠造影扫描,可以在保证图像质量同时有效降低辐射剂量。

Objective To investigate the application value of iterative model reconstruction(IMR)in contrast-enhanced low-dose CT enterography.Methods Forty patients with small intestinal stromal tumors were randomly divided into routine dose group A and low dose group B.The data of portal venous phase were taken as the research objects.The voltage of portal venous phase was fixed at 120 kV in group A and 80 kV in group B.Six groups of images were obtained:A1(120 kV,FBP),A2(120 kV,iDose4),A3(120 kV,IMR),B1(80 kV,FBP),B2(80 kV,iDose4),and B3(80 kV,IMR).The CT value and standard deviation(SD),signal-to-noise ratio(SNR)and contrast-to-noise ratio(CNR)were measured,and the subjective image quality was evaluated by five-point method.Effective dose(ED)was calculated.Results The image noise in group A3 was significantly lower than that in group A1 and A2,and the SNR and CNR were significantly higher than those in group A1 and A2.The evaluation in group B was the same as group A.The quality scores of A3 and B3 groups were better than those of FBP and iDose4 groups,except that there was no statistical difference between A1 and A2 groups,there were statistical differences among other groups.ED in group B was 68%,lower than that in group A.Conclusion Enhanced multi-phase CT enterography based on IMR technology can guarantee the image quality and reduce radiation dose effectively.