模型迭代重组技术在低剂量CT增强中评价胃癌图像质量的可行性  

The Feasibility Study of Evaluating the Image Quality of Gastric Carcinoma with Iterative Model Reconstruction Technique in Low Dose Contrast-enhanced CT

作　　者：王晓红 谢道海[1] 黄周[1] 

机构地区：[1]苏州大学附属第一医院放射科,苏州215000

出　　处：《临床放射学杂志》2017年第11期1690-1694,共5页Journal of Clinical Radiology

摘　　要：目的比较滤波反投影(FBP)、高级迭代重组算法(iDose^4)、模型迭代重组技术(IMR)在胃癌CT增强扫描的图像质量和辐射剂量,评价IMR的临床应用价值。方法 40例患者按随机数表法分为低剂量组(A组)和常规剂量组(B组),每组20例,患者均行上腹部CT平扫和动态增强扫描,将门静脉期扫描数据作为研究对象。为保证图像质量,每组患者扫描时均固定噪声比(DRI),根据辐射剂量和重组算法不同将图像分为6组,包括A1组(120 kV,FBP),A2组(120 kV,iDose^4),A3组(120 kV,IMR),B1组(80 kV,FBP),B2组(80 kV,iDose^4),B3组(80kV,IMR)。分别比较A1、A2、A3组和B1、B2、B3组的图像质量客观评价指标[图像噪声、图像信噪比(SNR)、对比噪声比(CNR)]和主观评价指标(低对比分辨力、病灶边缘锐利度、图像失真和诊断信心度),并计算有效辐射剂量(ED)。结果低剂量组ED较常规剂量组平均降低73.7%。A组IMR重组的图像噪声显著低于FBP重组和iDose^4重组(P<0.01),CNR及SNR显著高于FBP重组和iDose^4重组(P<0.01);B组的客观评价结果同A组。A、B两组IMR重组的低对比分辨力(LCD)、病灶边缘锐利度(LES)、图像失真(ID)和诊断信心度(DC)优于FBP重组和iDose^4重组,其中,A1组和A3组,B1组和B2、B3组的差异有统计学意义(P<0.05)。结论在显示胃癌病灶方面,IMR相比较iDose^4、FBP技术能大幅度降低图像噪声,提高图像质量。Objective To compare the image quality and radiation dose among filtered back-projection（FBP）、iDose^4 and iterative model reconstruction（IMR） in contrast-enhanced CT of gastric carcinoma,and to evaluate the value of clinical application of IMR. Methods Forty patients were randomly assigned into two groups（group A and group B,20 each） according to random number table. All patients underwent upper abdominal CT scanning and dynamic enhanced CT scanning.Portal scanning data of venous phase were taken as the research object. In order to ensure the quality of the image,the noise ratio of each patient was fixed. According to the different radiation dose and reconstruction algorithm,the images were divided into 6 groups： group A1（120 kV,FBP）,group A2（120 kV,iDose^4,group A3（120 kV,IMR）,group B1（80 kV,FBP）,group B2（80 kV,iDose^4,group B3（80 kV,IMR）. Objective evaluation indexes for image quality included image noise,signal-to-noise ratio（SNR） and contrast-to-noise（CNR）. Subjective evaluation indexes included low-contrast detectability,lesion edge sharpness,image distortion and diagnostic confidence,which were assessed and compared among group A1 and A2 and A3,group B1 and B2 and B3. Effective radiation doses were calculated. Results Effective radiation dose in group B was reduced 73. 7% compared to group A. In group A,image noise with IMR was significantly lower than that with FBP and iDose^4（P〈0. 01）,the former CNR and SNR were significantly higher than the latter（P〈0. 01）; While the objective evaluation indexes of group B was the same as group A. In group A and B,the low-contrast detectability,lesion edge sharpness,image distortion and diagnoses with IMR were better than FBP and iDose^4,and the difference between A1 and A3,B1 and B2、B3 were statistically significant. Conclusion Compared with FBP and iDose^4,IMR significantly reduces the image noise and enhances image quality of gastric carcinoma.

关 键 词：迭代模型重组技术 体层摄影术 X线计算机 胃癌 低辐射剂量 图像质量 

分 类 号：R730.44[医药卫生—肿瘤] R735.2[医药卫生—临床医学]