迭代模型重建技术不同辐射剂量对肝脏CT增强扫描图像质量的影响

发布时间：2018-02-15 08:51

  本文关键词： 肝疾病 肝 体层摄影术 X线计算机 迭代重建算法 图像增强 辐射剂量 质量控制　出处：《中国医学影像学杂志》2015年01期 　论文类型：期刊论文

【摘要】：目的比较迭代模型重建(IMR)技术在不同辐射剂量条件下对肝脏CT增强扫描图像质量的影响,探讨IMR技术在不同辐射剂量条件下在肝脏CT增强扫描中的价值。资料与方法 54例行上腹部CT增强扫描患者,根据不同门静脉期扫描方案分为A组29例(120 k V,250 m As)和B组25例(80 k V,500 m As)。采用滤波反投影(FBP)重建技术和IMR技术重建门静脉期原始数据,得到4组图像,包括A1组(120 k V,FBP)、A2组(120 k V,IMR)、B1组(80 k V,FBP)和B2组(80 k V,IMR),比较各组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率、图像失真及诊断信心度,并计算有效辐射剂量。结果 B组有效辐射剂量较A组降低42.7%(t=15.27,P0.001)。A2组图像噪声低于A1组,B2组图像噪声低于B1组,而B2组SNR及CNR较其他3组均显著增高(F噪声=81.98、FSNR=65.19、FCNR=37.42,P0.001)。各组低对比分辨率评分A2B2A1B1(χ2=58.21,P0.001),各组图像失真评分A1B1A2B2(χ2=12.94,P0.001),B2组与A1组、B1组间差异有统计学意义(P0.05);各组诊断信心评分A2A1B2B1(χ2=34.06,P0.001),A1组与B2组间差异无统计学意义(P0.05),其余组间差异有统计学意义(P0.05)。结论与FBP比较,IMR技术不同辐射剂量扫描均可以降低肝脏CT增强扫描图像噪声并能提高图像质量,改变效果尤以80 k V、500 m As CT扫描明显。
[Abstract]:Objective to compare the effects of iterative model reconstruction (IMR) technique on the quality of liver CT enhanced scanning images under different radiation doses. To investigate the value of IMR technique in liver CT enhanced scanning under different radiation doses. Materials and methods 54 patients with upper abdominal CT enhanced scanning were performed. According to different portal phase scanning schemes, 29 patients in group A were divided into two groups: group A (n = 29) and group B (n = 25), and group B (n = 25) were divided into two groups: group A (n = 29) and group B (n = 25). The original data of portal vein phase were reconstructed by filtering backprojection technique and IMR technique, and 4 groups of images were obtained. Group A1 (120 kV) and group B2 (80 kV) were compared with each other in terms of image quality, image noise, image signal-to-noise ratio (SNR), contrast noise ratio (CNR) and subjective evaluation index, low contrast resolution, image distortion and diagnostic confidence. Results the effective radiation dose in group B was 42.7 lower than that in group A. the image noise in group A was lower than that in group A (15.27) P 0.001. A2 was lower than that in group B _ 1, and that in group B _ 2 was lower than that in group B _ 1. The SNR and CNR of group B2 were significantly higher than those of other three groups (P < 0.05). The low contrast resolution score A 2B 2A 1B 1 (蠂 2 58.21g P 0.001) and the image distortion score A 1B 1A 2B 2 (蠂 2 12.94U P 0.001B 2) were significantly higher than those of group A1 (P 0.05), and the diagnostic confidence score A 2A 1B 2B 1 (蠂 2 34.06n P 0.001B 1) was significantly higher than that of the other three groups (P < 0.05). The diagnostic confidence score of each group was A2A1B2B1 (蠂 2 34.06P 0.001B 1) and the diagnostic confidence score (A2A1B2B1) was significantly higher than that of the other three groups (蠂 2 12.94U P 0.001 P 0.001); the diagnostic confidence score of each group was A2A1B2B1 (蠂 2 34.06P 0.001B 1). There was no significant difference (P 0.05) between the other groups. Conclusion compared with FBP, different doses of FBP can reduce the noise and improve the image quality of liver CT enhanced scanning. The change effect was especially obvious in 80 kV as 500 m as CT scan.
【作者单位】： 南方医科大学;广东省人民医院 广东省医学科学院放射科;飞利浦中国影像研究院;广州市第一人民医院放射科;
【基金】：国家自然科学基金项目(81271569,81271654)
【分类号】：R816.5;R575
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