迭代重建技术在肝脏低kVpCT增强扫描中的价值

发布时间：2018-06-18 23:12

本文选题：计算机体层摄影 + 迭代重建　；参考：《贵州医科大学》2017年硕士论文

【摘要】：目的:探讨正弦图确定迭代重建(sinogram affirmed iterative reconstruction,SAFIRE)技术在肝脏低kVpCT增强扫描中的价值。方法:收集贵州医科大学附属医院2015年7月~2016年6月以各种原因行上腹部CT增强扫描的受检者59例,回顾性分析其影像学检查及临床资料,按照扫描时的管电压不同分为A组(120kVp)和B组(80kVp),A组29例,男性16例,女性13例,年龄39~79岁,平均年龄(55.79±10.96)岁;B组30例,男性18例,女性12例,年龄32~79岁,平均年龄(56.93±13.71)岁,所有受检者的身体质量指数(body mass index,BMI)均在18.5~24kg/m2。所有受检者均采用德国西门子公司SIEMENS128层SOMATOM Definition AS+螺旋CT扫描仪进行扫描。均采用轴位扫描,扫描范围自膈顶至肝下缘。A组(n=29)采用120kVp条件扫描后,对动脉期原始图像进行滤波反投影重建(filtered back projection,FBP),B组(n=30)采用80kVp条件扫描后,对动脉期原始图像进行SAFIRE重建,重建级别为1~5级,分别编号为B1~B5组,共得到6组重建图像,卷积核分别为B40f及I40f,重建层厚为1.0mm,间隔为1.0mm,在西门子后处理工作站Syngo MMWP(Version 2008A)上进行数据分析测量。在动脉期图像中选择肝门层面,测量肝脏CT值、空气CT值。记录CT设备上提供的扫描时的容积CT剂量指数(Volume CT dose index,CTDIvol)和剂量长度乘积(dose length product,DLP)。比较A、B两组辐射剂量以及图像质量的评价指标。辐射剂量评价指标包括:CTDIvol、DLP及有效剂量(effective dose,ED);图像质量的客观评价指标包括:肝实质CT值、图像噪声及信噪比(signal to noise ratio,SNR);图像质量的主观评价指标包括:对图像噪声、血管显示、伪影及图像整体质量进行主观评分。采用SPPSS19.0软件进行统计学分析,采用独立样本t检验对A、B两组的辐射剂量评价指标CTDIvol、DLP及ED进行比较;采用方差分析对6组图像的客观评价指标及主观评价指标进行组间比较,组内多重比较采用LSD法。结果:A、B两组辐射剂量评价指标CTDIvol、DLP及ED差异均有统计学意义(P均㩳0.05),B组的ED较A组约减少了40.33%。6组图像肝实质CT值差异无统计学意义(P均㧐0.05)、SD及SNR差异均有统计学意义(P均㩳0.05),两两比较发现,B1~B5组与A组图像肝脏CT值差异均有统计学意义(P均㩳0.05),而B组(B1~B5组)肝实质CT值组内比较,差异均无统计学意义(P均㧐0.05),B3~B5组与A组图像SD及SNR差异均有统计学意义(P均㩳0.05),B5组与其他各组的SD及SNR差异均有统计学意义(P均㩳0.05),说明B5组图像的SD最小,SNR最大。6组图像的主观评分差异均有统计学意义(P均㩳0.05),两两比较发现,B5组图像的噪声、血管显示及硬化伪影的得分均高于其他各组(P均㩳0.05),但“腊样”伪影的得分均低于其他各组(P均㩳0.05),B3组重建图像的整体评分最高(P均㩳0.05)。结论:80kVp肝脏CT增强扫描结合SAFIRE-3重建技术,能得到较好的图像质量,同时能够降低有效辐射剂量。
[Abstract]:Objective: to investigate the value of sinogram affirmed iterative reconstructionsSAFIREE technique in liver low-kVpCT enhanced scanning. Methods: a total of 59 patients with upper abdominal CT enhanced scanning from July 2015 to June 2016 in affiliated Hospital of Guizhou Medical University were collected and their imaging and clinical data were analyzed retrospectively. They were divided into two groups: group A (n = 29) and group B (n = 29). There were 16 males, 13 females, aged 390.79 years, with an average age of 55.79 卤10.96 years, 30 patients in group B, 18 males and 12 females, aged 3279 years with an average age of 56.93 卤13.71), were divided into two groups: group A (n = 30) and group B (n = 29). Body mass index (BMI) of all participants was 18.5kg / m ~ (2) at 24 kg / m ~ (2). All the subjects were scanned by Siemens 128 layer SOMATOM definition as spiral CT scanner. All of them were scanned by axial scan. The scanning range was from the top of the diaphragm to the lower hepatic margin. Group A was scanned with 120kVp condition. The original images of arterial phase were reconstructed by filtered back projection. Group B was scanned with 80kVp condition, and the original images of arterial phase were reconstructed with SAFIRE. The reconstruction grade was 1 / 5 and numbered B1 / B5 respectively. Six groups of reconstructed images were obtained. The convolution cores were B40f and I40f.The reconstruction layer thickness was 1.0 mm and the interval was 1.0 mm. The data were analyzed and measured on Syngo MMWPPU version 2008A, a Siemens post processing workstation. Hepatic CT value and air CT value were measured on hilar plane in arterial phase image. The volume CT dose index (CTDIvoll) and dose length product (DLP) were recorded. The radiation dose and image quality of two groups of Agna B were compared. The evaluation indexes of radiation dose include: 1: CTDIvoll DLP and effective dose DLP, the objective evaluation indexes of image quality include: Ct value of liver parenchyma, image noise and signal-to-noise ratio signal to noise signal to SNR, subjective evaluation index of image quality include: image noise, vascular display. Artifact and overall image quality were evaluated subjectively. SPPSS 19.0 software was used to carry on the statistical analysis, the independent sample t test was used to compare the radiation dose evaluation index CTDIvoll DLP and Ed of the two groups, the objective evaluation index and the subjective evaluation index of the six groups were compared with each other by the analysis of variance. Multiple intra-group comparisons were performed by LSD. Results there were significant differences in DLP and Ed between the two groups. The Ed of group B was decreased by 40.33g than that of group A, there was no significant difference in CT value of hepatic parenchyma between group A and group A (P < 0.05). There were significant differences in CT value of liver parenchyma between group A and group A (P < 0.05). It was found that the CT value of liver in group B _ (1) B _ (5) was significantly different from that in group A (P < 0.05), but that in group B (group B _ (1) B _ (1) B _ (5) the CT value of liver parenchyma was higher than that in group A (P < 0.05). There was no significant difference in SD and SNR between group B 5 and group A. There were significant differences in SD and SNR between group B 5 and group A. There were significant differences in SD and SNR between group B 5 and other groups. There were significant differences in subjective scores of images (P < 0.05). The scores of vessel display and sclerosing artifact were higher than those of other groups (P < 0.05), but the scores of "wax" artifact were lower than those of other groups (P < 0.05). Conclusion the enhanced CT scan combined with SAFIRE-3 reconstruction technique can obtain good image quality and reduce the effective radiation dose.
【学位授予单位】：贵州医科大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：R816.5

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