基于模型的迭代重建在胸廓出口处超低剂量CT扫描中的可行性  

Application of iterative reconstruction to reduce noise in the low-dose chest CT imaging of thoracic outlet level

作　　者：赵永为[1] 王鹤[1] 王霄英[1] 刘建新[1] 

机构地区：[1]北京大学第一医院医学影像科,北京100034

出　　处：《放射学实践》2013年第3期288-290,共3页Radiologic Practice

摘　　要：目的:探讨基于模型的迭代重建(MBIR)技术在超低剂量胸部螺旋CT扫描中对胸廓出口处图像噪声的抑制程度。方法:选取连续20例患者行超低剂量胸部CT平扫,扫描范围为双侧颈根部层面至胸2椎体下缘层面胸廓出口处层面。扫描参数:120kVp,应用管电流调制技术(10～400mA),噪声指数(NI)40,重建层厚及层距0.625mm。根据重建方式不同分为30%ASIR组和MBIR组。在AW4.5工作站上两组所得图像取胸廓出口处相同层面,分别测量双侧竖脊肌、甲状腺、肺尖、椎体及气管内CT值及SD值并进行统计学分析(配对t检验)。结果:两组间各兴趣区CT值差异均无统计学意义(P>0.05),噪声(SD)值间差异均有统计学意义(P<0.05)。结论:应用MBIR技术对超低剂量胸部CT数据进行重建,能够有效地降低胸廓出口层面图像的噪声。Objective：To study the ability of inhibition of noise in the ultra-low-dose chest spiral CT scan of the tho racic outlet by using model-based iterative reconstruction （MBIR） technology. Methods： Twenty consecutive patients who underwent ultra-low-dose CT scan at the level of thoracic outlet were enrolled in this study. Scan range covered from bilateral carotid roots to the second thoracic vertebrae. Scanning conditions： 120kVp,using tube current modulation technology, 10- 400mA,noise index 40,reconstruction thickness 0. 625mm, slice distance 0. 625mm. According to the reconstruction mode, the CT images were divided into AS1R group and MBIR group. Images at the same level of the two groups were taken at thoracic outlet,and regions of interest （ROD were drawn in the same area in bilateral erector spinae muscles,thyroid,lung apex,vertebra,and tracheal lumen. CT value and SD value were measured on a AW4.5 workstation. CT value and SD value of the ROI in the 2 groups were compared by paired sample t-test respectively. There was significant difference when P〈 0.05. Results; Average CT value of ROI of AS1R group was （349.86±96.70）HU,average SD value was （82.89±26.05）, Meanwhile, those of MBIR group were （328.89 ± 160.29）HU and （31.03 ± 16.19）, There was no significant difference between the CT values of the ROI of the 2 groups （P〉 0.05）. There was significant difference between the SD values of the ROI of the 2 groups （P〈0.05）. Conclusion： MBIR technology can effectively reduce the image noise of the thoracic out let level compared to ASIR reconstruction images.

关 键 词：体层摄影术 X线计算机 迭代重建 辐射量 

分 类 号：R816.4[医药卫生—放射医学]