结肠CT仿真内镜成像的影响因素及对策的实验研究  

Study on affecting factors and measures of CT virtual colonoscopy imaging

作　　者：兰永树[1] 吕亚萍[1] 黄新文[1] 刘艾艾[1] 唐光才[1] 

机构地区：[1]泸州医学院附属医院CT室,四川泸州646000

出　　处：《中国介入影像与治疗学》2008年第6期409-412,共4页Chinese Journal of Interventional Imaging and Therapy

摘　　要：目的探讨结肠CT仿真内镜（CTC）的影响因素及应对策略。方法在4段新鲜离体猪结肠的不同位置植入0．5～2cm大小、形态各异的4小块肌肉或淋巴组织模拟病变；先后在充气和灌注2．5％的泛影葡胺溶液后采用GE公司64层螺旋CT以不同的毫安和螺距比的组合进行50cm范围的4次扫描，观察并比较每段结肠及其病变在不同状态下随扫描条件、观察阈值的变化情况。结果每段结肠及其病变随毫安的缩小和螺距比的增大，CT剂量指数和剂量长度乘积同步降低，两组图像的质量都变差，CTC观察阈值的范围逐渐变窄，肠内壁在观察阈值范围的中间区域平滑，向两端的伪影逐渐增多，但4个模拟病灶通过改变观察阈值都可以被发现。充气组随着观察阈值的逐渐降低，肠壁逐渐变厚而管腔逐渐缩小，突入肠管的致密病灶逐渐增大，而扁平病灶及小结节灶在观察阈值范围的中间区域较两端显示更清楚；灌注泛影葡胺组与此相反，并且图像质量更差。结论结肠内的充填物及扫描条件对结肠CTC的成像有影响，但其成像效果可以通过改变观察阈值来进行解决。Objective To evaluate the affecting factors and measures of CT virtual colonoscopy imaging. Methods Four fresh colons of swine were used, and 4 small deform muscles or adenoid tissues （sized 0.5--2 cm） were imbedded into each colon in different position. The colons were successively inflated and perfused with 2.5% meglumine diatrizoate solution. Four scans with 64-slice spiral CT were performed on 50 cm scope at different mAs and pitch ratios. The variability of each colon and lesion in alternative conditions was observed and compared. Results Along with milliampere reduction and pitch ratio increasing, the CT dosage index and dosage length product of each colon and its lesions synchronization reduced, and the quality of images in two groups degraded. The amplitude of CTC observation threshold value tapered narrowing, furthermore, the endhymenine of intestines was smooth in the intermediate region of observation threshold value scope, and the constructed defect gradually increased from the meso to each end, but 4 simulation focuses could all be discovered by changing the observation threshold value. In the inflatable group, with the observed threshold decreased, the bowel paries was thicker but the luminal was deflating. The focuses into the intestine increased gradually, but the lesions and nodules could be observed more clearly in the middle threshold region than the two end. In contrary, in the perfusion meglumine diatrizoate group, the quality of the images was even worse. Conclusion The filling and the CT scan conditions of colons are influential to the virtual colonoscopy imaging, but the imaging results could be improved by changing the observation threshold value.

关 键 词：结肠 仿真内镜 体层摄影术 X线计算机 

分 类 号：R816.5[医药卫生—放射医学] R814.42[医药卫生—临床医学]