【摘要】 目的:研究16层螺旋CT低剂量仿真结肠镜对结肠病变的显示能力,及各种后处理技术对不同大小息肉的显示率。方法:对15例患者行16层螺旋CT结肠仿真内镜和结肠镜检查。采集220 mA7、0 mA2、0 mA的影像,采用多平面重组(MPR)、CT仿真结肠镜(CTC)、容积再现(VR)、结肠全景展平显示(VD)显示病变。采用成组设计多个样本比较的秩和检验和多个样本两两比较的秩和检验。结果:不同剂量显示层厚10 mm的影像质量、2.5 mm准直宽度采集的影像质量差异有统计学意义(P<0.01),不同剂量的MPR与CTC影像差异无统计学意义(P>0.05)。CT仿真结肠镜在检测结肠病变的敏感度为96%,特异度为94%,阳性预测值为98%,阴性预测值为88%。20 mA检测>10 mm息肉的敏感度为100%,6~10 mm 90%,<5 mm 59%。CTC显示不同大小的息肉的敏感性最高,VD次之,MPR对于小息肉的检出率下降,VR不能检出小息肉。结论:低剂量仿真结肠镜将为结肠病变普查提供广阔的前景。更多还原

【Abstract】 Objective:To study the ability of CT oolonography by 16 detector-row MSCT using ultra-low X-ray dose scanning technique in the detection of colorectal lesions and to evaluate the relative detection rates by using different post-processing techniques(MPR,CTC,VR,VD).Methods:15 patients with colon diseases were scanned with a 16 detector-row MSCT scanner using 220mA,70mA,20mA parameters respectively.Conventional colonography was performed as a gold standard.Statistically,rank sum test and four table test were used to evaluate the images.Results:There were statistical differences in image quality between the images with 10mm and those with 2.5mm of slice thickness acquired by using different X-ray dose techniques(P<0.01).There were no statistical differences(P>0.05) in image quality between the images of MPR and CTC acquired by using various X-ray dose acquisition techniques respectively.In comparison to conventional colonogrphy,the sensitivity,specificity,positive and negative predictive rates of CT virtual endoscopy were 96%,94%,98% and 88% respectively.The detection rates of 20mA images for colon polyps with different dimensions were as follows:100%(25/25) for the ones with diameters of >10mm,90%(18/20) for the ones of 6～10mm in diameter and 59%(10/17) for those of <5mm in diameter.CTC was the most sensitive post-processing technique for showing polyps of different size,while VD was in the second place,MPR is less sensitive for demonstrating polyps with less than 5mm in diameter.VR was not useful for detecting small sized polyps.Conclusion:MSCT virtual colnography using low X-ray dose technique provided a promising screening method for patients with colorectal lesions.更多还原