螺旋CT仿真内窥镜在结肠隆起性病变的临床应用研究

Study and clinical application of CT virtual endoscopy in neoplasms of colorectum

目的探讨螺旋CT仿真内窥镜（CTVE）诊断大肠隆起性病变的检查方法和临床应用价值。方法CT扫描电流65～150mA，螺距（pitch）1．5～2．0，重建间隔1．5～2mm。应用Voyager（导航者）软件，以不同视角、视距“飞越”形式观察，综合分析二维和三维影像，并与32例结肠镜、11例手术结果对照分析。结果小电流、大螺距扫描和小间距重建能显示直径3mm大小的隆起性病变，并能分辨表面形态。以结肠镜检查为标准，直径≥5mm的隆起性病变的检出率达92％；以手术为标准，直径＜5mm的病变的检出率为74％。CTVE不受结肠癌阻挡的影响。三维影像转换为二维观察肠壁及壁外结构，有利于做出定性诊断和发现意外病变。结肠炎及平坦型结肠癌CTVE未显示。结论CTVE是一种无创、易被患者接受的显示结肠隆起性病变的新方法，能部分替代和补充结肠镜检查。炎性病变及平坦型病变是CTVE技术上的难题。

Objective To evaluate the methodology and clinical application of CT virtual endoscopy (CTVE) for diagnosing colorectal masses. Methods Fifty-three cases were classifid into 2 groups which underwent CT scans after the colon was cleaned and insufflated with air. The parameters used were:small milliampere(65 - 150 mA), large pitch (1 .5 - 2.0), and small interval (1 .5-2.0 mm). Reconstruction was done with 4D angio and voyager, different opacity were assigned and viewed by 'fly-through'. 3-dimensional images were compared with 2-dimensional images. Of the 53 cases, 32 cases were proved by colonoscopy and 11 cases by operation. Results The fecal debris retained was less in those who undrwent scans 1-2 h later after cleaning colon than those done within 30 min after cleaning the colon. CTVE allowed assessment of protuberant mass 3 mm in diameter and its morphology. Compeared with colonoscopy, detection rate by CTVE for masses 5 mm was 92%. Compared with operation, dstection rate by CFVE for masses < 5 mm was 74%. CT could evaluate the wall and outside structure of colon. Eight cases of colorectitis and 1 case of flat mass confirmed by colonoscope were missed by CTVE. Conclusion CTVE is a non-invasive method to detect colorectal masses, it can partially replace and is a supplement to colonoscopy.