多层螺旋CT多平面重组技术在胆总管结石中的应用

Assessment of CT multiplanar reformation in detection of choledocholithiasis

目的比较多层螺旋CT增强前后横断面扫描图像和增强后MPR技术在诊断可疑低位胆道梗阻患者中差异,探讨MPR技术在胆总管结石诊断中的应用价值。方法对46例胆道扩张的患者行MSCT扫描。两位医师进行盲法阅片,以手术或胆道造影为标准,比较增强前后横断面扫描图像对胆总管结石检出的差异,评价了增强后横断面扫描图像和增强后MPR图像的价值并进行统计学处理。分析以上三者对不同类型结石的诊断差异。结果增强前后横断面扫描图像对胆总管结石诊断的敏感性分别为82.1%和89.3%,特异性分别为77.8%和88.9%,准确性分别为80.4%和89.1%。在结石诊断中,增强后MPR图像的价值显著高于增强后横断面扫描图像(P<0.05)。增强前后横断面扫描图像和增强后MPR对软组织密度结石(6/8例,8/8例,8/8例)和胆汁密度结石(0/4例,2/4例,4/4例)的检出不同。结论增强后MPR提高了低位胆道梗阻的鉴别诊断能力,有利于常规平扫或增强横断面扫描图像难以发现的胆汁密度结石及小结石的检出,且能直观显示胆道内结石的数目。

Objective To compare unenhanced CT images, enhanced CT images and multiplanar reformation （MPR） images in the detection of choledocholithiasis. Methods In a prospective series, 46 patients with suspicion of biliary obstruction were scanned using 16-slice spiral CT scanner and studied with unenhanced images, enhanced images and MPR images. Enhanced axial data were used to construct MPR images. Two radiologists evaluated the images by consensus and determined the presence of stones. We used surgery, endoscopic retrograde cholangiopancreatography or percutaneous transhepatic cholangiography as the standard of reference. Sensitivity and accuracy of unenhanced and enhanced images were calculated in diagnosis of stones. The value of enhanced images and MPR images were rated and compared using the nonparametric tests of two related samples. Results In the detection of choledocholithiasis, the sensitivity of unenhanced and enhanced images was 82. 1% and 89.3%, the specificity was 77.8% and 88.9%, the accuracy was 80.4% and 89.1% respectively. The value of MPR images was higher than that of enhanced images （P〈0.05）. Unenhanced, enhanced images and MPR images were similar in the detection of dense and faint stones （16/16 cases）, and were different in stones of dense with parenchyma （6/8 cases, 8/8 cases, and 8/8 cases） or dense with saline （0/4 cases, 2/4 cases, and 4,/4 cases）. Conclusion In the detection of choledocholithiasis, MPR images could provide helpful information in differentiating biliary obstruction, recognizing stones of dense with saline, small stones and the number of stones.