动态增强MRI在中下段直肠癌T_3分期中的应用研究

Gadolinium-enhanced MR imaging for T_3 staging in mid-low rectal carcinoma

目的探讨动态增强MRI在中下段直肠癌T3分期中的价值。方法本研究共纳入84例中下段直肠癌病人,包括经病理证实为T3期直肠癌的66例。所有病人术前均接受动态增强MRI检查。分析T3期直肠癌局部浸润的MRI征象,进行影像-病理对照,计算动态增强MRI诊断T3分期的准确度、敏感度、特异度、阳性预测值和阴性预测值。对直肠系膜内癌性与非癌性索条影在边缘和强化形式上的差异进行统计学分析。结果 MRI对中下段直肠癌T3分期的诊断准确度、敏感度、特异度、阳性预测值和阴性预测值分别为86.90%、90.91%、72.22%、92.31%和68.42%。直肠系膜内癌性与非癌性索条影在边缘和强化形式上的差异均有统计学意义(P<0.05)。在判断T3期直肠癌局部浸润深度时,将直肠系膜内癌性索条影误判为非癌性索条影是导致分期不足的主要原因。结论通过分析直肠系膜内异常索条影的边缘及强化形式有助于提高中下段直肠癌T3分期的准确性。

Objective To evaluate the value of dynamic gadolinium-enhanced MR imaging for T3 staging in midlow rectal carcinoma. Methods Eighty-four patients with histopathologically proven rectal carcinoma underwent dynamic gadolinium-enhanced MRI examination before surgery. Sixty-six cases had T3 stage cancer. Signs of the depth of local invasion of T3 stage on gadolinium-enhanced MR imaging were analyzed. The imaging findings were compared with pathological findings. Diagnostic accuracy,sensitivity,specificity,positive predictive value （PPV）,and negative predictive value （NPV） of T3-staging were calculated. Differences in border contour and enhancement pattern between cancerous and non-cancerous speculations in mesorectal fat were compared. Results The diagnostic accuracy,sensitivity,specificity,PPV and NPV of T3-staging were 86.90%,90.91%,72.22%,92.31%,and 68.42%,respectively. The border contour and the enhanced pattern significantly differed between cancerous and non-cancerous speculations （P〈0.05）. Incorrectly judging the cancerous spiculations as non-cancerous spiculations on gadolinium-enhanced MR imaging would lead to a lower T-stage. Conclusion Correctly analyzing the border contour and enhancement pattern of spiculations in mesorectal fat could improve diagnostic accuracy of T3-staging in mid-low rectal carcinoma.