Okizuka H, Sugimura K, Ishida T
Department of Radiology, Shimane Medical University, Enya Izumo, Japan.
J Magn Reson Imaging. 1993 Mar-Apr;3(2):329-35. doi: 10.1002/jmri.1880030207.
Magnetic resonance (MR) imaging for the preoperative assessment of rectal carcinoma was evaluated. Thirty-three patients underwent MR imaging with a 1.5-T unit. On the basis of results of barium enema studies and/or digital examination, a balloon catheter was inserted to the level of the lesion before MR imaging. Both T1- and T2-weighted axial spin-echo images were obtained in all patients. With the balloon catheter, the three layers of the normal bowel wall could be seen on T2-weighted images. Muscular invasion was detected with a sensitivity of 90%, a specificity of 84%, a positive predictive value of 90%, a negative predictive value of 84%, and an overall accuracy of 88%. False-positive results were related to chemical shift artifact and intramural lymph node metastases. Perirectal fat invasion was detected with a sensitivity of 64%, a specificity of 89%, a positive predictive value of 82%, a negative predictive value of 77%, and an overall accuracy of 79%. One of the false-positive results was related to intramural lymph node metastases and the other to perirectal vessels. Evaluation of adjacent organ invasion was accurate in all patients. Lymph node metastasis was correctly detected in six of nine patients. Absence of lymph node metastasis was correctly predicted in 23 of 24 patients. Thus, MR imaging with a balloon catheter was useful for detection of tumor invasion into muscularis propria and adjacent organs; however, its demonstration of perirectal fat and lymph node involvement was less accurate.
对磁共振（MR）成像用于直肠癌术前评估进行了评价。33例患者接受了1.5-T设备的MR成像检查。在钡灌肠研究和/或指诊结果的基础上，在MR成像前将球囊导管插入至病变水平。所有患者均获得了T1加权和T2加权轴向自旋回波图像。借助球囊导管，在T2加权图像上可以看到正常肠壁的三层结构。检测肌层浸润的敏感度为90%，特异度为84%，阳性预测值为90%，阴性预测值为84%，总体准确率为88%。假阳性结果与化学位移伪影和壁内淋巴结转移有关。检测直肠周围脂肪浸润的敏感度为64%，特异度为89%，阳性预测值为82%，阴性预测值为77%，总体准确率为79%。其中一个假阳性结果与壁内淋巴结转移有关，另一个与直肠周围血管有关。所有患者对邻近器官浸润的评估均准确。9例患者中有6例正确检测到淋巴结转移。24例患者中有23例正确预测无淋巴结转移。因此，使用球囊导管的MR成像有助于检测肿瘤浸润至固有肌层和邻近器官；然而，其对直肠周围脂肪和淋巴结受累情况的显示准确性较低。
