水脂分离增强序列在3.0T磁共振直肠癌术前分期中的应用

Value of water-fat suppression technique with a 3.0T scanner for preoperative MRI staging of rectal cancer

目的:将水脂分离增强扫描序列应用于直肠癌磁共振术前分期检查,探讨其在直肠癌术前分期中的应用价值。方法:选择经肠镜活检证实为直肠癌患者46例,随机盲法均分为两组,一组序列采用常规序列及T1脂肪抑制增强扫描序列;另一组序列采用常规序列及水脂分离增强扫描序列,结果与病理分期对照,比较两组序列图像信噪比及T、N分期。结果:组一T分期总敏感度为74%,特异度为78%。N分期总敏感度为74%,特异度为74%;N0分期敏感度78.6%,特异度66.7%,准确率为78%;N1分期敏感度57%,特异度81%,准确率为71%;N2分期敏感度100%,特异度100%,准确率为100%。组二T分期总敏感度为83%、特异度为83%;N分期总敏感度91%,特异度为91%;N0分期敏感度94%,特异度83%,准确率为94%;N1分期敏感度75%,特异度95%,准确率为75%;N2分期敏感度100%,特异度94.5%,准确率为100%。结论:水脂分离序列可提高图像信噪比,脂相有助于提高N分期,此序列在直肠癌术前分期中具有一定的临床应用价值。

Objective：To investigate the value of water-fat suppression MRI technique in the diagnoses and staging of rectal cancer before surgery. Methods： 46 patients with primary rectal cancer, proved by coloscopy and biopsy, were random ly divided into two groups. Patients all underwent routine MRI sequences and contrast-enhanced T1 WI with fat suppression were performed in Group 1 and contrast-enhancement three-point dixon technique （water-fat suppression） in Group 2. MR findings were correlated with histology. The signal-noise ratio （SNR） of images and T.N staging of the 2 groups were compared. Results： For Group Ⅰ ： The overall sensitivity, specificity in the diagnosis of T staging was 74 %, 78 % respectively; of N staging was 74% ,74% respectively. The sensitivity, specificity and accuracy was 78. 6%, 66. 7%, 78% respectively for N0,57%,81%,71% respectively for N1,and 100% ,100%,100% respectively for N2. For Group Ⅱ ：The overall sensitivity, specificity in the diagnosis of T staging was 83 %, 83 % respectively, of N staging was 91%, 91% respectively. The sensi tivity, specificity and accuracy was 94 %, 83 %, 94 % respectively for NO, 75 %, 95 %, 75% respectively for N1 and 100 %, 94.5 %, 100 % respectively for N2. Conclusion： The image SNR could be improved by water-fat suppression technique and the diagnosis accuracy of N staging could be improved by fat phase,which is helpful in the staging of rectal carcinoma before surgery.