The Application Value of Background Suppression Diffusion-Weighted Imaging (DWIBS) in Preoperative Staging of Rectal Cancer

Purpose: To explore the applied value of magnetic resonance background suppression diffusion weighted imaging (DWIBS) for preoperative staging of rectal cancer. Methods: 39 cases of rectal cancer, which were confirmed by colonoscopy, underwent DWIBS before the surgery. The data was divided into three groups (T2, T3, T4) on the basis of pathological results about T-stage of rectal cancer. The relative signal intensity and the ADC values of the tumor were measured, the length, perimeter and thickness of the lesion were examined on DWIBS sequence. Analyze the difference of every index among groups and do correlative analysis with T stage. The NM staging was done by DWIBS. Then, the results were compared with the results of pathological NM staging and determine the accuracy, specificity and sensitivity of DWIBS NM staging. Results: The perimeter and thickness of the lesion had significant difference (P 0.05) among groups. On diagnosing metastatic lymph nodes the overall accuracy rate of N staging was 84.61%, For N0 stage, the accuracy was 100%, the sensitivity was 85.71%, the specificity was 83.33%. For N1 stage, the accuracy was 77.78% the diagnostic sensitivity was 70.00%, the specificity was 89.66%. For N2 stage, the accuracy was 66.67%, the sensitivity was 100%, the specificity was 80.65%. 6 cases of distant metastasis were correctly diagnosed by DWIBS. Conclusion: DWIBS is sensitivity and accuracy in NM staging of rectal cancer. It is an effective method to show the metastatic lymph node and distant metastasis. DWIBS can clear display rectal cancer, and has certain application value in T staging. Combined with conventional MRI sequence would help to improve the accuracy of the T stage.