PREOPERATIVE LOCAL STAGING WITH CONVENTIONAL MRI AND DWI - MRI IN CORRELATION WITH OTHERS PREOPERATIVE METHODICS AND WITH HISTOLOGICAL RESULTS CAN CHANGE SURGICAL TREATMENT IN GASTRIC CANCER?

Purpose : To prospectively evaluate accuracy of diffusion - weighted - imaging ( DWI) for preoperative staging of gastric cancer by using others preoperative methodics, surgical and histopathologic results as reference standards. Materials and Methods : 87 patients with gastric adenocarcinoma, which underwent preoperative staging with 3 Tesla Magnetic Resonance Imaging (MRI), were enrolled. The radiologists evaluated the tumor staging in DWI. Results were compared to postsurgical pa thologic findings. Results: Conventional MRI has identified 69 cases and DWI was able to identify 81 cases of cancer (sensitivity of 80% and 93%). The T factor accuracy of conventional MRI and DWI was 73% and 82% respectively; while the N staging accuracy of conventional MRI and DWI was 79% and 93%, respectively. Conclusion: DWI showed to be useful in preoperative staging of gastric cancer, in particular for the assessment of lymph nodes and peritoneal involvement. In fact DWI - MRI showed an improved diagn ostic sensitivity compared to MRI standard protocol.