The Role Of Multislic Spiral Computed Tomography (MSCT) For Pre-operative Staging In Rectal Carcinoma

Purpose: Image preoperative MSCT with rectal air insufflation standardly,then staging depended on the standard classification of TNM staging. The results were compared with those of surgical and pathological examination depened on the standard of UICC, Detecting the value and confine of the preoperative MSCT staging in rectal carcinoma.Material and methods: 49 cases who have been diagnosed by colonoscopy and pathology from March 2005 to December 2006(male 31, female 18, with range from 37-72 years old, average of 54), were involved in our study. All patients underwent MSCT examination with rectal air insufflation. The patients were cleaned intestine before examination and injected 654-2 by muscle before 20 minutes when examination. All patients'colon distended by rectal air about 500-900ml that the patient can tolerate which can make colon and rectum distend enough. On plain MSCT scan,according to the materials of colonoscopy , the suspected region of the primary tumor was covered, collimation 5mm. In the arterial phase(20-25s) , only the region of the primary tumor was covered. The whole abdomen and pelvis was examined in the venous phase(65-70s), and have examination of epuilibrium phase(90-95s) in necessary case. Stage depended on TNM classification of staging, compared with surgical and pathological TNM stage examination in all results of cases who had operation after MSCT scan.Results: All patients succeefuly fulfilled the scan of MSCT with rectal air insufflation. All lesions in the 49 cases were demonstrated clearly and the sensitivity was 100%. 41 cases of 49 were correctly staged with TNM and the accuracy was 83.7%. The accuracy of T was 87.8%(43/49), the advanced cases are more accurate . The accuracy of N was 85.7% (42/49), the accuracy of M was 97.9%(48/49). MSCT features included primary tumor invasion,regional lymph node metastasis, distant metastasis and TNM staging were very correlated with postoperative pathological stage of rectal carcinoma(P<0.01).Conclusion: MSCT can display the primary tumor's location, size and shape efficiently. The extension to adjacent tissues and lymph node metastased and the metastasis to other tissue can be assessed correctly, this is more reliable for the advanced case. The scan of MSCT with air insufflation is valuable in preoperative staging of rectal carcinoma. It is reasonable that MSCT can be adopted as a complementary criterion for preoperative staging in rectal carcinoma. The technique and standard of stage in examination are very important. There is no credible criterion for early stage because MSCT cannot distinguish the histology delamination of most rectal walls. There are false negative and positive in the N staging, it is necessary to have further studies inclosing more cases.