Comparative Study On Transrectal Ultrasonography VS.Magnetic Resonance In Circumferential Resection Margin Of Mid-Low Rectal Cancer

Objective To compare the report of transrectal ultrasonography(TRUS) VS. magnetic resonance imaging(MRI) in assessing preoperative circumferential resection margin(CRM) of mid-low rectal cancer, and explore the clinical value of TRUS in diagnosing the circumferential resection margin(CRM) of mid-low rectal cancer.Methods Both TRUS and MRI were performed prior to surgery in 111 patients with mid-low rectal cancer, which had been diagnosed by endoscopic biopsy. The CRM was evaluated and compared with the postoperative pathologic findings. The accuracy, specificity and sensitivity between TRUS and MRI for CRM were compared by chi-square test. The consistency of the results between TRUS and pathology was compared by kappa index, the consistency of the results between MR and pathology was compared by kappa index either, to get the report of kappa respectively.Results The positive rate of CRM which were diagnosed by pathology was 24.3%(27/111),. The positive rate of CRM which were assessed by TRUS and MRI respectively was 25.2%(28/111) and 333.3%(37/111), and there was no statistical significance between them(P=0.184). The accuracy of TRUS and MRI for CRM was 91.9%(102/111) and 85.6%(95/111), there was no statistical significance between them(P=0.137); The specificity of them was 94.0%(79/84)and 84.5%(71/84), there was statistical significance between them(P=0.046).The consistency of the results between TRUS and pathology was superior to MRI and pathology(the former Kappa1=0.783> the latter Kappa2=0.652).Conclusion TRUS has high accuracy, specificity and sensitivity for CRM of mid-low rectal cancer, and better consistency. Meanwhile TRUS is simpler to operate and repeat, and cheaper, which could be regarded as the preferred assessment method, and is valuable for popularization and has broad application prospect.