Comparative study of endorectal ultrasonography and magnetic resonance imaging in preoperative staging of rectal cancer

Abstract

To evaluate the diagnostic value of endorectal ultrasonography (ERUS) and magnetic resonance imaging (MRI) in preoperative staging of rectal carcinoma. A total of 44 patients with biopsy proven rectal tumor underwent preoperative ERUS and MRI examinations. All patients were evaluated to determine the diagnostic accuracy of depth of transmural tumor invasion and lymph node metastases.Imaging results were compared with histopathological findings. The accuracy of T staging (uT1, uT2, uT3, uT4) for ERUS was 95.5%, 90.9%, 93.2% and 97.7% and the overall accuracy 88.6% (39/44) . The sensitivity was 83.3%, 72.7%, 72.2%, 77.8% and the specificity 97.3%, 92.9%, 96.2% and 97.6%. The accuracy of T staging (T1, T2, T3, T4) for MRI was 93.2%, 90.9%, 93.2%, 100.0% and the overall accuracy 86.4% (38/44) . The sensitivity was 71.4%, 93.8%, 94.4% and 100.0% and the specificity 97.3%, 89.3%, 92.3% and 100.0%. Detection of lymph node metastases:the accuracy of ERUS was 75.0% (33/44), MRI 93.2% (41/44). The sensitivity and specificity was found to be 68.4% (13/19) and 80.0% (20/25) on ERUS, 94.7% (18/19) and 92.0% (23/25) on MRI respectively. ERUS and MRI may be used for accurate preoperative staging of rectal cancer.ERUS has higher accuracy and sensitivity for T1 stage while MRI is preferred for lymph node metastasis.