Endorectal ultrasonography versus phased-array magnetic resonance imaging for preoperative staging of rectal cancer

Abstract

AIM:To compare the diagnostic accuracy of pelvic phased-array magnetic resonance imaging (MRI) and endorectal ultrasonography (ERUS) in the preoperative staging of rectal carcinoma. METHODS: Thirty-four patients (15 males, 19 females) with ages ranging between 29 and 75 who have biopsy proven rectal tumor underwent both MRI and ERUS examinations before surgery. All patients were evaluated to determine the diagnostic accuracy of depth of transmural tumor invasion and lymph node metastases. Imaging results were correlated with histopathological findings regarded as the gold standard and both modalities were compared in terms of predicting preoperative local staging of rectal carcinoma. RESULTS: The pathological T stage of the tumors was: pT1 in 1 patient, pT2 in 9 patients, pT3 in 21 patients and pT4 in 3 patients. The pathological N stage of the tumors was: pN0 in 19 patients, pN1 in 9 patients and pN2 in 6 patients. The accuracy of T staging for MRI was 89.70% (27 out of 34). The sensitivity was 79.41% and the specificity was 93.14%. The accuracy of T staging for ERUS was 85.29% (24 out of 34). The sensitivity was 70.59% and the specificity was 90.20%. Detection of lymph node metastases using phased-array MRI gave an accuracy of 74.50% (21 out of 34). The sensitivity and specificity was found to be 61.76% and 80.88%, respectively. By using ERUS in the detection of lymph node metastases, an accuracy of 76.47% (18 out of 34) was obtained. The sensitivity and specificity were found to be 52.94% and 84.31%, respectively. CONCLUSION: ERUS and phased-array MRI are complementary methods in the accurate preoperative staging of rectal cancer. In conclusion, we can state that phased-array MRI was observed to be slightly superior in determining the depth of transmural invasion (T stage) and has same value in detecting lymph node metastases (N stage) as compared to ERUS.

The ability of phased-array MRI in preoperative staging of primary rectal cancer: correlation with histopathological results

“…However, the overall accuracy of MRI for the detection of lymph node involvement ranges between 59% and 95% (34). Many studies suggest an increase in lymph node size as a predictor of nodal involvement (58,59).…”

“…MRI using an endorectal coil has the same limitations as EUS, including a poor resolution of the pelvic structures surrounding the rectum due to the small field of view and the inability to insert the coil into patients with stenosing tumors (34).…”

“…It cannot be performed in stenotic tumors or in tumors that are localized close to the sigmoid colon. The assessment of the mesorectal fascia and tumor extension into neighboring organs is not possible because of the limited field of view (27,34).…”

Endoscopic ultrasound and magnetic resonance imaging forre-staging rectal cancer after radiotherapy

“…Many imaging techniques are available, but each one differs in accuracy and applicability [11][12][13] . Accurate staging is important for planning surgery and deciding on adjuvant treatment.…”

Transanal endoscopic surgery: patient selection and perspectives

“…One study found MRI to be slightly superior in detecting wall invasion when compared to ERUS (89.7% vs 85.29%) with a similar value of detecting lymph node involvement (74.5% vs 76.47%). 47 A meta-analysis comparing ERUS, computed tomography scan, and MRI found ERUS to be more accurate at assessing local invasion, whereas all the three modalities were found to have similar sensitivities for detecting lymph node involvement. 48 Computed tomography and MRI have also been used to evaluate iliac, mesenteric, and retroperitoneal lymph nodes, as opposed to ERUS that specifically assesses mesorectal lymph nodes.…”