Aim: To compare high-resolution pelvic magnetic resonance imaging (MRI) with positron emission tomography (PET)/computed tomography (CT) for the preoperative assessment of nodal staging in rectal cancer.
Materials and Methods: Thirty patients who had surgery for rectal cancer were retrospectively enrolled during a 6-month period. Each patient underwent high-resolution pelvic MRI and PET/CT preoperatively within the same week. An experienced radiologist predicted nodal staging on MR, and an experienced nuclear medicine physician similarly predicted nodal staging on PET/CT. Their predictions were compared with pathologic staging results, retrospectively.
Results: The accuracies of nodal status prediction from MR and PET/CT were 83% and 70%, respectively. Magnetic resonance imaging had a sensitivity of 94% and a specificity of 67%, whereas PET/CT had a sensitivity of 61% and a specificity of 83%. A combination of MRI and PET/CT revealed a sensitivity of 94%, a specificity of 83%, and an accuracy of 90%.
Conclusion: High-resolution pelvic MRI was more accurate than PET/CT for the prediction of regional nodal status. Magnetic resonance imaging had a high sensitivity and PET/CT had a high specificity for N staging in rectal cancer.