Staging of colon cancer: whole-body MRI vs. whole-body PET-CT-initial clinical experience

Background: To assess the accuracy of whole-body MR imaging (WB-MRI) in comparison with whole-body [18(F)]-2-fluoro-2-deoxy-d-glucose (FDG) PET-CT in staging patients with diagnosed colorectal carcinoma (CRC). Methods: Twenty consecutive patients with previously diagnosed CRC underwent WB-MRI (3T) and PET-CT for staging of lymph node (N) and distant metastases ( M). Evaluation was done according to the American Joint Committee on Cancer Staging Criteria. MR images were evaluated by two radiologists while PET-CT images by one radiologist and one nuclear medicine physician. Histology and/or a clinical follow-up of 3-6 months served as standard of reference. Results: Lymph node involvement was determined in 10/20 cases as N-positive in WB-MRI and in 15/20 in PETCT. M-stage was evaluated for liver metastases ( 27 lesions in 15 patients with WB-MRI, 23/15 patients with PET-CT), lung (19/5 patients with WB-MRI, 25/7 patients with PET-CT), and bone (9/3 patients with WB-MRI, 9/3 patients with PET-CT). Two patients showed peritoneal implants and three patients demonstrated local recurrence at the surgery site on both modalities. No brain metastases were found. Conclusions: WB-MRI is a feasible method for examining colon cancer patients but cannot displace the present role of PET-CT.