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 PET-CT. 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.