Assessment of liver metastases from colorectal adenocarcinoma following chemotherapy: SPIO-MRI versus FDG-PET/CT

Purpose. This study compared superparamagnetic iron-oxide-enhanced magnetic resonance imaging (SPIO-MRI) and combined fluorodeoxyglucose positron emission tomography and computed tomography (FDG-PET/CT) in evaluating liver metastases from colorectal adenocarcinoma following chemotherapy. Materials and methods. Nineteen patients were included in this retrospective study. SPIO-MRI and PET/CT results were compared with surgery, intraoperative ultrasound and pathology results in I I patients and with the follow-up in eight patients. Results. SPIO-MRI and PET/CT identified 125 and 71 metastases, respectively. False negative lesions were 11 for SPIO-MRI and 65 for PET/CT. In the whole study population, the per-lesion analysis of SPIO-MRI and PET/CT showed a sensitivity of 92% and 52% (p<0.001) and the per-segment analysis a sensitivity of 99% and 79% (p<0.001), respectively. In patients who underwent surgery, the per-lesion analysis of SPIO-MRI and PET/CT showed a sensitivity of 85% and 58% (p<0.05) and the persegment analysis a sensitivity of 97% and 63% (p<0.05), respectively. In patients who underwent follow-up, the perlesion analysis of SPIO-MRI and PET/CT showed a sensitivity of 97% and 47% (p<0.001) and the per-segment analysis a sensitivity of 100% and 63% (p<0.007), respectively. For lesions >= 15 and <30mm and for lesions <15 mm, SPIO-MRI demonstrated a higher sensitivity than PET/CT (p<0.001). Conclusions. SPIO-MRI appears superior to PET/CT in evaluating liver metastases from colorectal adenocarcinoma following chemotherapy.