[Impact of whole body magnetic resonance imaging (MRI) in the management of melanoma patients, in comparison with positron emission tomography/computed tomography (TEP/CT) and CT]

PET/CT has proven extremely useful in the management of melanoma patients, with great sensitivity (Se), but it tends to give false-positive results. Whole-body MRI (wb-MRI) is a new method that has made considerable progress.The aim of this study was to assess the Se and specificity (Sp) of wb-MRI with a diffusion sequence for detecting melanoma metastasis compared to PET/CT.This was a prospective study, including patients at any AJCC (American Joint Committee on Cancer) stage of melanoma. PET/CT, wb-MRI and CT, including the brain, were performed on the same day. For each of the three exams, the number of lesions per patient was counted. The treatments proposed by the doctor immediately after PET/CT and then MRI were compared.Forty patients were included and a total of 72 metastases were noted. CT detected 53 of these metastases (Se 80%, Sp 95%), while PET/CT detected 53 metastases, with four false-positive (Se 74%, Sp 89%) and Wb-MRI detected 59, with two false-positive (Se 83%, Sp 96%). The sensitivity of MRI was distinctly superior to PET/CT for both hepatic and pulmonary lesions. The treatment proposed after PET/CT and MRI differed in three cases: one patient was falsely reclassified by MRI (AJCC IV instead of IIB) while two others were falsely reclassified by PET/CT (AJCC IV instead of IB and IIIC). Exclusively whole-body scan influenced the treatment of four patients (10%).Wb-MRI with diffusion sequence, which is less costly than PET/CT and is also non-radioactive, could play an important role in the detection of metastases in melanoma patients.