[Magnetic resonance in the study of Wilm's tumor and neuroblastoma]

Eleven patients suffering from neuroblastoma and Wilms' tumor were examined with MR imaging (25 examinations). The results were compared with those obtained with other diagnostic methods--e.g. CT--to verify MR reliability in locating and staging the lesions. Signal patterns were studied, as recorded on T1- and T2-weighted sequences using various repetition and echo times. An attempt was made to verify the presence of pathognomonic findings and to differentiate tumors from post-therapy fibroses. All findings were subsequently confirmed at biopsy or, in the patients who underwent surgery, by surgical findings. To carry out all the procedures, the patients had to be sedated or to be administered a general anesthetic. When possible, a brain or surface coil was used to obtain a clear, well-defined image in thin-section (7-8 mm) sequences. MR imaging allowed all lesions to be detected and located in the examined population. A large thrombus in the vena cava and local adenopathy were observed in a patients suffering from Wilms' tumor. Spread into the spinal canal was present in 2 cases of neuroblastoma. One of the main advantages of MR imaging is its multiplanarity which usually allows lesion extent to be demonstrated, together with the involved organs. The additional advantages of MR imaging over CT should not be underestimated. MR allows images of the abdomen to be obtained devoid of respiratory artifacts and provides a sharp contrast between pathological and healthy tissue without contrast medium administration. In all the patients who underwent it, MR imaging proved superior to CT in the evaluation of the intraspinal spread of paraspinal lesions. MR also allowed serial follow-up to be carried out, with no risk of subsequent proteximetric problems, thus helping distinguish tumor masses from fibrous tissue in all patients.