OBJECTIVES: Primary * Compare non-inferior diagnostic performance of whole-body MRI (i.e., combination of turbo short-tau inversion-recovery (STIR) and out-of-phase imaging) vs conventional imaging (i.e., the combination of chest CT scan, scintigraphy \[bone, gallium, meta-iodobenzylguanidine (MIBG), or optional fludeoxyglucose F 18 positron emission tomography (FDG-PET)\] and abdominal/pelvic CT scan/MRI as indicated) for detecting distant metastases for use in staging common tumors in pediatric patients. Secondary * Determine the incremental benefit of adding out-of-phase T1-weighted gradient-recalled echo imaging to turbo STIR for detecting distant disease in these patients. * Determine, preliminarily, the relative accuracies of FDG-PET, whole-body MRI, and a combination of FDG-PET and whole-body MRI in detecting stage IV disease in these patients. * Determine the effects of multiple factors, including cancer type, site of primary tumor, and patient age, on diagnostic accuracy of whole-body MRI in these patients. * Determine the interobserver variability associated with interpreting whole-body MRI exams for detecting distant metastases in these patients. OUTLINE: This is a multicenter study. Patients undergo conventional MRI, CT scan, and/or scintigraphy (e.g., bone, meta-iodobenzylguanidine \[MIBG\], or gallium) and experimental whole-body MRI sequences. Patients may optionally undergo fludeoxyglucose F18 positron emission tomography (FDG-PET). Patients with a lesion (or lesions) detected on whole-body MRI or FDG-PET at initial staging that are not confirmed by biopsy or other conventional imaging studies at staging repeat standard imaging at 3- to 6-month follow-up. Patients with an abnormality that is considered highly suspicious for a metastasis or when biopsy proof of that metastasis is obtained receive treatment at the discretion of the treating physician. Patients are followed annually for 3 years. PROJECTED ACCRUAL: A total of 226 patients (45 with neuroblastoma, 54 with rhabdomyosarcoma, 27 with other sarcoma, and 100 with lymphoma) will be accrued for this study within 1 year.
DISEASE CHARACTERISTICS: * Confirmed diagnosis OR newly diagnosed mass strongly suspected to represent 1 of the following: * Rhabdomyosarcoma * Ewing's sarcoma family of tumors * Neuroblastoma * Hodgkin's lymphoma * Non-Hodgkin's lymphoma * All imaging examinations (e.g., CT scan, MRI, or scintigraphy) must be performed within 14 days of each other and within 2 months of any diagnostic or operative procedure * Whole body MRI and positron emission tomography (PET) scanning (if PET scan is being done) must be done before treatment * Prior CT scan, conventional MRI, bone scintigraphy, gallium scintigraphy, or meta-iodobenzylguanidine (MIBG) scintigraphy performed at outside institutions allowed provided the same technical standards specified in this study were practiced * Bone scintigraphy required for patients with neuroblastoma, rhabdomyosarcoma, or other sarcomas * Gallium scintigraphy not required in lymphoma patients if PET scan is performed * No CNS primary tumor PATIENT CHARACTERISTICS: Age * 21 and under Performance status * Not specified Life expectancy * Not specified Hematopoietic * Not specified Hepatic * Not specified Renal * Not specified Cardiovascular * No active cardiac pacemakers Other * Not pregnant or nursing * No prior malignancy * No uncontrolled diabetes mellitus (for patients undergoing optional PET) * Patients with controlled diabetes mellitus must have a fasting blood glucose no greater than 200 mg/dL * No contraindications to MRI or CT scan (e.g., intracranial vascular clips) PRIOR CONCURRENT THERAPY: Biologic therapy * Not specified Chemotherapy * Not specified Endocrine therapy * Not specified Radiotherapy * Not specified Surgery * Prior biopsy or surgery allowed provided no more than 2 months has passed since the procedure