Fludeoxyglucose F 18 Positron Emission Tomography and Magnetic Resonance Perfusion Imaging in Patients With Neurofibromatosis 1 and Plexiform Neurofibroma

DISEASE CHARACTERISTICS: Stratum 1: Diagnosis of neurofibromatosis 1 (NF1) and plexiform neurofibromas At high risk for progression, as defined by any of the following: Anatomic location such that progression carries a high risk of impairment of function, pain, or disfigurement (e.g., neck/mediastinum, paraspinal nerve roots, orbit, and face) Tumors that the patient, family, or caregiver believes have increased in size within the past year, but appear stable by standard clinical or radiographic measures No plexiform neurofibromas that are small, cause no pain or functional impairment, or are not likely to cause pain or functional impairment over the succeeding 12 months Stratum 2: Diagnosis of NF1 and progressive plexiform neurofibromas Neurofibroma progression documented by increase in lesion size on MRI Currently being enrolled on a clinical therapeutic trial at Children's Hospital of Philadelphia PATIENT CHARACTERISTICS: Age 25 and under Performance status Not specified Life expectancy Not specified Hematopoietic Not specified Hepatic Not specified Renal Not specified Other Not pregnant or nursing Negative pregnancy test PRIOR CONCURRENT THERAPY: Biologic therapy Not specified Chemotherapy Stratum 1: No prior or concurrent chemotherapy No concurrent enrollment on a chemotherapy clinical trial Stratum 2: At least 4 weeks since prior chemotherapy Endocrine therapy Not specified Radiotherapy At least 6 weeks since prior radiotherapy (stratum 2) Surgery Prior surgery for progressive plexiform neurofibroma allowed if incompletely resected and measurable disease remains (stratum 2)