RATIONALE: New imaging procedures such as fludeoxyglucose F 18 positron emission tomography (FDG-PET) and magnetic resonance (MR) perfusion imaging may improve the ability to detect disease progression, help doctors predict a patient's response to treatment, and help plan the most effective treatment.

PURPOSE: This diagnostic trial is studying how well FDG-PET and MR perfusion imaging work in finding disease progression and determining response to treatment in patients with neurofibromatosis 1 and plexiform neurofibroma.

OBJECTIVES:

• Determine whether fludeoxyglucose F 18 positron emission tomography (FDG-PET) and MR perfusion studies can predict plexiform neurofibroma growth rates in patients with neurofibromatosis 1.
• Determine whether FDG-PET and MR perfusion studies can predict the likelihood of response in patients who are undergoing investigational treatment for plexiform neurofibromas.
• Identify neuroimaging characteristics that distinguish patients who have responded to therapy from those who have not after completion of treatment.

OUTLINE:

• Stratum 1: Patients undergo MR perfusion scan with gadopentetate dimeglumine and fludeoxyglucose F 18 positron emission tomography (FDG-PET) at baseline and quantitative MRI evaluation at baseline and 1 year.
• Stratum 2: Patients undergo quantitative MRI, MR perfusion scan with gadopentetate dimeglumine, and FDG-PET at baseline and 1 year.

PROJECTED ACCRUAL: A total of 48 patients (32 for stratum 1 and 16 for stratum 2) will be accrued for this study.

• Neurofibromatosis Type 1
• Precancerous/Nonmalignant Condition

• Procedure: magnetic resonance imaging
• Procedure: positron emission tomography
• Procedure: radionuclide imaging
• Radiation: fludeoxyglucose F 18
• Radiation: gadopentetate dimeglumine

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)