Multi-parametric Biomarker Development to Predict Malignant Conversion in Patients With Neurofibromatosis Type 1

The goal of this prospective observational study is to learn about the utility of imaging and clinical features in patients with Neurofibromatosis type 1 categorized as high risk for the development of malignant peripheral nerve sheath tumors. The main objectives are: * To evaluate the prevalence, multi-parametric imaging features of distinct nodular lesions ("DNLs") and natural history in people with NF1 with clinical and genetic features deemed "high-risk" for malignancy. * To assess the relationship between individual clinical, genetic and imaging factors that have been suggested to be risk factors for malignant peripheral nerve sheath tumors (MPNST) and the confirmation of atypical neurofibromas (aNF)/ atypical neurofibromatous neoplasm of unknown biologic potential (ANNUBP) or MPNST on pathology. In this research study, the participants will be asked to undergo whole body MRI, provide blood sample and clinical evaluation annually.