title: Delayed development of radiation vasculopathy of the brain stem confirmed by F-18 FDG PET in a case of anaplastic astrocytoma.
abstract: We present the imaging findings of a 38-year-old female patient who underwent resection and radiation therapy for an anaplastic astrocytoma in her left temporal lobe 12 years ago. She was symptom-free until 1 month before admission at which time she presented with symptoms of right hemiparesis, right facial droop, and slurred speech. Magnetic resonance imaging (MRI) of the brain showed a new mass lesion in the left pontine region of the brain stem. Magnetic resonance spectroscopy imaging of the lesion demonstrated an increase in choline (Ch)/N-acetyl aspartate (NAA) metabolite values which were nondiagnostic. Since viable tumor recurrence was strongly suspected, a biopsy was planned, although this posed significant risk. Therefore, an F-18 FDG brain PET scan was performed, which demonstrated no metabolic activity in the pontine lesion leading to the less common diagnosis of long-term postradiation vasculopathy. Over the next 6 months, the patient's symptoms slowly improved and a follow-up MRI scan showed a decrease in the size of the lesion, consistent with postradiation vasculopathy and infarction. This case illustrates the importance of considering the rare diagnosis of radiation-induced vasculopathy in the differential diagnosis when symptoms of recurrent brain tumor occur.
authors.affiliation: Division of Nuclear Medicine, Department of Radiology, University of Pittsburgh Medical Center, Pittsburgh, PA 15213, USA.
authors.forename: Ashok
authors.initials: A
authors.lastname: Muthukrishnan
authors.forename: Mehran
authors.initials: M
authors.lastname: Bajoghli
authors.forename: James M
authors.initials: JM
authors.lastname: Mountz
mesh_terms: D000328:Adult; D001254:Astrocytoma / Q000000981:diagnostic imaging / Q000532:radiotherapy; D001933:Brain Stem / Q000098:blood supply / Q000000981:diagnostic imaging*; D002561:Cerebrovascular Disorders / Q000000981:diagnostic imaging* / Q000209:etiology*; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D049268:Positron-Emission Tomography / Q000379:methods; D011832:Radiation Injuries / Q000000981:diagnostic imaging* / Q000209:etiology*; D019275:Radiopharmaceuticals; D011878:Radiotherapy / Q000009:adverse effects*; D013997:Time Factors
chemical_list: D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18