BACKGROUND AND PURPOSE:Abscesses caused by aerobic bacteria (aerobic abscesses) can simulate intracranial glioblastomas multiforme (GBMs) in MR imaging appearance and single voxel (SV) proton MR spectroscopy of the central cavity. The purpose of our study was to determine whether MR spectroscopic imaging (SI) can be used to differentiate aerobic abscesses from GBMs. Our hypothesis was that metabolite levels of choline (Cho) are decreased in the ring-enhancing portion of abscesses compared with GBMs.

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Pilocytic astrocytomas are found predominantly in the pediatric population; reports of these tumors are extremely rare in adults. We report 2 cases of adult pilocytic astrocytoma with intracranial hemorrhage. A 32-year-old male presented with neck stiffness and severe headache, and a 34-year-old male was referred for headache and double vision. Computed tomography (CT) and magnetic resonance imaging (MRI) revealed a well-enhanced and circumscribed cystic hemorrhagic tumor with mural nodule over the cerebral hemisphere region. Perfusion-weighted MRI (PWI) was also performed in both patients. The measured relative cerebral blood volume ratios of the mural nodules in these 2 cases were, respectively, 1.34 and 2.81 when compared with normal white matter. After surgical resection, microscopic examination of the lesions showed pilocytic astrocytomas. Since pilocytic astrocytoma and other cystic tumors with mural nodule (such as hemangioblastoma) have similar findings on conventional CT and MRI, PWI is helpful in the differential diagnosis. The literature on hemorrhagic pilocytic astrocytoma is also reviewed.

PTA could effectively prolong the lifetime of immature AVFs with high technical success. Vessel rupture was predictive of shorter primary patency, and long-term secondary patency was acceptable.