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Posterior reversible encephalopathy syndrome (PRES) is a clinico-radiological phenomenon seen in a wide spectrum of clinical conditions and is characterized clinically by headache, altered mental status, visual loss and seizures and reversible neuroimaging findings. This study evaluated MR imaging in PRES in a clinical oncology setting. MR findings may be helpful in disclosing the underlying pathophysiological mechanisms of the syndrome. The MR imaging protocol consisted of T2-weighted, fluid attenuation inversion recovery (FLAIR), diffusion weighting imaging (DWI) and apparent diffusion coefficient (ADC) sequences. Contrast enhanced computed tomography (CT) of the brain revealed bilateral symmetric subcortical hypodense lesions in the parieto-occipital regions. T2-weighted and FLAIR sequences showed bilateral, symmetrical focal cortical and subcortical hyperintensities involving the parietal and occipital lobes. These areas appeared hyperintense on DWI while the ADC (Apparent Diffusion Coefficient) maps demonstrated higher apparent diffusion coefficients in areas of FLAIR abnormalities thus confirming vasogenic edema. Follow-up scan five days later showed improvement or resolution of the abnormalities. Transient DWI hyperintensities seen in cortical watershed areas corresponding to the hyperintense foci in FLAIR imaging are suggestive of foci of vasogenic edema secondary to vasospasm in highly ischemia-sensitive cerebral tissue. [ABSTRACT FROM AUTHOR]

We describe the proton (¹H) magnetic resonance spectroscopic (MRS) imaging of central neurocytoma (CNC), a rare benign intraventricular neuronal tumor. Multivoxel MR Spectroscopy is a feasible and reproducible non-invasive tool for the specific diagnosis of CNC and to distinguish CNC from other intraventricular tumor types. The detection of glycine and alanine peaks, high choline and lactate and low NAA levels are characteristic of CNC. [ABSTRACT FROM AUTHOR]

A 33-year-old man presented with a long history of intractable partial seizures with the first episode at the age of 18 years. The seizure frequency had increased in the recent past. CT imaging revealed a low attenuation lesion in the left frontal cortex with calvarial scalloping. MR imaging revealed a heterogeneous signal intensity lesion with involvement of the cortex and the subcortical white matter. In dysembryoplastic neuroepithelial tumor the neoplastic elements adjacent to the cortex might cause disorganization of cortical layers in the developmental stage leading to cortical dysplasia. Architectural dysplasia is characterized by cortical thickening and ectopic neurons in the white matter. MR imaging features reflect the characteristics of cortical dysplasia and ectopic neurons in the sub-cortical white matter. [ABSTRACT FROM AUTHOR]