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MRI Techniques: Bilateral Findings and “Normal Findings”

Published online by Cambridge University Press:  02 December 2014

Donald H. Lee*
Affiliation:
Department of Diagnostic Radiology, London Health Sciences Centre, London, ON Canada.
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Abstract

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Magnetic resonance imaging (MRI) techniques allow for significantly better imaging of the temporal lobe compared to computed tomography (CT) or other non-invasive modalities. For detection of foreign tissue lesions, MRI surpasses CT. For the highest non-invasive yield for detection of mesial temporal sclerosis, optimal sequences that should be employed are a heavily T1-weighted volumetric acquisition (to enable both volumetric calculation of hippocampal volume, and, if needed, intracranial volume), T2-weighted coronal sequences, with or without T2-mapping, fluid-attenuated inversion recovery (FLAIR) and, to exclude subtle susceptibility effects from hematoma or cavernoma, gradient echo scans. Magnetic resonance spectroscopy (MRS) may show a decrease in N-acetyl aspartate (NAA) concentration, or NAA: Choline + creatine ratio. Functional MRI is a new and exciting tool that offers the promise of accurately localizing hemispheric functions; its role in the preoperative evaluation of temporal lobe seizures remains uncertain at present.

Type
Research Article
Copyright
Copyright © The Canadian Journal of Neurological 2000

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