Comparative Lateralizing Ability of Multimodality MRI in Temporal Lobe Epilepsy

Abstract

Purpose. The objective is to compare lateralizing ability of three quantitative MR (qMRI) modalities to depict changes of hippocampal architecture with clinical entities in temporal lobe epilepsy. Methods. We evaluated 14 patients with clinical and EEG proven diagnosis of unilateral TLE and 15 healthy volunteers. T1-weighted 3D dataset for volumetry, single-voxel 1H MR spectroscopy (MRS), and diffusion tensor imaging (DTI) were performed for bilateral hippocampi of all subjects. Results. Individual volumetric measurements provided accurate lateralization in 85% of the patients, spectroscopy in 57%, and DTI in 57%. Higher lateralization ratios were acquired combining volumetry-spectroscopy (85%), spectroscopy-DTI (85%), and volumetry-DTI (100%). Significantly decreased NAA/(Cho+Cr) ratios (p = 0.002) and increased FA (p = 0.001) values were obtained in ipsilateral to epileptogenic hippocampus. Duration of epilepsy and FA values showed a significant negative correlation (p = 0.016, r = −0.847). The history of febrile convulsion associated with ipsilateral increased ADC values (p = 0.015, r = 0.851) and reduced NAA/(Cho+Cr) ratios (p = 0.047, r = −761). Conclusion. Volumetry, MRS, and DTI studies provide complementary information of hippocampal pathology. For lateralization of epileptogenic focus and preoperative examination, volumetry-DTI combination may be indicative of diagnostic accuracy.

Widespread abnormalities in white matter integrity and their relationship with duration of illness in temporal lobe epilepsy

“…showed that the duration of illness was correlated significantly with reduced FA of the ipsilateral parahippocampal gyrus and temporal lobe, bilateral thalamus, and posterior regions of the corpus callosum, using region of interest (ROI) manual approaches . Some previous TLE studies reported significant correlations between duration of illness and reduced FA and increased MD in the whole brain and with reduced FA and increased MD in the hippocampus, using ROI manual approaches. Scanlon et al .…”

Lateralization Value of Low Frequency Band Beamformer Magnetoencephalography Source Imaging in Temporal Lobe Epilepsy

“…In MRI-negative TLE cases, the 1 H-MRS using an asymmetry index provided accurate lateralization in 87% of the patients ( 24 ), or had a 60–75% concordance with EEG or intracranial EEG findings ( 25 ). In patients with positive MRI findings, 1 H-MRS provided accurate lateralization in 57% of the patients ( 26 ) and indicated 100% concordant lateralization with EEG findings in unilateral TLE and 75% concordance with intracranial EEG findings in bilateral TLE ( 25 ). DTI is able to indirectly evaluate structural integrity by providing information about the direction and magnitude of water diffusion.…”

“…DTI is able to indirectly evaluate structural integrity by providing information about the direction and magnitude of water diffusion. In patients with positive MRI findings, DTI lateralized accurately in 57% of the patients ( 26 ). Neither of these neuroimaging modalities alone achieved satisfactory lateralization.…”

A meta-analysis to investigate the role of magnetic resonance spectroscopy in the detection of temporal lobe epilepsy

“…Similarly, Aun et al reported that MRS enables multiparametric mapping of TLE in less time and with a high sensitivity, and is a promising tool in evaluating patients with TLE. 13 In a prospective study by Ercan et al 14 evaluating 14 patients, and a multimodal imaging study by Voets et al 15 evaluating 12 patients, MRS was reported to be the preferred tool for studying the lateralization of epileptogenic foci and evaluating patients preoperatively. Meanwhile, a study by Liao et al reported that magnetic resonance (MR) fingerprinting is more sensitive and accurate compared to MRS in the detection of temporal lobe seizures.…”