Magnetization Transfer Ratio Is Unable to Lateralize Epileptic Foci in Patients with Temporal Lobe Epilepsy
Li Min Lia,
Sridar Narayanana,
Gilbert Bruce Pikea,
Frederick Andermanna,
François Dubeaua and
Douglas L. Arnolda,b
a From the Department of Neurology and Neurosurgery, McGill University and the Montreal Neurological Institute and Hospital, Montreal, Quebec, Canada.
b Address reprint requests to Douglas L. Arnold, MD, Montreal Neurological Hospital and Institute, 3801 University Street, Montreal, Quebec, Canada H3A 2B4.
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FIG 1. Computation of MTR in amygdala and hippocampus.>>A, Fifty transverse sections (3 mm) covering the whole brain and angled along the temporal plane by use of a pair of 3D gradient-echo acquisitions, without (No Sat) and with (Sat) MT saturation pulses, respectively, were obtained using 35/10/1 and a flip angle of 40 degrees. Semisolid spin saturation was achieved using 1.2-ms on-resonance 121 binomial pulses (|B1| = 19 µT) placed just before each section selective excitation.
B, Percentage difference (100 x [No Sat—Sat]/No Sat) MT images were calculated after thresholding above the noise background.
C, Amygdala (white arrow) and hippocampus (black arrow) were outlined on volumetric T1-weighted 1-mm isotropic voxel acquisition.
D, Volumetric T1-weighted images, with outlined mesial temporal structures, and MT images were coregistered. The MTR of amygdalae, hippocampi, and asymmetry index were computed.
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