PMC4003487_01
Axial T2- weighted image (3 Tesla) indicates a subtle blurring of the gray-white matter junction suggesting malformation of cortical development in the right orbitofrontal gyrus (white arrow).
nihms348541f1.jpg
PMC4003487_01_nihms348541f1.jpg
F1
A new MRI study, this time at 3T, detected a subtle blurring at the gray-white matter junction in the right posterior orbitofrontal gyrus, suggesting malformation of cortical development (Fig. 1).
Upper Column EEG and MEG waveforms and dipole analysis of the spikes. The set of spikes exemplified by the discharge enclosed by the broken line and labeled as #1 were detected with MEG only (MEG unique) whereas the set labeled as #2 are typical of those that were detected with both EEG and MEG (EEG/MEG spike). Lower column: A magnified spike waveform, MEG contour map, and spike dipole source locations on the patient's individual MRI for spikes #1 and 2 are shown. MEG contour maps: Arrows on the contour maps reflect the estimated dipoles projected to the sensor surface. The solid line indicates the efflux of the magnetic field from the head surface, and the broken line indicates influx of the magnetic field into the head. MRI: The circle and bar on the MRI scans indicate the dipole location and orientation, respectively. Note that the patient has two types of spikes: MEG unique spikes (#1) and EEG/MEG spikes (#2). Spike dipoles of both are estimated on the same area, the right orbito-frontal area, where an axial T2- weighted image (3 Tesla) indicates as abnormal.
nihms348541f2.jpg
PMC4003487_01_nihms348541f2.jpg
F2
A representative plot is shown in Fig. 2 (upper column). Curiously, dipole localization (employing a single equivalent current dipole model) estimated both MEG unique spike (#1) and EEG/MEG spike (#2) in the same area, the right orbitofrontal gyrus (Fig. 2, lower column), conicident with the area indcated as abnormal on the 3T MRI.
Spike amplitude of a MEG sensor is defined from baseline to peak.
nihms348541f3.jpg
PMC4003487_01_nihms348541f3.jpg
F3
The magnetic amplitude of MEG spike was measured (baseline to peak, see Fig. 3)  at the four sensors showing the highest responses over the right fronto-temporal area, and we calculated the average of the four responses ("average").