Microstructural white matter abnormalities in nodular heterotopia with overlying polymicrogyria

(Top panel) The video/EEG interictal recording, with frequent left temporal spike and sharp-wave discharges. (Bottom panel) Ictal recording with left temporal onset of 1–2s⁻¹ sharp wave discharges at seizure onset.

Top row is composed by three different orthogonal planes of the structural T1 weighted MRI, showing the unilateral temporal polymicrogyria. Middle row shows the FA map, on the left, followed by the histogram showing the distribution (in frequency of voxels) of FA between the normal and polymicrogyric temporal lobes. Bottom row shows the MD map followed by the histogram showing the distribution of the MD values between temporal lobes. Images are in neurological convention.

White matter tractography generated by two 15mm×15mm seeds (red circles on axial slice demonstrated in the insert) shows asymmetry regarding the complexity of the connections between the side with polymicrogyria (left) and the normal side.

Left panel shows the location of the temporal lobe masks, from which data was extracted for DTI and structural analyses. The histogram shows the distribution of T1 signal for both temporal lobes, demonstrating the reduced frequency of signal corresponding to the white matter on the abnormal side. The bar graph shows the ratio of gray and white matter for the normal and abnormal side. The abnormal side shows a greater ratio of gray over white matter than the normal side.