Combined Ex Vivo 9.4T MRI and Quantitative Histopathological Study in Normal and Pathological Neocortical Resections in Focal Epilepsy

摘要

High‐resolution magnetic resonance imaging (MRI) may improve the preoperative diagnosis of focal cortical dysplasia (FCD) in epilepsy. Quantitative 9.4T MRI was carried out (T1, T2, T2* and magnetization transfer ratio) on 13 cortical resections, representing pathologically confirmed FCD (five cases) and normal cortex. Quantitative immunohistochemistry for myelination (myelin basic protein/SMI94), neuronal populations [microtubule‐associated protein 2 (MAP2), neurofilament (SMI31, SMI32), synaptophysin, NeuN, calbindin], reactive glia (GFAP), microglia (CD68) and blood–brain barrier permeability (albumin) was carried out in 43 regions of interest (ROI) from normal and abnormal white matter and cortex. MRI was spatially aligned and quantitative analysis carried out on corresponding style="fixed-case">ROI. Line profile analysis ( style="fixed-case">LPA) of intensity gradients through the cortex was carried out on style="fixed-case">MRI and immunostained sections. An inverse correlation was noted between myelin/ style="fixed-case">SMI94 and style="fixed-case">T1, style="fixed-case">T2 (P < 0.005) and style="fixed-case">T2* (P < 0.05; Spearman's correlation) and a positive correlation between neuronal style="fixed-case">MAP2 and style="fixed-case">T1 (P < 0.005) and style="fixed-case">T2* (P < 0.05) over all style="fixed-case">ROI. Similar pathology– style="fixed-case">MRI correlations were observed for histologically unremarkable white matter style="fixed-case">ROI only. style="fixed-case">LPA showed altered gradient contours in regions of style="fixed-case">FCD, reflecting abnormal cortical lamination and myelo‐architecture, including a preoperatively undetected style="fixed-case">FCD case. This study demonstrates the ability of quantitative 9.4 style="fixed-case">T MRI to detect subtle differences in neuronal numbers and myelination in histologically normal appearing white matter and style="fixed-case">LPA in the evaluation of cortical dyslamination. These methods may be translatable to the in vivo detection of mild cortical malformations.