OBJECTIVES: The purpose of the study was to investigate the abnormalities of cortical lamination observed in temporal lobe specimens obtained during surgery for intractable temporal lobe epilepsy (TLE) with hippocampal sclerosis. Specifically, we aimed to 1) correlate high-field ex vivo MRI with histopathologic analysis and 2) evaluate the effect of tissue fixation on image contrast. METHODS: A cohort of 13 specimens was considered. T2-weighted imaging and relaxometry were performed during and after fixation using a 7-T experimental scanner. After imaging, the specimens were studied with histopathologic (Black Gold myelin fiber staining) and immunohistochemical (NeuN neuronal staining) methods in order to explore the correspondence between MRI and histopathologic features. RESULTS: The principal findings of this study are that 1) superior MRI contrast is obtained among the cortical layers using completely fixed specimens as opposed to recently excised tissue, 2) the intensity of the T2-weighted MRI signal is lowest (hypointensity) at the site of highest fiber concentration and cellular density, and highest (hyperintensity) when the density of fibers and cells is lowest, and 3) the MRI signal is altered in presence of abnormal cortical lamination (focal cortical dysplasia type IA). CONCLUSIONS: High resolution ex vivo MRI enables the study of intracortical organization in normal and pathologic areas. Comparisons between MRI, NeuN, and Black Gold indicate that the differences apparent in T2-weighted images are mainly related to fiber concentration, although neuronal density might also play a role.
OBJECTIVES: The purpose of the study was to investigate the abnormalities of cortical lamination observed in temporal lobe specimens obtained during surgery for intractable temporal lobe epilepsy (TLE) with hippocampal sclerosis. Specifically, we aimed to 1) correlate high-field ex vivo MRI with histopathologic analysis and 2) evaluate the effect of tissue fixation on image contrast. METHODS: A cohort of 13 specimens was considered. T2-weighted imaging and relaxometry were performed during and after fixation using a 7-T experimental scanner. After imaging, the specimens were studied with histopathologic (Black Gold myelin fiber staining) and immunohistochemical (NeuN neuronal staining) methods in order to explore the correspondence between MRI and histopathologic features. RESULTS: The principal findings of this study are that 1) superior MRI contrast is obtained among the cortical layers using completely fixed specimens as opposed to recently excised tissue, 2) the intensity of the T2-weighted MRI signal is lowest (hypointensity) at the site of highest fiber concentration and cellular density, and highest (hyperintensity) when the density of fibers and cells is lowest, and 3) the MRI signal is altered in presence of abnormal cortical lamination (focal cortical dysplasia type IA). CONCLUSIONS: High resolution ex vivo MRI enables the study of intracortical organization in normal and pathologic areas. Comparisons between MRI, NeuN, and Black Gold indicate that the differences apparent in T2-weighted images are mainly related to fiber concentration, although neuronal density might also play a role.
Authors: E Bartolini; M Cosottini; M Costagli; C Barba; L Tassi; R Spreafico; R Garbelli; L Biagi; A Buccoliero; F Giordano; R Guerrini Journal: AJNR Am J Neuroradiol Date: 2019-11-14 Impact factor: 3.825
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Authors: S Patodia; M Tachrount; A Somani; I Scheffer; T Yousry; X Golay; S M Sisodiya; M Thom Journal: Neuropathol Appl Neurobiol Date: 2020-07-15 Impact factor: 8.090
Authors: Sophie Adler; Sara Lorio; Thomas S Jacques; Barbora Benova; Roxana Gunny; J Helen Cross; Torsten Baldeweg; David W Carmichael Journal: Neuroimage Clin Date: 2017-04-20 Impact factor: 4.881
Authors: Cheryl Reeves; Mohamed Tachrount; David Thomas; Zuzanna Michalak; Joan Liu; Matthew Ellis; Beate Diehl; Anna Miserocchi; Andrew W McEvoy; Sofia Eriksson; Tarek Yousry; Maria Thom Journal: Brain Pathol Date: 2015-09-06 Impact factor: 6.508