Pai Akila, Marcuse Lara V, Alper Judy, Delman Bradley N, Rutland John W, Feldman Rebecca E, Hof Patrick R, Fields Madeline, Young James, Balchandani Priti
Icahn School of Medicine at Mount Sinai, New York, NY, United States.
Department of Neurology, Icahn School of Medicine at Mount Sinai, New York, NY, United States.
Front Neurol. 2021 Nov 15;12:682615. doi: 10.3389/fneur.2021.682615. eCollection 2021.
While the etiology of hippocampal sclerosis (HS) in epilepsy patients remains unknown, distinct phenotypes of hippocampal subfield atrophy have been associated with different clinical presentations and surgical outcomes. The advent of novel techniques including ultra-high field 7T magnetic resonance imaging (MRI) and automated subfield volumetry have further enabled detection of hippocampal pathology in patients with epilepsy, however, studies combining both 7T MRI and automated segmentation in epilepsy patients with normal-appearing clinical MRI are limited. In this study, we present a novel application of the automated segmentation of hippocampal subfields (ASHS) software to determine subfield volumes of the CA1, CA2/3, CA4/DG, and the subiculum using ultra high-field 7T MRI scans, including T1-weighted MP2RAGE and T2-TSE sequences, in 27 patients with either mesial temporal lobe epilepsy (mTLE) or neocortical epilepsy (NE) compared to age and gender matched healthy controls. We found that 7T improved visualization of structural abnormalities not otherwise seen on clinical strength MRIs in patients with unilateral mTLE. Additionally, our automated segmentation algorithm was able to detect structural differences in volume and asymmetry across hippocampal subfields in unilateral mTLE patients compared to controls. Specifically, amongst unilateral mTLE patients with longer disease durations, volume loss was observed in the ipsilateral CA1 and CA2/3 subfields and contralateral CA1. There were no differences in subfield volumes in patients with NE compared to controls. We report the first application of 7T with automated segmentation to characterize the relationship between disease duration burden and asymmetry across specific hippocampal subfields in this population. Disease duration was found to have a statistically significant positive relationship with subfield asymmetry within the unilateral mTLE cohort. These findings highlight the ability of 7T MRI and automated segmentation to provide novel qualitative and quantitative information in epilepsy patients who are otherwise MRI-negative at clinical field strengths.
虽然癫痫患者海马硬化（HS）的病因尚不清楚，但海马亚区萎缩的不同表型与不同的临床表现和手术结果相关。包括超高场7T磁共振成像（MRI）和自动亚区容积测量在内的新技术的出现，进一步使得能够检测癫痫患者的海马病变，然而，将7T MRI和自动分割技术结合应用于临床MRI表现正常的癫痫患者的研究却很有限。在本研究中，我们展示了海马亚区自动分割（ASHS）软件的一种新应用，该软件使用超高场7T MRI扫描（包括T1加权MP2RAGE和T2-TSE序列）来确定27例内侧颞叶癫痫（mTLE）或新皮质癫痫（NE）患者与年龄和性别匹配的健康对照相比，CA1、CA2/3、CA4/DG和海马下托的亚区容积。我们发现，7T能更好地显示单侧mTLE患者临床强度MRI上未发现的结构异常。此外，与对照组相比，我们的自动分割算法能够检测单侧mTLE患者海马亚区在容积和不对称性方面的结构差异。具体而言，在病程较长的单侧mTLE患者中，同侧CA1和CA2/3亚区以及对侧CA1出现了容积丢失。与对照组相比，NE患者的亚区容积没有差异。我们报告了首次将7T与自动分割技术结合应用于该人群，以表征特定海马亚区的病程负担与不对称性之间的关系。发现在单侧mTLE队列中，病程与亚区不对称性存在统计学上显著的正相关。这些发现突出了7T MRI和自动分割技术在临床场强下MRI阴性的癫痫患者中提供新的定性和定量信息的能力。
