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Seven‐tesla susceptibility‐weighted analysis of hippocampal venous structures: Application to magnetic‐resonance–normal focal epilepsy
Author(s) -
Feldman Rebecca Emily,
Marcuse Lara Vanessa,
Verma Gaurav,
Brown Stephanie Sian Gabriella,
Rus Alexandru,
Rutland John Watson,
Delman Bradley Neil,
Balchandani Priti,
Fields Madeline Cara
Publication year - 2020
Publication title -
epilepsia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.687
H-Index - 191
eISSN - 1528-1167
pISSN - 0013-9580
DOI - 10.1111/epi.16433
Subject(s) - epilepsy , magnetic resonance imaging , hippocampal sclerosis , hippocampal formation , hippocampus , asymmetry , medicine , temporal lobe , nuclear medicine , radiology , neuroscience , psychology , physics , quantum mechanics
Objective Vascular structures may play a significant role in epileptic pathology. Although previous attempts to characterize vasculature relative to epileptogenic zones and hippocampal sclerosis have been inconsistent, an in vivo method of analysis would assist in resolving these inconsistencies and facilitate a comparison against healthy controls in a human model. Magnetic resonance imaging is a noninvasive technique that provides excellent soft tissue contrast, and the relatively recent development of susceptibility‐weighted imaging has dramatically improved the visibility of small veins. Methods We built and tested a Hessian‐based segmentation technique, which takes advantage of the increased signal and contrast available at 7 T to detect venous structures in vivo. We investigate the ability of this technique to quantify vessels in the brain and apply it to an asymmetry analysis of vessel density in the hippocampus in patients with mesial temporal lobe epilepsy (MTLE) and neocortical epilepsy. Results Vessel density was highly symmetric in the hippocampus in controls (mean asymmetry = 0.080 ± 0.076, median = 0.05027), whereas average vessel density asymmetry was greater in neocortical (mean asymmetry = 0.23 ± 0.17, median = 0.14) and MTLE (mean asymmetry = 0.37 ± 0.46, median = 0.26) patients, with the decrease in vessel density ipsilateral to the suspected seizure onset zone. Post hoc testing with one‐way analysis of variance and Tukey post hoc test indicated significant differences in the group means ( P < .02) between MTLE and the control group only. Significance Asymmetry in vessel density in the hippocampus is visible in patients with MTLE, even when qualitative and quantitative measures of hippocampal asymmetry show little volumetric difference between epilepsy patients and healthy controls.