Hippocampal “gliosis only” on MR imaging represents a distinct entity in epilepsy patients

Abstract

"Gliosis only" has different MRI hippocampal characteristics than HS: less volume loss, less increase of the T2-w signal intensity, preservation of internal architecture, and more contralateral affection.

Cortical Changes in Epilepsy Patients With Focal Cortical Dysplasia: New Insights With T2 Mapping

“…Importantly, clusters indicating atrophy were not observed in the investigated cohort, which is in line with a previous study demonstrating hippocampal T 2 changes in temporal lobe epilepsy, even in patients showing no signs of atrophy 14 . Furthermore, it has been reported that hippocampal gliosis may occur without atrophy 32 . Since T 2 depends on the free water content in tissue, 12,13 cortical reconstruction characterized by tissue damage and replacement of cells in nervous tissue by water on a microstructural level could potentially be another mechanism leading to increased cortical T 2 values in epilepsy patients with FCD.…”

“…14 Furthermore, it has been reported that hippocampal gliosis may occur without atrophy. 32 Since T 2 depends on the free water content in tissue, 12,13 cortical reconstruction characterized by tissue damage and replacement of cells in nervous tissue by water on a microstructural level could potentially be another mechanism leading to increased cortical T 2 values in epilepsy patients with FCD.…”

Chronic clomipramine treatment increases hippocampal volume in rats exposed to chronic unpredictable mild stress

“…Besides, it has been demonstrated that hippocampal cell proliferation, as well as neurogenesis, could be promoted by chronic clomipramine treatment [ 14 , 57 ], which may account for the changes in hippocampal volume [ 58 , 59 ]. On the other hand, clomipramine likely increased the rat’s hippocampal volume by promoting gliosis, which could have something to do with the increase of hippocampal volume under pathological conditions [ 60 , 61 ] since our previous work indicated that chronic clomipramine treatment increased GFAP level in the hippocampus of rats exposed to chronic unpredictable stress [ 48 ]. Furthermore, Peixoto-Santos et al found that the extracellular matrix also plays an important role in the maintenance of hippocampal volume except for cellular constituents [ 62 ].…”

Schläfenlappenepilepsie

“…Als erwartbares Resultat aufgrund des geringeren Zellverlustes war die interne Histoarchitektur der Hippocampusformation besser erhalten. Interessanterweise zeigte sich die Gegenseite stärker in die Pathologie einbezogen [37]. Vor dem Hintergrund der Rolle von Astroglia als Immunzellen kann dieser Befund auch auf eine mögliche pathogenetisch relevante Rolle der Astroglia für die Emergenz der Schläfenlappenepilepsie und Anfallsentstehung spielen [38].…”