title: T2 relaxometry improves detection of non-sclerotic epileptogenic hippocampus.
abstract: The use of T2 relaxometry was investigated to detect non-sclerotic epileptogenic abnormality of the hippocampus in presurgical evaluation of temporal lobe epilepsy (TLE).
  
  
  
  This prospective study included 30 patients who underwent hippocampectomy as part of surgical treatment of refractory TLE. Ten patients had structural epileptogenic lesions in the extra-hippocampal temporal lobe. Twelve patients underwent intracranial electroencephalography (iEEG) study before surgery. Visual assessment of atrophy and increased T2 signal intensity, volumetry, and T2 relaxometry of hippocampus were performed pre-operatively using 3T magnetic resonance imaging, and compared with the neuropathological findings and iEEG findings. Magnetic resonance imaging of 30 age- and sex-matched healthy controls was used to establish normal values, which were defined as z score within 2.
  
  
  
  Visual assessment, volumetry, and T2 relaxometry detected hippocampal abnormalities on the surgical side in 16 (53%), 16 (53%), and 26 (87%) patients, respectively. Hippocampal volume loss was always associated with prolonged T2 relaxation time, and supported by histopathological diagnosis of HS in all cases except one. Hippocampal abnormality was detected only by T2 relaxometry in nine patients (30%). Pathological diagnosis of these cases included mild HS in one, microdysgenesis in one, and granule cell pathology in three. Four patients with normal hippocampal volume and T2 relaxation time had no HS or granule cell pathology. Prolonged T2 relaxation time was associated with medial temporal seizure onset in iEEG (p<0.05).
  
  
  
  T2 relaxometry improves the detection of non-sclerotic epileptogenic abnormality of the hippocampus.
authors.affiliation: Department of Diagnostic Radiology, Tohoku University Graduate School of Medicine, 1-1 Seiryo-machi, Aoba-ku, Sendai 980-8574, Japan. Electronic address: Shihosato0809@gmail.com.
authors.forename: Shiho
authors.initials: S
authors.lastname: Sato
authors.affiliation: Department of Neurosurgery, Tohoku University Graduate School of Medicine, 1-1 Seiryo-machi, Aoba-ku, Sendai 980-8574, Japan. Electronic address: iwa@nsg.med.tohoku.ac.jp.
authors.forename: Masaki
authors.initials: M
authors.lastname: Iwasaki
authors.affiliation: Department of Diagnostic Pathology, Sendai Medical Center, 2-8-8 Miyagino, Miyagino-ku, Sendai 983-8520, Japan. Electronic address: hirosuzsnh@gmail.com.
authors.forename: Hiroyoshi
authors.initials: H
authors.lastname: Suzuki
authors.affiliation: Department of Diagnostic Radiology, Tohoku University Graduate School of Medicine, 1-1 Seiryo-machi, Aoba-ku, Sendai 980-8574, Japan. Electronic address: mugi844@gmail.com.
authors.forename: Shunji
authors.initials: S
authors.lastname: Mugikura
authors.affiliation: Department of Epileptology, Tohoku University Graduate School of Medicine, 1-1 Seiryo-machi, Aoba-ku, Sendai 980-8574, Japan. Electronic address: jinkazu2007@gmail.com.
authors.forename: Kazutaka
authors.initials: K
authors.lastname: Jin
authors.affiliation: Department of Neurosurgery, Tohoku University Graduate School of Medicine, 1-1 Seiryo-machi, Aoba-ku, Sendai 980-8574, Japan. Electronic address: tomi@nsg.med.tohoku.ac.jp.
authors.forename: Teiji
authors.initials: T
authors.lastname: Tominaga
authors.affiliation: Department of Diagnostic Radiology, Tohoku University Graduate School of Medicine, 1-1 Seiryo-machi, Aoba-ku, Sendai 980-8574, Japan. Electronic address: ktakase@rad.med.tohoku.ac.jp.
authors.forename: Kei
authors.initials: K
authors.lastname: Takase
authors.affiliation: Department of Diagnostic Radiology, Tohoku University Graduate School of Medicine, 1-1 Seiryo-machi, Aoba-ku, Sendai 980-8574, Japan. Electronic address: t-shoki@rad.med.tohoku.ac.jp.
authors.forename: Shoki
authors.initials: S
authors.lastname: Takahashi
authors.affiliation: Department of Epileptology, Tohoku University Graduate School of Medicine, 1-1 Seiryo-machi, Aoba-ku, Sendai 980-8574, Japan. Electronic address: nkst@med.tohoku.ac.jp.
authors.forename: Nobukazu
authors.initials: N
authors.lastname: Nakasato
mesh_terms: D000293:Adolescent; D000328:Adult; D001284:Atrophy / Q000000981:diagnostic imaging / Q000473:pathology; D000069279:Drug Resistant Epilepsy / Q000000981:diagnostic imaging* / Q000473:pathology / Q000601:surgery; D000069280:Electrocorticography; D004833:Epilepsy, Temporal Lobe / Q000000981:diagnostic imaging* / Q000473:pathology / Q000601:surgery; D005260:Female; D019788:Fluorodeoxyglucose F18; D006624:Hippocampus / Q000002:abnormalities / Q000000981:diagnostic imaging* / Q000473:pathology / Q000601:surgery; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009929:Organ Size; D049268:Positron-Emission Tomography; D011446:Prospective Studies; D019275:Radiopharmaceuticals; D012598:Sclerosis / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery; D055815:Young Adult
chemical_list: D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18
keywords: Epilepsy surgery; Hippocampus; T2 relaxometry; Temporal lobe epilepsy; Volumetry