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Lang M, Colby S, Ashby-Padial C, Bapna M, Jaimes C, Rincon SP, Buch K. An imaging review of the hippocampus and its common pathologies. J Neuroimaging 2024; 34:5-25. [PMID: 37872430 DOI: 10.1111/jon.13165] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2023] [Revised: 10/07/2023] [Accepted: 10/12/2023] [Indexed: 10/25/2023] Open
Abstract
The hippocampus is a complex structure located in the mesial temporal lobe that plays a critical role in cognitive and memory-related processes. The hippocampal formation consists of the dentate gyrus, hippocampus proper, and subiculum, and its importance in the neural circuitry makes it a key anatomic structure to evaluate in neuroimaging studies. Advancements in imaging techniques now allow detailed assessment of hippocampus internal architecture and signal features that has improved identification and characterization of hippocampal abnormalities. This review aims to summarize the neuroimaging features of the hippocampus and its common pathologies. It provides an overview of the hippocampal anatomy on magnetic resonance imaging and discusses how various imaging techniques can be used to assess the hippocampus. The review explores neuroimaging findings related to hippocampal variants (incomplete hippocampal inversion, sulcal remnant and choroidal fissure cysts), and pathologies of neoplastic (astrocytoma and glioma, ganglioglioma, dysembryoplastic neuroepithelial tumor, multinodular and vacuolating neuronal tumor, and metastasis), epileptic (mesial temporal sclerosis and focal cortical dysplasia), neurodegenerative (Alzheimer's disease, progressive primary aphasia, and frontotemporal dementia), infectious (Herpes simplex virus and limbic encephalitis), vascular (ischemic stroke, arteriovenous malformation, and cerebral cavernous malformations), and toxic-metabolic (transient global amnesia and opioid-associated amnestic syndrome) etiologies.
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Affiliation(s)
- Min Lang
- Department of Radiology, Massachusetts General Hospital, Boston, Massachusetts, USA
- Harvard Medical School, Boston, Massachusetts, USA
| | - Samantha Colby
- Department of Neurosurgery, University of Utah Health, Salt Lake City, Utah, USA
| | | | - Monika Bapna
- School of Medicine, Georgetown University, Washington, DC, USA
| | - Camilo Jaimes
- Department of Radiology, Massachusetts General Hospital, Boston, Massachusetts, USA
- Harvard Medical School, Boston, Massachusetts, USA
| | - Sandra P Rincon
- Department of Radiology, Massachusetts General Hospital, Boston, Massachusetts, USA
- Harvard Medical School, Boston, Massachusetts, USA
| | - Karen Buch
- Department of Radiology, Massachusetts General Hospital, Boston, Massachusetts, USA
- Harvard Medical School, Boston, Massachusetts, USA
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Durrleman C, Grevent D, Aubart M, Kossorotoff M, Roux CJ, Kaminska A, Rio M, Barcia G, Boddaert N, Munnich A, Nabbout R, Desguerre I. Clinical and radiological description of 120 pediatric stroke-like episodes. Eur J Neurol 2023; 30:2051-2061. [PMID: 37046408 DOI: 10.1111/ene.15821] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2022] [Revised: 03/27/2023] [Accepted: 04/03/2023] [Indexed: 04/14/2023]
Abstract
BACKGROUND AND PURPOSE Stroke-like episodes (SLEs) are defined as acute onset of neurological symptoms mimicking a stroke and radiological lesions non-congruent to vascular territory. We aimed to analyze the acute clinical and radiological features of SLEs to determine their pathophysiology. METHODS We performed a monocenter retrospective analysis of 120 SLEs in 60 children over a 20-year period. Inclusion criteria were compatible clinical symptoms and stroke-like lesions on brain magnetic resonance imaging (MRI; performed for all 120 events) with focal hyperintensity on diffusion-weighted imaging in a non-vascular territory. RESULTS Three groups were identified: children with mitochondrial diseases (n = 22) involving mitochondrial DNA mutations (55%) or nuclear DNA mutations (45%); those with other metabolic diseases or epilepsy disorders (n = 22); and those in whom no etiology was found despite extensive investigations (n = 16). Age at first SLE was younger in the group with metabolic or epilepsy disorders (18 months vs. 128 months; p < 0.0001) and an infectious trigger was more frequent (69% vs. 20%; p = 0.0001). Seizures occurred in 75% of episodes, revealing 50% episodes of SLEs and mainly leading to status epilepticus (90%). Of the 120 MRI scans confirming the diagnosis, 28 were performed within a short and strict 48-h period and were further analyzed to better understand the underlying mechanisms. The scans showed primary cortical hyperintensity (n = 28/28) with decreased apparent diffusion coefficient in 52% of cases. Systematic hyperperfusion was found on spin labeling sequences when available (n = 18/18). CONCLUSION Clinical and radiological results support the existence of a vicious circle based on two main mechanisms: energy deficit and neuronal hyperexcitability at the origin of SLE.
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Affiliation(s)
- Chloe Durrleman
- Pediatric Neurology Department, Necker Enfants Malades Hospital, APHP, Université Paris Cité, Paris, France
| | - David Grevent
- Pediatric Imaging Department, Necker Enfants Malades Hospital, APHP, Université Paris Cité, Paris, France
- Lumiere Platform, Université Paris Cité, Paris, France
| | - Melodie Aubart
- Pediatric Neurology Department, Necker Enfants Malades Hospital, APHP, Université Paris Cité, Paris, France
| | - Manoelle Kossorotoff
- Pediatric Neurology Department, Necker Enfants Malades Hospital, APHP, Université Paris Cité, Paris, France
| | - Charles-Joris Roux
- Pediatric Imaging Department, Necker Enfants Malades Hospital, APHP, Université Paris Cité, Paris, France
| | - Anna Kaminska
- Neurophysiology Department, Necker Enfants Malades Hospital, APHP, Université Paris Cité, Paris, France
| | - Marlene Rio
- Genetic Department, Necker Enfants Malades Hospital, APHP, Université Paris Cité, Paris, France
| | - Giulia Barcia
- Genetic Department, Necker Enfants Malades Hospital, APHP, Université Paris Cité, Paris, France
| | - Nathalie Boddaert
- Pediatric Imaging Department, Necker Enfants Malades Hospital, APHP, Université Paris Cité, Paris, France
- Lumiere Platform, Université Paris Cité, Paris, France
| | - Arnold Munnich
- Genetic Department, Necker Enfants Malades Hospital, APHP, Université Paris Cité, Paris, France
| | - Rima Nabbout
- Pediatric Neurology Department, Necker Enfants Malades Hospital, APHP, Université Paris Cité, Paris, France
| | - Isabelle Desguerre
- Pediatric Neurology Department, Necker Enfants Malades Hospital, APHP, Université Paris Cité, Paris, France
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Nagarajan L, Ghosh S, Palumbo L, Lee S, Shipman P, Dyke J. Discordant electroencephalogram epileptiform activity and hemispherectomy in children with refractory epilepsy and encephaloclastic lesions: a case series. Dev Med Child Neurol 2022; 64:387-394. [PMID: 34495552 DOI: 10.1111/dmcn.15047] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/22/2021] [Revised: 08/01/2021] [Accepted: 08/06/2021] [Indexed: 11/28/2022]
Abstract
This is a case series of six children with unilateral cerebral palsy and hemispheric encephaloclastic lesions who were evaluated for epilepsy surgery. Seizure onset was in the neonatal period in three children, at 17 months in two, and at 5 years in one. Their ictal and interictal electroencephalogram (EEG) abnormalities showed paradoxical lateralization to the incorrect/'normal' hemisphere or showed bilateral abnormalities. After cautious discussion regarding the discordant electroclinical profile and implications for outcome, they proceeded to a functional hemispherectomy (between ages 4-11y) with good outcomes (at 1-10y follow-up). Their clinical details, EEG findings, electrocorticography, neuroimaging, and histology are reported. Possible surgical candidacy should be evaluated early in children with refractory epilepsy, even those with complex profiles and discordant data from the different investigations. Contralateral or bilateral EEG abnormalities should not preclude consideration of hemispherectomy in children with refractory epilepsy, hemiparesis, and uniclastic lesions.
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Affiliation(s)
- Lakshmi Nagarajan
- Children's Neuroscience Service, Department of Neurology, Perth Children's Hospital, Nedlands, Western Australia, Australia.,School of Medicine, University of Western Australia, Perth, Western Australia, Australia.,Telethon Kids Institute, Nedlands, Western Australia, Australia
| | - Soumya Ghosh
- Children's Neuroscience Service, Department of Neurology, Perth Children's Hospital, Nedlands, Western Australia, Australia.,Perron Institute for Neurological and Translational Science, University of Western Australia, Perth, Western Australia, Australia
| | - Linda Palumbo
- Children's Neuroscience Service, Department of Neurology, Perth Children's Hospital, Nedlands, Western Australia, Australia
| | - Sharon Lee
- Department of Neurosurgery, Perth Children's Hospital, Nedlands, Western Australia, Australia.,WA Statewide Neurosurgery Service, Royal Perth Hospital, Perth, Western Australia, Australia
| | - Peter Shipman
- Department of Radiology, Perth Children's Hospital, Nedlands, Western Australia, Australia
| | - Jason Dyke
- School of Medicine, University of Western Australia, Perth, Western Australia, Australia.,PathWest Neuropathology, Royal Perth Hospital, Perth, Western Australia, Australia
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Suzuki T, Kidokoro H, Kubota T, Fukasawa T, Suzui R, Tsuji T, Kato T, Yamamoto H, Ohno A, Nakata T, Saitoh S, Okumura A, Natsume J. Transient cortical diffusion restriction in children immediately after prolonged febrile seizures. Eur J Paediatr Neurol 2020; 27:30-36. [PMID: 32473849 DOI: 10.1016/j.ejpn.2020.05.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/23/2019] [Revised: 04/29/2020] [Accepted: 05/10/2020] [Indexed: 11/18/2022]
Abstract
AIM Little is known about acute febrile status epilepticus-induced injury of extrahippocampal structures. To clarify the presence and clinical significance of acute extrahippocampal injuries, we performed diffusion-weighted imaging (DWI) in children immediately after prolonged febrile seizure (PFS). METHOD We performed a retrospective cohort study in children younger than 6 years old who visited one of two hospitals due to PFSs between January 2013 and October 2018. PFS was defined as a febrile seizure that persisted for 15 min or longer. We collected brain DWI data within 6 h of the end of PFS. When the initial DWI detected an abnormality, a follow-up DWI was performed a few days later. RESULTS The study population consisted of 101 patients with PFSs. DWI was performed within 6 h in 51 patients, while the remaining 50 patients did not undergo imaging because of good recovery of consciousness. Restricted cortical diffusion was evident in 9 (18%) patients on initial DWI. All of them underwent DWI within 100 min after PFS. Restricted cortical diffusion was associated with male sex, asymmetrical PFS symptoms, and a shorter duration between the end of the seizure and DWI, but was not associated with seizure duration. All cortical abnormalities had resolved on follow-up DWI of these patients within 72 h after the initial imaging, but ipsilateral hippocampal hyperintensity appeared in one patient. All 9 patients with restricted cortical diffusion were finally diagnosed with PFS and discharged without sequelae. CONCLUSIONS Some children with PFSs exhibit transient restricted diffusion in the regional cortex on DWI performed immediately after the end of PFS. These transient diffusion changes were not associated with unfavorable epileptic sequelae or neuroimaging in the short-term.
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Affiliation(s)
- Takeshi Suzuki
- Department of Pediatrics, Nagoya University Graduate School of Medicine, Nagoya, Japan; Department of Pediatrics, Anjo Kosei Hospital, Anjo, Japan
| | - Hiroyuki Kidokoro
- Department of Pediatrics, Nagoya University Graduate School of Medicine, Nagoya, Japan.
| | - Tetsuo Kubota
- Department of Pediatrics, Anjo Kosei Hospital, Anjo, Japan
| | | | - Ryosuke Suzui
- Department of Pediatrics, Okazaki City Hospital, Okazaki, Japan
| | - Takeshi Tsuji
- Department of Pediatrics, Okazaki City Hospital, Okazaki, Japan
| | - Toru Kato
- Department of Pediatrics, Okazaki City Hospital, Okazaki, Japan
| | - Hiroyuki Yamamoto
- Department of Pediatrics, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Atsuko Ohno
- Department of Pediatrics, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Tomohiko Nakata
- Department of Pediatrics, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Shinji Saitoh
- Department of Pediatrics and Neonatology, Nagoya City University Graduate School of Medicinal Sciences, Nagoya, Japan
| | - Akihisa Okumura
- Department of Pediatrics, Aichi Medical University, Nagakute, Japan
| | - Jun Natsume
- Department of Pediatrics, Nagoya University Graduate School of Medicine, Nagoya, Japan
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Myers KA, Scheffer IE, Archer JS. Hemiconvulsion-hemiplegia-epilepsy evolving to contralateral hemi-Lennox-Gastaut-like phenotype. Brain Dev 2018; 40:425-428. [PMID: 29459061 DOI: 10.1016/j.braindev.2018.01.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/07/2017] [Revised: 01/10/2018] [Accepted: 01/18/2018] [Indexed: 11/17/2022]
Abstract
BACKGROUND Hemiconvulsion-hemiplegia-epilepsy (HHE) involves infantile-onset acute hemiconvulsive febrile status epilepticus with subsequent unilateral cerebral atrophy and hemiparesis. Chronic epilepsy later develops, typically involving refractory focal seizures; however, the underlying pathophysiology of this epilepsy is not well understood. PATIENT We present a boy who had a typical acute presentation of HHE at 23 months, but an unusual evolution to chronic epilepsy in which the initially unaffected hemisphere was significantly abnormal. His initial acute presentation was right-sided hemiconvulsive febrile status epilepticus, with subsequent left cerebral hemiatrophy and hemiparesis affecting the right face, arm and leg. Focal seizures began at 5 years and were refractory to medical treatment. At 9 years, video EEG monitoring showed a striking pattern of interictal slow spike-wave and paroxysmal fast activity, maximal over the right, initially unaffected, hemisphere. He had primarily focal tonic seizures involving left-sided stiffening, also appearing to originate from the right hemisphere. Following left functional hemispherotomy he became seizure-free and parents reported improved cognitive function, attention and quality of life. DISCUSSION This boy had classic features of Lennox-Gastaut syndrome, but expressed almost exclusively over the right hemisphere, which was initially unaffected in his acute presentation of HHE. His evolution to "hemi-Lennox-Gastaut-like phenotype" illustrates the importance of monitoring chronic epilepsy in patients with HHE; early surgical intervention might prevent pathologic recruitment of bilateral secondary networks leading to the refractory seizures and cognitive impairment associated with Lennox-Gastaut syndrome.
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Affiliation(s)
- Kenneth A Myers
- Epilepsy Research Centre, Department of Medicine, The University of Melbourne, Austin Health, Heidelberg, Victoria, Australia; Department of Pediatrics, Faculty of Medicine, McGill University, Montreal, Quebec, Canada; Division of Child Neurology, Montreal Children's Hospital, McGill University Health Centre, Montreal, Quebec, Canada.
| | - Ingrid E Scheffer
- Epilepsy Research Centre, Department of Medicine, The University of Melbourne, Austin Health, Heidelberg, Victoria, Australia; The Florey Institute of Neuroscience and Mental Health, Heidelberg, Victoria, Australia; Department of Paediatrics, The University of Melbourne, Parkville, Victoria, Australia; Department of Neurology, Royal Children's Hospital, Parkville, Victoria, Australia
| | - John S Archer
- Epilepsy Research Centre, Department of Medicine, The University of Melbourne, Austin Health, Heidelberg, Victoria, Australia; The Florey Institute of Neuroscience and Mental Health, Heidelberg, Victoria, Australia
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