1
|
Naji N, Wilman A. Thin slab quantitative susceptibility mapping. Magn Reson Med 2023; 90:2290-2305. [PMID: 37526029 DOI: 10.1002/mrm.29800] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2023] [Revised: 06/27/2023] [Accepted: 06/30/2023] [Indexed: 08/02/2023]
Abstract
PURPOSE Susceptibility maps reconstructed from thin slabs may suffer underestimation due to background-field removal imperfections near slab boundaries and the increased difficulty of solving a 3D-inversion problem with reduced support, particularly in the direction of the main magnetic field. Reliable QSM reconstruction from thin slabs would enable focal acquisitions in a much-reduced scan time. METHODS This work proposes using additional rapid low-resolution data of extended spatial coverage to improve background-field estimation and regularize the inversion-to-susceptibility process for high resolution, thin slab data. The new method was tested using simulated and in-vivo brain data of high resolution (0.33 × 0.33 × 0.33 mm3 and 0.54 × 0.54 × 0.65 mm3 , respectively) at 3T, and compared to the standard large volume approach. RESULTS Using the proposed method, in-vivo high-resolution QSM at 3T was obtained from slabs of width as small as 10.4 mm, aided by a lower-resolution dataset of 24 times coarser voxels. Simulations showed that the proposed method produced more consistent measurements from slabs of at least eight slices. Reducing the mean ROI error to 5% required the low-resolution data to cover ˜60 mm in the direction of the main field, have at least 2-mm isotropic resolution that is not coarser than the high-resolution data by more than four-fold in any direction. CONCLUSION Applying the proposed method enabled focal QSM acquisitions at sub-millimeter resolution within reasonable acquisition time.
Collapse
Affiliation(s)
- Nashwan Naji
- Department of Biomedical Engineering, University of Alberta, Edmonton, Alberta, Canada
| | - Alan Wilman
- Department of Biomedical Engineering, University of Alberta, Edmonton, Alberta, Canada
| |
Collapse
|
2
|
Vinci-Booher S, Schlichting ML, Preston AR, Pestilli F. Development of human hippocampal subfield microstructure and relation to associative inference. Cereb Cortex 2023; 33:10207-10220. [PMID: 37557916 PMCID: PMC10502573 DOI: 10.1093/cercor/bhad276] [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: 02/16/2023] [Revised: 06/30/2023] [Accepted: 07/01/2023] [Indexed: 08/11/2023] Open
Abstract
The hippocampus is a complex brain structure composed of subfields that each have distinct cellular organizations. While the volume of hippocampal subfields displays age-related changes that have been associated with inference and memory functions, the degree to which the cellular organization within each subfield is related to these functions throughout development is not well understood. We employed an explicit model testing approach to characterize the development of tissue microstructure and its relationship to performance on 2 inference tasks, one that required memory (memory-based inference) and one that required only perceptually available information (perception-based inference). We found that each subfield had a unique relationship with age in terms of its cellular organization. While the subiculum (SUB) displayed a linear relationship with age, the dentate gyrus (DG), cornu ammonis field 1 (CA1), and cornu ammonis subfields 2 and 3 (combined; CA2/3) displayed nonlinear trajectories that interacted with sex in CA2/3. We found that the DG was related to memory-based inference performance and that the SUB was related to perception-based inference; neither relationship interacted with age. Results are consistent with the idea that cellular organization within hippocampal subfields might undergo distinct developmental trajectories that support inference and memory performance throughout development.
Collapse
Affiliation(s)
- Sophia Vinci-Booher
- Indiana University, Psychological and Brain Sciences, 1101 E. 10th St., Bloomington, Indiana, 47405, United States
- Vanderbilt University, Psychology and Human Development, 230 Appleton Pl., Nashville, TN 37203, United States
| | - Margaret L Schlichting
- University of Toronto, Psychology, 100 St. George St., Toronto, ON M5S 3G3, Canada
- University of Texas at Austin, Psychology, 108 E. Dean Keeton Street, Austin, TX 78712, United States
| | - Alison R Preston
- University of Texas at Austin, Psychology, 108 E. Dean Keeton Street, Austin, TX 78712, United States
| | - Franco Pestilli
- University of Texas at Austin, Psychology, 108 E. Dean Keeton Street, Austin, TX 78712, United States
| |
Collapse
|
3
|
Adel SAA, Treit S, Abd Wahab W, Little G, Schmitt L, Wilman AH, Beaulieu C, Gross DW. Longitudinal hippocampal diffusion-weighted imaging and T2 relaxometry demonstrate regional abnormalities which are stable and predict subfield pathology in temporal lobe epilepsy. Epilepsia Open 2023; 8:100-112. [PMID: 36461649 PMCID: PMC9977756 DOI: 10.1002/epi4.12679] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2022] [Accepted: 11/15/2022] [Indexed: 12/04/2022] Open
Abstract
OBJECTIVE High-resolution (1 mm isotropic) diffusion tensor imaging (DTI) of the hippocampus in temporal lobe epilepsy (TLE) patients has shown patterns of hippocampal subfield diffusion abnormalities, which were consistent with hippocampal sclerosis (HS) subtype on surgical histology. The objectives of this longitudinal imaging study were to determine the stability of focal hippocampus diffusion changes over time in TLE patients, compare diffusion and quantitative T2 abnormalities of the sclerotic hippocampus, and correlate presurgical mean diffusivity (MD) and T2 maps with postsurgical histology. METHODS Nineteen TLE patients and 19 controls underwent two high-resolution (1 mm isotropic) DTI and 1.1 × 1.1 × 1 mm3 T2 relaxometry scans (in a subset of 16 TLE patients and 9 controls) of the hippocampus at 3T, with a 2.6 ± 0.8 year inter-scan interval. Within-participant hippocampal volume, MD and T2 were compared between the scans. Contralateral hippocampal changes 2.3 ± 1.0 years after surgery and ipsilateral preoperative MD maps versus postoperative subfield histopathology were evaluated in eight patients who underwent surgical resection of the hippocampus. RESULTS Reduced volume and elevated MD and T2 of sclerotic hippocampi remained unchanged between longitudinal scans. Focal regions of elevated MD and T2 in bilateral hippocampi of HS TLE were detected consistently at both scans. Regions of high MD and T2 correlated and remained consistent over time. Volume, MD, and T2 remained unchanged in postoperative contralateral hippocampus. Regional elevations of MD identified subfield neuron loss on postsurgical histology with 88% sensitivity and 88% specificity. Focal T2 elevations identified subfield neuron loss with 75% sensitivity and 88% specificity. SIGNIFICANCE Diffusion and T2 abnormalities in ipsilateral and contralateral hippocampi remained unchanged between the scans suggesting permanent microstructural alterations. MD and T2 demonstrated good sensitivity and specificity to detect hippocampal subfield neuron loss on postsurgical histology, supporting the potential that high-resolution hippocampal DTI and T2 could be used to diagnose HS subtype before surgery.
Collapse
Affiliation(s)
- Seyed Amir Ali Adel
- Department of Biomedical Engineering, University of Alberta, Edmonton, Alberta, Canada
| | - Sarah Treit
- Department of Biomedical Engineering, University of Alberta, Edmonton, Alberta, Canada
| | - Wasan Abd Wahab
- Division of Neurology, University of Alberta, Edmonton, Alberta, Canada
| | - Graham Little
- Department of Biomedical Engineering, University of Alberta, Edmonton, Alberta, Canada.,Department of Computer Science, Université de Sherbrooke, Sherbrooke, Quebec, Canada
| | - Laura Schmitt
- Department of Laboratory Medicine and Pathology, University of Alberta, Edmonton, Alberta, Canada
| | - Alan H Wilman
- Department of Biomedical Engineering, University of Alberta, Edmonton, Alberta, Canada
| | - Christian Beaulieu
- Department of Biomedical Engineering, University of Alberta, Edmonton, Alberta, Canada
| | - Donald W Gross
- Division of Neurology, University of Alberta, Edmonton, Alberta, Canada
| |
Collapse
|
4
|
Rasmussen JM, Tuulari JJ, Nolvi S, Thompson PM, Merisaari H, Lavonius M, Karlsson L, Entringer S, Wadhwa PD, Karlsson H, Buss C. Maternal pre-pregnancy body mass index is associated with newborn offspring hypothalamic mean diffusivity: a prospective dual-cohort study. BMC Med 2023; 21:57. [PMID: 36788536 PMCID: PMC9930241 DOI: 10.1186/s12916-023-02743-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/17/2022] [Accepted: 01/18/2023] [Indexed: 02/16/2023] Open
Abstract
BACKGROUND An extensive body of animal literature supports the premise that maternal obesity during pregnancy can alter the development of the fetal hypothalamus (HTH, a critical regulator of energy balance) with implications for offspring obesity risk (i.e., long-term energy imbalance). Yet, the relationship in humans between maternal overweight/obesity during pregnancy and fetal hypothalamic development remains largely unknown. Here, using an international (Finland and California, USA) multi-site diffusion tensor imaging (DTI) dataset, we test the hypothesis that maternal pre-pregnancy BMI is associated with newborn offspring HTH mean diffusivity (HTH MD, a replicable neural correlate of BMI in adults). METHODS HTH MD was independently quantified in two separate BMI-matched cohorts (up to class II obesity; BMIRange = 17-35) using a high-resolution atlas-based definition of HTH. A total of n = 231 mother-child dyads were available for this analysis (nSite,1 = 152, age at MRI = 26.7 ± 8.1 days, gestational age at birth = 39.9 ± 1.2 weeks, nM/F = 82/70, BMI = 24.2 ± 3.8; nSite,2 = 79, age at MRI = 25.6 ± 12.5 days, gestational age at birth = 39.3 ± 1.5 weeks, nM/F = 45/34, BMI = 25.1 ± 4.0). The association between maternal pre-pregnancy BMI and newborn offspring HTH MD was examined separately in each cohort using linear regression adjusting for gestational age at birth, postnatal age at scan, sex, whole white matter mean diffusivity, and DTI quality control criteria. In post hoc analyses, additional potentially confounding factors including socioeconomic status, ethnicity, and obstetric risk were adjusted where appropriate. RESULTS The distribution of maternal pre-pregnancy BMI was comparable across sites but differed by ethnicity and socioeconomic status. A positive linear association between maternal pre-pregnancy BMI and newborn offspring HTH MD was observed at both sites ([Formula: see text]Site,1 = 0.17, pSite,1 = 0.01; [Formula: see text]Site,2 = 0.22, pSite,2 = 0.03) and remained significant after adjusting for cohort-relevant covariates. CONCLUSIONS These findings translate the preclinically established association between maternal obesity during pregnancy and offspring hypothalamic microstructure to the human context. In addition to further replication/generalization, future efforts to identify biological mediators of the association between maternal obesity and fetal HTH development are warranted to develop targeted strategies for the primary prevention of childhood obesity.
Collapse
Affiliation(s)
- Jerod M Rasmussen
- Development, Health and Disease Research Program, University of California, Irvine, CA, 92697, USA.
- Department of Pediatrics, University of California, Irvine, CA, 92697, USA.
| | - Jetro J Tuulari
- FinnBrain Birth Cohort Study, Turku Brain and Mind Center, Department of Clinical Medicine, University of Turku, Lemminkäisenkatu 2, 20520, Turku, Finland
- Turku Collegium for Science Technology and Medicine (TCSMT), University of Turku, Turku, Finland
- Department of Psychiatry, University of Turku and Turku University Hospital, Turku, Finland
- Department of Psychiatry, University of Oxford (Sigrid Juselius Fellowship), Oxford, UK
| | - Saara Nolvi
- FinnBrain Birth Cohort Study, Turku Brain and Mind Center, Department of Clinical Medicine, University of Turku, Lemminkäisenkatu 2, 20520, Turku, Finland
- Turku Institute for Advanced Studies, Department of Psychology and Speech-Language Pathology, University of Turku, Turku, Finland
| | - Paul M Thompson
- Imaging Genetics Center, Mark and Mary Stevens Institute for Neuroimaging and Informatics, Keck School of Medicine, University of Southern California, Los Angeles, CA, 90033, USA
| | - Harri Merisaari
- FinnBrain Birth Cohort Study, Turku Brain and Mind Center, Department of Clinical Medicine, University of Turku, Lemminkäisenkatu 2, 20520, Turku, Finland
| | - Maria Lavonius
- FinnBrain Birth Cohort Study, Turku Brain and Mind Center, Department of Clinical Medicine, University of Turku, Lemminkäisenkatu 2, 20520, Turku, Finland
| | - Linnea Karlsson
- FinnBrain Birth Cohort Study, Turku Brain and Mind Center, Department of Clinical Medicine, University of Turku, Lemminkäisenkatu 2, 20520, Turku, Finland
- Centre for Population Health Research, Turku University Hospital and University of Turku, Turku, Finland
- Department of Clinical Medicine, Paediatrics and Adolescent Medicine, Turku University Hospital and University of Turku, Turku, Finland
| | - Sonja Entringer
- Development, Health and Disease Research Program, University of California, Irvine, CA, 92697, USA
- Department of Pediatrics, University of California, Irvine, CA, 92697, USA
- Department of Medical Psychology, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Augustenburger Platz 1, 13353, Berlin, Germany
| | - Pathik D Wadhwa
- Development, Health and Disease Research Program, University of California, Irvine, CA, 92697, USA
- Department of Pediatrics, University of California, Irvine, CA, 92697, USA
- Department of Psychiatry and Human Behavior, University of California, Irvine, CA, 92697, USA
- Department of Obstetrics & Gynecology, University of California, Irvine, CA, 92697, USA
- Department of Epidemiology, University of California, Irvine, CA, 92697, USA
| | - Hasse Karlsson
- FinnBrain Birth Cohort Study, Turku Brain and Mind Center, Department of Clinical Medicine, University of Turku, Lemminkäisenkatu 2, 20520, Turku, Finland
- Department of Psychiatry, University of Turku and Turku University Hospital, Turku, Finland
| | - Claudia Buss
- Development, Health and Disease Research Program, University of California, Irvine, CA, 92697, USA
- Department of Pediatrics, University of California, Irvine, CA, 92697, USA
- Department of Medical Psychology, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Augustenburger Platz 1, 13353, Berlin, Germany
| |
Collapse
|
5
|
Ali TS, Lv J, Calamante F. Gradual changes in microarchitectural properties of cortex and juxtacortical white matter: Observed by anatomical and diffusion MRI. Magn Reson Med 2022; 88:2485-2503. [PMID: 36045582 DOI: 10.1002/mrm.29413] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2022] [Revised: 07/18/2022] [Accepted: 07/22/2022] [Indexed: 01/07/2023]
Abstract
PURPOSE Characterization of cerebral cortex is challenged by the complexity and heterogeneity of its cyto- and myeloarchitecture. This study evaluates quantitative MRI metrics, measured across two cortical depths and in subcortical white matter (WM) adjacent to cortex (juxtacortical WM), indicative of myelin content, neurite density, and diffusion microenvironment, for a comprehensive characterization of cortical microarchitecture. METHODS High-quality structural and diffusion MRI data (N = 30) from the Human Connectome Project were processed to compute myelin index, neurite density index, fractional anisotropy, mean diffusivity, axial diffusivity, and radial diffusivity from superficial cortex, deep cortex, and juxtacortical WM. The distributional patterns of these metrics were analyzed individually, correlated to one another, and were compared to established parcellations. RESULTS Our results supported that myeloarchitectonic and the coexisting cytoarchitectonic structures influence the diffusion properties of water molecules residing in cortex. Full cortical thickness showed myelination patterns similar to those previously observed in humans. Higher myelin indices with similar distributional patterns were observed in deep cortex whereas lower myelin indices were observed in superficial cortex. Neurite density index and other diffusion MRI derived parameters provided complementary information to myelination. Reliable and reproducible correlations were identified among the cortical microarchitectural properties and fiber distributional patterns in proximal WM structures. CONCLUSION We demonstrated gradual changes across the cortical sheath by assessing depth-specific cortical micro-architecture using anatomical and diffusion MRI. Mutually independent but coexisting features of cortical layers and juxtacortical WM provided new insights towards structural organizational units and variabilities across cortical regions and through depth.
Collapse
Affiliation(s)
- Tonima S Ali
- School of Biomedical Engineering, The University of Sydney, Sydney, Australia.,Brain and Mind Centre, The University of Sydney, Sydney, Australia
| | - Jinglei Lv
- School of Biomedical Engineering, The University of Sydney, Sydney, Australia.,Brain and Mind Centre, The University of Sydney, Sydney, Australia.,Sydney Imaging, The University of Sydney, Sydney, Australia
| | - Fernando Calamante
- School of Biomedical Engineering, The University of Sydney, Sydney, Australia.,Brain and Mind Centre, The University of Sydney, Sydney, Australia.,Sydney Imaging, The University of Sydney, Sydney, Australia
| |
Collapse
|
6
|
Juengling FD, Wuest F, Kalra S, Agosta F, Schirrmacher R, Thiel A, Thaiss W, Müller HP, Kassubek J. Simultaneous PET/MRI: The future gold standard for characterizing motor neuron disease-A clinico-radiological and neuroscientific perspective. Front Neurol 2022; 13:890425. [PMID: 36061999 PMCID: PMC9428135 DOI: 10.3389/fneur.2022.890425] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2022] [Accepted: 07/20/2022] [Indexed: 01/18/2023] Open
Abstract
Neuroimaging assessment of motor neuron disease has turned into a cornerstone of its clinical workup. Amyotrophic lateral sclerosis (ALS), as a paradigmatic motor neuron disease, has been extensively studied by advanced neuroimaging methods, including molecular imaging by MRI and PET, furthering finer and more specific details of the cascade of ALS neurodegeneration and symptoms, facilitated by multicentric studies implementing novel methodologies. With an increase in multimodal neuroimaging data on ALS and an exponential improvement in neuroimaging technology, the need for harmonization of protocols and integration of their respective findings into a consistent model becomes mandatory. Integration of multimodal data into a model of a continuing cascade of functional loss also calls for the best attempt to correlate the different molecular imaging measurements as performed at the shortest inter-modality time intervals possible. As outlined in this perspective article, simultaneous PET/MRI, nowadays available at many neuroimaging research sites, offers the perspective of a one-stop shop for reproducible imaging biomarkers on neuronal damage and has the potential to become the new gold standard for characterizing motor neuron disease from the clinico-radiological and neuroscientific perspectives.
Collapse
Affiliation(s)
- Freimut D. Juengling
- Division of Oncologic Imaging, University of Alberta, Edmonton, AB, Canada
- Neuroscience and Mental Health Institute, University of Alberta, Edmonton, AB, Canada
- Faculty of Medicine, University Bern, Bern, Switzerland
| | - Frank Wuest
- Division of Oncologic Imaging, University of Alberta, Edmonton, AB, Canada
| | - Sanjay Kalra
- Neuroscience and Mental Health Institute, University of Alberta, Edmonton, AB, Canada
- Department of Neurology, University of Alberta, Edmonton, AB, Canada
| | - Federica Agosta
- Division of Neuroscience, San Raffaele Scientific Institute, University Vita Salute San Raffaele, Milan, Italy
| | - Ralf Schirrmacher
- Division of Oncologic Imaging, University of Alberta, Edmonton, AB, Canada
- Medical Isotope and Cyclotron Facility, University of Alberta, Edmonton, AB, Canada
| | - Alexander Thiel
- Lady Davis Institute for Medical Research, Department of Neurology and Neurosurgery, McGill University, Montreal, QC, Canada
| | - Wolfgang Thaiss
- Department of Nuclear Medicine, University of Ulm Medical Center, Ulm, Germany
- Department of Diagnostic and Interventional Radiology, University of Ulm Medical Center, Ulm, Germany
| | - Hans-Peter Müller
- Department of Neurology, Ulm University Medical Center, Ulm, Germany
| | - Jan Kassubek
- Department of Neurology, Ulm University Medical Center, Ulm, Germany
| |
Collapse
|
7
|
Just N, Chevillard PM, Migaud M. Imaging and spectroscopic methods to investigate adult neurogenesis in vivo: New models and new avenues. Front Neurosci 2022; 16:933947. [PMID: 35992937 PMCID: PMC9389108 DOI: 10.3389/fnins.2022.933947] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2022] [Accepted: 07/11/2022] [Indexed: 11/25/2022] Open
Abstract
Adult neurogenesis (AN) can be defined as the birth and development of new neurons in adulthood. Until the 1990s, AN was deemed not to happen after birth. Gradually, several groups demonstrated that specific zones of the brain of various species had a neurogenic potential. AN could be the key to treating a large range of neurodegenerative, neuropsychiatric, and metabolic diseases, with a better understanding of the mechanisms allowing for regeneration of new neurons. Despite this promising prospect, the existence of AN has not been validated in vivo in humans and therefore remains controversial. Moreover, the weight of AN-induced plasticity against other mechanisms of brain plasticity is not known, adding to the controversy. In this review, we would like to show that recent technical advances in brain MR imaging methods combined with improved models can resolve the debate.
Collapse
Affiliation(s)
- Nathalie Just
- Danish Research Centre for Magnetic Resonance, Center for Functional and Diagnostic Imaging and Research, Copenhagen University Hospital Amager og Hvidovre, Hvidovre, Denmark
- Physiologie de la Reproduction et des Comportements, Centre INRAE Val de Loire, CNRS, IFCE, INRAE, and Université de Tours, Nouzilly, France
- *Correspondence: Nathalie Just
| | - Pierre-Marie Chevillard
- Physiologie de la Reproduction et des Comportements, Centre INRAE Val de Loire, CNRS, IFCE, INRAE, and Université de Tours, Nouzilly, France
| | - Martine Migaud
- Physiologie de la Reproduction et des Comportements, Centre INRAE Val de Loire, CNRS, IFCE, INRAE, and Université de Tours, Nouzilly, France
| |
Collapse
|
8
|
Nwaubani P, Cercignani M, Colasanti A. In vivo quantitative imaging of hippocampal inflammation in autoimmune neuroinflammatory conditions: a systematic review. Clin Exp Immunol 2022; 210:24-38. [PMID: 35802780 PMCID: PMC9585553 DOI: 10.1093/cei/uxac058] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2021] [Revised: 05/17/2022] [Accepted: 07/04/2022] [Indexed: 01/25/2023] Open
Abstract
The hippocampus is a morphologically complex region of the brain limbic system centrally involved in important cognitive, affective, and behavioural regulatory roles. It has exquisite vulnerability to neuroinflammatory processes, with some of its subregions found to be specific sites of neuroinflammatory pathology in ex-vivo studies. Optimizing neuroimaging correlates of hippocampal neuroinflammation would enable the direct study of functional consequences of hippocampal neuroinflammatory pathology, as well as the definition of therapeutic end-points for treatments targeting neuroinflammation, and their related affective or cognitive sequelae. However, in vivo traditional imaging of the hippocampus and its subregions is fraught with difficulties, due to methodological challenges deriving from its unique anatomical characteristics. The main objective of this review is to provide a current update on the characterization of quantitative neuroimaging correlates of hippocampal neuroinflammation by focusing on three prototypical autoimmune neuro-inflammatory conditions [multiple sclerosis (MS), systemic lupus erythematosus (SLE), and autoimmune encephalitis (AE)]. We focused on studies employing TSPO-targeting positron emission tomography (PET), quantitative magnetic resonance imaging (MRI), and spectroscopy techniques assumed to be sensitive to neuroinflammatory tissue changes. We found 18 eligible studies (14, 2, and 2 studies in MS, AE, and SLE, respectively). Across conditions, the largest effect was seen in TSPO PET and diffusion-weighted MRI studies. No study examined neuroinflammation-related changes at the hippocampal subfield level. Overall, results were largely inconsistent due to heterogeneous imaging methods, small sample sizes, and different population studies. We discuss how these data could inform future study design and conclude by suggesting further methodological directions aimed at improving the precision and sensitivity of neuroimaging techniques to characterize hippocampal neuroinflammatory pathology in the human brain.
Collapse
Affiliation(s)
- P Nwaubani
- Department of Clinical Neuroscience and Neuroimaging, Brighton and Sussex Medical School, University of Sussex, Falmer, Brighton, UK
| | - M Cercignani
- Cardiff University Brain Research Imaging Centre, Cardiff University, Cardiff, UK
| | - A Colasanti
- Correspondence: Alessandro Colasanti, Department of Clinical Neuroscience and Neuroimaging, Brighton and Sussex Medical School, University of Sussex, Trafford Centre for Medical Research, University of Sussex, Falmer, Brighton, BN1 4RY, UK.
| |
Collapse
|
9
|
Liu X, Chen L, Duan W, Li H, Kong L, Shu Y, Li P, Li K, Xie W, Zeng Y, Peng D. Abnormal Functional Connectivity of Hippocampal Subdivisions in Obstructive Sleep Apnea: A Resting-State Functional Magnetic Resonance Imaging Study. Front Neurosci 2022; 16:850940. [PMID: 35546892 PMCID: PMC9082679 DOI: 10.3389/fnins.2022.850940] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2022] [Accepted: 03/14/2022] [Indexed: 01/16/2023] Open
Abstract
The hippocampus is involved in various cognitive function, including memory. Hippocampal structural and functional abnormalities have been observed in patients with obstructive sleep apnoea (OSA), but the functional connectivity (FC) patterns among hippocampal subdivisions in OSA patients remain unclear. The purpose of this study was to investigate the changes in FC between hippocampal subdivisions and their relationship with neurocognitive function in male patients with OSA. Resting-state fMRI were obtained from 46 male patients with untreated severe OSA and 46 male good sleepers. The hippocampus was divided into anterior, middle, and posterior parts, and the differences in FC between hippocampal subdivisions and other brain regions were determined. Correlation analysis was used to explore the relationships between abnormal FC of hippocampal subdivisions and clinical characteristics in patients with OSA. Our results revealed increased FC in the OSA group between the left anterior hippocampus and left middle temporal gyrus; between the left middle hippocampus and the left inferior frontal gyrus, right anterior central gyrus, and left anterior central gyrus; between the left posterior hippocampus and right middle frontal gyrus; between the right middle hippocampus and left inferior frontal gyrus; and between the right posterior hippocampus and left middle frontal gyrus. These FC abnormalities predominantly manifested in the sensorimotor network, fronto-parietal network, and semantic/default mode network, which are closely related to the neurocognitive impairment observed in OSA patients. This study advances our understanding of the potential pathophysiological mechanism of neurocognitive dysfunction in OSA.
Collapse
Affiliation(s)
- Xiang Liu
- Department of Radiology, The First Affiliated Hospital of Nanchang University, Nanchang, China
| | - Liting Chen
- Medical Imaging Center, First Affiliated Hospital of Jinan University, Guangzhou, China
| | - Wenfeng Duan
- Department of Radiology, The First Affiliated Hospital of Nanchang University, Nanchang, China
| | - Haijun Li
- Department of Radiology, The First Affiliated Hospital of Nanchang University, Nanchang, China
| | - Linghong Kong
- Department of Radiology, The First Affiliated Hospital of Nanchang University, Nanchang, China
| | - Yongqiang Shu
- Department of Radiology, The First Affiliated Hospital of Nanchang University, Nanchang, China
| | - Panmei Li
- Department of Radiology, The First Affiliated Hospital of Nanchang University, Nanchang, China
| | - Kunyao Li
- Department of Radiology, The First Affiliated Hospital of Nanchang University, Nanchang, China
| | - Wei Xie
- Department of Radiology, The First Affiliated Hospital of Nanchang University, Nanchang, China
| | - Yaping Zeng
- Department of Radiology, The First Affiliated Hospital of Nanchang University, Nanchang, China
| | - Dechang Peng
- Department of Radiology, The First Affiliated Hospital of Nanchang University, Nanchang, China
| |
Collapse
|
10
|
Solar KG, Treit S, Beaulieu C. High-resolution diffusion tensor imaging identifies hippocampal volume loss without diffusion changes in individuals with prenatal alcohol exposure. Alcohol Clin Exp Res 2022; 46:1204-1219. [PMID: 35567310 DOI: 10.1111/acer.14857] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2022] [Revised: 04/27/2022] [Accepted: 05/05/2022] [Indexed: 11/29/2022]
Abstract
BACKGROUND Magnetic resonance imaging (MRI) studies of prenatal alcohol exposure (PAE) commonly report reduced hippocampal volumes, which animal models suggest may result from microstructural changes that include cell loss and altered myelination. Diffusion tensor imaging (DTI) is sensitive to microstructural changes but has not yet been used to study the hippocampus in PAE. METHODS Thirty-six healthy controls (19 females; 8 to 24 years) and 19 participants with PAE (8 females; 8 to 23 years) underwent high-resolution (1 mm isotropic) DTI, anatomical T1-weighted imaging, and cognitive testing. Whole-hippocampus, head, body, and tail subregions were manually segmented to yield DTI metrics (mean, axial, and radial diffusivities-MD, AD, and RD; fractional anisotropy-FA), volumes, and qualitative assessments of hippocampal morphology and digitations. Automated segmentation of T1-weighted images was used to corroborate manual whole-hippocampus volumes. RESULTS Gross morphology and digitation counts were similar in both groups. Whole-hippocampus volumes were 18% smaller in the PAE than the control group on manually traced diffusion images, but automated T1-weighted image segmentations were not significantly different. Subregion segmentation on DTI revealed reduced volumes of the body and tail, but not the head. There were no significant differences in diffusion metrics between groups for any hippocampal region. Correlations between age and volume were not significant in either group, whereas negative correlations between age and whole-hippocampus MD/AD/RD, and head/body (but not tail) MD/AD/RD were significant in both groups. There were no significant effects of sex, group by age, or group by sex for any hippocampal metric. In controls, seven positive linear correlations were found between hippocampal volume and cognition; five of these were left lateralized and included episodic and working memory, and two were right lateralized and included working memory and processing speed. In PAE, left tail MD positively correlated with executive functioning, and right head MD negatively correlated with episodic memory. CONCLUSIONS Reductions of hippocampal volumes and altered relationships with memory suggest disrupted hippocampal development in PAE.
Collapse
Affiliation(s)
- Kevin Grant Solar
- Department of Biomedical Engineering, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
| | - Sarah Treit
- Department of Biomedical Engineering, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
| | - Christian Beaulieu
- Department of Biomedical Engineering, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
| |
Collapse
|
11
|
Snider SB, Fischer D, McKeown ME, Cohen AL, Schaper FLWVJ, Amorim E, Fox MD, Scirica B, Bevers MB, Lee JW. Regional Distribution of Brain Injury After Cardiac Arrest: Clinical and Electrographic Correlates. Neurology 2022; 98:e1238-e1247. [PMID: 35017304 PMCID: PMC8967331 DOI: 10.1212/wnl.0000000000013301] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2021] [Accepted: 12/27/2021] [Indexed: 11/15/2022] Open
Abstract
BACKGROUND AND OBJECTIVES Disorders of consciousness, EEG background suppression, and epileptic seizures are associated with poor outcome after cardiac arrest. Our objective was to identify the distribution of diffusion MRI-measured anoxic brain injury after cardiac arrest and to define the regional correlates of disorders of consciousness, EEG background suppression, and seizures. METHODS We analyzed patients from a single-center database of unresponsive patients who underwent diffusion MRI after cardiac arrest (n = 204). We classified each patient according to recovery of consciousness (command following) before discharge, the most continuous EEG background (burst suppression vs continuous), and the presence or absence of seizures. Anoxic brain injury was measured with the apparent diffusion coefficient (ADC) signal. We identified ADC abnormalities relative to controls without cardiac arrest (n = 48) and used voxel lesion symptom mapping to identify regional associations with disorders of consciousness, EEG background suppression, and seizures. We then used a bootstrapped lasso regression procedure to identify robust, multivariate regional associations with each outcome variable. Last, using area under receiver operating characteristic curves, we then compared the classification ability of the strongest regional associations to that of brain-wide summary measures. RESULTS Compared to controls, patients with cardiac arrest demonstrated ADC signal reduction that was most significant in the occipital lobes. Disorders of consciousness were associated with reduced ADC most prominently in the occipital lobes but also in deep structures. Regional injury more accurately classified patients with disorders of consciousness than whole-brain injury. Background suppression mapped to a similar set of brain regions, but regional injury could no better classify patients than whole-brain measures. Seizures were less common in patients with more severe anoxic injury, particularly in those with injury to the lateral temporal white matter. DISCUSSION Anoxic brain injury was most prevalent in posterior cerebral regions, and this regional pattern of injury was a better predictor of disorders of consciousness than whole-brain injury measures. EEG background suppression lacked a specific regional association, but patients with injury to the temporal lobe were less likely to have seizures. Regional patterns of anoxic brain injury are relevant to the clinical and electrographic sequelae of cardiac arrest and may hold importance for prognosis. CLASSIFICATION OF EVIDENCE This study provides Class IV evidence that disorders of consciousness after cardiac arrest are associated with widely lower ADC values on diffusion MRI and are most strongly associated with reductions in occipital ADC.
Collapse
Affiliation(s)
- Samuel B Snider
- From the Division of Neurocritical Care, Department of Neurology, (S.B.S., D.F., M.E.M., M.B.B.), Departments of Neurology, Psychiatry, and Radiology (A.L.C., F.L.W.V.J.S., M.D.F.), Center for Brain Circuit Therapeutics, Division of Cardiology, Department of Medicine (B.S.), and Division of Epilepsy, Department of Neurology (J.W.L.), Brigham and Women's Hospital, Harvard Medical School; Departments of Neurology and Radiology (A.L.C.), Computational Radiology Laboratory, Boston Children's Hospital, Harvard Medical School, MA; Department of Neurology (E.A.), Weill Institute for Neurosciences, University of California at San Francisco; Neurology Service (E.A.), Zuckerberg San Francisco General Hospital, CA; Departments of Neurology and Radiology (M.D.F.), Athinoula A. Martinos Centre for Biomedical Imaging, Massachusetts General Hospital, Charlestown; and Department of Neurology (M.D.F.), Berenson-Allen Center for Noninvasive Brain Stimulation, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA.
| | - David Fischer
- From the Division of Neurocritical Care, Department of Neurology, (S.B.S., D.F., M.E.M., M.B.B.), Departments of Neurology, Psychiatry, and Radiology (A.L.C., F.L.W.V.J.S., M.D.F.), Center for Brain Circuit Therapeutics, Division of Cardiology, Department of Medicine (B.S.), and Division of Epilepsy, Department of Neurology (J.W.L.), Brigham and Women's Hospital, Harvard Medical School; Departments of Neurology and Radiology (A.L.C.), Computational Radiology Laboratory, Boston Children's Hospital, Harvard Medical School, MA; Department of Neurology (E.A.), Weill Institute for Neurosciences, University of California at San Francisco; Neurology Service (E.A.), Zuckerberg San Francisco General Hospital, CA; Departments of Neurology and Radiology (M.D.F.), Athinoula A. Martinos Centre for Biomedical Imaging, Massachusetts General Hospital, Charlestown; and Department of Neurology (M.D.F.), Berenson-Allen Center for Noninvasive Brain Stimulation, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA
| | - Morgan E McKeown
- From the Division of Neurocritical Care, Department of Neurology, (S.B.S., D.F., M.E.M., M.B.B.), Departments of Neurology, Psychiatry, and Radiology (A.L.C., F.L.W.V.J.S., M.D.F.), Center for Brain Circuit Therapeutics, Division of Cardiology, Department of Medicine (B.S.), and Division of Epilepsy, Department of Neurology (J.W.L.), Brigham and Women's Hospital, Harvard Medical School; Departments of Neurology and Radiology (A.L.C.), Computational Radiology Laboratory, Boston Children's Hospital, Harvard Medical School, MA; Department of Neurology (E.A.), Weill Institute for Neurosciences, University of California at San Francisco; Neurology Service (E.A.), Zuckerberg San Francisco General Hospital, CA; Departments of Neurology and Radiology (M.D.F.), Athinoula A. Martinos Centre for Biomedical Imaging, Massachusetts General Hospital, Charlestown; and Department of Neurology (M.D.F.), Berenson-Allen Center for Noninvasive Brain Stimulation, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA
| | - Alexander Li Cohen
- From the Division of Neurocritical Care, Department of Neurology, (S.B.S., D.F., M.E.M., M.B.B.), Departments of Neurology, Psychiatry, and Radiology (A.L.C., F.L.W.V.J.S., M.D.F.), Center for Brain Circuit Therapeutics, Division of Cardiology, Department of Medicine (B.S.), and Division of Epilepsy, Department of Neurology (J.W.L.), Brigham and Women's Hospital, Harvard Medical School; Departments of Neurology and Radiology (A.L.C.), Computational Radiology Laboratory, Boston Children's Hospital, Harvard Medical School, MA; Department of Neurology (E.A.), Weill Institute for Neurosciences, University of California at San Francisco; Neurology Service (E.A.), Zuckerberg San Francisco General Hospital, CA; Departments of Neurology and Radiology (M.D.F.), Athinoula A. Martinos Centre for Biomedical Imaging, Massachusetts General Hospital, Charlestown; and Department of Neurology (M.D.F.), Berenson-Allen Center for Noninvasive Brain Stimulation, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA
| | - Frederic L W V J Schaper
- From the Division of Neurocritical Care, Department of Neurology, (S.B.S., D.F., M.E.M., M.B.B.), Departments of Neurology, Psychiatry, and Radiology (A.L.C., F.L.W.V.J.S., M.D.F.), Center for Brain Circuit Therapeutics, Division of Cardiology, Department of Medicine (B.S.), and Division of Epilepsy, Department of Neurology (J.W.L.), Brigham and Women's Hospital, Harvard Medical School; Departments of Neurology and Radiology (A.L.C.), Computational Radiology Laboratory, Boston Children's Hospital, Harvard Medical School, MA; Department of Neurology (E.A.), Weill Institute for Neurosciences, University of California at San Francisco; Neurology Service (E.A.), Zuckerberg San Francisco General Hospital, CA; Departments of Neurology and Radiology (M.D.F.), Athinoula A. Martinos Centre for Biomedical Imaging, Massachusetts General Hospital, Charlestown; and Department of Neurology (M.D.F.), Berenson-Allen Center for Noninvasive Brain Stimulation, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA
| | - Edilberto Amorim
- From the Division of Neurocritical Care, Department of Neurology, (S.B.S., D.F., M.E.M., M.B.B.), Departments of Neurology, Psychiatry, and Radiology (A.L.C., F.L.W.V.J.S., M.D.F.), Center for Brain Circuit Therapeutics, Division of Cardiology, Department of Medicine (B.S.), and Division of Epilepsy, Department of Neurology (J.W.L.), Brigham and Women's Hospital, Harvard Medical School; Departments of Neurology and Radiology (A.L.C.), Computational Radiology Laboratory, Boston Children's Hospital, Harvard Medical School, MA; Department of Neurology (E.A.), Weill Institute for Neurosciences, University of California at San Francisco; Neurology Service (E.A.), Zuckerberg San Francisco General Hospital, CA; Departments of Neurology and Radiology (M.D.F.), Athinoula A. Martinos Centre for Biomedical Imaging, Massachusetts General Hospital, Charlestown; and Department of Neurology (M.D.F.), Berenson-Allen Center for Noninvasive Brain Stimulation, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA
| | - Michael D Fox
- From the Division of Neurocritical Care, Department of Neurology, (S.B.S., D.F., M.E.M., M.B.B.), Departments of Neurology, Psychiatry, and Radiology (A.L.C., F.L.W.V.J.S., M.D.F.), Center for Brain Circuit Therapeutics, Division of Cardiology, Department of Medicine (B.S.), and Division of Epilepsy, Department of Neurology (J.W.L.), Brigham and Women's Hospital, Harvard Medical School; Departments of Neurology and Radiology (A.L.C.), Computational Radiology Laboratory, Boston Children's Hospital, Harvard Medical School, MA; Department of Neurology (E.A.), Weill Institute for Neurosciences, University of California at San Francisco; Neurology Service (E.A.), Zuckerberg San Francisco General Hospital, CA; Departments of Neurology and Radiology (M.D.F.), Athinoula A. Martinos Centre for Biomedical Imaging, Massachusetts General Hospital, Charlestown; and Department of Neurology (M.D.F.), Berenson-Allen Center for Noninvasive Brain Stimulation, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA
| | - Benjamin Scirica
- From the Division of Neurocritical Care, Department of Neurology, (S.B.S., D.F., M.E.M., M.B.B.), Departments of Neurology, Psychiatry, and Radiology (A.L.C., F.L.W.V.J.S., M.D.F.), Center for Brain Circuit Therapeutics, Division of Cardiology, Department of Medicine (B.S.), and Division of Epilepsy, Department of Neurology (J.W.L.), Brigham and Women's Hospital, Harvard Medical School; Departments of Neurology and Radiology (A.L.C.), Computational Radiology Laboratory, Boston Children's Hospital, Harvard Medical School, MA; Department of Neurology (E.A.), Weill Institute for Neurosciences, University of California at San Francisco; Neurology Service (E.A.), Zuckerberg San Francisco General Hospital, CA; Departments of Neurology and Radiology (M.D.F.), Athinoula A. Martinos Centre for Biomedical Imaging, Massachusetts General Hospital, Charlestown; and Department of Neurology (M.D.F.), Berenson-Allen Center for Noninvasive Brain Stimulation, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA
| | - Matthew B Bevers
- From the Division of Neurocritical Care, Department of Neurology, (S.B.S., D.F., M.E.M., M.B.B.), Departments of Neurology, Psychiatry, and Radiology (A.L.C., F.L.W.V.J.S., M.D.F.), Center for Brain Circuit Therapeutics, Division of Cardiology, Department of Medicine (B.S.), and Division of Epilepsy, Department of Neurology (J.W.L.), Brigham and Women's Hospital, Harvard Medical School; Departments of Neurology and Radiology (A.L.C.), Computational Radiology Laboratory, Boston Children's Hospital, Harvard Medical School, MA; Department of Neurology (E.A.), Weill Institute for Neurosciences, University of California at San Francisco; Neurology Service (E.A.), Zuckerberg San Francisco General Hospital, CA; Departments of Neurology and Radiology (M.D.F.), Athinoula A. Martinos Centre for Biomedical Imaging, Massachusetts General Hospital, Charlestown; and Department of Neurology (M.D.F.), Berenson-Allen Center for Noninvasive Brain Stimulation, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA
| | - Jong Woo Lee
- From the Division of Neurocritical Care, Department of Neurology, (S.B.S., D.F., M.E.M., M.B.B.), Departments of Neurology, Psychiatry, and Radiology (A.L.C., F.L.W.V.J.S., M.D.F.), Center for Brain Circuit Therapeutics, Division of Cardiology, Department of Medicine (B.S.), and Division of Epilepsy, Department of Neurology (J.W.L.), Brigham and Women's Hospital, Harvard Medical School; Departments of Neurology and Radiology (A.L.C.), Computational Radiology Laboratory, Boston Children's Hospital, Harvard Medical School, MA; Department of Neurology (E.A.), Weill Institute for Neurosciences, University of California at San Francisco; Neurology Service (E.A.), Zuckerberg San Francisco General Hospital, CA; Departments of Neurology and Radiology (M.D.F.), Athinoula A. Martinos Centre for Biomedical Imaging, Massachusetts General Hospital, Charlestown; and Department of Neurology (M.D.F.), Berenson-Allen Center for Noninvasive Brain Stimulation, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA
| |
Collapse
|
12
|
Yoo J, Kerkelä L, Hales PW, Seunarine KK, Clark CA. High-resolution microscopic diffusion anisotropy imaging in the human hippocampus at 3T. Magn Reson Med 2021; 87:1903-1913. [PMID: 34841566 DOI: 10.1002/mrm.29104] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2021] [Revised: 11/10/2021] [Accepted: 11/10/2021] [Indexed: 11/06/2022]
Abstract
PURPOSE Several neurological conditions are associated with microstructural changes in the hippocampus that can be observed using DWI. Imaging studies often use protocols with whole-brain coverage, imposing limits on image resolution and worsening partial-volume effects. Also, conventional single-diffusion-encoding methods confound microscopic diffusion anisotropy with size variance of microscopic diffusion environments. This study addresses these issues by implementing a multidimensional diffusion-encoding protocol for microstructural imaging of the hippocampus at high resolution. METHODS The hippocampus of 8 healthy volunteers was imaged at 1.5-mm isotropic resolution with a multidimensional diffusion-encoding sequence developed in house. Microscopic fractional anisotropy (µFA) and normalized size variance (CMD ) were estimated using q-space trajectory imaging, and their values were compared with DTI metrics. The overall scan time was 1 hour. The reproducibility of the protocol was confirmed with scan-rescan experiments, and a shorter protocol (14 minutes) was defined for situations with time constraints. RESULTS Mean µFA (0.47) was greater than mean FA (0.20), indicating orientation dispersion in hippocampal tissue microstructure. Mean CMD was 0.17. The reproducibility of q-space trajectory imaging metrics was comparable to DTI, and microstructural metrics in the healthy hippocampus are reported. CONCLUSION This work shows the feasibility of high-resolution microscopic anisotropy imaging in the human hippocampus at 3 T and provides reference values for microstructural metrics in a healthy hippocampus.
Collapse
Affiliation(s)
- Jiyoon Yoo
- Developmental Imaging and Biophysics Section, UCL Great Ormond Street Institute of Child Health, London, United Kingdom
| | - Leevi Kerkelä
- Developmental Imaging and Biophysics Section, UCL Great Ormond Street Institute of Child Health, London, United Kingdom
| | - Patrick W Hales
- Developmental Imaging and Biophysics Section, UCL Great Ormond Street Institute of Child Health, London, United Kingdom
| | - Kiran K Seunarine
- Developmental Imaging and Biophysics Section, UCL Great Ormond Street Institute of Child Health, London, United Kingdom
| | - Christopher A Clark
- Developmental Imaging and Biophysics Section, UCL Great Ormond Street Institute of Child Health, London, United Kingdom
| |
Collapse
|
13
|
Abstract
This article discusses new diffusion-weighted imaging (DWI) sequences, diffusion tensor imaging (DTI), and fiber tractography (FT), as well as more advanced diffusion imaging in pediatric brain and spine. Underlying disorder and pathophysiology causing diffusion abnormalities are discussed. Multishot echo planar imaging (EPI) DWI and non-EPI DWI provide higher spatial resolution with less susceptibility artifact and distortion, which are replacing conventional single-shot EPI DWI. DTI and FT have established clinical significance in pediatric brain and spine. This article discusses advanced diffusion imaging, including diffusion kurtosis imaging, neurite orientation dispersion and density imaging, diffusion spectrum imaging, intravoxel incoherent motion, and oscillating-gradient spin-echo.
Collapse
Affiliation(s)
- Toshio Moritani
- Division of Neuroradiology, Department of Radiology, University of Michigan, 1500 East Medical Center Drive, UH B2 A209K, Ann Arbor, MI 48109, USA.
| |
Collapse
|
14
|
Solar KG, Treit S, Beaulieu C. High resolution diffusion tensor imaging of the hippocampus across the healthy lifespan. Hippocampus 2021; 31:1271-1284. [PMID: 34599623 DOI: 10.1002/hipo.23388] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Revised: 08/23/2021] [Accepted: 09/11/2021] [Indexed: 12/21/2022]
Abstract
The human hippocampus is difficult to image given its small size, location, shape, and complex internal architecture. Structural magnetic resonance imaging (MRI) has shown age-related hippocampal volume changes that vary along the anterior-posterior axis. Diffusion tensor imaging (DTI) provides complementary measures related to microstructure, but there are few hippocampus DTI studies investigating change with age in healthy participants, and all have been limited by low spatial resolution. The current study uses high resolution 1 mm isotropic DTI of 153 healthy volunteers aged 5-74 years to investigate diffusion and volume trajectories of the hippocampus (whole, head, body, and tail) and correlations with memory. Hippocampal volume showed age-related changes that differed between head (peaking at midlife), body (no changes), and tail (decreasing across the age span). Fractional anisotropy (FA) and mean, axial, and radial diffusivities (MD, AD, RD) yielded peaks or minima, respectively, at ~30-35 years in all three subregions of the hippocampus. Greater magnitude changes were observed during development than in aging. Age trajectories for both volume and DTI were similar between males and females. Correlations between tests of memory and FA and/or volume were significant in younger subjects (5-17 years), but not in 18-49 year olds or 50-74 year olds. MD was significantly correlated with memory performance in 18-49 year olds, but not in other age groups. Given the diffusion-weighted image contrast and resolution, head digitations could be examined revealing that the majority of subjects had 3-4 (48%) or 2 (32%) bilaterally with no effect of age. One millimeter isotropic DTI yielded high quality diffusion-weighted maps of the human hippocampus that showed regionally specific age effects and cognitive correlations along the anterior-posterior axis from 5 to 74 years.
Collapse
Affiliation(s)
- Kevin Grant Solar
- Department of Biomedical Engineering, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
| | - Sarah Treit
- Department of Biomedical Engineering, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
| | - Christian Beaulieu
- Department of Biomedical Engineering, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
| |
Collapse
|
15
|
Development of brain atlases for early-to-middle adolescent collision-sport athletes. Sci Rep 2021; 11:6440. [PMID: 33742031 PMCID: PMC7979742 DOI: 10.1038/s41598-021-85518-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2020] [Accepted: 02/15/2021] [Indexed: 01/31/2023] Open
Abstract
Human brains develop across the life span and largely vary in morphology. Adolescent collision-sport athletes undergo repetitive head impacts over years of practices and competitions, and therefore may exhibit a neuroanatomical trajectory different from healthy adolescents in general. However, an unbiased brain atlas targeting these individuals does not exist. Although standardized brain atlases facilitate spatial normalization and voxel-wise analysis at the group level, when the underlying neuroanatomy does not represent the study population, greater biases and errors can be introduced during spatial normalization, confounding subsequent voxel-wise analysis and statistical findings. In this work, targeting early-to-middle adolescent (EMA, ages 13-19) collision-sport athletes, we developed population-specific brain atlases that include templates (T1-weighted and diffusion tensor magnetic resonance imaging) and semantic labels (cortical and white matter parcellations). Compared to standardized adult or age-appropriate templates, our templates better characterized the neuroanatomy of the EMA collision-sport athletes, reduced biases introduced during spatial normalization, and exhibited higher sensitivity in diffusion tensor imaging analysis. In summary, these results suggest the population-specific brain atlases are more appropriate towards reproducible and meaningful statistical results, which better clarify mechanisms of traumatic brain injury and monitor brain health for EMA collision-sport athletes.
Collapse
|
16
|
Plachti A, Eickhoff SB, Hoffstaedter F, Patil KR, Laird AR, Fox PT, Amunts K, Genon S. Multimodal Parcellations and Extensive Behavioral Profiling Tackling the Hippocampus Gradient. Cereb Cortex 2019; 29:4595-4612. [PMID: 30721944 PMCID: PMC6917521 DOI: 10.1093/cercor/bhy336] [Citation(s) in RCA: 55] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2018] [Revised: 03/12/2018] [Accepted: 12/11/2018] [Indexed: 12/16/2022] Open
Abstract
The hippocampus displays a complex organization and function that is perturbed in many neuropathologies. Histological work revealed a complex arrangement of subfields along the medial-lateral and the ventral-dorsal dimension, which contrasts with the anterior-posterior functional differentiation. The variety of maps has raised the need for an integrative multimodal view. We applied connectivity-based parcellation to 1) intrinsic connectivity 2) task-based connectivity, and 3) structural covariance, as complementary windows into structural and functional differentiation of the hippocampus. Strikingly, while functional properties (i.e., intrinsic and task-based) revealed similar partitions dominated by an anterior-posterior organization, structural covariance exhibited a hybrid pattern reflecting both functional and cytoarchitectonic subdivision. Capitalizing on the consistency of functional parcellations, we defined robust functional maps at different levels of partitions, which are openly available for the scientific community. Our functional maps demonstrated a head-body and tail partition, subdivided along the anterior-posterior and medial-lateral axis. Behavioral profiling of these fine partitions based on activation data indicated an emotion-cognition gradient along the anterior-posterior axis and additionally suggested a self-world-centric gradient supporting the role of the hippocampus in the construction of abstract representations for spatial navigation and episodic memory.
Collapse
Affiliation(s)
- Anna Plachti
- Institute of Systems Neuroscience, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
- Institute of Neuroscience and Medicine (INM-1, INM-7), Research Centre Jülich, Jülich, Germany
| | - Simon B Eickhoff
- Institute of Systems Neuroscience, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
- Institute of Neuroscience and Medicine (INM-1, INM-7), Research Centre Jülich, Jülich, Germany
| | - Felix Hoffstaedter
- Institute of Systems Neuroscience, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
- Institute of Neuroscience and Medicine (INM-1, INM-7), Research Centre Jülich, Jülich, Germany
| | - Kaustubh R Patil
- Institute of Systems Neuroscience, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
- Institute of Neuroscience and Medicine (INM-1, INM-7), Research Centre Jülich, Jülich, Germany
| | - Angela R Laird
- Department of Physics, Florida International University, Miami, FL, USA
| | - Peter T Fox
- Research Imaging Institute, University of Texas Health Science Center at San Antonio, TX, USA
| | - Katrin Amunts
- Institute of Neuroscience and Medicine (INM-1, INM-7), Research Centre Jülich, Jülich, Germany
- C. & O. Vogt Institute for Brain Research, Heinrich Heine University, Düsseldorf. Germany
| | - Sarah Genon
- Institute of Systems Neuroscience, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
- Institute of Neuroscience and Medicine (INM-1, INM-7), Research Centre Jülich, Jülich, Germany
- GIGA-CRC In vivo Imaging, University of Liege, Liege, Belgium
| |
Collapse
|
17
|
Treit S, Little G, Steve T, Nowacki T, Schmitt L, Wheatley BM, Beaulieu C, Gross DW. Regional hippocampal diffusion abnormalities associated with subfield-specific pathology in temporal lobe epilepsy. Epilepsia Open 2019; 4:544-554. [PMID: 31819910 PMCID: PMC6885671 DOI: 10.1002/epi4.12357] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2019] [Accepted: 08/26/2019] [Indexed: 12/22/2022] Open
Abstract
OBJECTIVE Hippocampal sclerosis (HS) is the most common pathology and best predictor of surgical outcome for medically refractory patients with temporal lobe epilepsy (TLE). Current clinical MRI methods can detect HS, but subfield pathology is poorly characterized, limiting accurate prediction of seizure-free outcomes after surgery. Diffusion tensor imaging (DTI) can probe regional microstructural changes associated with focal hippocampal pathology, but is typically limited by low-resolution whole-brain acquisitions. METHODS High-resolution (1 × 1 × 1 mm3) DTI, T1, and quantitative T2 of the hippocampus was acquired in 18 preoperative TLE patients and 19 healthy controls. Diffusion images were qualitatively assessed for loss of internal architecture, and whole-hippocampus diffusion, volume, and quantitative T2 were compared across groups. Regional hippocampal diffusion abnormalities were examined in all subjects and compared to histology in four subjects who underwent anterior temporal lobectomy. RESULTS High-resolution mean diffusion-weighted images enabled visualization of internal hippocampal architecture, used to visually identify HS with 86% specificity and 93% sensitivity. Mean diffusivity (MD) elevations were regionally heterogenous within the hippocampus and varied across TLE patients. The spatial location of diffusion abnormalities corresponded with the location of focal subfield neuron loss, gliosis, and reduced myelin staining abnormalities identified with postsurgical histology in four subjects who underwent anterior temporal lobectomy. Whole-hippocampus MD and T2 relaxation times were higher, and fractional anisotropy (FA) and volumes were lower in TLE patients relative to controls. Left hippocampus MD correlated with verbal memory in the TLE group. SIGNIFICANCE Visualization of internal architecture and focal diffusion abnormalities on high-resolution diffusion imaging suggests potential clinical utility of diffusion imaging in TLE and may have significant implications for surgical planning and prediction of seizure-free outcomes in individual patients.
Collapse
Affiliation(s)
- Sarah Treit
- Department of Biomedical EngineeringFaculty of Medicine and DentistryUniversity of AlbertaEdmontonCanada
| | - Graham Little
- Department of Biomedical EngineeringFaculty of Medicine and DentistryUniversity of AlbertaEdmontonCanada
| | - Trevor Steve
- Division of NeurologyFaculty of Medicine & DentistryUniversity of AlbertaEdmontonCanada
| | - Tom Nowacki
- Division of NeurologyFaculty of Medicine & DentistryUniversity of AlbertaEdmontonCanada
| | - Laura Schmitt
- Department of Laboratory Medicine and PathologyFaculty of Medicine and DentistryUniversity of AlbertaEdmontonCanada
| | - B. Matt Wheatley
- Department of SurgeryFaculty of Medicine and DentistryUniversity of AlbertaEdmontonCanada
| | - Christian Beaulieu
- Department of Biomedical EngineeringFaculty of Medicine and DentistryUniversity of AlbertaEdmontonCanada
| | - Donald W. Gross
- Division of NeurologyFaculty of Medicine & DentistryUniversity of AlbertaEdmontonCanada
| |
Collapse
|
18
|
Zhong Q, Xu H, Qin J, Zeng LL, Hu D, Shen H. Functional parcellation of the hippocampus from resting-state dynamic functional connectivity. Brain Res 2019; 1715:165-175. [PMID: 30910629 DOI: 10.1016/j.brainres.2019.03.023] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2018] [Revised: 01/27/2019] [Accepted: 03/21/2019] [Indexed: 01/20/2023]
Abstract
The hippocampus consists of functionally and structurally heterogeneous regions that are involved in multiple functions such as learning and memory. Previous studies on connectivity-based functional subdivisions of the hippocampus, however, overlooked the dynamic nature of resting-state functional connectivity (FC). In this study, we selected 50 subjects with the lowest head motion from the Human Connectome Project dataset and performed a two-stage spectral clustering technique to windowed FC correlations for identifying the potential covariant structures during the spontaneous fluctuation of hippocampal-cortical FC. The obtained covariant structures were believed to be functionally homogeneous by coupling with whole-brain regions in all transient connectivity states and consequently subdivided the left and right hippocampus into six and five functional subregions, respectively. Further, we demonstrated that this dynamic-FC-derived hippocampal parcellation exhibited significantly improved reproducibility of segmented subregions across subjects compared with static FC analysis. The findings extend our understanding to the functional organization within the hippocampus and provide a more comprehensive view of the functional flexibility of the hippocampus over time.
Collapse
Affiliation(s)
- Qi Zhong
- College of Intelligence Science and Technology, National University of Defense Technology, Changsha, Hunan 410073, China
| | - Huaze Xu
- College of Intelligence Science and Technology, National University of Defense Technology, Changsha, Hunan 410073, China
| | - Jian Qin
- College of Intelligence Science and Technology, National University of Defense Technology, Changsha, Hunan 410073, China
| | - Ling-Li Zeng
- College of Intelligence Science and Technology, National University of Defense Technology, Changsha, Hunan 410073, China
| | - Dewen Hu
- College of Intelligence Science and Technology, National University of Defense Technology, Changsha, Hunan 410073, China
| | - Hui Shen
- College of Intelligence Science and Technology, National University of Defense Technology, Changsha, Hunan 410073, China.
| |
Collapse
|