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Sun W, Liu SH, Wei XJ, Sun H, Ma ZW, Yu XF. Potential of neuroimaging as a biomarker in amyotrophic lateral sclerosis: from structure to metabolism. J Neurol 2024; 271:2238-2257. [PMID: 38367047 DOI: 10.1007/s00415-024-12201-x] [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: 11/18/2023] [Revised: 01/14/2024] [Accepted: 01/16/2024] [Indexed: 02/19/2024]
Abstract
Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disease characterized by motor neuron degeneration. The development of ALS involves metabolite alterations leading to tissue lesions in the nervous system. Recent advances in neuroimaging have significantly improved our understanding of the underlying pathophysiology of ALS, with findings supporting the corticoefferent axonal disease progression theory. Current studies on neuroimaging in ALS have demonstrated inconsistencies, which may be due to small sample sizes, insufficient statistical power, overinterpretation of findings, and the inherent heterogeneity of ALS. Deriving meaningful conclusions solely from individual imaging metrics in ALS studies remains challenging, and integrating multimodal imaging techniques shows promise for detecting valuable ALS biomarkers. In addition to giving an overview of the principles and techniques of different neuroimaging modalities, this review describes the potential of neuroimaging biomarkers in the diagnosis and prognostication of ALS. We provide an insight into the underlying pathology, highlighting the need for standardized protocols and multicenter collaborations to advance ALS research.
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Affiliation(s)
- Wei Sun
- Department of Neurology and Neuroscience Center, The First Hospital of Jilin University, Changchun, 130021, China
| | - Si-Han Liu
- Department of Mechanical Engineering, The University of Hong Kong, Pokfulam, Hong Kong SAR, China
| | - Xiao-Jing Wei
- Department of Neurology and Neuroscience Center, The First Hospital of Jilin University, Changchun, 130021, China
| | - Hui Sun
- Department of Neurology and Neuroscience Center, The First Hospital of Jilin University, Changchun, 130021, China
| | - Zhen-Wei Ma
- Department of Neurology and Neuroscience Center, The First Hospital of Jilin University, Changchun, 130021, China
| | - Xue-Fan Yu
- Department of Neurology and Neuroscience Center, The First Hospital of Jilin University, Changchun, 130021, China.
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2
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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.
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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
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3
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White matter connectometry in patients with disorders of consciousness revealed by 7-Tesla magnetic resonance imaging. Brain Imaging Behav 2022; 16:1983-1991. [DOI: 10.1007/s11682-022-00668-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2021] [Revised: 03/01/2022] [Accepted: 03/21/2022] [Indexed: 11/02/2022]
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4
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Clinical application of diffusion tensor imaging and fiber tractography in the management of brainstem cavernous malformations: a systematic review. Neurosurg Rev 2022; 45:2027-2040. [PMID: 35211879 DOI: 10.1007/s10143-022-01759-7] [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: 12/19/2021] [Revised: 02/02/2022] [Accepted: 02/18/2022] [Indexed: 10/19/2022]
Abstract
This study aimed to systematically review the literature to determine the clinical utility and perspectives of diffusion tensor imaging (DTI) in the management of patients with brainstem cavernous malformations (BSCMs). PubMed, Embase, and Cochrane were searched for English-language articles published until May 10, 2021. Clinical studies and case series describing DTI-based evaluation of patients with BSCMs were included. Fourteen articles were included. Preoperative DTI enabled to adjust the surgical approach and choose a brainstem safe entry zone in deep-seated BSCMs. Preoperatively lower fractional anisotropy (FA) of the corticospinal tract (CST) correlated with the severity of CST injury and motor deficits. Postoperatively increased FA and decreased apparent diffusion coefficient (ADC) corresponded with the normalization of the perilesional CST, indicating motor improvement. The positive (PPV) and negative predictive value (NPV) of qualitative DTI ranged from 20 to 75% and from 66.6 to 100%, respectively. The presence of preoperative and postoperative motor deficits was associated with a higher preoperative resting motor threshold (RMT) and lower FA. A higher preoperative CST score was indicative of a lower preoperative and follow-up Medical Research Council (MRC) grade. DTI facilitated the determination of a surgical trajectory with minimized risk of WMTs' damage. Preoperative FA and RMT might indicate the severity of preoperative and postoperative motor deficits. Preoperative CST score can reliably reflect patients' preoperative and follow-up motor status. Due to high NPV, normal CST morphology might predict intact neurological outcomes. Contrarily, sparse and relatively low PPV limits the reliable prediction of neurological deficits.
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5
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Brain Connectivity and Network Analysis in Amyotrophic Lateral Sclerosis. Neurol Res Int 2022; 2022:1838682. [PMID: 35178253 PMCID: PMC8844436 DOI: 10.1155/2022/1838682] [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: 11/13/2021] [Accepted: 01/13/2022] [Indexed: 12/11/2022] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease with no effective treatment or cure. ALS is characterized by the death of lower motor neurons (LMNs) in the spinal cord and upper motor neurons (UMNs) in the brain and their networks. Since the lower motor neurons are under the control of UMN and the networks, cortical degeneration may play a vital role in the pathophysiology of ALS. These changes that are not apparent on routine imaging with CT scans or MRI brain can be identified using modalities such as diffusion tensor imaging, functional MRI, arterial spin labelling (ASL), electroencephalogram (EEG), magnetoencephalogram (MEG), functional near-infrared spectroscopy (fNIRS), and positron emission tomography (PET) scan. They can help us generate a representation of brain networks and connectivity that can be visualized and parsed out to characterize and quantify the underlying pathophysiology in ALS. In addition, network analysis using graph measures provides a novel way of understanding the complex network changes occurring in the brain. These have the potential to become biomarker for the diagnosis and treatment of ALS. This article is a systematic review and overview of the various connectivity and network-based studies in ALS.
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6
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Kassubek J, Müller HP. Advanced neuroimaging approaches in amyotrophic lateral sclerosis: refining the clinical diagnosis. Expert Rev Neurother 2020; 20:237-249. [PMID: 31937156 DOI: 10.1080/14737175.2020.1715798] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Introduction: In the last decade, multiparametric magnetic resonance imaging (MRI) has achieved tremendous advances in applications to amyotrophic lateral sclerosis (ALS) to increase the understanding of the associated pathophysiology. The aim of this review is to summarize recent progress in the development of MRI-based techniques aiming to support the clinical diagnosis in ALS.Areas covered: The review of structural and functional MRI applications to ALS and its variants (restricted phenotypes) is focused on the potential of MRI techniques which contribute to the diagnostic work-up of patients with the clinical presentation of a motor neuron disease. The potential of specific MRI methods for patient diagnosis and monitoring is discussed, and the future design of clinical MRI applications to ALS is conceptualized.Expert opinion: Current multiparametric MRI allows for the use as a clinical biological marker and a technical instrument in the clinical diagnosis of patients with ALS and also of patients with ALS variants. Composite neuroimaging indices of specific anatomical areas derived from different MRI techniques might guide in the diagnostic applications to ALS. Such a development of ALS-specific MRI-based composite scores with sufficient discriminative power versus ALS mimics at an individual level requires standardized advanced protocols and comprehensive analysis approaches.
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Affiliation(s)
- Jan Kassubek
- Department of Neurology, University of Ulm, Ulm, Germany
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7
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Yeh FC, Zaydan IM, Suski VR, Lacomis D, Richardson RM, Maroon JC, Barrios-Martinez J. Differential tractography as a track-based biomarker for neuronal injury. Neuroimage 2019; 202:116131. [PMID: 31472253 DOI: 10.1016/j.neuroimage.2019.116131] [Citation(s) in RCA: 62] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2019] [Revised: 08/24/2019] [Accepted: 08/24/2019] [Indexed: 12/12/2022] Open
Abstract
Diffusion MRI tractography has been used to map the axonal structure of the human brain, but its ability to detect neuronal injury is yet to be explored. Here we report differential tractography, a new type of tractography that utilizes repeat MRI scans and a novel tracking strategy to map the exact segment of fiber pathways with a neuronal injury. We examined differential tractography on multiple sclerosis, Huntington's disease, amyotrophic lateral sclerosis, and epileptic patients. The results showed that the affected pathways shown by differential tractography matched well with the unique clinical symptoms of the patients, and the false discovery rate of the findings could be estimated using a sham setting to provide a reliability measurement. This novel approach enables a quantitative and objective method to monitor neuronal injury in individuals, allowing for diagnostic and prognostic evaluation of brain diseases.
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Affiliation(s)
- Fang-Cheng Yeh
- Department of Neurological Surgery, University of Pittsburgh School of Medicine, Pittsburgh, PA, United States; Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, United States.
| | - Islam M Zaydan
- Department of Neurology, University of Pittsburgh School of Medicine, Pittsburgh, PA, United States
| | - Valerie R Suski
- Department of Neurology, University of Pittsburgh School of Medicine, Pittsburgh, PA, United States
| | - David Lacomis
- Department of Neurology, University of Pittsburgh School of Medicine, Pittsburgh, PA, United States; Live Like Lou Center for ALS Research, University of Pittsburgh School of Medicine, Pittsburgh, PA, United States
| | - R Mark Richardson
- Department of Neurological Surgery, University of Pittsburgh School of Medicine, Pittsburgh, PA, United States
| | - Joseph C Maroon
- Department of Neurological Surgery, University of Pittsburgh School of Medicine, Pittsburgh, PA, United States
| | - Jessica Barrios-Martinez
- Department of Neurological Surgery, University of Pittsburgh School of Medicine, Pittsburgh, PA, United States
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8
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Trojsi F, Caiazzo G, Siciliano M, Femiano C, Passaniti C, Russo A, Bisecco A, Monsurrò MR, Cirillo M, Esposito F, Tedeschi G, Santangelo G. Microstructural correlates of Edinburgh Cognitive and Behavioural ALS Screen (ECAS) changes in amyotrophic lateral sclerosis. Psychiatry Res Neuroimaging 2019; 288:67-75. [PMID: 30987770 DOI: 10.1016/j.pscychresns.2019.04.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/06/2018] [Revised: 03/30/2019] [Accepted: 04/01/2019] [Indexed: 11/17/2022]
Abstract
Edinburgh Cognitive and Behavioural ALS Screen (ECAS) was designed for testing patients with amyotrophic lateral sclerosis (ALS), a multi-system neurodegenerative disease characterized by progressive physical disability. In this study, we aim to explore the potential brain microstructural substrates associated with performance on ECAS in the early stages of ALS, using a whole-brain tract-based spatial statistics diffusion tensor imaging approach. Thirty-six non-demented ALS patients, assessed using ECAS, and 35 age-, sex- and education-matched healthy controls underwent magnetic resonance imaging at 3 Tesla. The ALS patients showed decreased fractional anisotropy (FA) in the cortico-spinal tracts and corpus callosum (CC) and significant association between verbal fluency score, among ALS-specific ECAS scores, and FA measures in several long association fiber tracts in the frontal, temporal and parietal lobes. Furthermore, the ALS non-specific total score was inversely related to axial diffusivity (AD) in the mediodorsal nucleus of the thalamus, with more extended areas of correlation in the CC, when considering only the memory subscore. Our results point towards microstructural degeneration across motor and extra-motor areas in ALS, underlining that alterations in verbal fluency performances may be related to impairment of frontotemporal connectivity, while alterations of memory may be associated with damage of thalamocortical circuits.
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Affiliation(s)
- Francesca Trojsi
- Department of Advanced Medical and Surgical Sciences, MRI Research Centre "SUN-FISM", University of Campania "Luigi Vanvitelli", P.zza Miraglia 2, Naples 80138, Italy.
| | - Giuseppina Caiazzo
- Department of Advanced Medical and Surgical Sciences, MRI Research Centre "SUN-FISM", University of Campania "Luigi Vanvitelli", P.zza Miraglia 2, Naples 80138, Italy
| | - Mattia Siciliano
- Department of Advanced Medical and Surgical Sciences, MRI Research Centre "SUN-FISM", University of Campania "Luigi Vanvitelli", P.zza Miraglia 2, Naples 80138, Italy; Department of Psychology, University of Campania "Luigi Vanvitelli", Caserta, Italy
| | - Cinzia Femiano
- Department of Advanced Medical and Surgical Sciences, MRI Research Centre "SUN-FISM", University of Campania "Luigi Vanvitelli", P.zza Miraglia 2, Naples 80138, Italy
| | - Carla Passaniti
- Department of Advanced Medical and Surgical Sciences, MRI Research Centre "SUN-FISM", University of Campania "Luigi Vanvitelli", P.zza Miraglia 2, Naples 80138, Italy; Department of Psychology, University of Campania "Luigi Vanvitelli", Caserta, Italy
| | - Antonio Russo
- Department of Advanced Medical and Surgical Sciences, MRI Research Centre "SUN-FISM", University of Campania "Luigi Vanvitelli", P.zza Miraglia 2, Naples 80138, Italy
| | - Alvino Bisecco
- Department of Advanced Medical and Surgical Sciences, MRI Research Centre "SUN-FISM", University of Campania "Luigi Vanvitelli", P.zza Miraglia 2, Naples 80138, Italy
| | - Maria Rosaria Monsurrò
- Department of Advanced Medical and Surgical Sciences, MRI Research Centre "SUN-FISM", University of Campania "Luigi Vanvitelli", P.zza Miraglia 2, Naples 80138, Italy
| | - Mario Cirillo
- Department of Advanced Medical and Surgical Sciences, MRI Research Centre "SUN-FISM", University of Campania "Luigi Vanvitelli", P.zza Miraglia 2, Naples 80138, Italy
| | - Fabrizio Esposito
- Department of Medicine, Surgery and Dentistry, "Scuola Medica Salernitana" University of Salerno, Baronissi, Salerno, Italy
| | - Gioacchino Tedeschi
- Department of Advanced Medical and Surgical Sciences, MRI Research Centre "SUN-FISM", University of Campania "Luigi Vanvitelli", P.zza Miraglia 2, Naples 80138, Italy
| | - Gabriella Santangelo
- Department of Psychology, University of Campania "Luigi Vanvitelli", Caserta, Italy
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9
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Connectometry evaluation in patients undergoing carotid endarterectomy: an exploratory study. Brain Imaging Behav 2018; 13:1708-1718. [DOI: 10.1007/s11682-018-0024-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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10
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Wirth AM, Khomenko A, Baldaranov D, Kobor I, Hsam O, Grimm T, Johannesen S, Bruun TH, Schulte-Mattler W, Greenlee MW, Bogdahn U. Combinatory Biomarker Use of Cortical Thickness, MUNIX, and ALSFRS-R at Baseline and in Longitudinal Courses of Individual Patients With Amyotrophic Lateral Sclerosis. Front Neurol 2018; 9:614. [PMID: 30104996 PMCID: PMC6077217 DOI: 10.3389/fneur.2018.00614] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2018] [Accepted: 07/09/2018] [Indexed: 11/13/2022] Open
Abstract
Objective: Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative process affecting upper and lower motor neurons as well as non-motor systems. In this study, precentral and postcentral cortical thinning detected by structural magnetic resonance imaging (MRI) were combined with clinical (ALS-specific functional rating scale revised, ALSFRS-R) and neurophysiological (motor unit number index, MUNIX) biomarkers in both cross-sectional and longitudinal analyses. Methods: The unicenter sample included 20 limb-onset classical ALS patients compared to 30 age-related healthy controls. ALS patients were treated with standard Riluzole and additional long-term G-CSF (Filgrastim) on a named patient basis after written informed consent. Combinatory biomarker use included cortical thickness of atlas-based dorsal and ventral subdivisions of the precentral and postcentral cortex, ALSFRS-R, and MUNIX for the musculus abductor digiti minimi (ADM) bilaterally. Individual cross-sectional analysis investigated individual cortical thinning in ALS patients compared to age-related healthy controls in the context of state of disease at initial MRI scan. Beyond correlation analysis of biomarkers at cross-sectional group level (n = 20), longitudinal monitoring in a subset of slow progressive ALS patients (n = 4) explored within-subject temporal dynamics of repeatedly assessed biomarkers in time courses over at least 18 months. Results: Cross-sectional analysis demonstrated individually variable states of cortical thinning, which was most pronounced in the ventral section of the precentral cortex. Correlations of ALSFRS-R with cortical thickness and MUNIX were detected. Individual longitudinal biomarker monitoring in four slow progressive ALS patients revealed evident differences in individual disease courses and temporal dynamics of the biomarkers. Conclusion: A combinatory use of structural MRI, neurophysiological and clinical biomarkers allows for an appropriate and detailed assessment of clinical state and course of disease of ALS.
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Affiliation(s)
- Anna M Wirth
- Department of Neurology, University Hospital of Regensburg, Regensburg, Germany.,Department of Experimental Psychology, University of Regensburg, Regensburg, Germany
| | - Andrei Khomenko
- Department of Neurology, University Hospital of Regensburg, Regensburg, Germany
| | - Dobri Baldaranov
- Department of Neurology, University Hospital of Regensburg, Regensburg, Germany
| | - Ines Kobor
- Department of Neurology, University Hospital of Regensburg, Regensburg, Germany
| | - Ohnmar Hsam
- Department of Neurology, University Hospital of Regensburg, Regensburg, Germany
| | - Thomas Grimm
- Department of Neurology, University Hospital of Regensburg, Regensburg, Germany
| | - Siw Johannesen
- Department of Neurology, University Hospital of Regensburg, Regensburg, Germany
| | - Tim-Henrik Bruun
- Department of Neurology, University Hospital of Regensburg, Regensburg, Germany
| | | | - Mark W Greenlee
- Department of Experimental Psychology, University of Regensburg, Regensburg, Germany
| | - Ulrich Bogdahn
- Department of Neurology, University Hospital of Regensburg, Regensburg, Germany
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11
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Kassubek J, Müller HP, Del Tredici K, Lulé D, Gorges M, Braak H, Ludolph AC. Imaging the pathoanatomy of amyotrophic lateral sclerosis in vivo: targeting a propagation-based biological marker. J Neurol Neurosurg Psychiatry 2018; 89:374-381. [PMID: 29101254 PMCID: PMC5869447 DOI: 10.1136/jnnp-2017-316365] [Citation(s) in RCA: 69] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/03/2017] [Revised: 10/06/2017] [Accepted: 10/06/2017] [Indexed: 11/04/2022]
Abstract
OBJECTIVE Neuropathological studies in amyotrophic lateral sclerosis (ALS) have shown a dissemination in a regional sequence in four anatomically defined patterns. The aim of this retrospective study was to see whether longitudinal diffusion tensor imaging (DTI) data support the pathological findings. METHODS The application of DTI analysis to fibre structures that are prone to be involved at each neuropathological pattern of ALS was performed in a monocentre sample of 67 patients with ALS and 31 controls that obtained at least one follow-up scan after a median of 6 months. RESULTS At the group level, longitudinal ALS data showed significant differences for the stage-related tract systems. At the individual level, 27% of the longitudinally scanned patients with ALS showed an increase in ALS stage, while the remaining were stable or were at the highest ALS stage. Longitudinal fractional anisotropy changes in the respective tract systems correlated significantly with the slope of the revised ALS functional rating scale. INTERPRETATION The DTI-based protocol was able to image the disease patterns of ALS in vivo cross-sectionally and longitudinally, in support of DTI as a technical marker to image ALS stages.
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Affiliation(s)
- Jan Kassubek
- Department of Neurology, University of Ulm, Ulm, Germany
| | | | - Kelly Del Tredici
- Clinical Neuroanatomy, Department of Neurology, University of Ulm, Ulm, Germany
| | - Dorothée Lulé
- Department of Neurology, University of Ulm, Ulm, Germany
| | - Martin Gorges
- Department of Neurology, University of Ulm, Ulm, Germany
| | - Heiko Braak
- Clinical Neuroanatomy, Department of Neurology, University of Ulm, Ulm, Germany
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12
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Bauer CM, Cattaneo Z, Merabet LB. Early blindness is associated with increased volume of the uncinate fasciculus. Eur J Neurosci 2018; 47:427-432. [PMID: 29380459 DOI: 10.1111/ejn.13848] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2017] [Revised: 01/08/2018] [Accepted: 01/15/2018] [Indexed: 12/13/2022]
Abstract
Growing evidence demonstrates dramatic structural and functional neuroplastic changes in individuals born with early-onset blindness. For example, cross-modal sensory processing at the level of the occipital cortex appears to be associated with adaptive behaviors in the blind. However, detailed studies examining the structural properties of key white matter pathways in other regions of the brain remain limited. Given that blind individuals rely heavily on their sense of hearing, we examined the structural properties of two important pathways involved with auditory processing, namely the uncinate and arcuate fasciculi. High angular resolution diffusion imaging (HARDI) tractography was used to examine structural parameters (i.e., tract volume and quantitative anisotropy, or QA) of these two fasciculi in a sample of 13 early blind individuals and 14 normally sighted controls. Compared to controls, early blind individuals showed a significant increase in the volume of the left uncinate fasciculus. A small area of increased QA was also observed halfway along the right arcuate fasciculus in the blind group. These findings contribute to our knowledge regarding the broad neuroplastic changes associated with profound early blindness.
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Affiliation(s)
- Corinna M Bauer
- Laboratory for Visual Neuroplasticity, Department of Ophthalmology, Massachusetts Eye and Ear Infirmary, Harvard Medical School, 20 Staniford Street, Boston, MA, 02114, USA
| | - Zaira Cattaneo
- Department of Psychology, University of Milano-Biococca, Milan, Italy.,Brain Connectivity Center, IRCCS Mondino Foundation, Pavia, Italy
| | - Lotfi B Merabet
- Laboratory for Visual Neuroplasticity, Department of Ophthalmology, Massachusetts Eye and Ear Infirmary, Harvard Medical School, 20 Staniford Street, Boston, MA, 02114, USA
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13
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Baldaranov D, Khomenko A, Kobor I, Bogdahn U, Gorges M, Kassubek J, Müller HP. Longitudinal Diffusion Tensor Imaging-Based Assessment of Tract Alterations: An Application to Amyotrophic Lateral Sclerosis. Front Hum Neurosci 2017; 11:567. [PMID: 29259550 PMCID: PMC5723297 DOI: 10.3389/fnhum.2017.00567] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2017] [Accepted: 11/07/2017] [Indexed: 12/03/2022] Open
Abstract
Objective: The potential of magnetic resonance imaging (MRI) as a technical biomarker for cerebral microstructural alterations in neurodegenerative diseases is under investigation. In this study, a framework for the longitudinal analysis of diffusion tensor imaging (DTI)-based mapping was applied to the assessment of predefined white matter tracts in amyotrophic lateral sclerosis (ALS), as an example for a rapid progressive neurodegenerative disease. Methods: DTI was performed every 3 months in six patients with ALS (mean (M) = 7.7; range 3 to 15 scans) and in six controls (M = 3; range 2–5 scans) with the identical scanning protocol, resulting in a total of 65 longitudinal DTI datasets. Fractional anisotropy (FA), mean diffusivity (MD), axonal diffusivity (AD), radial diffusivity (RD), and the ratio AD/RD were studied to analyze alterations within the corticospinal tract (CST) which is a prominently affected tract structure in ALS and the tract correlating with Braak’s neuropathological stage 1. A correlation analysis was performed between progression rates based on DTI metrics and the revised ALS functional rating scale (ALS-FRS-R). Results: Patients with ALS showed an FA and AD/RD decline along the CST, while DTI metrics of controls did not change in longitudinal DTI scans. The FA and AD/RD decrease progression correlated significantly with ALS-FRS-R decrease progression. Conclusion: On the basis of the longitudinal assessment, DTI-based metrics can be considered as a possible noninvasive follow-up marker for disease progression in neurodegeneration. This finding was demonstrated here for ALS as a fast progressing neurodegenerative disease.
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Affiliation(s)
- Dobri Baldaranov
- Department of Neurology, University of Regensburg, Regensburg, Germany
| | - Andrei Khomenko
- Department of Neurology, University of Regensburg, Regensburg, Germany
| | - Ines Kobor
- Department of Neurology, University of Regensburg, Regensburg, Germany
| | - Ulrich Bogdahn
- Department of Neurology, University of Regensburg, Regensburg, Germany
| | - Martin Gorges
- Department of Neurology, University of Ulm, Ulm, Germany
| | - Jan Kassubek
- Department of Neurology, University of Ulm, Ulm, Germany
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Abstract
BACKGROUND Deterministic diffusion tractography obtained from high angular resolution diffusion imaging (HARDI) requires user-defined quantitative anisotropy (QA) thresholds. Most studies employ a common threshold across all subjects even though there is a strong degree of individual variation within groups. We sought to explore whether it would be beneficial to use individual thresholds in order to accommodate individual variance. To do this, we conducted two independent experiments. METHOD First, tractography of the arcuate fasciculus and network connectivity measures were examined in a sample of 14 healthy participants. Second, we assessed the effects of QA threshold on group differences in network connectivity measures between healthy young (n=19) and old (n=14) individuals. RESULTS The results of both experiments were significantly influenced by QA threshold. Common thresholds set too high failed to produce sufficient reconstructions in most subjects, thus decreasing the likelihood of detecting meaningful group differences. On the other hand, common thresholds set too low resulted in spurious reconstructions, providing deleterious results. COMPARISON WITH EXISTING METHODS Subject specific thresholds acquired using our QA threshold selection method (QATS) appeared to provide the most meaningful networks while ensuring that data from all subjects contributed to the analyses. CONCLUSIONS Together, these results support the use of a subject-specific threshold to ensure that data from all subjects are included in the analyses being conducted.
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Delaparte L, Yeh FC, Adams P, Malchow A, Trivedi MH, Oquendo MA, Deckersbach T, Ogden T, Pizzagalli DA, Fava M, Cooper C, McInnis M, Kurian BT, Weissman MM, McGrath PJ, Klein DN, Parsey RV, DeLorenzo C. A comparison of structural connectivity in anxious depression versus non-anxious depression. J Psychiatr Res 2017; 89:38-47. [PMID: 28157545 PMCID: PMC5374003 DOI: 10.1016/j.jpsychires.2017.01.012] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/09/2016] [Revised: 12/16/2016] [Accepted: 01/19/2017] [Indexed: 12/13/2022]
Abstract
BACKGROUND Major depressive disorder (MDD) and anxiety disorders are highly co-morbid. Research has shown conflicting evidence for white matter alteration and amygdala volume reduction in mood and anxiety disorders. To date, no studies have examined differences in structural connectivity between anxious depressed and non-anxious depressed individuals. This study compared fractional anisotropy (FA) and density of selected white matter tracts and amygdala volume between anxious depressed and non-anxious depressed individuals. METHODS 64- direction DTI and T1 scans were collected from 110 unmedicated subjects with MDD, 39 of whom had a co-morbid anxiety disorder diagnosis. Region of interest (ROI) and tractography methods were performed to calculate amygdala volume and FA in the uncinate fasciculus, respectively. Diffusion connectometry was performed to identify whole brain group differences in white matter health. Correlations were computed between biological and clinical measures. RESULTS Tractography and ROI analyses showed no significant differences between bilateral FA values or bilateral amygdala volumes when comparing the anxious depressed and non-anxious depressed groups. The diffusion connectometry analysis showed no significant differences in anisotropy between the groups. Furthermore, there were no significant relationships between MRI-based and clinical measures. CONCLUSION The lack of group differences could indicate that structural connectivity and amygdalae volumes of those with anxious-depression are not significantly altered by a co-morbid anxiety disorder. Improving understanding of anxiety co-morbid with MDD would facilitate development of treatments that more accurately target the underlying networks.
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Affiliation(s)
- Lauren Delaparte
- Department of Psychology, Stony Brook University, Stony Brook, NY, USA; Department of Psychiatry, Stony Brook University, Stony Brook, NY, USA.
| | - Fang-Cheng Yeh
- Department of Neurological Surgery, University of Pittsburgh, Pittsburgh, Pittsburgh
| | - Phil Adams
- Department of Psychiatry, New York State Psychiatric Institute, Columbia University College of Physicians and Surgeons, New York, New York
| | - Ashley Malchow
- Department of Psychiatry, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Madhukar H. Trivedi
- Department of Psychiatry, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Maria A. Oquendo
- Department of Psychiatry, New York State Psychiatric Institute, Columbia University College of Physicians and Surgeons, New York, New York
| | - Thilo Deckersbach
- Department of Psychiatry, Massachusetts General Hospital, Boston, Massachusetts
| | - Todd Ogden
- Department of Psychiatry, New York State Psychiatric Institute, Columbia University College of Physicians and Surgeons, New York, New York
| | | | - Maurizio Fava
- Department of Psychiatry, Massachusetts General Hospital, Boston, Massachusetts
| | - Crystal Cooper
- Department of Psychiatry, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Melvin McInnis
- Department of Psychiatry, University of Michigan School of Medicine, Ann Arbor, Michigan
| | - Benji T. Kurian
- Department of Psychiatry, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Myrna M. Weissman
- Department of Psychiatry, New York State Psychiatric Institute, Columbia University College of Physicians and Surgeons, New York, New York
| | - Patrick J. McGrath
- Department of Psychiatry, New York State Psychiatric Institute, Columbia University College of Physicians and Surgeons, New York, New York
| | - Daniel N. Klein
- Department of Psychology, Stony Brook University, Stony Brook, New York
| | - Ramin V. Parsey
- Department of Psychiatry, Stony Brook University, Stony Brook, New York,Department of Radiology, Stony Brook University, Stony Brook, New York
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Macular sub-layer thinning and association with pulmonary function tests in Amyotrophic Lateral Sclerosis. Sci Rep 2016; 6:29187. [PMID: 27383525 PMCID: PMC4935870 DOI: 10.1038/srep29187] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2015] [Accepted: 06/16/2016] [Indexed: 01/24/2023] Open
Abstract
Amyotrophic Lateral Sclerosis (ALS) is a complex neurodegenerative disorder that may have anterior visual pathway involvement. In this study, we compare the macular structure of patients with ALS to healthy controls, and examine correlations between macular sub-layer thickness measurements and pulmonary function tests and disease duration. ALS patients underwent optical coherence tomography (OCT) imaging to obtain macular cube scans of the right eye. Macular cube OCT data from age-matched healthy subjects were provided by the OCT reading center. Semi-automated retinal segmentation software was used to quantify macular sub-layers. Pulmonary function tests and time since symptom onset were collected retrospectively from the electronic medical records of ALS patients. Macular retinal nerve fiber layer was significantly thinner in ALS patients compared to healthy controls (P < 0.05). Total macular and other sub-layer thicknesses were not reduced in the ALS cohort. Macular retinal nerve fiber layer thickness positively correlated with forced vital capacity % predicted and forced expiratory volume in 1 second % predicted (P < 0.05). In conclusion, analysis of OCT measurements supports the involvement of the anterior visual pathway in ALS. Subtle structural thinning in the macular retinal nerve fiber layer correlates with pulmonary function tests.
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Yeh FC, Badre D, Verstynen T. Connectometry: A statistical approach harnessing the analytical potential of the local connectome. Neuroimage 2016; 125:162-171. [DOI: 10.1016/j.neuroimage.2015.10.053] [Citation(s) in RCA: 108] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2015] [Revised: 09/29/2015] [Accepted: 10/19/2015] [Indexed: 12/13/2022] Open
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Olvet DM, Delaparte L, Yeh F, DeLorenzo C, McGrath PJ, Weissman MM, Adams P, Fava M, Deckersbach T, McInnis MG, Carmody TJ, Cooper CM, Kurian BT, Lu H, Toups MS, Trivedi MH, Parsey RV. A COMPREHENSIVE EXAMINATION OF WHITE MATTER TRACTS AND CONNECTOMETRY IN MAJOR DEPRESSIVE DISORDER. Depress Anxiety 2016; 33:56-65. [PMID: 26477532 PMCID: PMC4701622 DOI: 10.1002/da.22445] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/19/2015] [Revised: 09/04/2015] [Accepted: 09/21/2015] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND Major depressive disorder (MDD) is a debilitating disorder characterized by widespread brain abnormalities. The literature is mixed as to whether or not white matter abnormalities are associated with MDD. This study sought to examine fractional anisotropy (FA) in white matter tracts in individuals with MDD using diffusion tensor imaging (DTI). METHODS 139 participants with MDD and 39 healthy controls (HC) in a multisite study were included. DTI scans were acquired in 64 directions and FA was determined in the brain using four methods: region of interest (ROI), tract-based spatial statistics (TBSS), and diffusion tractography. Diffusion connectometry was used to identify white matter pathways associated with MDD. RESULTS There were no significant differences when comparing FA in MDD and HC groups using any method. In the MDD group, there was a significant relationship between depression severity and FA in the right medial orbitofrontal cortex, and between age of onset of MDD and FA in the right caudal anterior cingulate cortex using the ROI method. There was a significant relationship between age of onset and connectivity in the thalamocortical radiation, inferior longitudinal fasciculus, and cerebellar tracts using diffusion connectometry. CONCLUSIONS The lack of group differences in FA and connectometry analysis may result from the clinically heterogenous nature of MDD. However, the relationship between FA and depression severity may suggest a state biomarker of depression that should be investigated as a potential indicator of response. Age of onset may also be a significant clinical feature to pursue when studying white matter tracts.
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Affiliation(s)
- Doreen M. Olvet
- Department of PsychiatryStony Brook UniversityStony BrookNew York
| | - Lauren Delaparte
- Department of PsychologyStony Brook UniversityStony BrookNew York
| | - Fang‐Cheng Yeh
- Department of PsychologyCarnegie Mellon University, PittsburghPittsburgh
| | | | - Patrick J. McGrath
- Department of Psychiatry, New York State Psychiatric InstituteColumbia University College of Physicians and Surgeons, New YorkNew York
| | - Myrna M. Weissman
- Department of Psychiatry, New York State Psychiatric InstituteColumbia University College of Physicians and Surgeons, New YorkNew York
| | - Phillip Adams
- Department of Psychiatry, New York State Psychiatric InstituteColumbia University College of Physicians and Surgeons, New YorkNew York
| | - Maurizio Fava
- Department of PsychiatryMassachusetts General Hospital, BostonMassachusetts
| | - Thilo Deckersbach
- Department of PsychiatryMassachusetts General Hospital, BostonMassachusetts
| | - Melvin G. McInnis
- Department of PsychiatryUniversity of Michigan School of Medicine, Ann ArborMichigan
| | - Thomas J. Carmody
- Department of PsychiatryUniversity of Texas Southwestern Medical CenterDallasTexas
| | - Crystal M. Cooper
- Department of PsychiatryUniversity of Texas Southwestern Medical CenterDallasTexas
| | - Benji T. Kurian
- Department of PsychiatryUniversity of Texas Southwestern Medical CenterDallasTexas
| | - Hanzhang Lu
- Department of PsychiatryUniversity of Texas Southwestern Medical CenterDallasTexas
| | - Marisa S. Toups
- Department of PsychiatryUniversity of Texas Southwestern Medical CenterDallasTexas
| | - Madhukar H. Trivedi
- Department of PsychiatryUniversity of Texas Southwestern Medical CenterDallasTexas
| | - Ramin V. Parsey
- Department of PsychiatryStony Brook UniversityStony BrookNew York,Department of RadiologyStony Brook UniversityStony BrookNew York
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Faraji AH, Abhinav K, Jarbo K, Yeh FC, Shin SS, Pathak S, Hirsch BE, Schneider W, Fernandez-Miranda JC, Friedlander RM. Longitudinal evaluation of corticospinal tract in patients with resected brainstem cavernous malformations using high-definition fiber tractography and diffusion connectometry analysis: preliminary experience. J Neurosurg 2015; 123:1133-44. [PMID: 26047420 DOI: 10.3171/2014.12.jns142169] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
OBJECT Brainstem cavernous malformations (CMs) are challenging due to a higher symptomatic hemorrhage rate and potential morbidity associated with their resection. The authors aimed to preoperatively define the relationship of CMs to the perilesional corticospinal tracts (CSTs) by obtaining qualitative and quantitative data using high-definition fiber tractography. These data were examined postoperatively by using longitudinal scans and in relation to patients' symptomatology. The extent of involvement of the CST was further evaluated longitudinally using the automated "diffusion connectometry" analysis. METHODS Fiber tractography was performed with DSI Studio using a quantitative anisotropy (QA)-based generalized deterministic tracking algorithm. Qualitatively, CST was classified as being "disrupted" and/or "displaced." Quantitative analysis involved obtaining mean QA values for the CST and its perilesional and nonperilesional segments. The contralateral CST was used for comparison. Diffusion connectometry analysis included comparison of patients' data with a template from 90 normal subjects. RESULTS Three patients (mean age 22 years) with symptomatic pontomesencephalic hemorrhagic CMs and varying degrees of hemiparesis were identified. The mean follow-up period was 37.3 months. Qualitatively, CST was partially disrupted and displaced in all. Direction of the displacement was different in each case and progressively improved corresponding with the patient's neurological status. No patient experienced neurological decline related to the resection. The perilesional mean QA percentage decreases supported tract disruption and decreased further over the follow-up period (Case 1, 26%-49%; Case 2, 35%-66%; and Case 3, 63%-78%). Diffusion connectometry demonstrated rostrocaudal involvement of the CST consistent with the quantitative data. CONCLUSIONS Hemorrhagic brainstem CMs can disrupt and displace perilesional white matter tracts with the latter occurring in unpredictable directions. This requires the use of tractography to accurately define their orientation to optimize surgical entry point, minimize morbidity, and enhance neurological outcomes. Observed anisotropy decreases in the perilesional segments are consistent with neural injury following hemorrhagic insults. A model using these values in different CST segments can be used to longitudinally monitor its craniocaudal integrity. Diffusion connectometry is a complementary approach providing longitudinal information on the rostrocaudal involvement of the CST.
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Affiliation(s)
| | | | - Kevin Jarbo
- Department of Psychology, University of Pittsburgh; and
| | - Fang-Cheng Yeh
- Department of Biomedical Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania
| | | | - Sudhir Pathak
- Department of Psychology, University of Pittsburgh; and
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Volpe NJ, Simonett J, Fawzi AA, Siddique T. Ophthalmic Manifestations of Amyotrophic Lateral Sclerosis (An American Ophthalmological Society Thesis). TRANSACTIONS OF THE AMERICAN OPHTHALMOLOGICAL SOCIETY 2015; 113:T12. [PMID: 26877563 PMCID: PMC4731009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
PURPOSE To determine if clinical and histopathologic findings were present in the eyes of patients with amyotrophic lateral sclerosis (ALS) and explore correlations to an animal model of ALS. METHODS Two patients with ALS were studied histopathologically as well as the retinas of ALS/dementia transgenic mice with dysfunctional ubiquilin2, UBQLN2(P497H). Clinical study 1, an observational, cross-sectional study, was performed using optical coherence tomography (OCT) to obtain and compare mean total macular thickness and average and quadrant specific peripapillary retinal nerve fiber layer (pRNFL) scans from 16 patients with ALS to controls. Correlation analysis was performed to evaluate the association with disease duration. Clinical study 2 consisted of measuring visual acuity, color vision, contrast sensitivity, and quality of life in 12 patients. RESULTS Histopathologic studies demonstrated intraretinal inclusions in one patient and loss of ganglion cell axons in another. Mouse eyes had intraretinal inclusions in the inner plexiform layers. Total macular volume was thinner in patients compared to controls (P<.05), and 37.5% of patients with ALS had an average pRNFL below the 1st percentile. Total macular and pRNFL thickness correlated inversely with disease duration. CONCLUSIONS Histopathologic analysis of ALS eyes and mice with the UBQLN2(P497H) mutation, as well as OCT measurements, supports involvement of the anterior visual pathway. We identified pathologies, including intraretinal deposits and axonal loss. pRNFL and total macular thinning found on OCT correlated with disease duration. A pattern of vision loss specific for ALS was not identified. This study confirms ocular involvement in patients and transgenic animals with ALS/dementia.
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Affiliation(s)
- Nicholas J Volpe
- Department of Ophthalmology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois
| | - Joseph Simonett
- Department of Ophthalmology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois
| | - Amani A Fawzi
- Department of Ophthalmology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois
| | - Teepu Siddique
- Neurology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois
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Advanced diffusion MRI fiber tracking in neurosurgical and neurodegenerative disorders and neuroanatomical studies: A review. Biochim Biophys Acta Mol Basis Dis 2014; 1842:2286-2297. [PMID: 25127851 DOI: 10.1016/j.bbadis.2014.08.002] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2014] [Revised: 08/03/2014] [Accepted: 08/05/2014] [Indexed: 12/26/2022]
Abstract
Diffusion MRI enabled in vivo microstructural imaging of the fiber tracts in the brain resulting in its application in a wide range of settings, including in neurological and neurosurgical disorders. Conventional approaches such as diffusion tensor imaging (DTI) have been shown to have limited applications due to the crossing fiber problem and the susceptibility of their quantitative indices to partial volume effects. To overcome these limitations, the recent focus has shifted to the advanced acquisition methods and their related analytical approaches. Advanced white matter imaging techniques provide superior qualitative data in terms of demonstration of multiple crossing fibers in their spatial orientation in a three dimensional manner in the brain. In this review paper, we discuss the advancements in diffusion MRI and introduce their roles. Using examples, we demonstrate the role of advanced diffusion MRI-based fiber tracking in neuroanatomical studies. Results from its preliminary application in the evaluation of intracranial space occupying lesions, including with respect to future directions for prognostication, are also presented. Building upon the previous DTI studies assessing white matter disease in Huntington's disease and Amyotrophic lateral sclerosis; we also discuss approaches which have led to encouraging preliminary results towards developing an imaging biomarker for these conditions.
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