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Song N, Mei S, Wang X, Hu G, Lu M. Focusing on mitochondria in the brain: from biology to therapeutics. Transl Neurodegener 2024; 13:23. [PMID: 38632601 PMCID: PMC11022390 DOI: 10.1186/s40035-024-00409-w] [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: 12/10/2023] [Accepted: 03/13/2024] [Indexed: 04/19/2024] Open
Abstract
Mitochondria have multiple functions such as supplying energy, regulating the redox status, and producing proteins encoded by an independent genome. They are closely related to the physiology and pathology of many organs and tissues, among which the brain is particularly prominent. The brain demands 20% of the resting metabolic rate and holds highly active mitochondrial activities. Considerable research shows that mitochondria are closely related to brain function, while mitochondrial defects induce or exacerbate pathology in the brain. In this review, we provide comprehensive research advances of mitochondrial biology involved in brain functions, as well as the mitochondria-dependent cellular events in brain physiology and pathology. Furthermore, various perspectives are explored to better identify the mitochondrial roles in neurological diseases and the neurophenotypes of mitochondrial diseases. Finally, mitochondrial therapies are discussed. Mitochondrial-targeting therapeutics are showing great potentials in the treatment of brain diseases.
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Affiliation(s)
- Nanshan Song
- Department of Pharmacology, School of Medicine & Holistic Integrative Medicine, Nanjing University of Chinese Medicine, Nanjing, 210023, China
| | - Shuyuan Mei
- The First Clinical Medical College, Nanjing Medical University, Nanjing, 211166, China
| | - Xiangxu Wang
- Jiangsu Key Laboratory of Neurodegeneration, Department of Pharmacology, Neuroprotective Drug Discovery Key Laboratory, School of Basic Medical Sciences, Nanjing Medical University, Nanjing, 211166, China
| | - Gang Hu
- Department of Pharmacology, School of Medicine & Holistic Integrative Medicine, Nanjing University of Chinese Medicine, Nanjing, 210023, China.
- Jiangsu Key Laboratory of Neurodegeneration, Department of Pharmacology, Neuroprotective Drug Discovery Key Laboratory, School of Basic Medical Sciences, Nanjing Medical University, Nanjing, 211166, China.
| | - Ming Lu
- Jiangsu Key Laboratory of Neurodegeneration, Department of Pharmacology, Neuroprotective Drug Discovery Key Laboratory, School of Basic Medical Sciences, Nanjing Medical University, Nanjing, 211166, China.
- Changzhou Second People's Hospital, Changzhou Medical Center, Nanjing Medical University, Changzhou, 213000, China.
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Mitochondrial Mutations in Multiple Sclerosis Patients with Atypical Optic Neuropathy. Mult Scler Relat Disord 2021; 55:103166. [PMID: 34333271 DOI: 10.1016/j.msard.2021.103166] [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: 02/20/2021] [Revised: 05/03/2021] [Accepted: 07/22/2021] [Indexed: 11/23/2022]
Abstract
BACKGROUND Multiple sclerosis-related optic neuritis is mostly associated with good recovery. The aim of this study was to investigate the causes of progressive visual worsening in multiple sclerosis patients despite treatment. METHODS We retrospectively reviewed the medical records of multiple sclerosis patients with optic neuritis admitted to the ward of our Neurology Department between 2001 and 2020. The patients with unilateral/bilateral progressive visual loss or non-substantial recovery of visual acuity were screened for genetic testing for Leber's hereditary optic neuropathy. RESULTS Of 1014 multiple sclerosis patients, 411 (39%) reported having optic neuritis. During follow-up, 11 patients manifested atypical characteristics of multiple sclerosis-related optic neuritis (presence of one of the following clinical findings: bilateral simultaneous or sequential eye involvement, progressive visual loss, or no response to corticosteroids during hospitalization), while others presented with typical multiple sclerosis-related optic neuritis. Those multiple sclerosis patients with atypical characteristics of optic neuritis were screened for other possible etiologies of optic neuropathy. We found pathogenic mitochondrial mutations in 5 patients with multiple sclerosis in our study group. CONCLUSION In our study group, the prevalence of mitochondrial mutations among all multiple sclerosis patients with optic neuritis was 0.12%. We strongly recommend investigating Leber's hereditary optic neuropathy mutations in MS patients if they suffer from severe or bilateral visual loss without recovery during follow-up. Because Leber's hereditary optic neuropathy mitochondrial mutations indicate relatively poor visual prognosis and have important implications for genetic counseling.
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The Evaluation of Optic Nerves Using 7 Tesla "Silent" Zero Echo Time Imaging in Patients with Leber's Hereditary Optic Neuropathy with or without Idebenone Treatment. J Clin Med 2020; 9:jcm9041112. [PMID: 32295018 PMCID: PMC7230870 DOI: 10.3390/jcm9041112] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2020] [Revised: 04/08/2020] [Accepted: 04/09/2020] [Indexed: 11/16/2022] Open
Abstract
Magnetic Resonance Imaging (MRI) of the Optic Nerve is difficult due to the fine extended nature of the structure, strong local magnetic field distortions induced by anatomy, and large motion artefacts associated with eye movement. To address these problems we used a Zero Echo Time (ZTE) MRI sequence with an Adiabatic SPectral Inversion Recovery (ASPIR) fat suppression pulse which also imbues the images with Magnetisation Transfer contrast. We investigated an application of the sequence for imaging the optic nerve in subjects with Leber's hereditary optic neuropathy (LHON). Of particular note is the sequence's near-silent operation, which can enhance image quality of the optic nerve by reducing the occurrence of involuntary saccades induced during Magnetic Resonance (MR) scanning.
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Iorga RE, Mihailovici R, Ozturk MR, Costin D. Leber's hereditary optic neuropathy - Case report. Rom J Ophthalmol 2018; 62:64-71. [PMID: 29796436 PMCID: PMC5959027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Leber's hereditary optic neuropathy is the most common mitochondrial condition and is characterized by bilateral, painless, subacute visual loss that develops during young adult life. LHON is a rare condition and this lack of knowledge can make doctors suspect and treat for other causes of vision loss. Typically, a series of tests are performed to confirm LHON diagnosis or exclude any other conditions. We presented the case of two brothers, HB, of 40 years old and HF, of 38 years old, who presented with a decrease in visual acuity in both eyes. The patients had been diagnosed with optic atrophy of unknown cause a long time ago, but no further investigations were made. They were treated with corticosteroids, antioxidants and vasodilators, but with no significant benefit. A blood test of the mitochondrial DNA, a magnetic resonance imaging and an optic coherence tomography of the optic nerve and macula were part of the following assessment of our patients. The mitochondrial DNA analyses revealed the 3460 G>A mutation on the mtND1 gene in both patients. Based on the medical history, the fundus aspect, the optic coherence tomography and the paraclinical investigations of the diagnosis of Leber's hereditary optic neuropathy were established in both patients. We started the treatment with idebenone and we evaluated the patients after three months. ABBREVIATIONS LHON = Leber's hereditary optic neuropathy, mtDNA = mitochondrial DNA, VA = visual acuity, CF = count fingers, OCT = optical coherence tomography, RNFL = retinal nerve fiber layer, GCL = ganglion cells layer, MS = multiple sclerosis, MRI = magnetic resonance imaging, MTI = magnetization transfer imaging, MTR = magnetization transfer ratio.
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Affiliation(s)
- Raluca Eugenia Iorga
- Department of Ophthalmology, ”N. Oblu” Clinical Emergency Hospital, Iaşi, Romania
| | - Ruxandra Mihailovici
- Department of Ophthalmology, ”N. Oblu” Clinical Emergency Hospital, Iaşi, Romania
,Department of Ophthalmology, ”Gr. T. Popa” University of Medicine and Pharmacy, Iaşi, Romania
| | - Manuela Ramona Ozturk
- Department of Ophthalmology, ”Gr. T. Popa” University of Medicine and Pharmacy, Iaşi, Romania
| | - Dănuţ Costin
- Department of Ophthalmology, ”N. Oblu” Clinical Emergency Hospital, Iaşi, Romania
,Department of Ophthalmology, ”Gr. T. Popa” University of Medicine and Pharmacy, Iaşi, Romania
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5
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Rovaris M, Holtmannspötter M, Rocca MA, Iannucci G, Codella M, Viti B, Campi A, Comi G, Yousry TA, Filippi M. Contribution of cervical cord MRI and brain magnetization transfer imaging to the assessment of individual patients with multiple sclerosis: a preliminary study. Mult Scler 2017. [DOI: 10.1177/135245850200800110] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
This study was performed to assess how established diagnostic criteria for brain magnetic resonance imaging (MRI) interpretation in cases of suspected multiple sclerosis (MS) (Barkhofs criteria) would perform in the distinction of MS from other diseases and whether other MR techniques (cervical cord imaging and brain magnetization transfer imaging [MTI]), might help in the diagnostic work-up of these patients. We retrospectively identified 64 MS and 59 non-MS patients. The latter group included patients with systemic immune-mediated disorders (SID; n=44) and migraine (n=15). All patients had undergone MRI scans of the brain (dual echo and MTI) and of the cervical cord (fast short-tau inversion recovery). The number and location of brain T2-hyperintense lesions and the number and size of cervical cord lesions were assessed. Brain images were also postprocessed to quantify the total lesion volumes (TLV) and to create histograms of magnetization transfer ratio (MTR) values from the whole of the brain tissue. Barkhofs criteria correctly classified 108/123 patients, thus showing an accuracy of 87.8%. "False negative" MS patients were 13, while 2 patients with systemic lupus erythematosus (SLE) were considered as "false positives". Using brain T2 TLV, nine of the"false negative" patients were correctly classified. Correct classification of 10 MS patients and both the SLE patients was possible based upon the presence or absence of one cervical cord lesion. Two MS patients with negative Barkhofs criteria and no cervical cord lesions were correctly classified based on their brain MTR values. Overall, only one MS patient could not be correctly classified by any of the assessed MR quantities. These preliminary data support a more extensive use of cervical cord MRI and brain MTI to differentiate between MS and other disorders in case of inconclusive findings on T2-weighted MRI scans of the brain. Multiple Sclerosis (2002) 8, 52-58
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Affiliation(s)
- M. Rovaris
- Neuroimaging Research Unit, Scientific Institute and
University H San Raffaele, Milan, Italy
| | | | - MA Rocca
- Neuroimaging Research Unit, Scientific Institute and
University H San Raffaele, Milan, Italy
| | - G. Iannucci
- Neuroimaging Research Unit, Scientific Institute and
University H San Raffaele, Milan, Italy
| | - M. Codella
- Neuroimaging Research Unit, Scientific Institute and
University H San Raffaele, Milan, Italy
| | - B. Viti
- Neuroimaging Research Unit, Scientific Institute and
University H San Raffaele, Milan, Italy
| | - A. Campi
- Department of Neuroradiology, Scientific Institute and
University H San Raffaele, Milan, Italy
| | - G. Comi
- Clinical Trials Unit, Department of Neuroscience, Scientific
Institute and University H San Raffaele, Milan, Italy
| | - TA Yousry
- Department of Radiology, Klinikum Grosshadern, Munich,
Germany
| | - M. Filippi
- Neuroimaging Research Unit, Scientific Institute and
University H San Raffaele, Milan, Italy
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Zhang Y, Liang W, Wu G, Zhang X, Wen G. Magnetization transfer imaging reveals geniculocalcarine and striate area degeneration in primary glaucoma: a preliminary study. Acta Radiol Open 2016; 5:2058460116666876. [PMID: 27651931 PMCID: PMC5019197 DOI: 10.1177/2058460116666876] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2016] [Accepted: 08/01/2016] [Indexed: 11/23/2022] Open
Abstract
Background Glaucoma is a neurodegenerative disease that affects both the retina and central visual pathway. Magnetization transfer imaging (MTI) is a sensitive magnetic resonance imaging (MRI) technique that can detect degenerative changes in the brain. Purpose To investigate the geniculocalcarine (GCT) and striate areas in primary glaucoma patients using region of interest (ROI) analysis of magnetization transfer ratio (MTR). Material and Methods Twenty patients with primary glaucoma in both eyes were compared with 31 healthy control patients. All of the participants were examined on a 3.0 T scanner using a three-dimensional T1-weighted spoiled gradient recalled acquisition (SPGR) with and without a MT saturation pulse. A two-sample t-test was used to evaluate the MTR difference between the groups. P < 0.05 was used to determine statistical significance. Results The MTR of the glaucoma group was lower than the healthy controls in both the bilateral GCT (t = 3.781, P = 0.001) and striate areas (t = 4.177, P = 0.000). Conclusion The MTR reductions in the bilateral GCT and striate areas suggest that there is GCT demyelination and striate area degeneration in primary glaucoma. These neurodegenerative effects may be induced as a direct effect of retrograde axonal degeneration along with the indirect effect of anterograde trans-synaptic degeneration.
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Affiliation(s)
- Yan Zhang
- ZhongShan Ophthalmic center, State Key Laboratory of Ophthalmology Sun Yat-sen University, Guangzhou, GuangDong, PR China
| | - Wenwen Liang
- Department of Radiology, Nan Fang Hospital, Southern Medical University, Guangzhou, Guang Dong, PR China
| | - Guijun Wu
- Department of Ophthalmology, Nan Fang Hospital, Southern Medical University, Guangzhou, GuangDong, PR China
| | - Xuelin Zhang
- Department of Radiology, Nan Fang Hospital, Southern Medical University, Guangzhou, Guang Dong, PR China
| | - Ge Wen
- Department of Radiology, Nan Fang Hospital, Southern Medical University, Guangzhou, Guang Dong, PR China
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Martin AR, Aleksanderek I, Cohen-Adad J, Tarmohamed Z, Tetreault L, Smith N, Cadotte DW, Crawley A, Ginsberg H, Mikulis DJ, Fehlings MG. Translating state-of-the-art spinal cord MRI techniques to clinical use: A systematic review of clinical studies utilizing DTI, MT, MWF, MRS, and fMRI. Neuroimage Clin 2015; 10:192-238. [PMID: 26862478 PMCID: PMC4708075 DOI: 10.1016/j.nicl.2015.11.019] [Citation(s) in RCA: 152] [Impact Index Per Article: 16.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2015] [Revised: 10/23/2015] [Accepted: 11/27/2015] [Indexed: 12/12/2022]
Abstract
BACKGROUND A recent meeting of international imaging experts sponsored by the International Spinal Research Trust (ISRT) and the Wings for Life Foundation identified 5 state-of-the-art MRI techniques with potential to transform the field of spinal cord imaging by elucidating elements of the microstructure and function: diffusion tensor imaging (DTI), magnetization transfer (MT), myelin water fraction (MWF), MR spectroscopy (MRS), and functional MRI (fMRI). However, the progress toward clinical translation of these techniques has not been established. METHODS A systematic review of the English literature was conducted using MEDLINE, MEDLINE-in-Progress, Embase, and Cochrane databases to identify all human studies that investigated utility, in terms of diagnosis, correlation with disability, and prediction of outcomes, of these promising techniques in pathologies affecting the spinal cord. Data regarding study design, subject characteristics, MRI methods, clinical measures of impairment, and analysis techniques were extracted and tabulated to identify trends and commonalities. The studies were assessed for risk of bias, and the overall quality of evidence was assessed for each specific finding using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) framework. RESULTS A total of 6597 unique citations were identified in the database search, and after full-text review of 274 articles, a total of 104 relevant studies were identified for final inclusion (97% from the initial database search). Among these, 69 studies utilized DTI and 25 used MT, with both techniques showing an increased number of publications in recent years. The review also identified 1 MWF study, 11 MRS studies, and 8 fMRI studies. Most of the studies were exploratory in nature, lacking a priori hypotheses and showing a high (72%) or moderately high (20%) risk of bias, due to issues with study design, acquisition techniques, and analysis methods. The acquisitions for each technique varied widely across studies, rendering direct comparisons of metrics invalid. The DTI metric fractional anisotropy (FA) had the strongest evidence of utility, with moderate quality evidence for its use as a biomarker showing correlation with disability in several clinical pathologies, and a low level of evidence that it identifies tissue injury (in terms of group differences) compared with healthy controls. However, insufficient evidence exists to determine its utility as a sensitive and specific diagnostic test or as a tool to predict clinical outcomes. Very low quality evidence suggests that other metrics also show group differences compared with controls, including DTI metrics mean diffusivity (MD) and radial diffusivity (RD), the diffusional kurtosis imaging (DKI) metric mean kurtosis (MK), MT metrics MT ratio (MTR) and MT cerebrospinal fluid ratio (MTCSF), and the MRS metric of N-acetylaspartate (NAA) concentration, although these results were somewhat inconsistent. CONCLUSIONS State-of-the-art spinal cord MRI techniques are emerging with great potential to improve the diagnosis and management of various spinal pathologies, but the current body of evidence has only showed limited clinical utility to date. Among these imaging tools DTI is the most mature, but further work is necessary to standardize and validate its use before it will be adopted in the clinical realm. Large, well-designed studies with a priori hypotheses, standardized acquisition methods, detailed clinical data collection, and robust automated analysis techniques are needed to fully demonstrate the potential of these rapidly evolving techniques.
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Affiliation(s)
- Allan R Martin
- Division of Neurosurgery, Department of Surgery, University of Toronto, Toronto, Ontario, Canada
| | - Izabela Aleksanderek
- Division of Neurosurgery, Department of Surgery, University of Toronto, Toronto, Ontario, Canada
| | | | | | - Lindsay Tetreault
- Division of Neurosurgery, Department of Surgery, University of Toronto, Toronto, Ontario, Canada
| | | | - David W Cadotte
- Division of Neurosurgery, Department of Surgery, University of Toronto, Toronto, Ontario, Canada
| | - Adrian Crawley
- Department of Medical Imaging, University of Toronto, Toronto, Ontario, Canada
| | - Howard Ginsberg
- Division of Neurosurgery, Department of Surgery, University of Toronto, Toronto, Ontario, Canada
| | - David J Mikulis
- Department of Medical Imaging, University of Toronto, Toronto, Ontario, Canada
| | - Michael G Fehlings
- Division of Neurosurgery, Department of Surgery, University of Toronto, Toronto, Ontario, Canada
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Jančić J, Dejanović I, Radovanović S, Ostojić J, Kozić D, Đurić-Jovičić M, Samardžić J, Ćetković M, Kostić V. White Matter Changes in Two Leber's Hereditary Optic Neuropathy Pedigrees: 12-Year Follow-Up. Ophthalmologica 2015; 235:49-56. [DOI: 10.1159/000441089] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2015] [Accepted: 09/14/2015] [Indexed: 11/19/2022]
Abstract
We are presenting two Leber's hereditary optic neuropathy (LHON) pedigrees with abnormal magnetic resonance imaging (MRI) and proton magnetic resonance spectroscopy (H-MRS) findings but without neurological manifestation associated with LHON. The study included 14 LHON patients and 41 asymptomatic family members from 12 genealogically unrelated families. MRI showed white matter involvement and H-MRS exhibited metabolic anomalies within 12 LHON families. Main outcome measures were abnormal MRI and H-MRS findings in two pedigrees. MRI of the proband of the first pedigree showed a single demyelinating lesion in the right cerebellar hemisphere, while the proband of the second family displayed multiple supratentorial and infratentorial lesions, compatible with the demyelinating process, and both the absolute choline (Cho) concentration and Cho/creatinine ratio were increased. MRI and H-MRS profiles of both affected and unaffected mitochondrial DNA mutation carriers suggest more widespread central nervous involvement in LHON. Although even after 12 years our patients did not develop neurological symptoms, MRI could still be used to detect possible changes during the disease progression.
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Matthews L, Enzinger C, Fazekas F, Rovira A, Ciccarelli O, Dotti MT, Filippi M, Frederiksen JL, Giorgio A, Küker W, Lukas C, Rocca MA, De Stefano N, Toosy A, Yousry T, Palace J. MRI in Leber's hereditary optic neuropathy: the relationship to multiple sclerosis. J Neurol Neurosurg Psychiatry 2015; 86:537-42. [PMID: 25053773 PMCID: PMC4413690 DOI: 10.1136/jnnp-2014-308186] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/25/2014] [Accepted: 06/18/2014] [Indexed: 11/15/2022]
Abstract
BACKGROUND Leber's hereditary optic neuropathy (LHON) and a multiple sclerosis (MS)-like illness appear to coexist 50 times more frequently than would be expected by chance. This association of LHON and MS (LMS) raises an important question about whether there could be a common pathophysiological mechanism involving mitochondrial dysfunction. OBJECTIVE The primary aim was to define MRI features of LMS and LHON, and to assess the proportions of individuals displaying features typical of MS. Secondarily, we investigated the effect of gender on the risk of developing white matter lesions in the context of LHON. METHODS A blinded standardised review of conventional brain MRIs of 30 patients with MS, 31 patients with LHON and 11 patients with LMS was conducted by three independent experts in the field. MS-like MRI features were assessed. RESULTS All patients with LMS and 26% of patients with LHON had white matter lesions. Of these, all patients with LMS and 25% with LHON were found to have an MRI appearance typical of MS. Female patients with LHON had a significantly greater risk of having white matter lesions consistent with MS compared with male patients (relative risk 8.3). CONCLUSIONS A blinded review of conventional brain MRIs shows that patients with LMS have a scan appearance indistinguishable from MS. Mitochondrial dysfunction could be a common pathophysiological pathway in the formation of white matter lesions. There appears to be a strong female influence on the radiological appearance as well as clinical development of MS in patients with LHON.
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Affiliation(s)
- Lucy Matthews
- Oxford University Hospitals NHS Trust, Oxford, UK Nuffield Department of Clinical Neurosciences, Oxford University, Oxford, UK
| | - Christian Enzinger
- Department of Neurology, Medical University of Graz, Graz, Austria Department of Radiology, Division of Neuroradiology, Medical University of Graz, Graz, Austria
| | - Franz Fazekas
- Department of Neurology, Medical University of Graz, Graz, Austria
| | - Alex Rovira
- Department of Radiology, Hospital Vall d'Hebron, Barcelona, Spain
| | | | - Maria Teresa Dotti
- Department of Neurological and Behavioural Sciences, University of Siena, Siena, Italy
| | - Massimo Filippi
- Neuroimaging Research Unit and Department of Neurology, San Raffaele Scientific Institute, Vita-Salute San Raffaele University, Milan, Italy
| | - Jette L Frederiksen
- Department of Neurology, Glostrup Hospital, University of Copenhagen, Copenhagen, Denmark
| | - Antonio Giorgio
- Department of Neurological and Behavioural Sciences, University of Siena, Siena, Italy
| | - Wilhelm Küker
- Oxford University Hospitals NHS Trust, Oxford, UK Nuffield Department of Clinical Neurosciences, Oxford University, Oxford, UK
| | - Carsten Lukas
- Department of Radiology, St. Josef Hospital Ruhr-University, Bochum, Germany
| | - Maria A Rocca
- Neuroimaging Research Unit and Department of Neurology, San Raffaele Scientific Institute, Vita-Salute San Raffaele University, Milan, Italy
| | - Nicola De Stefano
- Department of Neurological and Behavioural Sciences, University of Siena, Siena, Italy
| | | | | | - Jacqueline Palace
- Oxford University Hospitals NHS Trust, Oxford, UK Nuffield Department of Clinical Neurosciences, Oxford University, Oxford, UK
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Distributed abnormalities of brain white matter architecture in patients with dominant optic atrophy and OPA1 mutations. J Neurol 2015; 262:1216-27. [DOI: 10.1007/s00415-015-7696-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2014] [Revised: 02/27/2015] [Accepted: 02/27/2015] [Indexed: 01/08/2023]
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11
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Manners DN, Rizzo G, La Morgia C, Tonon C, Testa C, Barboni P, Malucelli E, Valentino ML, Caporali L, Strobbe D, Carelli V, Lodi R. Diffusion Tensor Imaging Mapping of Brain White Matter Pathology in Mitochondrial Optic Neuropathies. AJNR Am J Neuroradiol 2015; 36:1259-65. [PMID: 25792533 DOI: 10.3174/ajnr.a4272] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2014] [Accepted: 12/05/2014] [Indexed: 01/04/2023]
Abstract
BACKGROUND AND PURPOSE Brain white matter is frequently affected in mitochondrial diseases; optic atrophy gene 1-autosomal dominant optic atrophy and Leber hereditary optic neuropathy are the most frequent mitochondrial monosymptomatic optic neuropathies. In this observational study, brain white matter microstructure was characterized by DTI in patients with optic atrophy gene 1-autosomal dominant optic atrophy and Leber hereditary optic neuropathy, in relation to clinical and genetic features. MATERIALS AND METHODS Nineteen patients with optic atrophy gene 1-autosomal dominant optic atrophy and 17 with Leber hereditary optic neuropathy older than 18 years of age, all genetically diagnosed, and 19 healthy volunteers underwent DTI by using a 1.5T MR imaging scanner and neurologic and ophthalmologic assessments. Brain white matter DTI metrics were calculated for all participants, and, in patients, their correlations with genetics and clinical findings were calculated. RESULTS Compared with controls, patients with optic atrophy gene 1-autosomal dominant optic atrophy had an increased mean diffusivity in 29.2% of voxels analyzed within major white matter tracts distributed throughout the brain, while fractional anisotropy was reduced in 30.3% of voxels. For patients with Leber hereditary optic neuropathy, the proportion of altered voxels was only 0.5% and 5.5%, respectively, of which half was found within the optic radiation and 3.5%, in the smaller acoustic radiation. In almost all regions, fractional anisotropy diminished with age in patients with optic atrophy gene 1-autosomal dominant optic atrophy and correlated with average retinal nerve fiber layer thickness in several areas. Mean diffusivity increased in those with a missense mutation. Patients with Leber hereditary optic neuropathy taking idebenone had slightly milder changes. CONCLUSIONS Patients with Leber hereditary optic neuropathy had preferential involvement of the optic and acoustic radiations, consistent with trans-synaptic degeneration, whereas patients with optic atrophy gene 1-autosomal dominant optic atrophy presented with widespread involvement suggestive of a multisystemic, possibly a congenital/developmental, disorder. White matter changes in Leber hereditary optic neuropathy and optic atrophy gene 1-autosomal dominant optic atrophy may be exploitable as biomarkers.
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Affiliation(s)
- D N Manners
- From the Functional MR Unit (D.N.M., G.R., C.Tonon, C.Testa, R.L.)
| | - G Rizzo
- From the Functional MR Unit (D.N.M., G.R., C.Tonon, C.Testa, R.L.) Neurology Unit (G.R., C.L.M., M.L.V., L.C., D.S., V.C.), Department of Biomedical and NeuroMotor Sciences
| | - C La Morgia
- Neurology Unit (G.R., C.L.M., M.L.V., L.C., D.S., V.C.), Department of Biomedical and NeuroMotor Sciences "Istituto di Ricovero e Cura a Carattere Scientifico Istituto delle Scienze Neurologiche di Bologna" (C.L.M., M.L.V., L.C., D.S., V.C.), Bologna, Italy
| | - C Tonon
- From the Functional MR Unit (D.N.M., G.R., C.Tonon, C.Testa, R.L.)
| | - C Testa
- From the Functional MR Unit (D.N.M., G.R., C.Tonon, C.Testa, R.L.)
| | - P Barboni
- Studio Oculistico d'Azeglio (P.B.), Bologna, Italy
| | - E Malucelli
- Department of Pharmacy and Biotechnology (E.M.), University of Bologna, Bologna, Italy
| | - M L Valentino
- Neurology Unit (G.R., C.L.M., M.L.V., L.C., D.S., V.C.), Department of Biomedical and NeuroMotor Sciences "Istituto di Ricovero e Cura a Carattere Scientifico Istituto delle Scienze Neurologiche di Bologna" (C.L.M., M.L.V., L.C., D.S., V.C.), Bologna, Italy
| | - L Caporali
- Neurology Unit (G.R., C.L.M., M.L.V., L.C., D.S., V.C.), Department of Biomedical and NeuroMotor Sciences "Istituto di Ricovero e Cura a Carattere Scientifico Istituto delle Scienze Neurologiche di Bologna" (C.L.M., M.L.V., L.C., D.S., V.C.), Bologna, Italy
| | - D Strobbe
- Neurology Unit (G.R., C.L.M., M.L.V., L.C., D.S., V.C.), Department of Biomedical and NeuroMotor Sciences "Istituto di Ricovero e Cura a Carattere Scientifico Istituto delle Scienze Neurologiche di Bologna" (C.L.M., M.L.V., L.C., D.S., V.C.), Bologna, Italy
| | - V Carelli
- Neurology Unit (G.R., C.L.M., M.L.V., L.C., D.S., V.C.), Department of Biomedical and NeuroMotor Sciences "Istituto di Ricovero e Cura a Carattere Scientifico Istituto delle Scienze Neurologiche di Bologna" (C.L.M., M.L.V., L.C., D.S., V.C.), Bologna, Italy
| | - R Lodi
- From the Functional MR Unit (D.N.M., G.R., C.Tonon, C.Testa, R.L.)
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Weisfeld-Adams JD, Katz Sand IB, Honce JM, Lublin FD. Differential diagnosis of Mendelian and mitochondrial disorders in patients with suspected multiple sclerosis. Brain 2015; 138:517-39. [PMID: 25636970 DOI: 10.1093/brain/awu397] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Several single gene disorders share clinical and radiologic characteristics with multiple sclerosis and have the potential to be overlooked in the differential diagnostic evaluation of both adult and paediatric patients with multiple sclerosis. This group includes lysosomal storage disorders, various mitochondrial diseases, other neurometabolic disorders, and several other miscellaneous disorders. Recognition of a single-gene disorder as causal for a patient's 'multiple sclerosis-like' phenotype is critically important for accurate direction of patient management, and evokes broader genetic counselling implications for affected families. Here we review single gene disorders that have the potential to mimic multiple sclerosis, provide an overview of clinical and investigational characteristics of each disorder, and present guidelines for when clinicians should suspect an underlying heritable disorder that requires diagnostic confirmation in a patient with a definite or probable diagnosis of multiple sclerosis.
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Affiliation(s)
- James D Weisfeld-Adams
- 1 Division of Clinical Genetics and Metabolism, Department of Paediatrics, University of Colorado School of Medicine, Aurora, Colorado 80045, USA 2 Inherited Metabolic Diseases Clinic, Children's Hospital Colorado, Aurora, Colorado 80045, USA 3 Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, New York 10029, USA
| | - Ilana B Katz Sand
- 4 Department of Neurology, Icahn School of Medicine at Mount Sinai, New York, New York 10029, USA
| | - Justin M Honce
- 5 Department of Radiology, University of Colorado School of Medicine, Aurora, Colorado 80045, USA
| | - Fred D Lublin
- 4 Department of Neurology, Icahn School of Medicine at Mount Sinai, New York, New York 10029, USA
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Novel use of 3T MRI in assessment of optic nerve volume in glaucoma. Graefes Arch Clin Exp Ophthalmol 2014; 252:995-1000. [DOI: 10.1007/s00417-014-2622-6] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2013] [Revised: 02/07/2014] [Accepted: 03/10/2014] [Indexed: 10/25/2022] Open
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Secondary post-geniculate involvement in Leber's hereditary optic neuropathy. PLoS One 2012; 7:e50230. [PMID: 23209682 PMCID: PMC3507727 DOI: 10.1371/journal.pone.0050230] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2012] [Accepted: 10/22/2012] [Indexed: 11/19/2022] Open
Abstract
Leber’s hereditary optic neuropathy (LHON) is characterized by retinal ganglion cell (RGC) degeneration with the preferential involvement of those forming the papillomacular bundle. The optic nerve is considered the main pathological target for LHON. Our aim was to investigate the possible involvement of the post-geniculate visual pathway in LHON patients. We used diffusion-weighted imaging for in vivo evaluation. Mean diffusivity maps from 22 LHON visually impaired, 11 unaffected LHON mutation carriers and 22 healthy subjects were generated and compared at level of optic radiation (OR). Prefrontal and cerebellar white matter were also analyzed as internal controls. Furthermore, we studied the optic nerve and the lateral geniculate nucleus (LGN) in post-mortem specimens obtained from a severe case of LHON compared to an age-matched control. Mean diffusivity values of affected patients were higher than unaffected mutation carriers (P<0.05) and healthy subjects (P<0.01) in OR and not in the other brain regions. Increased OR diffusivity was associated with both disease duration (B = 0.002; P<0.05) and lack of recovery of visual acuity (B = 0.060; P<0.01). Post-mortem investigation detected atrophy (41.9% decrease of neuron soma size in the magnocellular layers and 44.7% decrease in the parvocellular layers) and, to a lesser extent, degeneration (28.5% decrease of neuron density in the magnocellular layers and 28.7% decrease in the parvocellular layers) in the LHON LGN associated with extremely severe axonal loss (99%) in the optic nerve. The post-geniculate involvement in LHON patients is a downstream post-synaptic secondary phenomenon, reflecting de-afferentation rather than a primary neurodegeneration due to mitochondrial dysfunction of LGN neurons.
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Milesi J, Rocca MA, Bianchi-Marzoli S, Petrolini M, Pagani E, Falini A, Comi G, Filippi M. Patterns of white matter diffusivity abnormalities in Leber’s hereditary optic neuropathy: a tract-based spatial statistics study. J Neurol 2012; 259:1801-7. [PMID: 22249289 DOI: 10.1007/s00415-011-6406-1] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2011] [Revised: 12/21/2011] [Accepted: 12/28/2011] [Indexed: 11/25/2022]
Affiliation(s)
- Jacopo Milesi
- Neuroimaging Research Unit, Institute of Experimental Neurology, Division of Neuroscience, San Raffaele Scientific Institute, Vita-Salute San Raffaele University, Milan, Italy
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Yu-Wai-Man P, Griffiths PG, Chinnery PF. Mitochondrial optic neuropathies - disease mechanisms and therapeutic strategies. Prog Retin Eye Res 2011; 30:81-114. [PMID: 21112411 PMCID: PMC3081075 DOI: 10.1016/j.preteyeres.2010.11.002] [Citation(s) in RCA: 440] [Impact Index Per Article: 33.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Leber hereditary optic neuropathy (LHON) and autosomal-dominant optic atrophy (DOA) are the two most common inherited optic neuropathies in the general population. Both disorders share striking pathological similarities, marked by the selective loss of retinal ganglion cells (RGCs) and the early involvement of the papillomacular bundle. Three mitochondrial DNA (mtDNA) point mutations; m.3460G>A, m.11778G>A, and m.14484T>C account for over 90% of LHON cases, and in DOA, the majority of affected families harbour mutations in the OPA1 gene, which codes for a mitochondrial inner membrane protein. Optic nerve degeneration in LHON and DOA is therefore due to disturbed mitochondrial function and a predominantly complex I respiratory chain defect has been identified using both in vitro and in vivo biochemical assays. However, the trigger for RGC loss is much more complex than a simple bioenergetic crisis and other important disease mechanisms have emerged relating to mitochondrial network dynamics, mtDNA maintenance, axonal transport, and the involvement of the cytoskeleton in maintaining a differential mitochondrial gradient at sites such as the lamina cribosa. The downstream consequences of these mitochondrial disturbances are likely to be influenced by the local cellular milieu. The vulnerability of RGCs in LHON and DOA could derive not only from tissue-specific, genetically-determined biological factors, but also from an increased susceptibility to exogenous influences such as light exposure, smoking, and pharmacological agents with putative mitochondrial toxic effects. Our concept of inherited mitochondrial optic neuropathies has evolved over the past decade, with the observation that patients with LHON and DOA can manifest a much broader phenotypic spectrum than pure optic nerve involvement. Interestingly, these phenotypes are sometimes clinically indistinguishable from other neurodegenerative disorders such as Charcot-Marie-Tooth disease, hereditary spastic paraplegia, and multiple sclerosis, where mitochondrial dysfunction is also thought to be an important pathophysiological player. A number of vertebrate and invertebrate disease models has recently been established to circumvent the lack of human tissues, and these have already provided considerable insight by allowing direct RGC experimentation. The ultimate goal is to translate these research advances into clinical practice and new treatment strategies are currently being investigated to improve the visual prognosis for patients with mitochondrial optic neuropathies.
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MESH Headings
- Animals
- DNA, Mitochondrial/genetics
- Disease Models, Animal
- Humans
- Optic Atrophy, Autosomal Dominant/pathology
- Optic Atrophy, Autosomal Dominant/physiopathology
- Optic Atrophy, Autosomal Dominant/therapy
- Optic Atrophy, Hereditary, Leber/pathology
- Optic Atrophy, Hereditary, Leber/physiopathology
- Optic Atrophy, Hereditary, Leber/therapy
- Optic Nerve/pathology
- Phenotype
- Point Mutation
- Retinal Ganglion Cells/pathology
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Affiliation(s)
- Patrick Yu-Wai-Man
- Mitochondrial Research Group, Institute for Ageing and Health, The Medical School, Newcastle University, UK.
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Magnetic Resonance Findings in the Pregeniculate Visual Pathways in Leber Hereditary Optic Neuropathy. J Neuroophthalmol 2011; 31:48-51. [DOI: 10.1097/wno.0b013e3181f3f203] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Extra-visual functional and structural connection abnormalities in Leber's hereditary optic neuropathy. PLoS One 2011; 6:e17081. [PMID: 21347331 PMCID: PMC3037402 DOI: 10.1371/journal.pone.0017081] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2010] [Accepted: 01/21/2011] [Indexed: 11/19/2022] Open
Abstract
We assessed abnormalities within the principal brain resting state networks (RSNs) in patients with Leber's hereditary optic neuropathy (LHON) to define whether functional abnormalities in this disease are limited to the visual system or, conversely, tend to be more diffuse. We also defined the structural substrates of fMRI changes using a connectivity-based analysis of diffusion tensor (DT) MRI data. Neuro-ophthalmologic assessment, DT MRI and RS fMRI data were acquired from 13 LHON patients and 13 healthy controls. RS fMRI data were analyzed using independent component analysis and SPM5. A DT MRI connectivity-based parcellation analysis was performed using the primary visual and auditory cortices, bilaterally, as seed regions. Compared to controls, LHON patients had a significant increase of RS fluctuations in the primary visual and auditory cortices, bilaterally. They also showed decreased RS fluctuations in the right lateral occipital cortex and right temporal occipital fusiform cortex. Abnormalities of RS fluctuations were correlated significantly with retinal damage and disease duration. The DT MRI connectivity-based parcellation identified a higher number of clusters in the right auditory cortex in LHON vs. controls. Differences of cluster-centroid profiles were found between the two groups for all the four seeds analyzed. For three of these areas, a correspondence was found between abnormalities of functional and structural connectivities. These results suggest that functional and structural abnormalities extend beyond the visual network in LHON patients. Such abnormalities also involve the auditory network, thus corroborating the notion of a cross-modal plasticity between these sensory modalities in patients with severe visual deficits.
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Barcella V, Rocca MA, Bianchi-Marzoli S, Milesi J, Melzi L, Falini A, Pierro L, Filippi M. Evidence for retrochiasmatic tissue loss in Leber's hereditary optic neuropathy. Hum Brain Mapp 2010; 31:1900-6. [PMID: 20827728 DOI: 10.1002/hbm.20985] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Patients with Leber's hereditary optic neuropathy (LHON) have loss of central vision with severe damage of small-caliber fibers of the papillomacular bundle and optic nerve atrophy. The aim of this study was to define the presence and topographical distribution of brain grey matter (GM) and white matter (WM) injury in LHON patients using voxel-based morphometry (VBM). The correlation of such changes with neuro-ophthalmologic findings and measurements of peripapillary retinal nerve fiber layer (RNFL) thickness by optical coherence tomography (OCT) was also assessed. Dual-echo and fast-field echo scans were acquired from 12 LHON patients and 12 matched controls. VBM analysis was performed using SPM5 and an ANCOVA model. A complete neuro-ophthalmologic examination, including standardized automated Humphrey perimetry as well as average and temporal peripapillary RNFL thickness measurements were obtained in all the patients. Compared with controls, average peripapillary RNFL thickness was significantly decreased in LHON patients. LHON patients also had significant reduced GM volume in the bilateral primary visual cortex, and reduced WM volume in the optic chiasm, optic tract, and several areas located in the optic radiations (OR), bilaterally. Visual cortex and OR atrophy were significantly correlated with average and temporal peripapillary RNFL thickness (P < 0.001; r values ranging from 0.76 to 0.89). Brain damage in patients with LHON is not limited to the anterior visual pathways, but extends posteriorly to the OR and the primary visual cortex. Such a damage to the posterior parts of the visual pathways may be due either to trans-synaptic degeneration secondary to neuroaxonal damage in the retina and optic nerve or to local mitochondrial dysfunction.
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Affiliation(s)
- Valeria Barcella
- Neuroimaging Reseach Unit, Institute of Experimental Neurology, Scientific Institute and University Ospedale San Raffaele, Milan, Italy
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22
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Multiple sclerosis associated with Leber's Hereditary Optic Neuropathy. J Neurol Sci 2009; 286:24-7. [PMID: 19800080 DOI: 10.1016/j.jns.2009.09.009] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2009] [Revised: 09/07/2009] [Accepted: 09/15/2009] [Indexed: 11/21/2022]
Abstract
The cause of multiple sclerosis is unknown although it is recognised to involve an inflammatory process associated with demyelinating plaques and more widespread neurodegeneration. It appears to have become progressively more common in females which is further discussed in this issue, and genetic factors, as identified to date, appear to play only a moderate role. One curious observation is that Leber's Hereditary Optic Neuropathy (LHON), a rare genetic syndrome, presents clinically overwhelmingly in males, but can be associated with an MS-like illness and when it does it occurs mainly in females. It is interesting to examine this further to assess if this could give us any clues as to the pathogenesis of MS.
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Bellmann-Strobl J, Stiepani H, Wuerfel J, Bohner G, Paul F, Warmuth C, Aktas O, Wandinger KP, Zipp F, Klingebiel R. MR spectroscopy (MRS) and magnetisation transfer imaging (MTI), lesion load and clinical scores in early relapsing remitting multiple sclerosis: a combined cross-sectional and longitudinal study. Eur Radiol 2009; 19:2066-74. [PMID: 19308417 DOI: 10.1007/s00330-009-1364-z] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2008] [Revised: 01/12/2009] [Accepted: 01/21/2009] [Indexed: 11/28/2022]
Abstract
The purpose of this study was to correlate magnetic resonance imaging (MRI)-based lesion load assessment with clinical disability in early relapsing remitting multiple sclerosis (RRMS). Seventeen untreated patients (ten women, seven men; mean age 33.0 +/- 7.9 years) with the initial diagnosis of RRMS were included for cross-sectional as well as longitudinal (24 months) clinical and MRI-based assessment in comparison with age-matched healthy controls. Conventional MR sequences, MR spectroscopy (MRS) and magnetisation transfer imaging (MTI) were performed at 1.5 T. Lesion number and volume, MRS and MTI measurements for lesions and normal appearing white matter (NAWM) were correlated to clinical scores [Expanded Disability Status Scale (EDSS), Multiple Sclerosis Functional Composite (MSFC)] for monitoring disease course after treatment initiation (interferon beta-1a). MTI and MRS detected changes [magnetisation transfer ratio (MTR), N-acetylaspartate (NAA)/creatine ratio] in NAWM over time. EDSS and lesional MTR increases correlated throughout the disease course. Average MTR of NAWM raised during the study (p < 0.05) and correlated to the MSFC score (r = 0.476, p < 0.001). At study termination, NAA/creatine ratio of NAWM correlated to the MSFC score (p < 0.05). MTI and MRS were useful for initial disease assessment in NAWM. MTI and MRS correlated with clinical scores, indicating potential for monitoring the disease course and gaining new insights into treatment-related effects.
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Affiliation(s)
- J Bellmann-Strobl
- Cecilie Vogt Clinic for Neurology, Charité-University Medicine Berlin and Max Delbrueck Center for Molecular Medicine, Berlin, Germany
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24
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Xu J, Sun SW, Naismith RT, Snyder AZ, Cross AH, Song SK. Assessing optic nerve pathology with diffusion MRI: from mouse to human. NMR IN BIOMEDICINE 2008; 21:928-40. [PMID: 18756587 PMCID: PMC2603138 DOI: 10.1002/nbm.1307] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
The optic nerve is often affected in patients with glaucoma and multiple sclerosis. Conventional MRI can detect nerve damage, but it does not accurately assess the underlying pathologies. Mean diffusivity and diffusion anisotropy indices derived from diffusion tensor imaging have been shown to be sensitive to a variety of central nervous system white matter pathologies. Despite being sensitive, the lack of specificity limits the ability of these measures to differentiate the underlying pathology. Directional (axial and radial) diffusivities, measuring water diffusion parallel and perpendicular to the axonal tracts, have been shown to be specific to axonal and myelin damage in mouse models of optic nerve injury, including retinal ischemia and experimental autoimmune encephalomyelitis. The progression of Wallerian degeneration has also been detected using directional diffusivities after retinal ischemia. However, translating these findings to human optic nerve is technically challenging. The current status of diffusion MRI of human optic nerve, including imaging sequences and protocols, is summarized herein. Despite the lack of a consensus among different groups on the optimal sequence or protocol, increased mean diffusivity and decreased diffusion anisotropy have been observed in injured optic nerve from patients with chronic optic neuritis. From different mouse models of optic nerve injuries to the emerging studies on patients with optic neuritis, directional diffusivities show great potential to be specific biomarkers for axonal and myelin injury.
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Affiliation(s)
- Junqian Xu
- Department of Neurology Washington University in St. Louis, St. Louis, Missouri, USA
| | - Shu-Wei Sun
- Department of Radiology Washington University in St. Louis, St. Louis, Missouri, USA
| | - Robert T. Naismith
- Department of Neurology Washington University in St. Louis, St. Louis, Missouri, USA
| | - Abraham Z. Snyder
- Department of Neurology Washington University in St. Louis, St. Louis, Missouri, USA
- Department of Radiology Washington University in St. Louis, St. Louis, Missouri, USA
| | - Anne H. Cross
- Department of Neurology Washington University in St. Louis, St. Louis, Missouri, USA
| | - Sheng-Kwei Song
- Department of Radiology Washington University in St. Louis, St. Louis, Missouri, USA
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Hudson G, Yu-Wai-Man P, Chinnery PF. Leber hereditary optic neuropathy. EXPERT OPINION ON MEDICAL DIAGNOSTICS 2008; 2:789-99. [PMID: 23495818 DOI: 10.1517/17530059.2.7.789] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
BACKGROUND Leber hereditary optic neuropathy (LHON) is a cause of inherited blindness that typically presents with bilateral, painless, subacute visual failure in young adult males. Males are about four times more likely to be affected than females and 95% of LHON carriers become affected before the age of 50. Affected patients may have characteristic ocular fundal appearances and have evidence of optic nerve dysfunction in the form of impaired colour vision (dyschromatopsia), dense visual field defects (central or caecocentral scotoma) and abnormal visual electrophysiology. OBJECTIVES To summarise the current clinical approach to the molecular diagnosis and clinical management of LHON. METHODS To review the literature and present a review of current understanding. RESULTS/CONCLUSIONS The diagnosis of LHON is usually confirmed by molecular genetic analysis for one of three common mitochondrial DNA (mtDNA) mutations that all affect genes coding for complex I subunits of the respiratory chain: m.3460G > A, m.11778G > A and m.14484T > C. Sequencing of the entire mitochondrial genome can reveal the underlying cause in the minority of patients (∼ 5%) who do not harbour one of these three primary mutations, but a molecular diagnosis is not always possible. A minority of LHON patients exhibit a more widespread multi-system involvement with extra neurological features such as dystonia or a multiple sclerosis-like illness. Management is largely supportive, with the provision of low-vision aids, registration with the relevant social services and an important role for genetic counselling.
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Affiliation(s)
- Gavin Hudson
- Newcastle University, Mitochondrial Research Group, M4014, The Medical School, Framlington Place, Newcastle upon Tyne, NE2 4HH, UK +44 191 222 8233 ; +44 191 222 8553 ;
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Laule C, Vavasour IM, Kolind SH, Li DKB, Traboulsee TL, Moore GRW, MacKay AL. Magnetic resonance imaging of myelin. Neurotherapeutics 2007; 4:460-84. [PMID: 17599712 PMCID: PMC7479725 DOI: 10.1016/j.nurt.2007.05.004] [Citation(s) in RCA: 230] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
The ability to measure myelin in vivo has great consequences for furthering our knowledge of normal development, as well as for understanding a wide range of neurological disorders. The following review summarizes the current state of myelin imaging using MR. We consider five MR techniques that have been used to study myelin: 1) conventional MR, 2) MR spectroscopy, 3) diffusion, 4) magnetization transfer, and 5) T2 relaxation. Fundamental studies involving peripheral nerve and MR/histology comparisons have aided in the interpretation and validation of MR data. We highlight a number of important findings related to myelin development, damage, and repair, and we conclude with a critical summary of the current techniques available and their potential to image myelin in vivo.
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Affiliation(s)
- Cornelia Laule
- Department of Radiology, University of British Columbia, Vancouver, BC, V6T 2B5 Canada.
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27
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Filippi M, Rocca MA. Magnetization transfer magnetic resonance imaging of the brain, spinal cord, and optic nerve. Neurotherapeutics 2007; 4:401-13. [PMID: 17599705 PMCID: PMC7479733 DOI: 10.1016/j.nurt.2007.03.002] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Magnetic resonance imaging is highly sensitive in revealing CNS abnormalities associated with several neurological conditions, but lacks specificity for their pathological substrates. In addition, MRI does not allow evaluation of the presence and extent of damage in regions that appear normal on conventional MRI sequences and that postmortem studies have shown to be affected by pathology. Quantitative MR-based techniques with increased pathological specificity to the heterogeneous substrates of CNS pathology have the potential to overcome such limitations. Among these techniques, one of the most extensively used for the assessment of CNS disorders is magnetization transfer MRI (MT-MRI). The application of this technique for the assessment of damage in macroscopic lesions, in normal-appearing white and gray matter, and in the spinal cord and optic nerve of patients with several neurological conditions is providing important in vivo information-dramatically improving our understanding of the factors associated with the appearance of clinical symptoms and the accumulation of irreversible disability. MT-MRI also has the potential to contribute to the diagnostic evaluation of several neurological conditions and to improve our ability to monitor treatment efficacy in experimental trials.
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Affiliation(s)
- Massimo Filippi
- Neuroimaging Research Unit, Department of Neurology, Scientific Institute and University Hospital San Raffaele, Milan, Italy.
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Küker W, Weir A, Quaghebeur G, Palace J. White matter changes in Leber's hereditary optic neuropathy: MRI findings. Eur J Neurol 2007; 14:591-3. [PMID: 17437624 DOI: 10.1111/j.1468-1331.2007.01757.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Leber's hereditary optic neuropathy is a mitochondrial disorder causing bilateral optic nerve degeneration. It is sometimes associated with clinical signs of multiple sclerosis. We report MRI findings in two patients with LHON-MS and comment on possible distinguishing features of this disease entity.
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MESH Headings
- Adult
- Brain/pathology
- Brain/physiopathology
- Diagnosis, Differential
- Disease Progression
- Early Diagnosis
- Female
- Gait Disorders, Neurologic/etiology
- Gait Disorders, Neurologic/pathology
- Gait Disorders, Neurologic/physiopathology
- Humans
- Magnetic Resonance Imaging
- Middle Aged
- Multiple Sclerosis/pathology
- Multiple Sclerosis/physiopathology
- Nerve Fibers, Myelinated/pathology
- Optic Atrophy, Hereditary, Leber/diagnosis
- Optic Atrophy, Hereditary, Leber/pathology
- Optic Atrophy, Hereditary, Leber/physiopathology
- Optic Nerve/pathology
- Optic Nerve/physiopathology
- Predictive Value of Tests
- Sensation Disorders/etiology
- Sensation Disorders/pathology
- Sensation Disorders/physiopathology
- Vision, Low/etiology
- Vision, Low/pathology
- Vision, Low/physiopathology
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Affiliation(s)
- W Küker
- Department of Neuroradiology, The Radcliffe Infirmary, Oxford, UK.
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Abstract
Magnetization transfer (MT) is a relatively new way of generating contrast in magnetic resonance (MR) images that is sensitive to the density of the macromolecules found throughout tissue structures such as membranes, myelin, and organelles. MT imaging (MTI) can provide a quantitative measure of macromolecular density, and therefore of tissue damage, and has been applied in the central nervous system in multiple sclerosis (MS) and other diseases. This article introduces the contrast mechanisms behind MTI and gives some practical guidance about implementing MTI and about quantitative analysis of the MT scans. An overview of MT measurements made in animal studies, in postmortem tissue samples, and in other demyelinating diseases attempts to rationalize the pathological basis of changes in MT contrast in MS. The application of MTI to MS is reviewed, with emphasis on the contribution that MTI has made to the current understanding of the MS disease process, both its natural history and the response to treatment. The pathological basis of abnormal MT contrast is still open to debate, with many conflicting reports; indeed, it is unlikely that a simple measure of MT effect will reveal the details of pathology that is a combination of inflammation, demyelination, remyelination, and axonal loss. There is no doubt, however, that MT measurements have contributed to the current understanding of both disease progression and the response to treatment and will prove to be a valuable tool in the future, particularly if more refined techniques can be applied practically in multicenter studies.
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Affiliation(s)
- Mark A Horsfield
- Department of Cardiology, University of Leicester, Leicester Royal Infirmary, Leicester LE1 5WW, UK.
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Rocca MA, Hickman SJ, Bö L, Agosta F, Miller DH, Comi G, Filippi M. Imaging Spinal Cord Damage in Multiple Sclerosis. J Neuroimaging 2006. [DOI: 10.1111/j.1552-6569.2005.tb00327.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
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Abstract
AIMS To provide a clinical update on the hereditary optic neuropathies. METHODS Review of the literature. RESULTS The hereditary optic neuropathies comprise a group of disorders in which the cause of optic nerve dysfunction appears to be hereditable, based on familial expression or genetic analysis. In some hereditary optic neuropathies, optic nerve dysfunction is typically the only manifestation of the disease. In others, various neurologic and systemic abnormalities are regularly observed. CONCLUSION The most common hereditary optic neuropathies are autosomal dominant optic atrophy (Kjer's disease) and maternally inherited Leber's hereditary optic neuropathy. We review the clinical phenotypes of these and other inherited disorders with optic nerve involvement.
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MESH Headings
- Dysautonomia, Familial/complications
- Dysautonomia, Familial/genetics
- Female
- Friedreich Ataxia/complications
- Friedreich Ataxia/genetics
- Humans
- Male
- Muscular Dystrophies/complications
- Muscular Dystrophies/genetics
- Optic Atrophies, Hereditary/complications
- Optic Atrophies, Hereditary/genetics
- Optic Atrophies, Hereditary/physiopathology
- Optic Atrophy, Autosomal Dominant/complications
- Optic Atrophy, Autosomal Dominant/genetics
- Optic Atrophy, Autosomal Dominant/physiopathology
- Optic Atrophy, Hereditary, Leber/complications
- Optic Atrophy, Hereditary, Leber/genetics
- Optic Atrophy, Hereditary, Leber/physiopathology
- Pedigree
- Spinocerebellar Ataxias/complications
- Spinocerebellar Ataxias/genetics
- Vision Disorders/etiology
- Vision Disorders/genetics
- Vision Disorders/physiopathology
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Affiliation(s)
- N J Newman
- Department of Ophthalmology, Emory University School of Medicine, Atlanta, GA 30022, USA.
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32
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Filippi M, Rocca MA. Magnetization Transfer Magnetic Resonance Imaging in the Assessment of Neurological Diseases. J Neuroimaging 2004. [DOI: 10.1111/j.1552-6569.2004.tb00255.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
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Mascalchi M, Lolli F, Della Nave R, Tessa C, Petralli R, Gavazzi C, Politi LS, Macucci M, Filippi M, Piacentini S. Huntington disease: volumetric, diffusion-weighted, and magnetization transfer MR imaging of brain. Radiology 2004; 232:867-73. [PMID: 15215553 DOI: 10.1148/radiol.2322030820] [Citation(s) in RCA: 90] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
PURPOSE To investigate whether diffusion-weighted and magnetization transfer (MT) magnetic resonance (MR) imaging depict regional and/or global brain abnormalities in patients with Huntington disease (HD). MATERIALS AND METHODS Twenty-one carriers of the HD mutation (mean age, 58 years +/- 11 [SD]) and 21 healthy control subjects (mean age, 54 years +/- 13) underwent conventional, diffusion-weighted, and MT MR imaging. Volumes, mean apparent diffusion coefficients (ADCs), and MT ratios (MTRs) for left and right caudate nucleus, putamen, and cerebral periventricular white matter-as well as an index of normalized brain volume and whole-brain ADC and MT histograms-were computed. Asymmetry in volume, ADC, and MTR measurements in caudate nucleus, putamen, and periventricular white matter in control subjects and HD carriers were evaluated with Wilcoxon testing for paired samples. Differences in MR imaging variables between HD carriers and control subjects were evaluated with Mann-Whitney U testing; correlations between stages of clinical severity and MR imaging data were investigated with Spearman rank correlation testing. RESULTS No significant asymmetry was observed for any of the MR imaging variables. Caudate nucleus, putamen, and whole-brain volumes were smaller (P <.001 for all) in HD carriers than in control subjects. HD carriers also had increased ADC in the caudate nucleus (P =.002), putamen (P <. 001), cerebral periventricular white matter (P <.001), and whole brain (P <.001). MTR was not significantly different between HD carriers and control subjects. Correlation was observed between stages of increasing clinical disease severity and both decrease in volume of caudate nucleus (Spearman rho = -0.63), putamen (rho = -0.64), and whole brain (rho = -0.46) and increase in ADC in caudate nucleus (rho = 0.52), periventricular white matter (rho = 0.45), and whole brain (rho = 0.44). CONCLUSION Regional and global volume loss in HD is accompanied by an increase in ADC; this correlates with disease severity.
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Affiliation(s)
- Mario Mascalchi
- Radiodiagnostic Section, Department of Clinical Physiopathology and Department of Neurological Sciences, University of Florence, Viale Morgagni 85, Florence, Italy.
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Kurtenbach A, Leo-Kottler B, Zrenner E. Inner retinal contributions to the multifocal electroretinogram: patients with Leber's hereditary optic neuropathy (LHON). Doc Ophthalmol 2004; 108:231-40. [PMID: 15573947 DOI: 10.1007/s10633-004-8676-8] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
In this study we examine the multifocal electroretinogram (mfERG) recorded from patients suffering from Leber's hereditary optic neuropathy (LHON), a degeneration of the ganglion cell and nerve fibre layers of the retina. We compared the mfERGs recorded from 11 patients with LHON, to those from 11 control subjects. The pattern ERG (PERG) was additionally performed with 9 of the patients. MfERGs were recorded and analysed using the VERIS 3.01 system with a stimulus of 103 equal-sized hexagons. For analysis, hexagons were grouped according to distance from the optic nerve head (ONH) and according to distance from the fovea. Two significant differences were found between the waveforms of the two groups: In the first order kernel, the control group showed a component around 34 ms that decreased with distance from the ONH. This component was reduced in the LHON group of subjects. In the second order (first slice) kernel, the patient group was missing features that decrease with distance from the fovea in the control group. PERG amplitudes showed a significant correlation with the amplitude of the second order mfERG kernel. The results show that the damage to ganglion cells and nerve fibres caused by LHON can be detected in mfERG recordings and indicate that activity from the inner retina can contribute significantly to first and second order waveforms.
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Affiliation(s)
- Anne Kurtenbach
- Department of Pathophysiology of Vision and Neuro-ophthalmology, University Eye Hospital, Schleichstrasse 12-16, 72076 Tübingen, Germany.
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Parry A, Matthews PM. Roles for Imaging in Understanding the Pathophysiology, Clinical Evaluation, and Management of Patients with Mitochondrial Disease. J Neuroimaging 2003. [DOI: 10.1111/j.1552-6569.2003.tb00195.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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Filippi M, Rocca MA, Comi G. The use of quantitative magnetic-resonance-based techniques to monitor the evolution of multiple sclerosis. Lancet Neurol 2003; 2:337-46. [PMID: 12849150 DOI: 10.1016/s1474-4422(03)00408-3] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Conventional MRI can improve accuracy in the diagnosis of multiple sclerosis (MS) and monitor the efficacy of experimental treatments. However, conventional MRI provides only gross estimates of the extent and nature of tissue damage associated with this disease. Other quantitative magnetic-resonance-based techniques have the potential to overcome the limitations of conventional MRI and, as a consequence, to improve our understanding of the natural history of MS. Magnetisation-transfer, diffusion-weighted, and functional MRI--as well as proton magnetic-resonance spectroscopy--are helping us to elucidate the mechanisms that underlie injury, repair, and functional adaptation in patients with MS. These techniques are substantially changing our understanding of how MS causes irreversible disability and should be used more extensively in clinical trials and in studies of disease progression.
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Affiliation(s)
- Massimo Filippi
- Department of Neurology, Scientific Institute and University Ospedale San Raffaele, Milan, Italy.
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Horsfield MA, Barker GJ, Barkhof F, Miller DH, Thompson AJ, Filippi M. Guidelines for using quantitative magnetization transfer magnetic resonance imaging for monitoring treatment of multiple sclerosis. J Magn Reson Imaging 2003; 17:389-97. [PMID: 12655577 DOI: 10.1002/jmri.10266] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Quantitative evaluation of brain magnetic resonance imaging (MRI) scans is now an accepted part of the trial of new putative treatments for multiple sclerosis (MS). However, conventional MRI is not pathologically specific, and it does not reveal the details of the pathological processes that underlie the progression of the disease. Magnetization transfer (MT) imaging is a relatively new quantitative technique that appears to offer some pathological specificity, and can be used to monitor the changes over time in both individual lesions and the central nervous system as a whole. This paper considers the case for incorporating MT imaging into new clinical trials, so that the utility of MT for monitoring the modification of MS progression by treatment can be assessed. Specific guidelines for implementing MT imaging as part of a large multicenter clinical trial are given, and practical considerations when planning such a trial are detailed. It is anticipated that MT imaging will be incorporated into many new trials in the near future.
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Affiliation(s)
- Mark A Horsfield
- Division of Medical Physics, University of Leicester, Leicester Royal Infirmary, Leicester, UK.
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Inglese M, DeStefano N, Pagani E, Dotti MT, Comi G, Federico A, Filippi M. Quantification of brain damage in cerebrotendinous xanthomatosis with magnetization transfer MR imaging. AJNR Am J Neuroradiol 2003; 24:495-500. [PMID: 12637303 PMCID: PMC7973612] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2002] [Accepted: 08/27/2002] [Indexed: 03/01/2023]
Abstract
BACKGROUND AND PURPOSE Conventional MR imaging for quantification of brain damage in monitoring the evolution of cerebrotendinous xanthomatosis (CTX) has limitations. Magnetization transfer (MT) MR imaging is overcoming these limitations. Using MT MR imaging, we sought to quantify, in vivo, the extent of brain and cerebellar damage in patients with CTX, with the ulimate goal to investigate the magnitude of the correlation between MT MR imaging findings and clinical disability. METHODS Conventional and MT MR images of the brain were obtained in nine patients with CTX and in 10 sex- and age-matched healthy volunteers. MT ratio histograms were derived of the whole brain, brain normal-appearing white matter (NAWM), brain normal-appearing gray matter (NAGM), cerebellar NAWM, and cerebellar NAGM. Clinical disability was measured by using the Expanded Disability Status Scale (EDSS). RESULTS Average MT ratio and peak heights of the whole brain, brain NAWM, and brain NAGM histograms in patients with CTX were significantly lower than the corresponding quantities in the control subjects. All cerebellar NAGM MT ratio histogram-derived metrics and average MT ratio of the cerebellar NAWM histogram in patients with CTX were also significantly lower than the corresponding quantities in the control subjects. Strong correlations were found between the EDSS score and a composite whole-brain MT ratio histogram score (r = 0.77, P <.01) and a composite brain white matter MT ratio histogram score (r = 0.71, P <.03). A strong correlation was also found between the cerebellar functional system score and a composite cerebellar NAWM score (r = 0.72, P <.02). CONCLUSION The quantitative assessment of brain damage in patients with CTX with use of MT MR imaging can provide powerful measures of disease outcome.
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Affiliation(s)
- Matilde Inglese
- Neuroimaging Research Unit, Department of Neuroscience, Milan, Italy
| | - Nicola DeStefano
- Neurometabolic Unit, Institute of Neurological Sciences, University of Siena, Siena, Italy
| | - Elisabetta Pagani
- Neuroimaging Research Unit, Department of Neuroscience, Milan, Italy
| | - Maria T. Dotti
- Neurometabolic Unit, Institute of Neurological Sciences, University of Siena, Siena, Italy
| | - Giancarlo Comi
- Department of Neurology, Scientific Institute and University Ospedale San Raffaele, Milan, Italy
| | - Antonio Federico
- Neurometabolic Unit, Institute of Neurological Sciences, University of Siena, Siena, Italy
| | - Massimo Filippi
- Neuroimaging Research Unit, Department of Neuroscience, Milan, Italy
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Abstract
The present review summarizes the major contributions given by magnetization transfer-magnetic resonance imaging to provide an accurate in vivo picture of the heterogeneity of central nervous system pathology and, ultimately, to improve our ability to monitor the evolution of various neurological conditions.
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Affiliation(s)
- M Filippi
- Department of Neuroscience, Scientific Institute and University Ospedale San Raffaele, Milan, Italy.
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Sadun AA, Carelli V, Bose S, Ross-Cisneros FN, Barboni P, Ahrens ET. First application of extremely high-resolution magnetic resonance imaging to study microscopic features of normal and LHON human optic nerve. Ophthalmology 2002; 109:1085-91. [PMID: 12045048 DOI: 10.1016/s0161-6420(02)01027-8] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
PURPOSE To apply new methods in magnetic resonance imaging (MRI) in resolving the histoarchitecture of the human optic nerve obtained from normal individuals and a Leber's hereditary optic neuropathy (LHON) case. DESIGN Small case series--clinicopathologic correlation. METHOD Three optic nerves were obtained from two normal subjects, aged 69 and 70, and a LHON/3460 patient, aged 75. The posterior pole of the eye with attached optic nerves was fixed in buffered paraformaldehyde and placed into a 10-mm quartz tube. Images were acquired in a Bruker AMX500 12 Tesla microimaging system. The three-dimensional data were acquired with 512 x 256 x 256 points, yielding a final isotopic resolution of 30 microm. RESULTS The sclera, choroids, and retina were easily distinguished. The nerve fiber layer was seen to enter the optic disc and traverse the lamina cribrosa (LC). The resolution of the image of the optic nerve head was such that the LC was visualized as multiple stacked plates. The fibers emerged from glial columns in the LC as distinct fascicles and could be made out to change appearance as they became myelinated and expanded in the more posterior nerve. The ophthalmic artery and vein were visualized, as were the optic nerve arachnoid and dural sheaths. In the Leber's case, the LC plates seemed collapsed or compressed. The axonal bundles were atrophic and the pial-collagen septae markedly thickened. The entire nerve had shrunk, creating space under the arachnoid, down and around the central ophthalmic artery and vein. CONCLUSIONS These results demonstrate the feasibility of using extremely high-resolution magnetic resonance imaging (microMRI) to examine the three-dimensional (30 microm) images of the human optic nerve. Several atrophic lesions, normally visible only by histopathologic examination, were visualized in the Leber's optic nerve. microMRI may eventually permit the in vivo visualization of lesions in or about the optic nerve.
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Affiliation(s)
- Alfredo A Sadun
- Department of Ophthalmology, Doheny Eye Institute, Keck/USC School of Medicine, Los Angeles, California 90033, USA
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Filippi M, Grossman RI. MRI techniques to monitor MS evolution: the present and the future. Neurology 2002; 58:1147-53. [PMID: 11971079 DOI: 10.1212/wnl.58.8.1147] [Citation(s) in RCA: 95] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Conventional MRI (cMRI) is limited in its ability to provide specific information about pathology in MS. Measures commonly derived from cMRI include T2 lesions, T1-enhanced lesions, atrophy, and possibly T1-hypointense lesions, which have been extensively investigated in many clinical trials. Better MRI measures are needed to advance our understanding of MS and design ideal clinical trials. This article reviews the strengths and weaknesses of the major MRI-based methods used to monitor MS evolution and submits that 1) metrics derived from magnetization transfer MRI, diffusion-weighted MRI, and proton MRS should be implemented to achieve reliable specific in vivo quantification of MS pathology; 2) targeted multiparametric MRI protocols rather than generic application of cMRI should be used in all possible clinical circumstances and trials; and 3) reproducible quantitative MR measures should ideally be used for the assessment of patients but are essential for clinical trials.
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Affiliation(s)
- Massimo Filippi
- Neuroimaging Research Unit, Department of Neuroscience, Scientific Institute and University Ospedale San Raffaele, Milan, Italy.
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Rovaris M, Holtmannspötter M, Rocca MA, Iannucci G, Codella M, Viti B, Campi A, Comi G, Yousry TA, Filippi M. Contribution of cervical cord MRI and brain magnetization transfer imaging to the assessment of individual patients with multiple sclerosis: a preliminary study. Mult Scler 2002; 8:52-8. [PMID: 11936489 DOI: 10.1191/1352458502ms772oa] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
This study was performed to assess how established diagnostic criteria for brain magnetic resonance imaging (MRI) interpretation in cases of suspected multiple sclerosis (MS) (Barkhofs criteria) would perform in the distinction of MS from other diseases and whether other MR techniques (cervical cord imaging and brain magnetization transfer imaging [MTI]), might help in the diagnostic work-up of these patients. We retrospectively identified 64 MS and 59 non-MS patients. The latter group included patients with systemic immune-mediated disorders (SID; n=44) and migraine (n=15). All patients had undergone MRI scans of the brain (dual echo and MTI) and of the cervical cord (fast short-tau inversion recovery). The number and location of brain T2-hyperintense lesions and the number and size of cervical cord lesions were assessed. Brain images were also postprocessed to quantify the total lesion volumes (TLV) and to create histograms of magnetization transfer ratio (MTR) values from the whole of the brain tissue. Barkhofs criteria correctly classified 108/123 patients, thus showing an accuracy of 87.8%. "False negative" MS patients were 13, while 2 patients with systemic lupus erythematosus (SLE) were considered as "false positives". Using brain T2 TLV, nine of the "false negative" patients were correctly classified. Correct classification of 10 MS patients and both the SLE patients was possible based upon the presence or absence of one cervical cord lesion. Two MS patients with negative Barkhofs criteria and no cervical cord lesions were correctly classified based on their brain MTR values. Overall, only one MS patient could not be correctly classified by any of the assessed MR quantities. These preliminary data support a more extensive use of cervical cord MRI and brain MTI to differentiate between MS and other disorders in case of incondusive findings on T2-weighted MRI scans of the brain.
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Affiliation(s)
- M Rovaris
- Neuroimaging Research Unit, Scientific Institute and University H San Raffaele, Milan, Italy
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Rovaris M, Comi G, Filippi M. The role of non-conventional MR techniques to study multiple sclerosis patients. J Neurol Sci 2001; 186 Suppl 1:S3-9. [PMID: 11334984 DOI: 10.1016/s0022-510x(01)00485-3] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Conventional magnetic resonance imaging (MRI) lacks pathological specificity to the heterogeneous substrates of multiple sclerosis (MS) lesions and is not able to detect subtle, disease-related changes in the normal-appearing white matter (NAWM). As a consequence, the correlation between MRI findings and the long-term evolution of MS is moderate at best. To overcome the limitations of conventional MRI, new quantitative magnetic resonance (MR) techniques, such as cell-specific imaging, magnetization transfer imaging (MTI), proton magnetic resonance spectroscopy (MRS), diffusion-weighted imaging (DWI) and functional MR imaging (fMRI) have all been recently applied to the study of MS. These techniques should provide more accurate and pathologically specific estimates of the MS lesion burden than conventional MR and should improve our understanding of the mechanisms leading to MS-related irreversible disability.
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Affiliation(s)
- M Rovaris
- Neuroimaging Research Unit, Department of Neuroscience, Scientific Institute and University Ospedale San Raffaele, via Olgettina 60, 20132 Milan, Italy
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Filippi M, Inglese M. Overview of diffusion-weighted magnetic resonance studies in multiple sclerosis. J Neurol Sci 2001; 186 Suppl 1:S37-43. [PMID: 11334988 DOI: 10.1016/s0022-510x(01)00489-0] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Diffusion-weighted magnetic resonance imaging (DW-MRI) provides a unique form of MR contrast that enables the diffusional motion of water molecules to be quantitatively measured. As a consequence, DW-MRI provides information about the size, shape, integrity, and orientation of brain structures. Pathological processes able to alter tissue integrity by removing or modifying some of the structural barriers that normally restrict water molecular motion in biological tissues cause changes in water diffusion characteristics, which can be measured in-vivo using DW-MRI. Although DW-MRI has been shown to be of great clinical utility in the assessment of patients with cerebral ischemia, it is also increasingly being used to quantify in-vivo the extent and severity of multiple sclerosis (MS) pathology. The pathological elements of MS have the potential to alter the permeability or geometry of structural barriers to water molecular motion in the brain, optic nerve and spinal cord. The present review outlines the major contributions given by DW-MRI for the quantification of MS-related damage and for the understanding of MS pathophysiology.
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Affiliation(s)
- M Filippi
- Neuroimaging Research Unit, Department of Neuroscience, Scientific Institute and University Ospedale San Raffaele, Via Olgettina, 60, 20132 Milan, Italy.
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