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Pierzchala K, Hadjihambi A, Mosso J, Jalan R, Rose CF, Cudalbu C. Lessons on brain edema in HE: from cellular to animal models and clinical studies. Metab Brain Dis 2024; 39:403-437. [PMID: 37606786 PMCID: PMC10957693 DOI: 10.1007/s11011-023-01269-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/09/2023] [Accepted: 07/24/2023] [Indexed: 08/23/2023]
Abstract
Brain edema is considered as a common feature associated with hepatic encephalopathy (HE). However, its central role as cause or consequence of HE and its implication in the development of the neurological alterations linked to HE are still under debate. It is now well accepted that type A and type C HE are biologically and clinically different, leading to different manifestations of brain edema. As a result, the findings on brain edema/swelling in type C HE are variable and sometimes controversial. In the light of the changing natural history of liver disease, better description of the clinical trajectory of cirrhosis and understanding of molecular mechanisms of HE, and the role of brain edema as a central component in the pathogenesis of HE is revisited in the current review. Furthermore, this review highlights the main techniques to measure brain edema and their advantages/disadvantages together with an in-depth description of the main ex-vivo/in-vivo findings using cell cultures, animal models and humans with HE. These findings are instrumental in elucidating the role of brain edema in HE and also in designing new multimodal studies by performing in-vivo combined with ex-vivo experiments for a better characterization of brain edema longitudinally and of its role in HE, especially in type C HE where water content changes are small.
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Affiliation(s)
- Katarzyna Pierzchala
- CIBM Center for Biomedical Imaging, Lausanne, Switzerland.
- Animal Imaging and Technology, EPFL, Lausanne, Switzerland.
| | - Anna Hadjihambi
- The Roger Williams Institute of Hepatology London, Foundation for Liver Research, London, SE5 9NT, UK
- Faculty of Life Sciences and Medicine, King's College London, London, UK
| | - Jessie Mosso
- CIBM Center for Biomedical Imaging, Lausanne, Switzerland
- Animal Imaging and Technology, EPFL, Lausanne, Switzerland
- Laboratory for Functional and Metabolic Imaging (LIFMET), EPFL, Lausanne, Switzerland
| | - Rajiv Jalan
- Liver Failure Group, Institute for Liver and Digestive Health, University College London, Royal Free Campus, London, UK
- European Foundation for the Study of Chronic Liver Failure (EF Clif), Barcelona, Spain
| | - Christopher F Rose
- Hépato-Neuro Laboratory, Centre de Recherche du Centre Hospitalier de l', Université de Montréal (CRCHUM), Montreal, QC, H2X 0A9, Canada
- Department of Medicine, Faculty of Medicine, Université de Montréal, QC, Montreal, H3T 1J4, Canada
| | - Cristina Cudalbu
- CIBM Center for Biomedical Imaging, Lausanne, Switzerland.
- Animal Imaging and Technology, EPFL, Lausanne, Switzerland.
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2
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Gogishvili A, Farrher E, Doppler CEJ, Seger A, Sommerauer M, Shah NJ. Quantification of the neurochemical profile of the human putamen using STEAM MRS in a cohort of elderly subjects at 3 T and 7 T: Ruminations on the correction strategy for the tissue voxel composition. PLoS One 2023; 18:e0286633. [PMID: 37267283 DOI: 10.1371/journal.pone.0286633] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2022] [Accepted: 05/19/2023] [Indexed: 06/04/2023] Open
Abstract
The aim of this work is to quantify the metabolic profile of the human putamen in vivo in a cohort of elderly subjects using single-voxel proton magnetic resonance spectroscopy. To obtain metabolite concentrations specific to the putamen, we investigated a correction method previously proposed to account for the tissue composition of the volume of interest. We compared the method with the conventional approach, which a priori assumes equal metabolite concentrations in GM and WM. Finally, we compared the concentrations acquired at 3 Tesla (T) and 7 T MRI scanners. Spectra were acquired from 15 subjects (age: 67.7 ± 8.3 years) at 3 T and 7 T, using an ultra-short echo time, stimulated echo acquisition mode sequence. To robustly estimate the WM-to-GM metabolite concentration ratio, five additional subjects were measured for whom the MRS voxel was deliberately shifted from the putamen in order to increase the covered amount of surrounding WM. The concentration and WM-to-GM concentration ratio for 16 metabolites were reliably estimated. These ratios ranged from ~0.3 for γ-aminobutyric acid to ~4 for N-acetylaspartylglutamate. The investigated correction method led to significant changes in concentrations compared to the conventional method, provided that the ratio significantly differed from unity. Finally, we demonstrated that differences in tissue voxel composition cannot fully account for the observed concentration difference between field strengths. We provide not only a fully comprehensive quantification of the neurochemical profile of the putamen in elderly subjects, but also a quantification of the WM-to-GM concentration ratio. This knowledge may serve as a basis for future studies with varying tissue voxel composition, either due to tissue atrophy, inconsistent voxel positioning or simply when pooling data from different voxel locations.
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Affiliation(s)
- Ana Gogishvili
- Institute of Neuroscience and Medicine 4, INM-4, Forschungszentrum Jülich, Jülich, Germany
- Faculty of Medicine, RWTH Aachen University, Aachen, Germany
- Engineering Physics Department, Georgian Technical University, Tbilisi, Georgia
| | - Ezequiel Farrher
- Institute of Neuroscience and Medicine 4, INM-4, Forschungszentrum Jülich, Jülich, Germany
| | - Christopher E J Doppler
- Cognitive Neuroscience, Institute of Neuroscience and Medicine 3, INM-3, Forschungszentrum Jülich, Jülich, Germany
- Department of Neurology, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany
| | - Aline Seger
- Cognitive Neuroscience, Institute of Neuroscience and Medicine 3, INM-3, Forschungszentrum Jülich, Jülich, Germany
- Department of Neurology, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany
| | - Michael Sommerauer
- Cognitive Neuroscience, Institute of Neuroscience and Medicine 3, INM-3, Forschungszentrum Jülich, Jülich, Germany
- Department of Neurology, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany
| | - N Jon Shah
- Institute of Neuroscience and Medicine 4, INM-4, Forschungszentrum Jülich, Jülich, Germany
- Institute of Neuroscience and Medicine 11, INM-11, JARA, Forschungszentrum Jülich, Jülich, Germany
- JARA - BRAIN - Translational Medicine, Aachen, Germany
- Department of Neurology, RWTH Aachen University, Aachen, Germany
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3
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Zöllner HJ, Thiel TA, Füllenbach ND, Jördens MS, Ahn S, Wilms LM, Ljimani A, Häussinger D, Butz M, Wittsack HJ, Schnitzler A, Oeltzschner G. J-difference GABA-edited MRS reveals altered cerebello-thalamo-cortical metabolism in patients with hepatic encephalopathy. Metab Brain Dis 2023; 38:1221-1238. [PMID: 36729261 PMCID: PMC10897767 DOI: 10.1007/s11011-023-01174-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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Accepted: 01/17/2023] [Indexed: 02/03/2023]
Abstract
Hepatic encephalopathy (HE) is a common neurological manifestation of liver cirrhosis and is characterized by an increase of ammonia in the brain accompanied by a disrupted neurotransmitter balance, including the GABAergic and glutamatergic systems. The aim of this study is to investigate metabolic abnormalities in the cerebello-thalamo-cortical system of HE patients using GABA-edited MRS and links between metabolite levels, disease severity, critical flicker frequency (CFF), motor performance scores, and blood ammonia levels. GABA-edited MRS was performed in 35 participants (16 controls, 19 HE patients) on a clinical 3 T MRI system. MRS voxels were placed in the right cerebellum, left thalamus, and left motor cortex. Levels of GABA+ and of other metabolites of interest (glutamine, glutamate, myo-inositol, glutathione, total choline, total NAA, and total creatine) were assessed. Group differences in metabolite levels and associations with clinical metrics were tested. GABA+ levels were significantly increased in the cerebellum of patients with HE. GABA+ levels in the motor cortex were significantly decreased in HE patients, and correlated with the CFF (r = 0.73; p < .05) and motor performance scores (r = -0.65; p < .05). Well-established HE-typical metabolite patterns (increased glutamine, decreased myo-inositol and total choline) were confirmed in all three regions and were closely linked to clinical metrics. In summary, our findings provide further evidence for alterations in the GABAergic system in the cerebellum and motor cortex in HE. These changes were accompanied by characteristic patterns of osmolytes and oxidative stress markers in the cerebello-thalamo-cortical system. These metabolic disturbances are a likely contributor to HE motor symptoms in HE. In patients with hepatic encephalopathy, GABA+ levels in the cerebello-thalamo-cortical loop are significantly increased in the cerebellum and significantly decreased in the motor cortex. GABA+ levels in the motor cortex strongly correlate with critical flicker frequency (CFF) and motor performance score (pegboard test tPEG), but not blood ammonia levels (NH3).
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Affiliation(s)
- Helge Jörn Zöllner
- Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD, USA.
- F. M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, USA.
- Institute of Clinical Neuroscience and Medical Psychology, Medical Faculty, Heinrich-Heine-University Düsseldorf, Düsseldorf, Germany.
- Department of Diagnostic and Interventional Radiology, Medical Faculty, Heinrich-Heine-University Düsseldorf, Düsseldorf, Germany.
| | - Thomas A Thiel
- Institute of Clinical Neuroscience and Medical Psychology, Medical Faculty, Heinrich-Heine-University Düsseldorf, Düsseldorf, Germany
- Department of Diagnostic and Interventional Radiology, Medical Faculty, Heinrich-Heine-University Düsseldorf, Düsseldorf, Germany
| | - Nur-Deniz Füllenbach
- Department of Gastroenterology, Hepatology and Infectiology, Medical Faculty, Heinrich-Heine-University Düsseldorf, Düsseldorf, Germany
| | - Markus S Jördens
- Department of Gastroenterology, Hepatology and Infectiology, Medical Faculty, Heinrich-Heine-University Düsseldorf, Düsseldorf, Germany
| | | | - Lena M Wilms
- Department of Diagnostic and Interventional Radiology, Medical Faculty, Heinrich-Heine-University Düsseldorf, Düsseldorf, Germany
| | - Alexandra Ljimani
- Department of Diagnostic and Interventional Radiology, Medical Faculty, Heinrich-Heine-University Düsseldorf, Düsseldorf, Germany
| | - Dieter Häussinger
- Department of Gastroenterology, Hepatology and Infectiology, Medical Faculty, Heinrich-Heine-University Düsseldorf, Düsseldorf, Germany
| | - Markus Butz
- Institute of Clinical Neuroscience and Medical Psychology, Medical Faculty, Heinrich-Heine-University Düsseldorf, Düsseldorf, Germany
| | - Hans-Jörg Wittsack
- Department of Diagnostic and Interventional Radiology, Medical Faculty, Heinrich-Heine-University Düsseldorf, Düsseldorf, Germany
| | - Alfons Schnitzler
- Institute of Clinical Neuroscience and Medical Psychology, Medical Faculty, Heinrich-Heine-University Düsseldorf, Düsseldorf, Germany
| | - Georg Oeltzschner
- Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
- F. M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, USA
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4
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C Thomas D, Oros-Peusquens AM, Poot D, Shah NJ. Whole-Brain Water Content Mapping Using Super-Resolution Reconstruction with MRI Acquisition in 3 Orthogonal Orientations. Magn Reson Med 2022; 88:2117-2130. [PMID: 35861258 DOI: 10.1002/mrm.29377] [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: 09/20/2021] [Revised: 06/13/2022] [Accepted: 06/13/2022] [Indexed: 11/11/2022]
Abstract
PURPOSE Brain water content provides rich tissue contrast comparable to that of longitudinal relaxation time T1 , but mapping is usually performed at modest resolution. In particular, the slice thickness in 2D mapping methods is limited. Here, we combine super-resolution reconstruction techniques with a fast water content mapping method to acquire high and isotropic resolution (0.75 mm) water content maps at 3 Tesla. METHODS A high-resolution multi-echo gradient echo image is super-resolution-reconstructed from 3 low-resolution, orthogonal multi-echo gradient echo image acquisitions, followed by water content mapping. The mapping accuracy and SNR of the proposed method are assessed using numerical simulations, phantom studies, and in vivo data acquired from 6 healthy volunteers at 3 Tesla. A high-resolution acquisition with an established mapping method is used as a reference. RESULTS Whole-brain water content maps with 0.75 mm isotropic resolution are demonstrated. No bias in the water content values was seen following super-resolution reconstruction. In the in vivo experiments, a lower SD of the mean water content values was observed with the proposed method compared to the reference method. CONCLUSIONS Super-resolution reconstruction of multi-echo gradient echo data is demonstrated, enabling whole-brain water content mapping with high and isotropic resolution. The accuracy of the proposed method is shown using phantoms and 6 healthy volunteers and was found to be unchanged compared to the conventional acquisition. The proposed method could increase the sensitivity of water content mapping sufficiently to enable the detection of very small lesions, such as cortical lesions in multiple sclerosis.
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Affiliation(s)
- Dennis C Thomas
- Institute of Neuroscience and Medicine 4, Jülich, Germany.,Faculty of Medicine, RWTH Aachen University, Aachen, Germany
| | | | - Dirk Poot
- Department of Radiology and Nuclear medicine, Erasmus Medical Centre, Rotterdam, The Netherlands
| | - N Jon Shah
- Institute of Neuroscience and Medicine 4, Jülich, Germany.,Institute of Neuroscience and Medicine 11, INM-11, JARA, Jülich, Germany.,JARA - BRAIN - Translational Medicine, Aachen, Germany.,Department of Neurology, RWTH Aachen University, Aachen, Germany
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5
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Oliveira MM, Monnet-Aimard A, Bosoi CR, Tremblay M, Rose CF. Sex is associated with differences in oxidative stress and susceptibility to severe hepatic encephalopathy in bile-duct ligated rats. J Neurochem 2022; 162:337-351. [PMID: 35771118 DOI: 10.1111/jnc.15661] [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: 01/18/2022] [Revised: 06/23/2022] [Accepted: 06/26/2022] [Indexed: 11/29/2022]
Abstract
Hepatic encephalopathy (HE) is a debilitating neurological complication of chronic liver disease (CLD). Hyperammonemia plays an important role in HE's pathogenesis, acting synergistically with systemic oxidative stress. During CLD, muscle plays a compensatory role in detoxifying ammonia, and therefore muscle loss leads to an increase in the risk of developing HE. With most animal studies involving males, sex's impact on the development of CLD and associated complications such as HE and muscle loss remains unknown. Therefore, we aimed to identify the impact of sex on CLD, HE, and muscle mass loss in a rodent model of CLD. Liver injury markers, hyperammonemia, oxidative stress, muscle mass and ammonia clearance were measured in female and male bile-duct ligated (BDL) rats. In addition, covert HE was assessed in females while ammonia-precipitated severe HE was assessed in female and male BDL rats, and male BDL rats treated with allopurinol (100mg/kg), an antioxidant (xanthine oxidase inhibitor). Female BDL developed CLD and HE (impaired motor-coordination and night activity) compared to respective SHAM. Hyperammonemia and muscle ammonia clearance were similar between female and male BDL. However, only female BDL rats did not develop muscle loss, brain edema, and short-term memory impairment (vs. female SHAM) and systemic oxidative stress and decreased albumin levels (vs. male BDL). Furthermore, both female BDL and allopurinol-treated male BDL rats were protected against ammonia-induced overt HE. In conclusion, female and male BDL rats develop distinct features of CLD and HE, with systemic oxidative stress playing a pivotal role in the susceptibility to ammonia precipitated overt HE.
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Affiliation(s)
- Mariana M Oliveira
- Hepato-Neuro Laboratory, CRCHUM, Université de Montréal, Montreal, Canada
| | - Alexis Monnet-Aimard
- Institut de Neurosciences de la Timone, Équipe inVibe, Université Aix-Marseille, France
| | - Cristina R Bosoi
- Hepato-Neuro Laboratory, CRCHUM, Université de Montréal, Montreal, Canada
| | - Mélanie Tremblay
- Hepato-Neuro Laboratory, CRCHUM, Université de Montréal, Montreal, Canada
| | - Christopher F Rose
- Hepato-Neuro Laboratory, CRCHUM, Université de Montréal, Montreal, Canada
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6
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Häussinger D, Dhiman RK, Felipo V, Görg B, Jalan R, Kircheis G, Merli M, Montagnese S, Romero-Gomez M, Schnitzler A, Taylor-Robinson SD, Vilstrup H. Hepatic encephalopathy. Nat Rev Dis Primers 2022; 8:43. [PMID: 35739133 DOI: 10.1038/s41572-022-00366-6] [Citation(s) in RCA: 55] [Impact Index Per Article: 27.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 05/12/2022] [Indexed: 01/18/2023]
Abstract
Hepatic encephalopathy (HE) is a prognostically relevant neuropsychiatric syndrome that occurs in the course of acute or chronic liver disease. Besides ascites and variceal bleeding, it is the most serious complication of decompensated liver cirrhosis. Ammonia and inflammation are major triggers for the appearance of HE, which in patients with liver cirrhosis involves pathophysiologically low-grade cerebral oedema with oxidative/nitrosative stress, inflammation and disturbances of oscillatory networks in the brain. Severity classification and diagnostic approaches regarding mild forms of HE are still a matter of debate. Current medical treatment predominantly involves lactulose and rifaximin following rigorous treatment of so-called known HE precipitating factors. New treatments based on an improved pathophysiological understanding are emerging.
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Affiliation(s)
- Dieter Häussinger
- Department of Gastroenterology, Hepatology and Infectious Diseases, Medical Faculty and University Hospital Düsseldorf, Heinrich Heine University Düsseldorf, Düsseldorf, Germany.
| | - Radha K Dhiman
- Department of Hepatology, Sanjay Gandhi Postgraduate Institute of Medical Sciences, Lucknow, (Uttar Pradesh), India
| | - Vicente Felipo
- Laboratory of Neurobiology, Centro de Investigación Principe Felipe, Valencia, Spain
| | - Boris Görg
- Department of Gastroenterology, Hepatology and Infectious Diseases, Medical Faculty and University Hospital Düsseldorf, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Rajiv Jalan
- Liver Failure Group ILDH, Division of Medicine, UCL Medical School, Royal Free Campus, London, UK.,European Foundation for the Study of Chronic Liver Failure, Barcelona, Spain
| | - Gerald Kircheis
- Department of Gastroenterology, Diabetology and Hepatology, University Hospital Brandenburg an der Havel, Brandenburg Medical School, Brandenburg an der Havel, Germany
| | - Manuela Merli
- Department of Translational and Precision Medicine, Universita' degli Studi di Roma - Sapienza, Roma, Italy
| | | | - Manuel Romero-Gomez
- UCM Digestive Diseases, Virgen del Rocío University Hospital, Institute of Biomedicine of Seville (HUVR/CSIC/US), University of Seville, Seville, Spain
| | - Alfons Schnitzler
- Institute of Clinical Neuroscience and Medical Psychology, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Simon D Taylor-Robinson
- Department of Surgery and Cancer, St. Mary's Hospital Campus, Imperial College London, London, UK
| | - Hendrik Vilstrup
- Department of Hepatology and Gastroenterology, Aarhus University Hospital, Aarhus, Denmark
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7
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Repeated Sub-Concussive Impacts and the Negative Effects of Contact Sports on Cognition and Brain Integrity. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2022; 19:ijerph19127098. [PMID: 35742344 PMCID: PMC9222631 DOI: 10.3390/ijerph19127098] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 01/23/2022] [Revised: 05/29/2022] [Accepted: 06/06/2022] [Indexed: 11/29/2022]
Abstract
Sports are yielding a wealth of benefits for cardiovascular fitness, for psychological resilience, and for cognition. The amount of practice, and the type of practiced sports, are of importance to obtain these benefits and avoid any side effects. This is especially important in the context of contact sports. Contact sports are not only known to be a major source of injuries of the musculoskeletal apparatus, they are also significantly related to concussion and sub-concussion. Sub-concussive head impacts accumulate throughout the active sports career, and thus can cause measurable deficits and changes to brain health. Emerging research in the area of cumulative sub-concussions in contact sports has revealed several associated markers of brain injury. For example, recent studies discovered that repeated headers in soccer not only cause measurable signs of cognitive impairment but are also related to a prolonged cortical silent period in transcranial magnetic stimulation measurements. Other cognitive and neuroimaging biomarkers are also pointing to adverse effects of heading. A range of fluid biomarkers completes the picture of cumulating effects of sub-concussive impacts. Those accumulating effects can cause significant cognitive impairment later in life of active contact sportswomen and men. The aim of this review is to highlight the current scientific evidence on the effects of repeated sub-concussive head impacts on contact sports athletes’ brains, identify the areas in need of further investigation, highlight the potential of advanced neuroscientific methods, and comment on the steps governing bodies have made to address this issue. We conclude that there are indeed neural and biofluid markers that can help better understand the effects of repeated sub-concussive head impacts and that some aspects of contact sports should be redefined, especially in situations where sub-concussive impacts and concussions can be minimized.
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8
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Shah NJ, Abbas Z, Ridder D, Zimmermann M, Oros-Peusquens AM. A Novel MRI-Based Quantitative Water Content Atlas of the Human Brain. Neuroimage 2022; 252:119014. [PMID: 35202813 DOI: 10.1016/j.neuroimage.2022.119014] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Revised: 02/08/2022] [Accepted: 02/17/2022] [Indexed: 11/19/2022] Open
Abstract
The measurement of quantitative, tissue-specific MR properties, e.g., water content, longitudinal relaxation time (T1) and effective transverse relaxation time (T2*), using quantitative MRI at a clinical field strength (1.5 T to 3T) is a well-explored topic. However, none of the commonly used standard brain atlases, such as MNI or JHU, provide quantitative information. Within the framework of quantitative MRI of the brain, this work reports on the development of the first quantitative brain atlas for tissue water content at 3T. A methodology to create this quantitative atlas of in vivo brain water content based on healthy volunteers is presented, and preliminary, practical examples of its potential applications are also shown. Established methods for the fast and reliable measurement of the absolute water content were used to achieve high precision and accuracy. Water content and T2* were mapped based on two different methods: an intermediate-TR, two-point method and a long-TR, single-scan method. Twenty healthy subjects (age 25.3 ± 2.5 years) were examined with these quantitative imaging protocols. The images were normalised to MNI stereotactic coordinates, and water content atlases of healthy volunteers were created for each method and compared. Regions-of-interest were generated with the help of a standard MNI template, and water content values averaged across the ROIs were compared to water content values from the literature. Finally, in order to demonstrate the strength of quantitative MRI, water content maps from patients with pathological changes in the brain due to stroke, tumour (glioblastoma) and multiple sclerosis were voxel-wise compared to the healthy brain. The water content atlases were largely independent of the method used to acquire the individual water maps. Global grey matter and white matter water content values between the methods agreed with each other to within 0.5 %. The feasibility of detecting abnormal water content in the brains of patients based on comparison to a healthy brain water content atlas was demonstrated. In summary, the first quantitative water content brain atlas in vivo has been developed and a voxel-wise assessment of pathology-related changes in the brain water content has been performed. These results suggest that qMRI, in combination with a water content atlas, allows for a quantitative interpretation of changes due to disease and could be used for disease monitoring.
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Affiliation(s)
- N Jon Shah
- Institute of Neuroscience and Medicine - 4, Forschungszentrum Juelich GmbH, Juelich, Germany; Institute of Neuroscience and Medicine - 11, Forschungszentrum Juelich GmbH, Juelich, Germany; Department of Neurology, Faculty of Medicine, RWTH Aachen University, Aachen, Germany; JARA - BRAIN - Translational Medicine, RWTH Aachen University, Aachen, Germany.
| | - Zaheer Abbas
- Institute of Neuroscience and Medicine - 4, Forschungszentrum Juelich GmbH, Juelich, Germany; Department of Neurology, Faculty of Medicine, RWTH Aachen University, Aachen, Germany
| | - Dominik Ridder
- Institute of Neuroscience and Medicine - 4, Forschungszentrum Juelich GmbH, Juelich, Germany
| | - Markus Zimmermann
- Institute of Neuroscience and Medicine - 4, Forschungszentrum Juelich GmbH, Juelich, Germany
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9
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Gupta P, Vyas S, Salan T, Jain C, Taneja S, Dhiman RK, Singh P, Ahuja CK, Ray N, Govind V. Whole brain atlas-based diffusion kurtosis imaging parameters for evaluation of minimal hepatic encephalopathy. Neuroradiol J 2022; 35:67-76. [PMID: 34187242 PMCID: PMC8826285 DOI: 10.1177/19714009211026924] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
BACKGROUND AND PURPOSES Minimal hepatic encephalopathy (MHE) has no recognizable clinical symptoms, but patients have cognitive and psychomotor deficits. Hyperammonemia along with neuroinflammation lead to microstructural changes in cerebral parenchyma. Changes at conventional imaging are detected usually at the overt clinical stage, but microstructural alterations by advanced magnetic resonance imaging techniques can be detected at an early stage. MATERIALS AND METHODS Whole brain diffusion kurtosis imaging (DKI) data acquired at 3T was analyzed to investigate microstructural parenchymal changes in 15 patients with MHE and compared with 15 age- and sex-matched controls. DKI parametric maps, namely kurtosis fractional anisotropy (kFA), mean kurtosis (MK), axial kurtosis (AK) and radial kurtosis (RK), were evaluated at 64 white matter (WM) and gray matter (GM) regions of interest (ROIs) in the whole brain and correlated with the psychometric hepatic encephalopathy score (PHES). RESULTS The MHE group showed a decrease in kFA and AK across the whole brain, whereas MK and RK decreased in WM ROIs but increased in several cortical and deep GM ROIs. These alterations were consistent with brain regions involved in cognitive function. Significant moderate to strong correlations (-0.52 to -0.66; 0.56) between RK, MK and kFA kurtosis metrics and PHES were observed. CONCLUSION DKI parameters show extensive microstructural brain abnormalities in MHE with minor correlation between the severity of tissue damage and psychometric scores.
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Affiliation(s)
- Prateek Gupta
- Department of Radiodiagnosis and
Imaging, Postgraduate Institute of Medical Education and Research, Chandigarh,
India
| | - Sameer Vyas
- Department of Radiodiagnosis and
Imaging, Postgraduate Institute of Medical Education and Research, Chandigarh,
India,Sameer Vyas, Department of Radiodiagnosis
and Imaging, Postgraduate Institute of Medical Education and Research,
Chandigarh, India.
| | - Teddy Salan
- Department of Radiology, University
of Miami, USA
| | - Chirag Jain
- Department of Radiodiagnosis and
Imaging, Postgraduate Institute of Medical Education and Research, Chandigarh,
India
| | - Sunil Taneja
- Department of Hepatology,
Postgraduate Institute of Medical Education and Research, Chandigarh,
India
| | - RK Dhiman
- Department of Hepatology,
Postgraduate Institute of Medical Education and Research, Chandigarh,
India
| | - Paramjeet Singh
- Department of Radiodiagnosis and
Imaging, Postgraduate Institute of Medical Education and Research, Chandigarh,
India
| | - Chirag K Ahuja
- Department of Radiodiagnosis and
Imaging, Postgraduate Institute of Medical Education and Research, Chandigarh,
India
| | - Nirmalya Ray
- Department of Radiodiagnosis and
Imaging, Postgraduate Institute of Medical Education and Research, Chandigarh,
India
| | - Varan Govind
- Department of Radiology, University
of Miami, USA
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10
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Häussinger D, Butz M, Schnitzler A, Görg B. Pathomechanisms in hepatic encephalopathy. Biol Chem 2021; 402:1087-1102. [PMID: 34049427 DOI: 10.1515/hsz-2021-0168] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2021] [Accepted: 05/12/2021] [Indexed: 02/06/2023]
Abstract
Hepatic encephalopathy (HE) is a frequent neuropsychiatric complication in patients with acute or chronic liver failure. Symptoms of HE in particular include disturbances of sensory and motor functions and cognition. HE is triggered by heterogeneous factors such as ammonia being a main toxin, benzodiazepines, proinflammatory cytokines and hyponatremia. HE in patients with liver cirrhosis is triggered by a low-grade cerebral edema and cerebral oxidative/nitrosative stress which bring about a number of functionally relevant alterations including posttranslational protein modifications, oxidation of RNA, gene expression changes and senescence. These alterations are suggested to impair astrocyte/neuronal functions and communication. On the system level, a global slowing of oscillatory brain activity and networks can be observed paralleling behavioral perceptual and motor impairments. Moreover, these changes are related to increased cerebral ammonia, alterations in neurometabolite and neurotransmitter concentrations and cortical excitability in HE patients.
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Affiliation(s)
- Dieter Häussinger
- Clinic for Gastroenterology, Hepatology, and Infectious Diseases, Heinrich Heine University, Moorenstr. 5, D-40225 Düsseldorf, Germany
| | - Markus Butz
- Department of Neurology/Institute of Clinical Neuroscience and Medical Psychology, Medical Faculty, Heinrich Heine University, Moorenstr. 5, D-40225 Düsseldorf, Germany
| | - Alfons Schnitzler
- Department of Neurology/Institute of Clinical Neuroscience and Medical Psychology, Medical Faculty, Heinrich Heine University, Moorenstr. 5, D-40225 Düsseldorf, Germany
| | - Boris Görg
- Clinic for Gastroenterology, Hepatology, and Infectious Diseases, Heinrich Heine University, Moorenstr. 5, D-40225 Düsseldorf, Germany
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11
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Furtmann JK, Sichtermann T, Oros-Peusquens AM, Dekeyzer S, Shah NJ, Wiesmann M, Nikoubashman O. MRI Analysis Of the Water Content Change In the Brain During Acute Ethanol Consumption Via Quantitative Water Mapping. Alcohol Alcohol 2021; 57:429-436. [PMID: 34002208 DOI: 10.1093/alcalc/agab026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2020] [Revised: 03/15/2021] [Accepted: 03/16/2021] [Indexed: 11/13/2022] Open
Abstract
AIMS Alcohol consumption influences the water balance in the brain. While the impact of chronic alcohol misuse on cerebral water content has been the subject of several studies, less is known about the effects of acute alcohol misuse, with contradictory results in the literature. Therefore, we investigated the effects of acute alcohol intoxication on cerebral water content using a precise quantitative magnetic resonance imaging (MRI) sequence. METHODS In a prospective study, we measured cerebral water content in 20 healthy volunteers before alcohol consumption and after reaching a breath alcohol concentration of 1 ‰. A quantitative MRI water mapping sequence was conducted on a clinical 3 T system. Non-alcoholic fluid input and output were documented and accounted for. Water content was assessed for whole brain, grey and white matter and more specifically for regions known to be affected by acute or chronic alcohol misuse (occipital and frontal lobes, thalamus and pons). Changes in the volume of grey and white matter as well as the whole brain were examined. RESULTS Quantitative cerebral water content before and after acute alcohol consumption did not differ significantly (P ≥ 0.07), with changes often being within the range of measurement accuracy. Whole brain, white and grey matter volume did not change significantly (P ≥ 0.12). CONCLUSION The results of our study show no significant water content or volume change in the brain after recent alcohol intake in healthy volunteers. This accounts for the whole brain, grey and white matter, occipital and frontal lobes, thalamus and pons.
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Affiliation(s)
- Johanna K Furtmann
- Department of Diagnostic and Interventional Neuroradiology, University Hospital RWTH Aachen, Pauwelsstraße 30, 52074 Aachen, Germany
| | - Thorsten Sichtermann
- Department of Diagnostic and Interventional Neuroradiology, University Hospital RWTH Aachen, Pauwelsstraße 30, 52074 Aachen, Germany
| | - Ana-Maria Oros-Peusquens
- Institute of Neurosciences and Medicine 4 (INM-4), Forschungszentrum Jülich, 52425 Jülich, Germany
| | - Sven Dekeyzer
- Department of Radiology, Antwerp University Hospital, Drie Eikenstraat 655, 2650 Edegem, Belgium
| | - Nadim J Shah
- Institute of Neurosciences and Medicine 4 (INM-4), Forschungszentrum Jülich, 52425 Jülich, Germany
| | - Martin Wiesmann
- Department of Diagnostic and Interventional Neuroradiology, University Hospital RWTH Aachen, Pauwelsstraße 30, 52074 Aachen, Germany
| | - Omid Nikoubashman
- Department of Diagnostic and Interventional Neuroradiology, University Hospital RWTH Aachen, Pauwelsstraße 30, 52074 Aachen, Germany
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12
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Du M, Di ZW, Gürsoy D, Xian RP, Kozorovitskiy Y, Jacobsen C. Upscaling X-ray nanoimaging to macroscopic specimens. J Appl Crystallogr 2021; 54:386-401. [PMID: 33953650 PMCID: PMC8056767 DOI: 10.1107/s1600576721000194] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2020] [Accepted: 01/06/2021] [Indexed: 11/10/2022] Open
Abstract
Upscaling X-ray nanoimaging to macroscopic specimens has the potential for providing insights across multiple length scales, but its feasibility has long been an open question. By combining the imaging requirements and existing proof-of-principle examples in large-specimen preparation, data acquisition and reconstruction algorithms, the authors provide imaging time estimates for howX-ray nanoimaging can be scaled to macroscopic specimens. To arrive at this estimate, a phase contrast imaging model that includes plural scattering effects is used to calculate the required exposure and corresponding radiation dose. The coherent X-ray flux anticipated from upcoming diffraction-limited light sources is then considered. This imaging time estimation is in particular applied to the case of the connectomes of whole mouse brains. To image the connectome of the whole mouse brain, electron microscopy connectomics might require years, whereas optimized X-ray microscopy connectomics could reduce this to one week. Furthermore, this analysis points to challenges that need to be overcome (such as increased X-ray detector frame rate) and opportunities that advances in artificial-intelligence-based 'smart' scanning might provide. While the technical advances required are daunting, it is shown that X-ray microscopy is indeed potentially applicable to nanoimaging of millimetre- or even centimetre-size specimens.
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Affiliation(s)
- Ming Du
- Advanced Photon Source, Argonne National Laboratory, Argonne, IL 60439, USA
| | - Zichao Wendy Di
- Advanced Photon Source, Argonne National Laboratory, Argonne, IL 60439, USA.,Mathematics and Computer Science Division, Argonne National Laboratory, Argonne, IL 60439, USA
| | - Doǧa Gürsoy
- Advanced Photon Source, Argonne National Laboratory, Argonne, IL 60439, USA.,Department of Electrical Engineering and Computer Science, Northwestern University, Evanston, IL 60208, USA
| | - R Patrick Xian
- Department of Neurobiology, Northwestern University, Evanston, IL 60208, USA
| | - Yevgenia Kozorovitskiy
- Department of Neurobiology, Northwestern University, Evanston, IL 60208, USA.,Chemistry of Life Processes Institute, Northwestern University, Evanston, IL 60208, USA
| | - Chris Jacobsen
- Advanced Photon Source, Argonne National Laboratory, Argonne, IL 60439, USA.,Chemistry of Life Processes Institute, Northwestern University, Evanston, IL 60208, USA.,Department of Physics and Astronomy, Northwestern University, Evanston, IL 60208, USA
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13
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Afara IO, Shaikh R, Nippolainen E, Querido W, Torniainen J, Sarin JK, Kandel S, Pleshko N, Töyräs J. Characterization of connective tissues using near-infrared spectroscopy and imaging. Nat Protoc 2021; 16:1297-1329. [PMID: 33462441 DOI: 10.1038/s41596-020-00468-z] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2020] [Accepted: 11/20/2020] [Indexed: 02/06/2023]
Abstract
Near-infrared (NIR) spectroscopy is a powerful analytical method for rapid, non-destructive and label-free assessment of biological materials. Compared to mid-infrared spectroscopy, NIR spectroscopy excels in penetration depth, allowing intact biological tissue assessment, albeit at the cost of reduced molecular specificity. Furthermore, it is relatively safe compared to Raman spectroscopy, with no risk of laser-induced photothermal damage. A typical NIR spectroscopy workflow for biological tissue characterization involves sample preparation, spectral acquisition, pre-processing and analysis. The resulting spectrum embeds intrinsic information on the tissue's biomolecular, structural and functional properties. Here we demonstrate the analytical power of NIR spectroscopy for exploratory and diagnostic applications by providing instructions for acquiring NIR spectra, maps and images in biological tissues. By adapting and extending this protocol from the demonstrated application in connective tissues to other biological tissues, we expect that a typical NIR spectroscopic study can be performed by a non-specialist user to characterize biological tissues in basic research or clinical settings. We also describe how to use this protocol for exploratory study on connective tissues, including differentiating among ligament types, non-destructively monitoring changes in matrix formation during engineered cartilage development, mapping articular cartilage proteoglycan content across bovine patella and spectral imaging across the depth-wise zones of articular cartilage and subchondral bone. Depending on acquisition mode and experiment objectives, a typical exploratory study can be completed within 6 h, including sample preparation and data analysis.
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Affiliation(s)
- Isaac O Afara
- Department of Applied Physics, University of Eastern Finland, Kuopio, Finland.
- School of Information Technology and Electrical Engineering, The University of Queensland, Brisbane, Queensland, Australia.
| | - Rubina Shaikh
- Department of Applied Physics, University of Eastern Finland, Kuopio, Finland
- Diagnostic Imaging Centre, Kuopio University Hospital, Kuopio, Finland
| | - Ervin Nippolainen
- Department of Applied Physics, University of Eastern Finland, Kuopio, Finland
| | - William Querido
- Department of Bioengineering, Temple University, Philadelphia, PA, USA
| | - Jari Torniainen
- Department of Applied Physics, University of Eastern Finland, Kuopio, Finland
| | - Jaakko K Sarin
- Diagnostic Imaging Centre, Kuopio University Hospital, Kuopio, Finland
| | - Shital Kandel
- Department of Bioengineering, Temple University, Philadelphia, PA, USA
| | - Nancy Pleshko
- Department of Bioengineering, Temple University, Philadelphia, PA, USA
| | - Juha Töyräs
- Department of Applied Physics, University of Eastern Finland, Kuopio, Finland
- School of Information Technology and Electrical Engineering, The University of Queensland, Brisbane, Queensland, Australia
- Diagnostic Imaging Centre, Kuopio University Hospital, Kuopio, Finland
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14
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Kitzbichler MG, Aruldass AR, Barker GJ, Wood TC, Dowell NG, Hurley SA, McLean J, Correia M, Clarke C, Pointon L, Cavanagh J, Cowen P, Pariante C, Cercignani M, Bullmore ET, Harrison NA. Peripheral inflammation is associated with micro-structural and functional connectivity changes in depression-related brain networks. Mol Psychiatry 2021; 26:7346-7354. [PMID: 34535766 PMCID: PMC8872995 DOI: 10.1038/s41380-021-01272-1] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Revised: 07/15/2021] [Accepted: 08/19/2021] [Indexed: 02/08/2023]
Abstract
Inflammation is associated with depressive symptoms and innate immune mechanisms are likely causal in some cases of major depression. Systemic inflammation also perturbs brain function and microstructure, though how these are related remains unclear. We recruited N = 46 healthy controls, and N = 83 depressed cases stratified by CRP (> 3 mg/L: N = 33; < 3 mg/L: N = 50). All completed clinical assessment, venous blood sampling for C-reactive protein (CRP) assay, and brain magnetic resonance imaging (MRI). Micro-structural MRI parameters including proton density (PD), a measure of tissue water content, were measured at 360 cortical and 16 subcortical regions. Resting-state fMRI time series were correlated to estimate functional connectivity between individual regions, as well as the sum of connectivity (weighted degree) of each region. Multiple tests for regional analysis were controlled by the false discovery rate (FDR = 5%). We found that CRP was significantly associated with PD in precuneus, posterior cingulate cortex (pC/pCC) and medial prefrontal cortex (mPFC); and with functional connectivity between pC/pCC, mPFC and hippocampus. Depression was associated with reduced weighted degree of pC/pCC, mPFC, and other nodes of the default mode network (DMN). Thus CRP-related increases in proton density-a plausible marker of extracellular oedema-and changes in functional connectivity were anatomically co-localised with DMN nodes that also demonstrated significantly reduced hubness in depression. We suggest that effects of peripheral inflammation on DMN node micro-structure and connectivity may mediate inflammatory effects on depression.
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Affiliation(s)
- Manfred G. Kitzbichler
- grid.5335.00000000121885934University of Cambridge, Brain Mapping Unit, Department of Psychiatry, Downing Site, Cambridge, UK
| | - Athina R. Aruldass
- grid.5335.00000000121885934University of Cambridge, Brain Mapping Unit, Department of Psychiatry, Downing Site, Cambridge, UK
| | - Gareth J. Barker
- grid.13097.3c0000 0001 2322 6764Institute of Psychiatry, Psychology and Neuroscience, Department of Psychological Medicine, King’s College London, London, UK
| | - Tobias C. Wood
- grid.13097.3c0000 0001 2322 6764Institute of Psychiatry, Psychology and Neuroscience, Department of Psychological Medicine, King’s College London, London, UK
| | - Nicholas G. Dowell
- grid.414601.60000 0000 8853 076XUniversity of Sussex, Brighton and Sussex Medical School, Clinical Imaging Sciences Centre, Brighton, UK
| | - Samuel A. Hurley
- grid.416938.10000 0004 0641 5119University of Oxford Department of Psychiatry, Warneford Hospital, Oxford, UK ,grid.14003.360000 0001 2167 3675University of Wisconsin, Department of Radiology, Madison, WI USA
| | - John McLean
- grid.8756.c0000 0001 2193 314XCollege of MVLS, Institute of Health and Wellbeing, University of Glasgow, Glasgow, UK
| | - Marta Correia
- grid.415036.50000 0001 2177 2032MRC Cognition and Brain Sciences Unit, Cambridge, UK
| | - Charlotte Clarke
- grid.414601.60000 0000 8853 076XUniversity of Sussex, Brighton and Sussex Medical School, Clinical Imaging Sciences Centre, Brighton, UK
| | - Linda Pointon
- grid.5335.00000000121885934University of Cambridge, Brain Mapping Unit, Department of Psychiatry, Downing Site, Cambridge, UK
| | - Jonathan Cavanagh
- grid.511123.50000 0004 5988 7216Centre for Immunobiology, University of Glasgow and Queen Elizabeth University Hospital, Glasgow, UK
| | - Phil Cowen
- grid.416938.10000 0004 0641 5119University of Oxford Department of Psychiatry, Warneford Hospital, Oxford, UK
| | - Carmine Pariante
- grid.13097.3c0000 0001 2322 6764Institute of Psychiatry, Psychology and Neuroscience, Department of Psychological Medicine, King’s College London, London, UK
| | - Mara Cercignani
- grid.414601.60000 0000 8853 076XUniversity of Sussex, Brighton and Sussex Medical School, Clinical Imaging Sciences Centre, Brighton, UK
| | | | - Edward T. Bullmore
- grid.5335.00000000121885934University of Cambridge, Brain Mapping Unit, Department of Psychiatry, Downing Site, Cambridge, UK
| | - Neil A. Harrison
- grid.414601.60000 0000 8853 076XUniversity of Sussex, Brighton and Sussex Medical School, Clinical Imaging Sciences Centre, Brighton, UK ,grid.5600.30000 0001 0807 5670Cardiff University Brain Research Imaging Centre, Cardiff University, Cardiff, UK
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15
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Kullmann S, Abbas Z, Machann J, Shah NJ, Scheffler K, Birkenfeld AL, Häring HU, Fritsche A, Heni M, Preissl H. Investigating obesity-associated brain inflammation using quantitative water content mapping. J Neuroendocrinol 2020; 32:e12907. [PMID: 33025697 DOI: 10.1111/jne.12907] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Revised: 08/28/2020] [Accepted: 08/28/2020] [Indexed: 12/11/2022]
Abstract
There is growing evidence that obesity is associated with inflammation in the brain, which could contribute to the pathogenesis of obesity. In humans, it is challenging to detect brain inflammation in vivo. Recently, quantitative magnetic resonance imaging (qMRI) has emerged as a tool for characterising pathophysiological processes in the brain with reliable and reproducible measures. Proton density imaging provides quantitative assessment of the brain water content, which is affected in different pathologies, including inflammation. We enrolled 115 normal weight, overweight and obese men and women (body mass index [BMI] range 20.1-39.7 kg m-2 , age range 20-75 years, 60% men) to acquire cerebral water content mapping in vivo using MRI at 3 Tesla. We investigated potential associations between brain water content with anthropometric measures of obesity, body fat distribution and whole-body metabolism. No global changes in water content were associated with obesity. However, higher water content values in the cerebellum, limbic lobe and sub-lobular region were detected in participants with higher BMI, independent of age. More specifically, the dorsal striatum, hypothalamus, thalamus, fornix, anterior limb of the internal capsule and posterior thalamic radiation showed the strongest relationship with BMI, independent of age. In a subgroup with available measurements (n = 50), we identified visceral adipose tissue to be the strongest tested link between higher water content values and obesity. Individuals with metabolic syndrome had the highest water content values in the hypothalamus and the fornix. There is accumulating evidence that inflammation of the hypothalamus contributed to obesity-associated insulin resistance in that area. Whether brain inflammation is a cause or consequence of obesity in humans still needs to be investigated using a longitudinal study design. Using qMRI, we were able to detect marked water content changes in young and older obese adults, which is most likely the result of chronic low-grade inflammation.
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Affiliation(s)
- Stephanie Kullmann
- Institute for Diabetes Research and Metabolic Diseases of the Helmholtz Center Munich at the University of Tübingen, Tübingen, Germany
- German Center for Diabetes Research (DZD e.V.), Tübingen, Germany
- Department of Internal Medicine IV, University of Tübingen, Tübingen, Germany
| | - Zaheer Abbas
- Institute of Neuroscience and Medicine - 4, Forschungszentrum Jülich GmbH, Jülich, Germany
- Department of Neurology, Faculty of Medicine, RWTH Aachen University, Aachen, Germany
| | - Jürgen Machann
- Institute for Diabetes Research and Metabolic Diseases of the Helmholtz Center Munich at the University of Tübingen, Tübingen, Germany
- German Center for Diabetes Research (DZD e.V.), Tübingen, Germany
- Section on Experimental Radiology, Department of Diagnostic and Interventional Radiology, University of Tübingen, Tübingen, Germany
| | - Nadim J Shah
- Institute of Neuroscience and Medicine - 4, Forschungszentrum Jülich GmbH, Jülich, Germany
- Department of Neurology, Faculty of Medicine, RWTH Aachen University, Aachen, Germany
- Institute of Neuroscience and Medicine - 11, Forschungszentrum Jülich GmbH, Jülich, Germany
- JARA - BRAIN - Translational Medicine, RWTH Aachen University, Aachen, Germany
- Monash Biomedical Imaging, School of Psychological Sciences, Monash University, Melbourne, VIC, Australia
| | - Klaus Scheffler
- Department of High-Field Magnetic Resonance, Max Planck Institute for Biological Cybernetics, Tübingen, Germany
- Department of Biomedical Magnetic Resonance, University of Tübingen, Tübingen, Germany
| | - Andreas L Birkenfeld
- Institute for Diabetes Research and Metabolic Diseases of the Helmholtz Center Munich at the University of Tübingen, Tübingen, Germany
- German Center for Diabetes Research (DZD e.V.), Tübingen, Germany
- Department of Internal Medicine IV, University of Tübingen, Tübingen, Germany
| | - Hans-Ulrich Häring
- Institute for Diabetes Research and Metabolic Diseases of the Helmholtz Center Munich at the University of Tübingen, Tübingen, Germany
- German Center for Diabetes Research (DZD e.V.), Tübingen, Germany
- Department of Internal Medicine IV, University of Tübingen, Tübingen, Germany
| | - Andreas Fritsche
- Institute for Diabetes Research and Metabolic Diseases of the Helmholtz Center Munich at the University of Tübingen, Tübingen, Germany
- German Center for Diabetes Research (DZD e.V.), Tübingen, Germany
- Department of Internal Medicine IV, University of Tübingen, Tübingen, Germany
| | - Martin Heni
- Institute for Diabetes Research and Metabolic Diseases of the Helmholtz Center Munich at the University of Tübingen, Tübingen, Germany
- German Center for Diabetes Research (DZD e.V.), Tübingen, Germany
- Department of Internal Medicine IV, University of Tübingen, Tübingen, Germany
- Institute for Clinical Chemistry and Pathobiochemistry, University Hospital Tübingen, Tübingen, Germany
| | - Hubert Preissl
- Institute for Diabetes Research and Metabolic Diseases of the Helmholtz Center Munich at the University of Tübingen, Tübingen, Germany
- German Center for Diabetes Research (DZD e.V.), Tübingen, Germany
- Department of Internal Medicine IV, University of Tübingen, Tübingen, Germany
- Institute for Diabetes and Obesity, Helmholtz Diabetes Center at Helmholtz Zentrum München, German Research Center for Environmental Health (GmbH), Neuherberg, Germany
- Department of Pharmacy and Biochemistry, Institute of Pharmaceutical Sciences, Eberhard Karls Universität Tübingen, Tübingen, Germany
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16
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Rose CF, Amodio P, Bajaj JS, Dhiman RK, Montagnese S, Taylor-Robinson SD, Vilstrup H, Jalan R. Hepatic encephalopathy: Novel insights into classification, pathophysiology and therapy. J Hepatol 2020; 73:1526-1547. [PMID: 33097308 DOI: 10.1016/j.jhep.2020.07.013] [Citation(s) in RCA: 183] [Impact Index Per Article: 45.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/18/2019] [Revised: 07/01/2020] [Accepted: 07/03/2020] [Indexed: 02/07/2023]
Abstract
Hepatic encephalopathy (HE) is a frequent and serious complication of both chronic liver disease and acute liver failure. HE manifests as a wide spectrum of neuropsychiatric abnormalities, from subclinical changes (mild cognitive impairment) to marked disorientation, confusion and coma. The clinical and economic burden of HE is considerable, and it contributes greatly to impaired quality of life, morbidity and mortality. This review will critically discuss the latest classification of HE, as well as the pathogenesis and pathophysiological pathways underlying the neurological decline in patients with end-stage liver disease. In addition, management strategies, diagnostic approaches, currently available therapeutic options and novel treatment strategies are discussed.
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Affiliation(s)
- Christopher F Rose
- Hepato-Neuro Laboratory, CRCHUM, Université de Montréal, Montreal, Canada.
| | - Piero Amodio
- Department of Medicine, University of Padova, Padova, Italy
| | - Jasmohan S Bajaj
- Division of Gastroenterology, Hepatology and Nutrition, Virginia Commonwealth University and McGuire VA Medical Center, Richmond, Virginia, USA
| | - Radha Krishan Dhiman
- Department of Hepatology, Postgraduate Institute of Medical Education and Research, Chandigarh, India
| | | | - Simon D Taylor-Robinson
- Department of Surgery and Cancer, St. Mary's Hospital Campus, Imperial College London, London, United Kingdom
| | - Hendrik Vilstrup
- Department of Hepatology and Gastroenterology, Aarhus University Hospital, Denmark
| | - Rajiv Jalan
- Liver Failure Group, Institute for Liver and Digestive Health, University College London, Royal Free Campus, London, United Kingdom; European Foundation for the Study of Chronic Liver Failure, Barcelona, Spain.
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17
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Tran TT, Wei K, Cole S, Mena E, Csete M, King KS. Brain MR Spectroscopy Markers of Encephalopathy Due to Nonalcoholic Steatohepatitis. J Neuroimaging 2020; 30:697-703. [PMID: 32705733 DOI: 10.1111/jon.12728] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2020] [Revised: 04/22/2020] [Accepted: 05/06/2020] [Indexed: 11/28/2022] Open
Abstract
BACKGROUND AND PURPOSE In hepatic encephalopathy (HE), osmotic stressors promoting brain edema result in a compensatory drop in the astrocyte metabolite myo-inositol (mI). Identifying differences between nonalcoholic steatohepatitis (NASH) with and without HE and healthy controls using proton magnetic resonance spectroscopy (MRS) and evaluating hypoalbuminemia and hyperammonemia as osmotic stressors that predict the reduction of mI allow further understanding of mechanisms that promote brain edema in HE. The aim of this study was to assess brain edema in HE using characteristic MRS markers and serum albumin. METHODS We evaluated between group differences among 19 NASH cirrhosis without HE (Crhs-HE) (age = 63 ± 8.7), 9 NASH cirrhosis with HE (Crhs+HE) (age = 63 ± 9.2), and 16 controls (age = 57.8 ± 11.7) using 1 H MRS. Glutamine (Gln/tCr) and serum albumin were evaluated as predictors of myo-inositol (mI/tCr) using linear regression. Statistical significance was set at P < .05 with adjustment for multiple comparisons. RESULTS Brain mI/tCr was decreased, and Gln/tCr increased in Crhs+HE compared to Crhs-HE and controls in both brain regions (P < .001 for all). Evaluated together as joint predictors, serum albumin but not Gln/tCr significantly predicted mI/tCr in GM (P = .02 and P = .2, respectively) and PWM (P = .01 and P = .1, respectively). CONCLUSION Low mI/tCr and increased Gln/tCr were characteristics of Crhs+HE. Low serum albumin was the strongest predictor of brain osmotic stress indicated by reduced mI/tCr, with no residual independent association seen for brain Gln/tCr concentration. This suggests that hypoalbuminemia in chronic liver disease may promote brain edema in HE.
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Affiliation(s)
| | - Ke Wei
- HMRI Imaging Center, Pasadena, CA
| | | | - Edward Mena
- California Liver Research Institute, Pasadena, CA
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18
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Cai Z, Zhu X, Zhang G, Wu F, Lin H, Tan M. Ammonia induces calpain-dependent cleavage of CRMP-2 during neurite degeneration in primary cultured neurons. Aging (Albany NY) 2020; 11:4354-4366. [PMID: 31278888 PMCID: PMC6660054 DOI: 10.18632/aging.102053] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2018] [Accepted: 06/19/2019] [Indexed: 01/07/2023]
Abstract
Hyperammonemia in the CNS induces irreversible damages to neurons due to ultimate cell loss. Neurite degeneration, a primary event that leads to neuronal cell death, remains less elucidated especially in hyperammonemia circumstances. Here, we found that the administration of ammonia induced neurite degeneration in cultured cerebellar granule neurons. The resulting altered neuronal morphology, rupture of neurites, and disassembly of the cytoskeleton led to cell death. Calcein and Fluo-4 staining revealed that ammonia induced intracellular calcium dysregulation. Subsequently activated calpain cleaved CRMP-2, a microtubule assembly protein. Pharmacologically inhibition of calpain, but not caspases or GSK-3, suppressed the cleavage of CRMP-2 and reversed neurite degeneration under ammonia treatment. Exposure to ammonia decreased whereas inhibition of calpain restored the amplitude and frequency of miniature excitatory postsynaptic currents. These data suggest a mechanism by which elevated ammonia level may induce neuronal dysfunction via abnormal calcium influx and calpain-dependent CRMP-2 cleavage, leading to abnormal synaptic transmission, cytoskeletal collapse, and neurite degeneration.
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Affiliation(s)
- Zhenbin Cai
- Department of Orthopedics, The First Affiliated Hospital of Jinan University, Guangzhou, China
| | - Xiaonan Zhu
- Department of Anatomy, Medical College of Jinan University, Guangzhou, China
| | - Guowei Zhang
- Department of Orthopedics, The First Affiliated Hospital of Jinan University, Guangzhou, China
| | - Fengming Wu
- Department of Anatomy, Medical College of Jinan University, Guangzhou, China
| | - Hongsheng Lin
- Department of Orthopedics, The First Affiliated Hospital of Jinan University, Guangzhou, China
| | - Minghui Tan
- Department of Orthopedics, The First Affiliated Hospital of Jinan University, Guangzhou, China
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19
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Liotta EM, Kimberly WT. Cerebral edema and liver disease: Classic perspectives and contemporary hypotheses on mechanism. Neurosci Lett 2020; 721:134818. [PMID: 32035166 DOI: 10.1016/j.neulet.2020.134818] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2019] [Revised: 02/01/2020] [Accepted: 02/03/2020] [Indexed: 02/07/2023]
Abstract
Liver disease is a growing public health concern. Hepatic encephalopathy, the syndrome of brain dysfunction secondary to liver disease, is a frequent complication of both acute and chronic liver disease and cerebral edema (CE) is a key feature. While altered ammonia metabolism is a key contributor to hepatic encephalopathy and CE in liver disease, there is a growing appreciation that additional mechanisms contribute to CE. In this review we will begin by presenting three classic perspectives that form a foundation for a discussion of CE in liver disease: 1) CE is unique to acute liver failure, 2) CE in liver disease is only cytotoxic, and 3) CE in liver disease is primarily an osmotically mediated consequence of ammonia and glutamine metabolism. We will present each classic perspective along with more recent observations that call in to question that classic perspective. After highlighting these areas of debate, we will explore the leading contemporary mechanisms hypothesized to contribute to CE during liver disease.
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Affiliation(s)
- Eric M Liotta
- Northwestern University-Feinberg School of Medicine, Department of Neurology, United States; Northwestern University-Feinberg School of Medicine, Department of Surgery, Division of Organ Transplantation, United States; Northwestern University Transplant Outcomes Research Collaboration, United States.
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Oros-Peusquens AM, Loução R, Abbas Z, Gras V, Zimmermann M, Shah NJ. A Single-Scan, Rapid Whole-Brain Protocol for Quantitative Water Content Mapping With Neurobiological Implications. Front Neurol 2019; 10:1333. [PMID: 31920951 PMCID: PMC6934004 DOI: 10.3389/fneur.2019.01333] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2019] [Accepted: 12/02/2019] [Indexed: 12/16/2022] Open
Abstract
Water concentration is tightly regulated in the healthy human brain and changes only slightly with age and gender in healthy subjects. Consequently, changes in water content are important for the characterization of disease. MRI can be used to measure changes in brain water content, but as these changes are usually in the low percentage range, highly accurate and precise methods are required for detection. The method proposed here is based on a long-TR (10 s) multiple-echo gradient-echo measurement with an acquisition time of 7:21 min. Using such a long TR ensures that there is no T1 weighting, meaning that the image intensity at zero echo time is only proportional to the water content, the transmit field, and to the receive field. The receive and transmit corrections, which are increasingly large at higher field strengths and for highly segmented coil arrays, are multiplicative and can be approached heuristically using a bias field correction. The method was tested on 21 healthy volunteers at 3T field strength. Calibration using cerebral-spinal fluid values (~100% water content) resulted in mean values and standard deviations of the water content distribution in white matter and gray matter of 69.1% (1.7%) and 83.7% (1.2%), respectively. Measured distributions were coil-independent, as seen by using either a 12-channel receiver coil or a 32-channel receiver coil. In a test-retest investigation using 12 scans on one volunteer, the variation in the mean value of water content for different tissue types was ~0.3% and the mean voxel variability was ~1%. Robustness against reduced SNR was assessed by comparing results for 5 additional volunteers at 1.5T and 3T. Furthermore, water content distribution in gray matter is investigated and regional contrast reported for the first time. Clinical applicability is illustrated with data from one stroke patient and one brain tumor patient. It is anticipated that this fast, stable, easy-to-use, high-quality mapping method will facilitate routine quantitative MR imaging of water content.
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Affiliation(s)
| | - Ricardo Loução
- Institute of Neurosciences and Medicine 4 (INM-4), Forschungszentrum Jülich, Jülich, Germany
| | - Zaheer Abbas
- Institute of Neurosciences and Medicine 4 (INM-4), Forschungszentrum Jülich, Jülich, Germany
| | - Vincent Gras
- Institute of Neurosciences and Medicine 4 (INM-4), Forschungszentrum Jülich, Jülich, Germany
| | - Markus Zimmermann
- Institute of Neurosciences and Medicine 4 (INM-4), Forschungszentrum Jülich, Jülich, Germany
| | - N J Shah
- Institute of Neurosciences and Medicine 4 (INM-4), Forschungszentrum Jülich, Jülich, Germany.,Institute of Neurosciences and Medicine 11 (INM-11), JARA, Forschungszentrum Jülich, Jülich, Germany.,JARA - BRAIN - Translational Medicine, Aachen, Germany.,Department of Neurology, RWTH Aachen University, Aachen, Germany
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21
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Braissant O, Rackayová V, Pierzchala K, Grosse J, McLin VA, Cudalbu C. Longitudinal neurometabolic changes in the hippocampus of a rat model of chronic hepatic encephalopathy. J Hepatol 2019; 71:505-515. [PMID: 31173812 DOI: 10.1016/j.jhep.2019.05.022] [Citation(s) in RCA: 49] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/26/2018] [Revised: 05/24/2019] [Accepted: 05/27/2019] [Indexed: 12/20/2022]
Abstract
BACKGROUND & AIMS The sequence of events in hepatic encephalopathy (HE) remains unclear. Using the advantages of in vivo 1H-MRS (9.4T) we aimed to analyse the time-course of disease in an established model of type C HE by analysing the longitudinal changes in a large number of brain metabolites together with biochemical, histological and behavioural assessment. We hypothesized that neurometabolic changes are detectable very early, and that these early changes will offer insight into the primary events underpinning HE. METHODS Wistar rats underwent bile-duct ligation (BDL) and were studied before BDL and at post-operative weeks 2, 4, 6 and 8 (n = 26). In vivo short echo-time 1H-MRS (9.4T) of the hippocampus was performed in a longitudinal manner, as were biochemical (plasma), histological and behavioural tests. RESULTS Plasma ammonium increased early after BDL and remained high during the study. Brain glutamine increased (+47%) as early as 2-4 weeks post-BDL while creatine (-8%) and ascorbate (-12%) decreased. Brain glutamine and ascorbate correlated closely with rising plasma ammonium, while brain creatine correlated with brain glutamine. The increases in brain glutamine and plasma ammonium were correlated, while plasma ammonium correlated negatively with distance moved. Changes in astrocyte morphology were observed at 4 weeks. These early changes were further accentuated at 6-8 weeks post-BDL, concurrently with the known decreases in brain organic osmolytes. CONCLUSION Using a multimodal, in vivo and longitudinal approach we have shown that neurometabolic changes are already noticeable 2 weeks after BDL. These early changes are suggestive of osmotic/oxidative stress and are likely the premise of some later changes. Early decreases in cerebral creatine and ascorbate are novel findings offering new avenues to explore neuroprotective strategies for HE treatment. LAY SUMMARY The sequence of events in chronic hepatic encephalopathy (HE) remains unclear, therefore using the advantages of in vivo proton magnetic resonance spectroscopy at 9.4T we aimed to test the hypothesis that neurometabolic changes are detectable very early in an established model of type C HE, offering insight into the primary events underpinning HE, before advanced liver disease confounds the findings. These early, previously unreported neurometabolic changes occurred as early as 2 to 4 weeks after bile-duct ligation, namely an increase in plasma ammonium and brain glutamine, a decrease in brain creatine and ascorbate together with behavioural and astrocyte morphology changes, and continued to progress throughout the 8-week course of the disease.
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Affiliation(s)
- Olivier Braissant
- Service of Clinical Chemistry, University of Lausanne and University Hospital of Lausanne, Lausanne, Switzerland
| | - Veronika Rackayová
- Laboratory of Functional and Metabolic Imaging, Center for Biomedical Imaging, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland; Centre d'Imagerie Biomedicale (CIBM), Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Katarzyna Pierzchala
- Centre d'Imagerie Biomedicale (CIBM), Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Jocelyn Grosse
- Laboratory of Behavioral Genetics, Brain Mind Institute, School Of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Valérie A McLin
- Swiss Pediatric Liver Center, Department of Pediatrics, Gynecology and Obstetrics, University Hospitals Geneva, and University of Geneva Medical School, Switzerland
| | - Cristina Cudalbu
- Centre d'Imagerie Biomedicale (CIBM), Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland.
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Winterdahl M, Abbas Z, Noer O, Thomsen KL, Gras V, Nahimi A, Vilstrup H, Shah NJ, Dam G. Cerebral water content mapping in cirrhosis patients with and without manifest HE. Metab Brain Dis 2019; 34:1071-1076. [PMID: 31089866 DOI: 10.1007/s11011-019-00427-y] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/17/2019] [Accepted: 05/01/2019] [Indexed: 02/07/2023]
Abstract
Hepatic encephalopathy (HE) is a frequent and debilitating complication of cirrhosis and its pathogenesis is not definitively clarified. Recent hypotheses focus on the possible existence of low-grade cerebral edema due to accumulation of osmolytes secondary to hyperammonemia. In the present study we investigated increases in cerebral water content by a novel magnetic resonance impedance (MRI) technique in cirrhosis patients with and without clinically manifest HE. We used a 3 T MRI technique for quantitative cerebral water content mapping in nine cirrhosis patients with an episode of overt HE, ten cirrhosis patients who never suffered from HE, and ten healthy aged-matched controls. We tested for differences between groups by statistical non-parametric mapping (SnPM) for a voxel-based spatial evaluation. The patients with HE had significantly higher water content in white matter than the cirrhosis patients (0.6%), who in turn, had significantly higher content than the controls (1.7%). Although the global gray matter water content did not differ between the groups, the patients with HE had markedly higher thalamic water content than patients who never experienced HE (6.0% higher). We found increased white matter water content in cirrhosis patients, predominantly in those with manifest HE. This confirms the presence of increasing degrees of low-grade edema with exacerbation of pathology. The thalamic edema in manifest HE may lead to compromised basal ganglia-thalamo-cortical circuits, in accordance with the major clinical symptoms of HE. The identification of the thalamus as particularly inflicted in manifest HE is potentially relevant to the pathophysiology of HE.
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Affiliation(s)
- Michael Winterdahl
- Department of Nuclear Medicine and PET Center, Aarhus University, Aarhus, Denmark
| | - Zaheer Abbas
- Institute of Neuroscience and Medicine (INM-4), Forschungszentrum Jülich, 52425, Jülich, Germany
- Department of Neurology, RWTH Aachen University Clinic, Aachen, Germany
- JARA - Jülich Aachen Research Alliance, Aachen, Germany
| | - Ove Noer
- Department of Nuclear Medicine and PET Center, Aarhus University, Aarhus, Denmark
| | - Karen Louise Thomsen
- Department of Hepatology & Gastroenterology, Aarhus University Hospital, Aarhus, Denmark
| | | | - Adjmal Nahimi
- Department of Nuclear Medicine and PET Center, Aarhus University, Aarhus, Denmark
| | - Hendrik Vilstrup
- Department of Hepatology & Gastroenterology, Aarhus University Hospital, Aarhus, Denmark
| | - Nadim Joni Shah
- Institute of Neuroscience and Medicine (INM-4), Forschungszentrum Jülich, 52425, Jülich, Germany
- Department of Neurology, RWTH Aachen University Clinic, Aachen, Germany
- JARA - Jülich Aachen Research Alliance, Aachen, Germany
| | - Gitte Dam
- Department of Hepatology & Gastroenterology, Aarhus University Hospital, Aarhus, Denmark.
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23
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Claeser R, Zimmermann M, Shah NJ. Sub-millimeter T 1 mapping of rapidly relaxing compartments with gradient delay corrected spiral TAPIR and compressed sensing at 3T. Magn Reson Med 2019; 82:1288-1300. [PMID: 31148282 DOI: 10.1002/mrm.27797] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2018] [Revised: 04/10/2019] [Accepted: 04/12/2019] [Indexed: 11/09/2022]
Abstract
PURPOSE The TAPIR sequence is an accurate and efficient method for T1 mapping. It combines a slice-interleaving Look-Locker read-out with an acquisition of multiple k-space lines in 1 shot. Whereas the acquisition of multiple lines per excitation increases imaging speed, the corresponding increase in TR and TE is detrimental to the T1 fitting performance. This is especially problematic for substances exhibiting rapid T2 * relaxation (e.g., myelin water). METHODS The T1 fitting performance of TAPIR is enhanced by using an interleaved spiral read-out with shorter TE and TR. Furthermore, an improvement to a method for fast gradient delay estimation is presented. Whereas previous methods assume the gradient delay to be stationary, the presented approach corrects the spiral k-space trajectory by using a polynomial fit of the measured gradient delays. RESULTS Gradient delay artifacts are largely eliminated, requiring very little additional scanning time. The sampling efficiency of the spiral read-out allows for a significant reduction of the acquisition time in comparison to Cartesian TAPIR. Spiral TAPIR enables the sampling of more slices and an accurate measurement of rapidly relaxing compartments. Over a wide T1 range (448-3115 ms), spiral TAPIR reduces the mean fitting error from -2.5% to -0.1%. Combining 50% undersampling with the shorter TR of spiral TAPIR, an increase in imaging speed by a factor of up to 3.3 was achieved. CONCLUSION Using a spiral read-out trajectory, the established TAPIR sequence enables measurement of rapidly relaxing T1 compartments, while improving T1 mapping performance and imaging speed.
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Affiliation(s)
- Robert Claeser
- Institute of Neuroscience and Medicine 4 (INM-4), Forschungszentrum Jülich, Jülich, Germany
| | - Markus Zimmermann
- Institute of Neuroscience and Medicine 4 (INM-4), Forschungszentrum Jülich, Jülich, Germany
| | - N Jon Shah
- Institute of Neuroscience and Medicine 4 (INM-4), Forschungszentrum Jülich, Jülich, Germany.,Institute of Neuroscience and Medicine 11 (INM-11), Forschungszentrum Jülich, Jülich, Germany.,Jülich Aachen Research Alliance (JARA-BRAIN), Translational Medicine, Aachen, Germany.,Department of Neurology, RWTH Aachen University, Aachen, Germany
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24
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Woodcock EA, Hillmer AT, Mason GF, Cosgrove KP. Imaging Biomarkers of the Neuroimmune System among Substance Use Disorders: A Systematic Review. MOLECULAR NEUROPSYCHIATRY 2019; 5:125-146. [PMID: 31312635 DOI: 10.1159/000499621] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2018] [Accepted: 03/13/2019] [Indexed: 12/14/2022]
Abstract
There is tremendous interest in the role of the neuroimmune system and inflammatory processes in substance use disorders (SUDs). Imaging biomarkers of the neuroimmune system in vivo provide a vital translational bridge between preclinical and clinical research. Herein, we examine two imaging techniques that measure putative indices of the neuroimmune system and review their application among SUDs. Positron emission tomography (PET) imaging of 18 kDa translocator protein availability is a marker associated with microglia. Proton magnetic resonance spectroscopy quantification of myo-inositol levels is a putative glial marker found in astrocytes. Neuroinflammatory responses are initiated and maintained by microglia and astrocytes, and thus represent important imaging markers. The goal of this review is to summarize neuroimaging findings from the substance use literature that report data using these markers and discuss possible mechanisms of action. The extant literature indicates abused substances exert diverse and complex neuroimmune effects. Moreover, drug effects may change across addiction stages, i.e. the neuroimmune effects of acute drug administration may differ from chronic use. This burgeoning field has considerable potential to improve our understanding and treatment of SUDs. Future research is needed to determine how targeting the neuroimmune system may improve treatment outcomes.
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Affiliation(s)
- Eric A Woodcock
- Departments of Psychiatry, and of Radiology and Biomedical Imaging, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Ansel T Hillmer
- Departments of Psychiatry, and of Radiology and Biomedical Imaging, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Graeme F Mason
- Departments of Psychiatry, and of Radiology and Biomedical Imaging, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Kelly P Cosgrove
- Departments of Psychiatry, and of Radiology and Biomedical Imaging, Yale University School of Medicine, New Haven, Connecticut, USA
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25
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Cudalbu C, Taylor-Robinson SD. Brain Edema in Chronic Hepatic Encephalopathy. J Clin Exp Hepatol 2019; 9:362-382. [PMID: 31360029 PMCID: PMC6637228 DOI: 10.1016/j.jceh.2019.02.003] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/17/2018] [Revised: 01/15/2019] [Accepted: 02/06/2019] [Indexed: 02/07/2023] Open
Abstract
Brain edema is a common feature associated with hepatic encephalopathy (HE). In patients with acute HE, brain edema has been shown to play a crucial role in the associated neurological deterioration. In chronic HE, advanced magnetic resonance imaging (MRI) techniques have demonstrated that low-grade brain edema appears also to be an important pathological feature. This review explores the different methods used to measure brain edema ex vivo and in vivo in animal models and in humans with chronic HE. In addition, an in-depth description of the main studies performed to date is provided. The role of brain edema in the neurological alterations linked to HE and whether HE and brain edema are the manifestations of the same pathophysiological mechanism or two different cerebral manifestations of brain dysfunction in liver disease are still under debate. In vivo MRI/magnetic resonance spectroscopy studies have allowed insight into the development of brain edema in chronic HE. However, additional in vivo longitudinal and multiparametric/multimodal studies are required (in humans and animal models) to elucidate the relationship between liver function, brain metabolic changes, cellular changes, cell swelling, and neurological manifestations in chronic HE.
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Key Words
- 1H MRS, proton magnetic resonance spectroscopy
- ADC, apparent diffusion coefficient
- ALF, acute liver failure
- AQP, aquaporins
- BBB, blood-brain barrier
- BDL, bile duct ligation
- CNS, central nervous system
- CSF, cerebrospinal fluid
- Cr, creatine
- DTI, diffusion tensor imaging
- DWI, diffusion-weighted imaging
- FLAIR, fluid-attenuated inversion recovery
- GM, gray matter
- Gln, glutamine
- Glx, sum of glutamine and glutamate
- HE, hepatic encephalopathy
- Ins, inositol
- LPS, lipopolysaccharide
- Lac, lactate
- MD, mean diffusivity
- MRI, magnetic resonance imaging
- MRS, magnetic resonance spectroscopy
- MT, magnetization transfer
- MTR, MT ratio
- NMR, nuclear magnetic resonance
- PCA, portocaval anastomosis
- TE, echo time
- WM, white matter
- brain edema
- chronic hepatic encephalopathy
- in vivo magnetic resonance imaging
- in vivo magnetic resonance spectroscopy
- liver cirrhosis
- mIns, myo-inositol
- tCho, total choline
- tCr, total creatine
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Affiliation(s)
- Cristina Cudalbu
- Centre d'Imagerie Biomedicale (CIBM), Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Simon D. Taylor-Robinson
- Division of Integrative Systems Medicine and Digestive Disease, Department of Surgery and Cancer, St Mary's Hospital Campus, Imperial College London, London, United Kingdom
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Sichtermann T, Furtmann JK, Dekeyzer S, Gilmour G, Oros-Peusquens AM, Bach JP, Wiesmann M, Shah NJ, Nikoubashman O. Increased Water Content in Periventricular Caps in Patients without Acute Hydrocephalus. AJNR Am J Neuroradiol 2019; 40:784-787. [PMID: 30975653 DOI: 10.3174/ajnr.a6033] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2019] [Accepted: 03/11/2019] [Indexed: 11/07/2022]
Abstract
BACKGROUND AND PURPOSE Periventricular caps are a common finding on MR imaging and are believed to reflect focally increased interstitial water content due to dysfunctional transependymal transportation rather than ischemic-gliotic changes. We compared the quantitative water content of periventricular caps and microvascular white matter lesions, hypothesizing that periventricular caps associated with increased interstitial fluid content display higher water content than white matter lesions and are therefore differentiable from microvascular white matter lesions by measurement of the water content. MATERIALS AND METHODS In a prospective study, we compared the water content of periventricular caps and white matter lesions in 50 patients using a quantitative multiple-echo, gradient-echo MR imaging water-mapping sequence. RESULTS The water content of periventricular caps was significantly higher than that of white matter lesions (P = .002). Compared with normal white matter, the mean water content of periventricular caps was 17% ± 5% higher and the mean water content of white matter lesions was 11% ± 4% higher. Receiver operating characteristic analysis revealed that areas in which water content was 15% higher compared with normal white matter correspond to periventricular caps rather than white matter lesions, with a specificity of 93% and a sensitivity of 60% (P < .001). There was no significant correlation between the water content of periventricular caps and whole-brain volume (P = .275), white matter volume (P = .243), gray matter volume (P = .548), lateral ventricle volume (P = .800), white matter lesion volume (P = .081), periventricular cap volume (P = .081), and age (P = .224). CONCLUSIONS Quantitative MR imaging allows differentiation between periventricular caps and white matter lesions. Water content quantification of T2-hyperintense lesions may be a useful additional tool for the characterization and differentiation of T2-hyperintense diseases.
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Affiliation(s)
- T Sichtermann
- From the Departments of Diagnostic and Interventional Neuroradiology (T.S., J.K.F., S.D., G.G., M.W., O.N.)
| | - J K Furtmann
- From the Departments of Diagnostic and Interventional Neuroradiology (T.S., J.K.F., S.D., G.G., M.W., O.N.)
| | - S Dekeyzer
- From the Departments of Diagnostic and Interventional Neuroradiology (T.S., J.K.F., S.D., G.G., M.W., O.N.)
- Department of Radiology (S.D.), Antwerp University Hospital (UZA), Antwerp, Belgium
| | - G Gilmour
- From the Departments of Diagnostic and Interventional Neuroradiology (T.S., J.K.F., S.D., G.G., M.W., O.N.)
| | - A M Oros-Peusquens
- Institute of Neuroscience and Medicine (A.M.O.-P., N.J.S.), Jülich, Germany
| | - J P Bach
- Neurology (J.P.B., N.J.S.), University Hospital, RWTH Aachen University, Aachen, Germany
| | - M Wiesmann
- From the Departments of Diagnostic and Interventional Neuroradiology (T.S., J.K.F., S.D., G.G., M.W., O.N.)
| | - N J Shah
- Neurology (J.P.B., N.J.S.), University Hospital, RWTH Aachen University, Aachen, Germany
- Institute of Neuroscience and Medicine (A.M.O.-P., N.J.S.), Jülich, Germany
| | - O Nikoubashman
- From the Departments of Diagnostic and Interventional Neuroradiology (T.S., J.K.F., S.D., G.G., M.W., O.N.)
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27
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Zöllner HJ, Butz M, Jördens M, Füllenbach ND, Häussinger D, Schmitt B, Wittsack HJ, Schnitzler A. Chemical exchange saturation transfer imaging in hepatic encephalopathy. NEUROIMAGE-CLINICAL 2019; 22:101743. [PMID: 30856541 PMCID: PMC6411782 DOI: 10.1016/j.nicl.2019.101743] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/12/2018] [Revised: 02/04/2019] [Accepted: 03/02/2019] [Indexed: 01/08/2023]
Abstract
Hepatic encephalopathy (HE) is a common complication in liver cirrhosis and associated with an invasion of ammonia into the brain through the blood-brain barrier. Resulting higher ammonia concentrations in the brain are suggested to lead to a dose-dependent gradual increase of HE severity and an associated impairment of brain function. Amide proton transfer-weighted (APTw) chemical exchange saturation transfer (CEST) imaging has been found to be sensitive to ammonia concentration. The aim of this work was to study APTw CEST imaging in patients with HE and to investigate the relationship between disease severity, critical flicker frequency (CFF), psychometric test scores, blood ammonia, and APTw signals in different brain regions. Whole-brain APTw CEST images were acquired in 34 participants (14 controls, 20 patients (10 minimal HE, 10 manifest HE)) on a 3 T clinical MRI system accompanied by T1 mapping and structural images. T1 normalized magnetization transfer ratio asymmetry analysis was performed around 3 ppm after B0 and B1 correction to create APTw images. All APTw images were spatially normalized into a cohort space to allow direct comparison. APTw images in 6 brain regions (cerebellum, occipital cortex, putamen, thalamus, caudate, white matter) were tested for group differences as well as the link to CFF, psychometric test scores, and blood ammonia. A decrease in APTw intensities was found in the cerebellum and the occipital cortex of manifest HE patients. In addition, APTw intensities in the cerebellum correlated positively with several psychometric scores, such as the fine motor performance scores MLS1 for hand steadiness / tremor (r = 0.466; p = .044) and WRT2 for motor reaction time (r = 0.523; p = .022). Moreover, a negative correlation between APTw intensities and blood ammonia was found for the cerebellum (r = −0.615; p = .007) and the occipital cortex (r = −0.478; p = .045). An increase of APTw intensities was observed in the putamen of patients with minimal HE and correlated negatively with the CFF (r = −0.423; p = .013). Our findings demonstrate that HE is associated with regional differential alterations in APTw signals. These variations are most likely a consequence of hyperammonemia or hepatocerebral degeneration processes, and develop in parallel with disease severity. Ammonia is suggested to play a key role in the emergence of HE. Increase of ammonia in HE patients might be studied with APTw CEST. HE leads to regionally decreasing APTw CEST signal. APTw CEST correlates with blood ammonia levels and psychometric test scores. APTw CEST is possibly linked to hyperammonemia or hepatocerebral degeneration.
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Affiliation(s)
- Helge Jörn Zöllner
- Institute of Clinical Neuroscience and Medical Psychology, Medical Faculty, Heinrich Heine University Düsseldorf, Germany; Department of Diagnostic and Interventional Radiology, Medical Faculty, Heinrich Heine University Düsseldorf, Germany.
| | - Markus Butz
- Institute of Clinical Neuroscience and Medical Psychology, Medical Faculty, Heinrich Heine University Düsseldorf, Germany
| | - Markus Jördens
- Department of Gastroenterology, Hepatology and Infectiology, Medical Faculty, Heinrich Heine University Düsseldorf, Germany
| | - Nur-Deniz Füllenbach
- Department of Gastroenterology, Hepatology and Infectiology, Medical Faculty, Heinrich Heine University Düsseldorf, Germany
| | - Dieter Häussinger
- Department of Gastroenterology, Hepatology and Infectiology, Medical Faculty, Heinrich Heine University Düsseldorf, Germany
| | - Benjamin Schmitt
- Siemens Ltd. Australia, Healthcare Sector, 160 Herring Road, Macquarie Park, NSW 2113,Australia
| | - Hans-Jörg Wittsack
- Department of Diagnostic and Interventional Radiology, Medical Faculty, Heinrich Heine University Düsseldorf, Germany
| | - Alfons Schnitzler
- Institute of Clinical Neuroscience and Medical Psychology, Medical Faculty, Heinrich Heine University Düsseldorf, Germany
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Lorio S, Tierney TM, McDowell A, Arthurs OJ, Lutti A, Weiskopf N, Carmichael DW. Flexible proton density (PD) mapping using multi-contrast variable flip angle (VFA) data. Neuroimage 2018; 186:464-475. [PMID: 30465865 DOI: 10.1016/j.neuroimage.2018.11.023] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2018] [Revised: 11/13/2018] [Accepted: 11/16/2018] [Indexed: 12/13/2022] Open
Abstract
Quantitative proton density (PD) maps measure the amount of free water, which is important for non-invasive tissue characterization in pathology and across lifespan. PD mapping requires the estimation and subsequent removal of factors influencing the signal intensity other than PD. These factors include the T1, T2* relaxation effects, transmit field inhomogeneities, receiver coil sensitivity profile (RP) and the spatially invariant factor that is required to scale the data. While the transmit field can be reliably measured, the RP estimation is usually based on image post-processing techniques due to limitations of its measurement at magnetic fields higher than 1.5 T. The post-processing methods are based on unified bias-field/tissue segmentation, fitting the sensitivity profile from images obtained with different coils, or on the linear relationship between T1 and PD. The scaling factor is derived from the signal within a specific tissue compartment or reference object. However, these approaches for calculating the RP and scaling factor have limitations particularly in severe pathology or over a wide age range, restricting their application. We propose a new approach for PD mapping based on a multi-contrast variable flip angle acquisition protocol and a data-driven estimation method for the RP correction and map scaling. By combining all the multi-contrast data acquired at different echo times, we are able to fully correct the MRI signal for T2* relaxation effects and to decrease the variance and the entropy of PD values within tissue class of the final map. The RP is determined from the corrected data applying a non-parametric bias estimation, and the scaling factor is based on the median intensity of an external calibration object. Finally, we compare the signal intensity and homogeneity of the multi-contrast PD map with the well-established effective PD (PD*) mapping, for which the RP is based on concurrent bias field estimation and tissue classification, and the scaling factor is estimated from the mean white matter signal. The multi-contrast PD values homogeneity and accuracy within the cerebrospinal fluid (CSF) and deep brain structures are increased beyond that obtained using PD* maps. We demonstrate that the multi-contrast RP approach is insensitive to anatomical or a priori tissue information by applying it in a patient with extensive brain abnormalities and for whole body PD mapping in post-mortem foetal imaging.
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Affiliation(s)
- Sara Lorio
- UCL Great Ormond Street Institute of Child Health, University College London, London, UK.
| | - Tim M Tierney
- Wellcome Centre for Human Neuroimaging, UCL Institute of Neurology, University College London, London, UK
| | - Amy McDowell
- UCL Great Ormond Street Institute of Child Health, University College London, London, UK
| | - Owen J Arthurs
- UCL Great Ormond Street Institute of Child Health, University College London, London, UK; Department of Radiology, Great Ormond Street Hospital for Children, London, UK
| | - Antoine Lutti
- Laboratory for Research in Neuroimaging, Department of Clinical Neuroscience, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland
| | - Nikolaus Weiskopf
- Department of Neurophysics, Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany
| | - David W Carmichael
- UCL Great Ormond Street Institute of Child Health, University College London, London, UK; EPSRC / Wellcome Centre for Medical Engineering, Biomedical Engineering, King's College, London, UK
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Görg B, Karababa A, Häussinger D. Hepatic Encephalopathy and Astrocyte Senescence. J Clin Exp Hepatol 2018; 8:294-300. [PMID: 30302047 PMCID: PMC6175776 DOI: 10.1016/j.jceh.2018.05.003] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/08/2018] [Accepted: 05/08/2018] [Indexed: 02/07/2023] Open
Abstract
Hepatic Encephalopathy (HE) is a severe complication of acute or chronic liver diseases with a broad spectrum of neurological symptoms including motor disturbances and cognitive impairment of different severity. Contrary to former beliefs, a growing number of studies suggest that cognitive impairment may not fully reverse after an acute episode of overt HE in patients with liver cirrhosis. The reasons for persistent cognitive impairment in HE are currently unknown but recent observations raise the possibility that astrocyte senescence may play a role here. Astrocyte senescence is closely related to oxidative stress and correlate with irreversible cognitive decline in aging and neurodegenerative diseases. In line with this, surrogate marker for oxidative stress and senescence were upregulated in ammonia-exposed cultured astrocytes and in post mortem brain tissue from patients with liver cirrhosis with but not without HE. Ammonia-induced senescence in astrocytes involves glutamine synthesis-dependent formation of reactive oxygen species (ROS), p53 activation and upregulation of cell cycle inhibitory factors p21 and GADD45α. More recent studies also suggest a role of ROS-induced downregulation of Heme Oxygenase (HO)1-targeting micro RNAs and upregulation of HO1 for ammonia-induced proliferation inhibition in cultured astrocytes. Further studies are required to identify the precise sequence of events that lead to astrocyte senescence and to elucidate functional implications of senescence for cognitive performance in patients with liver cirrhosis and HE.
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Key Words
- ARE, Antioxidant Response Elements
- BDNF, Brain-Derived Neurotrophic Factor
- Eph, Ephrine
- EphR, Ephrine Receptor
- GADD45α, Growth Arrest and DNA Damage Inducible 45α
- GS, Glutamine Synthetase
- HE, Hepatic Encephalopathy
- HO1, Heme Oxygenase 1
- LOLA, l-Ornithine-l-Aspartate
- MAP, Mitogen Activated Protein Kinases
- NAPDH, Reduced Form of Nicotinamide Adenine Dinucleotide Phosphate
- Nox, NADPH Oxidase
- Nrf2, Nuclear Factor-Like 2
- PBR, Peripheral-Type Benzodiazepine Receptor
- PTN, Protein Tyrosine Nitration
- RNOS, Reactive Nitrogen and Oxygen Species
- ROS, Reactive Oxygen Species
- SA-β-Gal, Senescence-Associated β-d-Galactosidase
- TSP, Trombospondin
- TrkBT, Truncated Tyrosine Receptor Kinase B
- ZnPP, Zinc Protoporphyrin
- ammonia
- astrocytes
- heme oxygenase 1
- hepatic encephalopathy
- mPT, Mitochondrial Permeability Transition
- miRNAs
- nNOS, Neuronal-Type Nitric-Oxide Synthase
- oxidative stress
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Affiliation(s)
| | | | - Dieter Häussinger
- Address for correspondence: Dieter Häussinger, Universitätsklinikum Düsseldorf, Klinik für Gastroenterologie, Hepatologie und Infektiologie, Moorenstrasse 5, 40225 Düsseldorf, Germany. Tel.: +49 211 811 7569; fax: +49 211 811 8838.
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Zöllner HJ, Butz M, Kircheis G, Klinker S, Häussinger D, Schmitt B, Schnitzler A, Wittsack HJ. Ammonia-weighted imaging by chemical exchange saturation transfer MRI at 3 T. NMR IN BIOMEDICINE 2018; 31:e3947. [PMID: 29975436 DOI: 10.1002/nbm.3947] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/24/2017] [Revised: 03/19/2018] [Accepted: 04/25/2018] [Indexed: 06/08/2023]
Abstract
Hepatic encephalopathy (HE) is triggered by liver cirrhosis and is associated with an increased ammonia level within the brain tissue. The goal of this study was to investigate effects of ammonia on in vitro amide proton transfer (APT)-weighted chemical exchange saturation transfer (CEST) imaging in order to develop an ammonia-sensitive brain imaging method. APT-weighted CEST imaging was performed on phantom solutions including pure ammonia, bovine serum albumin (BSA), and tissue homogenate samples doped with various ammonia concentrations. All CEST data were assessed by magnetization transfer ratio asymmetry. In addition, optical methods were used to determine possible structural changes of the proteins in the BSA phantom. In vivo feasibility measurements were acquired in one healthy participant and two patients suffering from HE, a disease associated with increased brain ammonia levels. The CEST effect of pure ammonia showed a base-catalyzed behavior. At pH values greater than 5.6 no CEST effect was observed. The APT-weighted signal was significantly reduced for ammonia concentrations of 5mM or more at fixed pH values within the different protein phantom solutions. The optical methods revealed no protein aggregation or denaturation for ammonia concentrations less than 5mM. The in vivo measurements showed tissue specific and global reduction of the observed CEST signal in patients with HE, possibly linked to pathologically increased ammonia levels. APT-weighted CEST imaging is sensitive to changes in ammonia concentrations. Thus, it seems useful for the investigation of pathologies with altered tissue ammonia concentrations such as HE. However, the underlying mechanism needs to be explored in more detail in future in vitro and in vivo investigations.
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Affiliation(s)
- Helge Jörn Zöllner
- Institute of Clinical Neuroscience and Medical Psychology, Medical Faculty, Heinrich Heine University Düsseldorf, Germany
- Department of Diagnostic and Interventional Radiology, Medical Faculty, Heinrich Heine University Düsseldorf, Germany
| | - Markus Butz
- Institute of Clinical Neuroscience and Medical Psychology, Medical Faculty, Heinrich Heine University Düsseldorf, Germany
| | - Gerald Kircheis
- Department of Gastroenterology, Hepatology and Infectiology, Medical Faculty, Heinrich Heine University Düsseldorf, Germany
| | - Stefan Klinker
- Institute of Physical Biology, Heinrich Heine University Düsseldorf, Germany
| | - Dieter Häussinger
- Department of Gastroenterology, Hepatology and Infectiology, Medical Faculty, Heinrich Heine University Düsseldorf, Germany
| | - Benjamin Schmitt
- Siemens Ltd. Australia, Healthcare Sector, Macquarie, Park, NSW, Australia
| | - Alfons Schnitzler
- Institute of Clinical Neuroscience and Medical Psychology, Medical Faculty, Heinrich Heine University Düsseldorf, Germany
| | - Hans-Jörg Wittsack
- Department of Diagnostic and Interventional Radiology, Medical Faculty, Heinrich Heine University Düsseldorf, Germany
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Schall M, Zimmermann M, Iordanishvili E, Gu Y, Shah NJ, Oros-Peusquens AM. A 3D two-point method for whole-brain water content and relaxation time mapping: Comparison with gold standard methods. PLoS One 2018; 13:e0201013. [PMID: 30161125 PMCID: PMC6116981 DOI: 10.1371/journal.pone.0201013] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2018] [Accepted: 07/06/2018] [Indexed: 12/23/2022] Open
Abstract
Quantitative imaging of the human brain is of great interest in clinical research as it enables the identification of a range of MR biomarkers useful in diagnosis, treatment and prognosis of a wide spectrum of diseases. Here, a 3D two-point method for water content and relaxation time mapping is presented and compared to established gold standard methods. The method determines free water content, H2O, and the longitudinal relaxation time, T1, quantitatively from a two-point fit to the signal equation including corrections of the transmit and receive fields. In addition, the effective transverse relaxation time, T2*, is obtained from an exponential fit to the multi-echo signal train and its influence on H2O values is corrected. The phantom results obtained with the proposed method show good agreement for H2O and T1 values with known and spectroscopically measured values, respectively. The method is compared in vivo to already established gold standard quantitative methods. For H2O and T2* mapping, the 3D two-point results were compared to a measurement conducted with a multiple-echo GRE with long TR and T1 is compared to results from a Look-Locker method, TAPIR. In vivo results show good overall agreement between the methods, but some systematic deviations are present. Besides an expected dependence of T2* on voxel size, T1 values are systematically larger in the 3D approach than those obtained with the gold standard method. This behaviour might be due to imperfect spoiling, influencing each method differently. Results for H2O differ due to differences in the saturation of cerebrospinal fluid and partial volume effects. In addition, ground truth values of in vivo studies are unknown, even when comparing to in vivo gold standard methods. A detailed region-of-interest analysis for H2O and T1 matches well published literature values.
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Affiliation(s)
- Melissa Schall
- Institute of Neuroscience and Medicine 4 (INM-4), Research Centre Jülich, Jülich, Germany
| | - Markus Zimmermann
- Institute of Neuroscience and Medicine 4 (INM-4), Research Centre Jülich, Jülich, Germany
| | - Elene Iordanishvili
- Institute of Neuroscience and Medicine 4 (INM-4), Research Centre Jülich, Jülich, Germany
| | - Yun Gu
- Institute of Neuroscience and Medicine 4 (INM-4), Research Centre Jülich, Jülich, Germany
| | - N. Jon Shah
- Institute of Neuroscience and Medicine 4 (INM-4), Research Centre Jülich, Jülich, Germany
- Institute of Neuroscience and Medicine 11 (INM-11), Research Centre Jülich, Jülich, Germany
- Jülich Aachen Research Alliance (JARA-BRAIN)—TranslationalMedicine, Aachen, Germany
- Department of Neurology of the RWTH Aachen University, Aachen, Germany
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Zimmermann M, Abbas Z, Dzieciol K, Shah NJ. Accelerated Parameter Mapping of Multiple-Echo Gradient-Echo Data Using Model-Based Iterative Reconstruction. IEEE TRANSACTIONS ON MEDICAL IMAGING 2018; 37:626-637. [PMID: 29408790 DOI: 10.1109/tmi.2017.2771504] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
A new reconstruction method, coined MIRAGE, is presented for accurate, fast, and robust parameter mapping of multiple-echo gradient-echo (MEGE) imaging, the basis sequence of novel quantitative magnetic resonance imaging techniques such as water content and susceptibility mapping. Assuming that the temporal signal can be modeled as a sum of damped complex exponentials, MIRAGE performs model-based reconstruction of undersampled data by minimizing the rank of local Hankel matrices. It further incorporates multi-channel information and spatial prior knowledge. Finally, the parameter maps are estimated using nonlinear regression. Simulations and retrospective undersampling of phantom and in vivo data affirm robustness, e.g., to strong inhomogeneity of the static magnetic field and partial volume effects. MIRAGE is compared with a state-of-the-art compressed sensing method, -ESPIRiT. Parameter maps estimated from reconstructed data using MIRAGE are shown to be accurate, with the mean absolute error reduced by up to 50% for in vivo results. The proposed method has the potential to improve the diagnostic utility of quantitative imaging techniques that rely on MEGE data.
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Oros-Peusquens A, Loução R, Zimmermann M, Langen KJ, Shah N. Methods for molecular imaging of brain tumours in a hybrid MR-PET context: Water content, T 2 ∗ , diffusion indices and FET-PET. Methods 2017; 130:135-151. [DOI: 10.1016/j.ymeth.2017.07.025] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2017] [Revised: 05/22/2017] [Accepted: 07/27/2017] [Indexed: 11/27/2022] Open
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Cordes D, Yang Z, Zhuang X, Sreenivasan K, Mishra V, Hua LH. A new algebraic method for quantitative proton density mapping using multi-channel coil data. Med Image Anal 2017; 40:154-171. [PMID: 28668358 DOI: 10.1016/j.media.2017.06.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2017] [Revised: 05/06/2017] [Accepted: 06/15/2017] [Indexed: 11/30/2022]
Abstract
A difficult problem in quantitative MRI is the accurate determination of the proton density, which is an important quantity in measuring brain tissue organization. Recent progress in estimating proton density in vivo has been based on using the inverse linear relationship between the longitudinal relaxation rate T1 and proton density. In this study, the same type of relationship is being used, however, in a more general framework by constructing 3D basis functions to model the receiver bias field. The novelty of this method is that the basis functions developed are suitable to cover an entire range of inverse linearities between T1 and proton density. The method is applied by parcellating the human brain into small cubes with size 30mm x 30mm x 30mm. In each cube the optimal set of basis functions is determined to model the receiver coil sensitivities using multi-channel (32 element) coil data. For validation, we use arbitrary data from a numerical phantom where the data satisfy the conventional MR signal equations. Using added noise of different magnitude and realizations, we show that the proton densities obtained have a bias close to zero and also low noise sensitivity. The obtained root-mean-square-error rate is less than 0.2% for the estimated proton density in a realistic 3D simulation. As an application, the method is used in a small cohort of MS patients, and proton density values for specific brain structures are determined.
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Affiliation(s)
- Dietmar Cordes
- Cleveland Clinic Lou Ruvo Center for Brain Health, 888W. Bonneville Ave, Las Vegas, NV 89106, USA; University of Colorado, Boulder, CO, USA.
| | - Zhengshi Yang
- Cleveland Clinic Lou Ruvo Center for Brain Health, 888W. Bonneville Ave, Las Vegas, NV 89106, USA
| | - Xiaowei Zhuang
- Cleveland Clinic Lou Ruvo Center for Brain Health, 888W. Bonneville Ave, Las Vegas, NV 89106, USA
| | - Karthik Sreenivasan
- Cleveland Clinic Lou Ruvo Center for Brain Health, 888W. Bonneville Ave, Las Vegas, NV 89106, USA
| | - Virendra Mishra
- Cleveland Clinic Lou Ruvo Center for Brain Health, 888W. Bonneville Ave, Las Vegas, NV 89106, USA
| | - Le H Hua
- Cleveland Clinic Lou Ruvo Center for Brain Health, 888W. Bonneville Ave, Las Vegas, NV 89106, USA
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35
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Meyers SM, Kolind SH, MacKay AL. Simultaneous measurement of total water content and myelin water fraction in brain at 3 T using a T 2 relaxation based method. Magn Reson Imaging 2017; 37:187-194. [DOI: 10.1016/j.mri.2016.12.001] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2016] [Revised: 11/05/2016] [Accepted: 12/01/2016] [Indexed: 01/19/2023]
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Brusilow WSA, Peters TJ. Therapeutic effects of methionine sulfoximine in multiple diseases include and extend beyond inhibition of glutamine synthetase. Expert Opin Ther Targets 2017; 21:461-469. [PMID: 28292200 DOI: 10.1080/14728222.2017.1303484] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
INTRODUCTION Methionine sulfoximine (MSO), a well-characterized inhibitor of glutamine synthetase, displays significant therapeutic benefits in animal models for several human diseases. This amino acid might therefore be a viable candidate for drug development to treat diseases for which there are few effective therapies. Areas covered: We describe the effects of MSO on brain swelling occurring in overt hepatic encephalopathy resulting from liver failure, the effects of MSO on excitotoxic damage involved in amyotrophic lateral sclerosis (ALS) or resulting from stroke, and the effects of MSO on a model for an inflammatory immune response involved in a range of diseases. We conclude that these results imply the existence of another therapeutic target for MSO in addition to glutamine synthetase. Expert opinion: We summarize the various diseases for which MSO treatment might be a candidate for drug development. We discuss why MSO has limited enthusiasm in the scientific and medical communities for use in humans, with a rebuttal to those negative opinions. And we conclude that MSO should be considered a candidate drug to treat brain swelling involved in overt hepatic encephalopathy and diseases involving an inflammatory immune response.
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Affiliation(s)
- William S A Brusilow
- a Department of Biochemistry and Molecular Biology , Wayne State University School of Medicine , Detroit , MI , USA
| | - Tyler J Peters
- a Department of Biochemistry and Molecular Biology , Wayne State University School of Medicine , Detroit , MI , USA
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Rackayova V, Braissant O, McLin VA, Berset C, Lanz B, Cudalbu C. 1H and 31P magnetic resonance spectroscopy in a rat model of chronic hepatic encephalopathy: in vivo longitudinal measurements of brain energy metabolism. Metab Brain Dis 2016; 31:1303-1314. [PMID: 26253240 DOI: 10.1007/s11011-015-9715-8] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/18/2015] [Accepted: 07/26/2015] [Indexed: 12/21/2022]
Abstract
Chronic liver disease (CLD) leads to a spectrum of neuropsychiatric disorders named hepatic encephalopathy (HE). Even though brain energy metabolism is believed to be altered in chronic HE, few studies have explored energy metabolism in CLD-induced HE, and their findings were inconsistent. The aim of this study was to characterize for the first time in vivo and longitudinally brain metabolic changes in a rat model of CLD-induced HE with a focus on energy metabolism, using the methodological advantages of high field proton and phosphorus Magnetic Resonance Spectroscopy (1H- and 31P-MRS). Wistar rats were bile duct ligated (BDL) and studied before BDL and at post-operative weeks 4 and 8. Glutamine increased linearly over time (+146 %) together with plasma ammonium (+159 %). As a compensatory effect, other brain osmolytes decreased: myo-inositol (-36 %), followed by total choline and creatine. A decrease in the neurotransmitters glutamate (-17 %) and aspartate (-28 %) was measured only at week 8, while no significant changes were observed for lactate and phosphocreatine. Among the other energy metabolites measured by 31P-MRS, we observed a non-significant decrease in ATP together with a significant decrease in ADP (-28 %), but only at week 8 after ligation. Finally, brain glutamine showed the strongest correlations with changes in other brain metabolites, indicating its importance in type C HE. In conclusion, mild alterations in some metabolites involved in energy metabolism were observed but only at the end stage of the disease when edema and neurological changes are already present. Therefore, our data indicate that impaired energy metabolism is not one of the major causes of early HE symptoms in the established model of type C HE.
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Affiliation(s)
- Veronika Rackayova
- Laboratory of Functional and Metabolic Imaging (LIFMET), Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Olivier Braissant
- Service of Biomedicine, University Hospital of Lausanne, Lausanne, Switzerland
| | - Valérie A McLin
- Swiss Center for Liver Disease in Children, Department of Pediatrics, University Hospitals Geneva, Geneva, Switzerland
| | - Corina Berset
- Centre d'Imagerie Biomedicale (CIBM), Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Bernard Lanz
- Laboratory of Functional and Metabolic Imaging (LIFMET), Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Cristina Cudalbu
- Centre d'Imagerie Biomedicale (CIBM), Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland.
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Bémeur C, Cudalbu C, Dam G, Thrane AS, Cooper AJL, Rose CF. Brain edema: a valid endpoint for measuring hepatic encephalopathy? Metab Brain Dis 2016; 31:1249-1258. [PMID: 27272740 DOI: 10.1007/s11011-016-9843-9] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/05/2015] [Accepted: 05/19/2016] [Indexed: 12/12/2022]
Abstract
Hepatic encephalopathy (HE) is a major complication of liver failure/disease which frequently develops during the progression of end-stage liver disease. This metabolic neuropsychiatric syndrome involves a spectrum of symptoms, including cognition impairment, attention deficits and motor dysfunction which eventually can progress to coma and death. Pathologically, HE is characterized by swelling of the astrocytes which consequently leads to brain edema, a common feature found in patients with acute liver failure (ALF) as well as in cirrhotic patients suffering from HE. The pathogenic factors involved in the onset of astrocyte swelling and brain edema in HE are unresolved. However, the role of astrocyte swelling/brain edema in the development of HE remains ambiguous and therefore measuring brain edema as an endpoint to evaluate HE is questioned. The following review will determine the effect of astrocyte swelling and brain edema on neurological function, discuss the various possible techniques to measure brain edema and lastly to propose a number of neurobehavioral tests to evaluate HE.
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Affiliation(s)
- Chantal Bémeur
- Département de nutrition, Université de Montréal, Montréal, Québec, Canada
- Hepato-Neuro Laboratory, CRCHUM, Université de Montréal, Montréal, Québec, Canada
| | - Cristina Cudalbu
- Centre d'Imagerie Biomédicale (CIBM), Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Gitte Dam
- Department of Medicine V (Hepatology and Gastroenterology), Aarhus, Denmark
| | - Alexander S Thrane
- Department of Ophthalmology, Haukeland University Hospital, 5012, Bergen, Norway
- Division of Glial Disease and Therapeutics, Center for Translational Neuromedicine, Department of Neurosurgery, University of Rochester Medical Center, Rochester, New York, 14642, USA
| | - Arthur J L Cooper
- Department of Biochemistry and Molecular Biology, New York Medical College, Valhalla, New York, 10595, USA
| | - Christopher F Rose
- Hepato-Neuro Laboratory, CRCHUM, Université de Montréal, Montréal, Québec, Canada.
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Morgan MY, Amodio P, Cook NA, Jackson CD, Kircheis G, Lauridsen MM, Montagnese S, Schiff S, Weissenborn K. Qualifying and quantifying minimal hepatic encephalopathy. Metab Brain Dis 2016; 31:1217-1229. [PMID: 26412229 DOI: 10.1007/s11011-015-9726-5] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/04/2015] [Accepted: 09/01/2015] [Indexed: 12/11/2022]
Abstract
Minimal hepatic encephalopathy is the term applied to the neuropsychiatric status of patients with cirrhosis who are unimpaired on clinical examination but show alterations in neuropsychological tests exploring psychomotor speed/executive function and/or in neurophysiological variables. There is no gold standard for the diagnosis of this syndrome. As these patients have, by definition, no recognizable clinical features of brain dysfunction, the primary prerequisite for the diagnosis is careful exclusion of clinical symptoms and signs. A large number of psychometric tests/test systems have been evaluated in this patient group. Of these the best known and validated is the Portal Systemic Hepatic Encephalopathy Score (PHES) derived from a test battery of five paper and pencil tests; normative reference data are available in several countries. The electroencephalogram (EEG) has been used to diagnose hepatic encephalopathy since the 1950s but, once popular, the technology is not as accessible now as it once was. The performance characteristics of the EEG are critically dependent on the type of analysis undertaken; spectral analysis has better performance characteristics than visual analysis; evolving analytical techniques may provide better diagnostic information while the advent of portable wireless headsets may facilitate more widespread use. A large number of other diagnostic tools have been validated for the diagnosis of minimal hepatic encephalopathy including Critical Flicker Frequency, the Inhibitory Control Test, the Stroop test, the Scan package and the Continuous Reaction Time; each has its pros and cons; strengths and weaknesses; protagonists and detractors. Recent AASLD/EASL Practice Guidelines suggest that the diagnosis of minimal hepatic encephalopathy should be based on the PHES test together with one of the validated alternative techniques or the EEG. Minimal hepatic encephalopathy has a detrimental effect on the well-being of patients and their care-givers. It responds well to treatment with resolution of test abnormalities and the associated detrimental effects on quality of life, liver-related mortality and morbidity. Patients will only benefit in this way if they can be effectively diagnosed. Corporate efforts and consensus agreements are needed to develop effective diagnostic algorithms.
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Affiliation(s)
- Marsha Y Morgan
- UCL Institute for Liver & Digestive Health, Division of Medicine, Royal Free Campus, University College London, Rowland Hill Street, London, NW32PF, UK.
| | - Piero Amodio
- Department of Medicine, University of Padova, Via Giustiniani, 2, 35128, Padova, Italy
| | - Nicola A Cook
- Department of Medicine, St Mary's Hospital Campus, Imperial College, London, W2 1NY, UK
| | - Clive D Jackson
- Department of Neurophysiology, Royal Free Hospital, Royal Free London NHS Foundation Trust, Pond Street, London, Hampstead, NW3 2QG, UK
| | - Gerald Kircheis
- Department of Gastroenterology, Hepatology and Infectious Diseases, Heinrich-Heine-University Düsseldorf, Düsseldorf, Germany
| | - Mette M Lauridsen
- Department of Gastroenterology, Hospital of South West Jutland, Finsensgade 35, 6700, Esbjerg, Denmark
| | - Sara Montagnese
- Department of Medicine, University of Padova, Via Giustiniani, 2, 35128, Padova, Italy
| | - Sami Schiff
- Department of Medicine, University of Padova, Via Giustiniani, 2, 35128, Padova, Italy
| | - Karin Weissenborn
- Department of Neurology, Hannover Medical School, 30623, Hannover, Germany
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Oeltzschner G, Butz M, Wickrath F, Wittsack HJ, Schnitzler A. Covert hepatic encephalopathy: elevated total glutathione and absence of brain water content changes. Metab Brain Dis 2016; 31:517-27. [PMID: 26563124 DOI: 10.1007/s11011-015-9760-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/22/2015] [Accepted: 11/06/2015] [Indexed: 01/20/2023]
Abstract
Recent pathophysiological models suggest that oxidative stress and hyperammonemia lead to a mild brain oedema in hepatic encephalopathy (HE). Glutathione (GSx) is a major cellular antioxidant and known to be involved in the interception of both. The aim of this work was to study total glutathione levels in covert HE (minimal HE and HE grade 1) and to investigate their relationship with local brain water content, levels of glutamine (Gln), myo-inositol (mI), neurotransmitter levels, critical flicker frequency (CFF), and blood ammonia. Proton magnetic resonance spectroscopy ((1)H MRS) data were analysed from visual and sensorimotor cortices of thirty patients with covert HE and 16 age-matched healthy controls. Total glutathione levels (GSx/Cr) were quantified with respect to creatine. Furthermore, quantitative MRI brain water content measures were evaluated. Data were tested for links with the CFF and blood ammonia. GSx/Cr was elevated in the visual (mHE) and sensorimotor (mHE, HE 1) MRS volumes and correlated with blood ammonia levels (both P < 0.001). It was further linked to Gln/Cr and mI/Cr (P < 0.01 in visual, P < 0.001 in sensorimotor) and to GABA/Cr (P < 0.01 in visual). Visual GSx/Cr correlated with brain water content in the thalamus, nucleus caudatus, and visual cortex (P < 0.01). Brain water measures did neither show group effects nor correlations with CFF or blood ammonia. Elevated total glutathione levels in covert HE (< HE 2) correlate with blood ammonia and may be a regional-specific reaction to hyperammonemia and oxidative stress. Brain water content is locally linked to visual glutathione levels, but appears not to be associated with changes of clinical parameters. This might suggest that cerebral oedema is only marginally responsible for the symptoms of covert HE.
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Affiliation(s)
- Georg Oeltzschner
- Institute of Clinical Neuroscience and Medical Psychology, Medical Faculty, Heinrich-Heine-University Düsseldorf, Universitätsstr. 1, D-40225, Düsseldorf, Germany.
- Department of Diagnostic and Interventional Radiology, Medical Faculty, Heinrich-Heine-University Düsseldorf, D-40225, Düsseldorf, Germany.
| | - Markus Butz
- Institute of Clinical Neuroscience and Medical Psychology, Medical Faculty, Heinrich-Heine-University Düsseldorf, Universitätsstr. 1, D-40225, Düsseldorf, Germany
| | - Frithjof Wickrath
- Department of Diagnostic and Interventional Radiology, Medical Faculty, Heinrich-Heine-University Düsseldorf, D-40225, Düsseldorf, Germany
| | - Hans-Jörg Wittsack
- Department of Diagnostic and Interventional Radiology, Medical Faculty, Heinrich-Heine-University Düsseldorf, D-40225, Düsseldorf, Germany
| | - Alfons Schnitzler
- Institute of Clinical Neuroscience and Medical Psychology, Medical Faculty, Heinrich-Heine-University Düsseldorf, Universitätsstr. 1, D-40225, Düsseldorf, Germany
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Li M, Gong S, Li Q, Yuan L, Meng F, Wang R. Ammonia toxicity induces glutamine accumulation, oxidative stress and immunosuppression in juvenile yellow catfish Pelteobagrus fulvidraco. Comp Biochem Physiol C Toxicol Pharmacol 2016; 183-184:1-6. [PMID: 26811908 DOI: 10.1016/j.cbpc.2016.01.005] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/10/2015] [Revised: 01/01/2016] [Accepted: 01/21/2016] [Indexed: 12/27/2022]
Abstract
A study was carried to test the response of yellow catfish for 28 days under two ammonia concentrations. Weight gain of fish exposure to high and low ammonia abruptly increased at day 3. There were no significant changes in fish physiological indexes and immune responses at different times during 28-day exposure to low ammonia. Fish physiological indexes and immune responses in the treatment of high ammonia were lower than those of fish in the treatment of low ammonia. When fish were exposed to high ammonia, the ammonia concentration in the brain increased by 19-fold on day 1. By comparison, liver ammonia concentration reached its highest level much earlier at hour 12. In spite of a significant increase in brain and liver glutamine concentration, there was no significant change in glutamate level throughout the 28-day period. The total superoxide dismutase (SOD), glutathione peroxidase (GPX) and glutathione reductase (GR) activities in the brain gradually decreased from hour 0 to day 28. Liver SOD, GPX and GR activities reached the highest levels at hour 12, and then gradually decreased. Thiobarbituric acid reactive substance brain and liver content gradually increased throughout the 28-day period. Lysozyme, acid phosphatase and alkaline phosphatase activities in the liver reached exceptionally low levels after day 14. This study indicated that glutamine accumulation in the brain was not the major cause of ammonia poisoning, the toxic reactive oxygen species is not fully counter acted by the antioxidant enzymes and immunosuppression is a process of gradual accumulation of immunosuppressive factors.
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Affiliation(s)
- Ming Li
- School of Marine Sciences, Ningbo University, Ningbo 315211, China
| | - Shiyan Gong
- School of Marine Sciences, Ningbo University, Ningbo 315211, China
| | - Qing Li
- School of Marine Sciences, Ningbo University, Ningbo 315211, China
| | - Lixia Yuan
- School of Marine Sciences, Ningbo University, Ningbo 315211, China
| | - Fanxing Meng
- School of Marine Sciences, Ningbo University, Ningbo 315211, China
| | - Rixin Wang
- School of Marine Sciences, Ningbo University, Ningbo 315211, China.
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Use of quantitative brain water imaging as concentration reference for J-edited MR spectroscopy of GABA. Magn Reson Imaging 2016; 34:1057-63. [PMID: 27109486 DOI: 10.1016/j.mri.2016.04.013] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2015] [Revised: 04/08/2016] [Accepted: 04/17/2016] [Indexed: 02/06/2023]
Abstract
PURPOSE To compare two different methods of obtaining the water reference for determination of quantitative water-scaled in vivo concentration estimates of γ-aminobutyric acid (GABA). METHODS Water-scaled GABA estimates from localized J-difference edited MR spectroscopy experiments can be computed using standard values for tissue-specific water content and relaxation times. Water content and relaxation may, however, be altered in pathology. This work re-analyzed data from a recent study in healthy controls and patients with minimal (mHE) or grade I (HE 1) hepatic encephalopathy, a disease associated with slight elevation of brain water content. J-difference edited MR spectroscopy data were combined with quantitative brain water measures, which provided individual water density references and T1 relaxation times. Resulting GABA estimates were compared to concentration values obtained using standard tissue-specific water content and relaxation values. RESULTS Occipital GABA concentration values obtained from individual water and T1 maps were 1.64±0.35mM in controls, and significantly higher (P<0.01) than in mHE (1.15±0.28mM) and HE 1 patients (1.18±0.09mM). Results from the tissue-dependent approach (1.58±0.30mM (controls), 1.10±0.27mM (mHE) and 1.12±0.12mM (HE 1)) were slightly lower (P<0.05 in each group). CONCLUSION Water-scaled in vivo GABA estimates can be obtained with individual water density and T1 relaxation mapping. This approach may be useful for studying GABA levels in pathologies with substantial brain water content or relaxation changes.
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Measuring water content using T2 relaxation at 3T: Phantom validations and simulations. Magn Reson Imaging 2016; 34:246-51. [DOI: 10.1016/j.mri.2015.11.008] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2015] [Revised: 07/23/2015] [Accepted: 11/29/2015] [Indexed: 12/14/2022]
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Baudrexel S, Reitz SC, Hof S, Gracien RM, Fleischer V, Zimmermann H, Droby A, Klein JC, Deichmann R. Quantitative T1 and proton density mapping with direct calculation of radiofrequency coil transmit and receive profiles from two-point variable flip angle data. NMR IN BIOMEDICINE 2016; 29:349-360. [PMID: 26756673 DOI: 10.1002/nbm.3460] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/2015] [Revised: 11/10/2015] [Accepted: 11/16/2015] [Indexed: 06/05/2023]
Abstract
Quantitative T1 mapping of brain tissue is frequently based on the variable flip angle (VFA) method, acquiring spoiled gradient echo (GE) datasets at different excitation angles. However, accurate T1 calculation requires a knowledge of the sensitivity profile B1 of the radiofrequency (RF) transmit coil. For an additional derivation of proton density (PD) maps, the receive coil sensitivity profile (RP) must also be known. Mapping of B1 and RP increases the experiment duration, which may be critical when investigating patients. In this work, a method is presented for the direct calculation of B1 and RP from VFA data. Thus, quantitative maps of T1 , PD, B1 and RP can be obtained from only two spoiled GE datasets. The method is based on: (1) the exploitation of the linear relationship between 1/PD and 1/T1 in brain tissue and (2) the assumption of smoothly varying B1 and RP, so that a large number of data points can be fitted across small volume elements where B1 and RP are approximately constant. The method is tested and optimized on healthy subjects. Copyright © 2016 John Wiley & Sons, Ltd.
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Affiliation(s)
- Simon Baudrexel
- Brain Imaging Center, Goethe University Frankfurt, Frankfurt/Main, Germany
- Department of Neurology, Goethe University Frankfurt, Frankfurt/Main, Germany
| | - Sarah C Reitz
- Brain Imaging Center, Goethe University Frankfurt, Frankfurt/Main, Germany
- Department of Neurology, Goethe University Frankfurt, Frankfurt/Main, Germany
| | - Stephanie Hof
- Brain Imaging Center, Goethe University Frankfurt, Frankfurt/Main, Germany
- Department of Neurology, Goethe University Frankfurt, Frankfurt/Main, Germany
| | - René-Maxime Gracien
- Brain Imaging Center, Goethe University Frankfurt, Frankfurt/Main, Germany
- Department of Neurology, Goethe University Frankfurt, Frankfurt/Main, Germany
| | - Vinzenz Fleischer
- Department of Neurology, Johannes Gutenberg University, Mainz, Germany
- Neuroimaging Center (NIC) of the Focus Program Translational Neuroscience (FTN), Johannes Gutenberg University, Mainz, Germany
| | - Hilga Zimmermann
- Department of Neurology, Johannes Gutenberg University, Mainz, Germany
- Neuroimaging Center (NIC) of the Focus Program Translational Neuroscience (FTN), Johannes Gutenberg University, Mainz, Germany
| | - Amgad Droby
- Department of Neurology, Johannes Gutenberg University, Mainz, Germany
- Neuroimaging Center (NIC) of the Focus Program Translational Neuroscience (FTN), Johannes Gutenberg University, Mainz, Germany
| | - Johannes C Klein
- Brain Imaging Center, Goethe University Frankfurt, Frankfurt/Main, Germany
- Department of Neurology, Goethe University Frankfurt, Frankfurt/Main, Germany
| | - Ralf Deichmann
- Brain Imaging Center, Goethe University Frankfurt, Frankfurt/Main, Germany
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45
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Shah NJ, Worthoff WA, Langen KJ. Imaging of sodium in the brain: a brief review. NMR IN BIOMEDICINE 2016; 29:162-174. [PMID: 26451752 DOI: 10.1002/nbm.3389] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/05/2015] [Revised: 07/30/2015] [Accepted: 08/07/2015] [Indexed: 06/05/2023]
Abstract
Sodium-based MRI plays a vital role in the study of metabolism and can unveil valuable information about emerging and existing pathology--in particular in the human brain. Sodium is the second most abundant MR active nucleus in living tissue and, due to its quadrupolar nature, has magnetic properties not common to conventional proton MRI, which can reveal further insights, such as information on the compartmental distribution of intra- and extracellular sodium. Nevertheless, the use of sodium nuclei for imaging comes at the expense of a lower sensitivity and significantly reduced relaxation times, making in vivo sodium studies feasible only at high magnetic field strength and by the use of dedicated pulse sequences. Hybrid imaging combining sodium MRI and positron emission tomography (PET) simultaneously is a novel and promising approach to access information on dynamic metabolism with much increased, PET-derived specificity. Application of this new methodology is demonstrated herein using examples from tumour imaging.
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Affiliation(s)
- N Jon Shah
- Institute of Neuroscience and Medicine-4, Forschungszentrum Juelich GmbH, 52425, Jülich, Germany
- Department of Neurology, Faculty of Medicine, RWTH Aachen University, Aachen, Germany
- Jülich Aachen Research Alliance (JARA) - Translational Brain Medicine, Aachen and Jülich, Germany
| | - Wieland A Worthoff
- Institute of Neuroscience and Medicine-4, Forschungszentrum Juelich GmbH, 52425, Jülich, Germany
| | - Karl-Josef Langen
- Institute of Neuroscience and Medicine-4, Forschungszentrum Juelich GmbH, 52425, Jülich, Germany
- Jülich Aachen Research Alliance (JARA) - Translational Brain Medicine, Aachen and Jülich, Germany
- Department of Nuclear Medicine, Faculty of Medicine, RWTH Aachen University, Aachen, Germany
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46
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Oeltzschner G, Butz M, Baumgarten TJ, Hoogenboom N, Wittsack HJ, Schnitzler A. Low visual cortex GABA levels in hepatic encephalopathy: links to blood ammonia, critical flicker frequency, and brain osmolytes. Metab Brain Dis 2015; 30:1429-38. [PMID: 26359122 DOI: 10.1007/s11011-015-9729-2] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/31/2015] [Accepted: 09/03/2015] [Indexed: 12/22/2022]
Abstract
The pathogenesis of hepatic encephalopathy (HE) is not fully understood yet. Hyperammonemia due to liver failure and subsequent disturbance of cerebral osmolytic balance is thought to play a pivotal role in the emergence of HE. The aim of this in-vivo MR spectroscopy study was to investigate the levels of γ-aminobutyric acid (GABA) and its correlations with clinical symptoms of HE, blood ammonia, critical flicker frequency, and osmolytic levels. Thirty patients with minimal HE or HE1 and 16 age-matched healthy controls underwent graduation of HE according to the West-Haven criteria and including the critical flicker frequency (CFF), neuropsychometric testing and blood testing. Edited proton magnetic resonance spectroscopy ((1)H MRS) was used to non-invasively measure the concentrations of GABA, glutamate (Glu), glutamine (Gln), and myo-inositol (mI) - all normalized to creatine (Cr) - in visual and sensorimotor cortex. GABA/Cr in the visual area was significantly decreased in mHE and HE1 patients and correlated both to the CFF (r = 0.401, P = 0.013) and blood ammonia levels (r = -0.434, P = 0.006). Visual GABA/Cr was also strongly linked to mI/Cr (r = 0.720, P < 0.001) and Gln/Cr (r = -0.699, P < 0.001). No group differences or correlations were found for GABA/Cr in the sensorimotor area. Hepatic encephalopathy is associated with a regional specific decrease of GABA levels in the visual cortex, while no changes were revealed for the sensorimotor cortex. Correlations of visual GABA/Cr with CFF, blood ammonia, and osmolytic regulators mI and Gln indicate that decreased visual GABA levels might contribute to HE symptoms, most likely as a consequence of hyperammonemia.
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Affiliation(s)
- Georg Oeltzschner
- Institute of Clinical Neuroscience and Medical Psychology, Medical Faculty, Heinrich Heine University Düsseldorf, Universitätsstr. 1, D-40225, Düsseldorf, Germany.
- Medical Faculty, Department of Diagnostic and Interventional Radiology, University Düsseldorf, D-40225, Düsseldorf, Germany.
| | - Markus Butz
- Institute of Clinical Neuroscience and Medical Psychology, Medical Faculty, Heinrich Heine University Düsseldorf, Universitätsstr. 1, D-40225, Düsseldorf, Germany
| | - Thomas J Baumgarten
- Institute of Clinical Neuroscience and Medical Psychology, Medical Faculty, Heinrich Heine University Düsseldorf, Universitätsstr. 1, D-40225, Düsseldorf, Germany
| | - Nienke Hoogenboom
- Institute of Clinical Neuroscience and Medical Psychology, Medical Faculty, Heinrich Heine University Düsseldorf, Universitätsstr. 1, D-40225, Düsseldorf, Germany
| | - Hans-Jörg Wittsack
- Medical Faculty, Department of Diagnostic and Interventional Radiology, University Düsseldorf, D-40225, Düsseldorf, Germany
| | - Alfons Schnitzler
- Institute of Clinical Neuroscience and Medical Psychology, Medical Faculty, Heinrich Heine University Düsseldorf, Universitätsstr. 1, D-40225, Düsseldorf, Germany
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47
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Rathi S, Dhiman RK. Hepatobiliary Quiz (Answers)-14 (2015). J Clin Exp Hepatol 2015; 5:175-8. [PMID: 26155047 PMCID: PMC4491639 DOI: 10.1016/j.jceh.2015.06.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/21/2015] [Accepted: 05/21/2015] [Indexed: 12/12/2022] Open
Affiliation(s)
| | - Radha K. Dhiman
- Department of Hepatology, Postgraduate Institute of Medical Education and Research, Chandigarh 160012, India
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Abstract
The presence of hepatic encephalopathy (HE) within 4 weeks is part of the criteria for defining acute-on-chronic liver failure (ACLF). The pathophysiology of HE is complex, and hyperammonemia and cerebral hemodynamic dysfunction appear to be central in the pathogenesis of encephalopathy. Recent data also suggest that inflammatory mediators may have a significant role in modulating the cerebral effect of ammonia. Multiple prospective and retrospective studies have shown that hepatic encephalopathy in ACLF patients is associated with higher mortality, especially in those with grade III-IV encephalopathy, similar to that of acute liver failure (ALF). Although significant cerebral edema detected by CT in ACLF patients appeared to be less common, specialized MRI imaging was able to detect cerebral edema even in low grade HE. Ammonia-focused therapy constitutes the basis of current therapy, as in the treatment of ALF. Emerging treatment strategies focusing on modulating the gut-liver-circulation-brain axis are discussed.
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Affiliation(s)
- Guan-Huei Lee
- Department of Medicine, National University Health System, 1E, Kent Ridge Road, Singapore, 119228, Singapore.
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49
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Reetz K, Abbas Z, Costa AS, Gras V, Tiffin-Richards F, Mirzazade S, Holschbach B, Frank RD, Vassiliadou A, Krüger T, Eitner F, Gross T, Schulz JB, Floege J, Shah NJ. Increased cerebral water content in hemodialysis patients. PLoS One 2015; 10:e0122188. [PMID: 25826269 PMCID: PMC4380497 DOI: 10.1371/journal.pone.0122188] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2014] [Accepted: 02/10/2015] [Indexed: 12/27/2022] Open
Abstract
Little information is available on the impact of hemodialysis on cerebral water homeostasis and its distribution in chronic kidney disease. We used a neuropsychological test battery, structural magnetic resonance imaging (MRI) and a novel technique for quantitative measurement of localized water content using 3T MRI to investigate ten hemodialysis patients (HD) on a dialysis-free day and after hemodialysis (2.4±2.2 hours), and a matched healthy control group with the same time interval. Neuropsychological testing revealed mainly attentional and executive cognitive dysfunction in HD. Voxel-based-morphometry showed only marginal alterations in the right inferior medial temporal lobe white matter in HD compared to controls. Marked increases in global brain water content were found in the white matter, specifically in parietal areas, in HD patients compared to controls. Although the global water content in the gray matter did not differ between the two groups, regional increases of brain water content in particular in parieto-temporal gray matter areas were observed in HD patients. No relevant brain hydration changes were revealed before and after hemodialysis. Whereas longer duration of dialysis vintage was associated with increased water content in parieto-temporal-occipital regions, lower intradialytic weight changes were negatively correlated with brain water content in these areas in HD patients. Worse cognitive performance on an attention task correlated with increased hydration in frontal white matter. In conclusion, long-term HD is associated with altered brain tissue water homeostasis mainly in parietal white matter regions, whereas the attentional domain in the cognitive dysfunction profile in HD could be linked to increased frontal white matter water content.
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Affiliation(s)
- Kathrin Reetz
- Department of Neurology, RWTH Aachen University Hospital, Germany
- Institute of Neuroscience and Medicine (INM-4), Research Centre Jülich GmbH, Jülich, Germany
- Jülich Aachen Research Alliance (JARA)—Translational Brain Medicine, Jülich and Aachen, Germany
- * E-mail:
| | - Zaheer Abbas
- Department of Neurology, RWTH Aachen University Hospital, Germany
- Institute of Neuroscience and Medicine (INM-4), Research Centre Jülich GmbH, Jülich, Germany
- Jülich Aachen Research Alliance (JARA)—Translational Brain Medicine, Jülich and Aachen, Germany
| | - Ana Sofia Costa
- Department of Neurology, RWTH Aachen University Hospital, Germany
- Jülich Aachen Research Alliance (JARA)—Translational Brain Medicine, Jülich and Aachen, Germany
| | - Vincent Gras
- Institute of Neuroscience and Medicine (INM-4), Research Centre Jülich GmbH, Jülich, Germany
| | - Frances Tiffin-Richards
- Department of Neurology, RWTH Aachen University Hospital, Germany
- Jülich Aachen Research Alliance (JARA)—Translational Brain Medicine, Jülich and Aachen, Germany
| | - Shahram Mirzazade
- Department of Neurology, RWTH Aachen University Hospital, Germany
- Institute of Neuroscience and Medicine (INM-4), Research Centre Jülich GmbH, Jülich, Germany
- Jülich Aachen Research Alliance (JARA)—Translational Brain Medicine, Jülich and Aachen, Germany
| | - Bernhard Holschbach
- KfH Kuratorium für Dialyse und Nierentransplantation e.V., Stolberg, Germany
| | - Rolf Dario Frank
- Department of Internal Medicine, St.-Antonius-Hospital Eschweiler, Eschweiler, Germany
| | | | - Thilo Krüger
- Division of Nephrology and Clinical Immunology, RWTH Aachen University, Aachen, Germany
| | - Frank Eitner
- Division of Nephrology and Clinical Immunology, RWTH Aachen University, Aachen, Germany
| | - Theresa Gross
- Division of Nephrology and Clinical Immunology, RWTH Aachen University, Aachen, Germany
| | - Jörg Bernhard Schulz
- Department of Neurology, RWTH Aachen University Hospital, Germany
- Jülich Aachen Research Alliance (JARA)—Translational Brain Medicine, Jülich and Aachen, Germany
| | - Jürgen Floege
- Division of Nephrology and Clinical Immunology, RWTH Aachen University, Aachen, Germany
| | - Nadim Jon Shah
- Department of Neurology, RWTH Aachen University Hospital, Germany
- Institute of Neuroscience and Medicine (INM-4), Research Centre Jülich GmbH, Jülich, Germany
- Jülich Aachen Research Alliance (JARA)—Translational Brain Medicine, Jülich and Aachen, Germany
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50
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Chavarria L, Cordoba J. Magnetic resonance imaging and spectroscopy in hepatic encephalopathy. J Clin Exp Hepatol 2015; 5:S69-74. [PMID: 26041961 PMCID: PMC4442861 DOI: 10.1016/j.jceh.2013.10.001] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/18/2013] [Accepted: 10/22/2013] [Indexed: 12/12/2022] Open
Abstract
Hepatic encephalopathy is a brain alteration associated to liver failure that produces cognitive impairments at long term. Neuroimaging are non-invasive methods for the study of the brain by means of spectroscopy and imaging techniques. These technologies give huge information about cerebral metabolism and water distribution to explore brain pathways involved in the pathogenesis of hepatic encephalopathy. Furthermore, new magnetic resonance implementations such as voxel-based morphometry or resting-state functional magnetic resonance imaging allow studying brain atrophy and neuronal connectivity of the cerebral network involved in the neurocognitive impairments observed in the patients. The development of magnetic resonance technology will generate handy tools for the brain study of liver failure to elucidate the time-course of the pathology and thus to obtain an early diagnosis of cerebral complications.
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Key Words
- ADC, apparent diffusion coefficient
- CFF, critical flicker frequency
- HE, hepatic encephalopathy
- MR, magnetic resonance
- MRI, magnetic resonance imaging
- MRS, magnetic resonance spectroscopy
- MT, magnetization transfer
- MTR, magnetization transfer ratio
- NAA, N-acetyl aspartate
- PHES, psychometric hepatic encephalopathy score
- VBM, voxel-based morphometry
- fMRI, functional magnetic resonance imaging
- hepatic encephalopathy
- imaging
- magnetic resonance
- spectroscopy
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Affiliation(s)
- Laia Chavarria
- Liver Unit, Hospital Vall Hebron, Barcelona, Spain,Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBEREHD), Instituto de Salud Carlos III, Madrid, Spain,Departament Medicina, Universitat Autònoma de Barcelona, Bellaterra, Spain
| | - Juan Cordoba
- Liver Unit, Hospital Vall Hebron, Barcelona, Spain,Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBEREHD), Instituto de Salud Carlos III, Madrid, Spain,Departament Medicina, Universitat Autònoma de Barcelona, Bellaterra, Spain,Address for correspondence: Juan Córdoba, Hospital Universitari Vall d'Hebron, Passeig Vall d'Hebron 119-129, Barcelona 08035, Spain. Tel.: +34 932476140; fax: +34 932476068.
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