1
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Mahmud SZ, Denney TS, Bashir A. Non-contrast estimate of blood-brain barrier permeability in humans using arterial spin labeling and magnetization transfer at 7 T. NMR IN BIOMEDICINE 2023; 36:e4908. [PMID: 36650646 DOI: 10.1002/nbm.4908] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/29/2022] [Revised: 12/17/2022] [Accepted: 01/16/2023] [Indexed: 06/15/2023]
Abstract
Blood-brain barrier (BBB) dysfunction is associated with a number of central nervous system diseases. This study demonstrates the application of a novel noninvasive technique to measure the BBB permeability in the human brain at 7 T. The technique exploits the fact that, when tissue macromolecules are saturated by off-resonance RF pulse, the intravascular and the extravascular (tissue) water experience different magnetization transfer effects. This principle was combined with arterial spin labeling to distinguish between the intravascular and the tissue water, and was used to calculate perfusion, water extraction fraction (E), and BBB permeability surface area product for water (PS). Simultaneous coregistered magnetization transfer ratio maps were also generated that can provide valuable additional information. Eighteen healthy volunteers (seven females), age = 27 ± 11 years and weight = 65 ± 9 kg, participated in the study. Average perfusion was 67 ± 5 and 29 ± 4 ml/100 g/min (p < 0.05); and E was 0.921 ± 0.025 and 0.962 ± 0.015 (p < 0.05) in the gray matter (GM) and the white matter (WM), respectively. PS was higher in the GM (171 ± 20 ml/100 g/min) compared with the WM (95 ± 18 ml/100 g/min) (p < 0.05). The parameters exhibited good reliability with test re-test experiments. The sensitivity of this technique was demonstrated by 200 mg caffeine intake, which resulted in a decrease in the resting PS by ~31%.
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Affiliation(s)
- Sultan Z Mahmud
- Department of Electrical and Computer Engineering, Auburn University, Auburn, Alabama, USA
- Auburn University MRI Research Center, Auburn University, Auburn, Alabama, USA
| | - Thomas S Denney
- Department of Electrical and Computer Engineering, Auburn University, Auburn, Alabama, USA
- Auburn University MRI Research Center, Auburn University, Auburn, Alabama, USA
| | - Adil Bashir
- Department of Electrical and Computer Engineering, Auburn University, Auburn, Alabama, USA
- Auburn University MRI Research Center, Auburn University, Auburn, Alabama, USA
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2
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Li M, Liu J, Chen F, Fan C, Yang X, Sun X. Contrast-induced encephalopathy following endovascular treatment for intracranial aneurysms-risk factors analysis and clinical strategy. Neuroradiology 2023; 65:629-635. [PMID: 36287224 DOI: 10.1007/s00234-022-03077-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2022] [Accepted: 10/19/2022] [Indexed: 10/31/2022]
Abstract
PURPOSE Contrast-induced encephalopathy (CIE) was defined as new onset of neurological deficits after exposure to contrast media, which could be observed after the endovascular treatment for intracranial aneurysms. METHODS We enrolled a consecutive cohort of patients who underwent endovascular treatment for unruptured intracranial aneurysms. CIE was defined as a reversible neuropathic syndrome that occurred after interventional therapy, accompanied by imaging abnormalities and excluding other diseases. Multivariable Poisson regression analysis was performed to show risk factors by incidence rate ratio (IRR) and a clinical strategy was proposed. RESULTS Among the 579 patients who underwent interventional therapy for intracranial aneurysms, the crude incidence rate of CIE was 2.4% (95% CI, 1.2-3.6%) at our center. Headache, hemiplegia, and disorientation could be initial symptoms, and cortical blindness was the most common localized deficit. Cerebral edema and sulci effacement on CT were observed, and re-revaluation after treatments on CT/MRI showed absent lesions. The risk factors were history of stroke (IRR, 7.752; P = 0.007), history of hypertension (IRR, 1.064; P = 0.042), posterior circulation aneurysms (IRR, 9.412; P = 0.004) and higher dosage of contrast agents (IRR, 1.018; P = 0.007). After the strategy of accelerating excretion of contrast agents, reduction of intracranial pressure and anti-inflammation/vasospasm therapy, the prognosis was favorable with most patients fully recovered within 72 h. CONCLUSION History of stroke and posterior circulation aneurysms were main risk factors for CIE. A higher dosage of contrast agents might induce CIE, and the history of hypertension should be considered as well.
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Affiliation(s)
- Mengxing Li
- Department of Interventional Neuroradiology, Beijing Neurosurgical Institute and Beijing Tiantan Hospital, Capital Medical University, Beijing, China
| | - Jian Liu
- Department of Interventional Neuroradiology, Beijing Neurosurgical Institute and Beijing Tiantan Hospital, Capital Medical University, Beijing, China
| | - Feng Chen
- Department of Medical Statistics, School of Public Health, Sun Yat-Sen University, Guangzhou, China
| | - Chengzhe Fan
- Department of Neurology, Beijing Anzhen Hospital, Capital Medical University, Beijing, China
| | - Xinjian Yang
- Department of Interventional Neuroradiology, Beijing Neurosurgical Institute and Beijing Tiantan Hospital, Capital Medical University, Beijing, China
| | - Xuan Sun
- Department of Interventional Neuroradiology, Beijing Tiantan Hospital, Capital Medical University, No. 119, South 4th Ring West Road, Fengtai District, Beijing, China.
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3
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Okada T, Suzuki H, Travis ZD, Zhang JH. The Stroke-Induced Blood-Brain Barrier Disruption: Current Progress of Inspection Technique, Mechanism, and Therapeutic Target. Curr Neuropharmacol 2020; 18:1187-1212. [PMID: 32484111 PMCID: PMC7770643 DOI: 10.2174/1570159x18666200528143301] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Revised: 04/23/2020] [Accepted: 05/23/2020] [Indexed: 02/07/2023] Open
Abstract
Stroke is one of the leading causes of mortality and morbidity worldwide. The blood-brain barrier (BBB) is a characteristic structure of microvessel within the brain. Under normal physiological conditions, the BBB plays a role in the prevention of harmful substances entering into the brain parenchyma within the central nervous system. However, stroke stimuli induce the breakdown of BBB leading to the influx of cytotoxic substances, vasogenic brain edema, and hemorrhagic transformation. Therefore, BBB disruption is a major complication, which needs to be addressed in order to improve clinical outcomes in stroke. In this review, we first discuss the structure and function of the BBB. Next, we discuss the progress of the techniques utilized to study BBB breakdown in in-vitro and in-vivo studies, along with biomarkers and imaging techniques in clinical settings. Lastly, we highlight the mechanisms of stroke-induced neuroinflammation and apoptotic process of endothelial cells causing BBB breakdown, and the potential therapeutic targets to protect BBB integrity after stroke. Secondary products arising from stroke-induced tissue damage provide transformation of myeloid cells such as microglia and macrophages to pro-inflammatory phenotype followed by further BBB disruption via neuroinflammation and apoptosis of endothelial cells. In contrast, these myeloid cells are also polarized to anti-inflammatory phenotype, repairing compromised BBB. Therefore, therapeutic strategies to induce anti-inflammatory phenotypes of the myeloid cells may protect BBB in order to improve clinical outcomes of stroke patients.
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Affiliation(s)
- Takeshi Okada
- Department of Physiology and Pharmacology, Loma Linda University, Loma Linda, CA, USA, Risley Hall, Room 219,
11041 Campus St, Loma Linda, CA 92354, USA,Department of Neurosurgery, Mie University Graduate School of Medicine, Mie, Japan, 2-174 Edobashi, Tsu, Mie 514-8507, Japan
| | - Hidenori Suzuki
- Department of Neurosurgery, Mie University Graduate School of Medicine, Mie, Japan, 2-174 Edobashi, Tsu, Mie 514-8507, Japan
| | - Zachary D Travis
- Department of Physiology and Pharmacology, Loma Linda University, Loma Linda, CA, USA, Risley Hall, Room 219,
11041 Campus St, Loma Linda, CA 92354, USA,Department of Earth and Biological Sciences, Loma Linda University, Loma Linda, CA, USA , Risley Hall, Room 219, 11041 Campus St, Loma Linda, CA 92354, USA
| | - John H Zhang
- Department of Physiology and Pharmacology, Loma Linda University, Loma Linda, CA, USA, Risley Hall, Room 219,
11041 Campus St, Loma Linda, CA 92354, USA,Department of Anesthesiology, Loma Linda University, Loma Linda, CA, USA, Risley Hall, Room 219, 11041 Campus St, Loma Linda, CA 92354, USA,Department of Neurosurgery, Loma Linda University, Loma Linda, CA, USA, Risley Hall, Room 219, 11041 Campus St, Loma Linda, CA 92354, USA
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4
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Morgan CA, Mesquita M, Ashioti M, Beech JS, Williams SCR, Irving E, Cash D. Late changes in blood-brain barrier permeability in a rat tMCAO model of stroke detected by gadolinium-enhanced MRI. Neurol Res 2020; 42:844-852. [PMID: 32600164 DOI: 10.1080/01616412.2020.1786637] [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] [Indexed: 10/24/2022]
Abstract
OBJECTIVES After cerebral ischaemia the blood-brain barrier (BBB) may be compromised and this has been observed in both clinical and preclinical studies. The timing of BBB disruption after ischaemia has long been considered to be biphasic, however some groups contest this view. Therefore, the purpose of this study was to characterize the BBB permeability timecourse in a rat model at both acute and chronic time points. METHODS Unilateral transient middle cerebral artery occlusion (tMCAO) was performed in 15 male Sprague Dawley rats. Change in T1-weighted MR signal before and after an injection of gadolinium-based contrast agent was calculated voxelwise to derive a BBB permeability index (BBBPI) at both early (6 h, 12 h, and 24 h) and late (7 and 14 days) time points. RESULTS As expected, BBBPI in the non-lesioned ROI was not significantly different from pre-occlusion baseline at any time point. However, BBBPI in the ipsilateral (lesioned) ROI was statistically different to baseline at day 7 (p < 0.001) and day 14 (p < 0.01) post-tMCAO. There was a small, but not-significant increase in BBBPI in the earlier phase (at 6 hours). DISCUSSION Our results indicate a significant late opening of the BBB. This is important as the majority of previous studies have only characterised an early acute BBB permeability in ischemia. However, the later period of increased permeability may indicate an optimal time for drug delivery across the BBB, when it is especially suited to drugs targeting delayed processes.
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Affiliation(s)
- Catherine A Morgan
- School of Psychology and Centre for Brain Research, The University of Auckland , Auckland, New Zealand.,Department of Neuroimaging, Institute of Psychiatry, Psychology and Neuroscience, King's College London , London, UK
| | - Michel Mesquita
- School of Psychology and Centre for Brain Research, The University of Auckland , Auckland, New Zealand
| | - Maria Ashioti
- School of Life Sciences, College of Liberal Arts and Sciences, University of Westminster , London, UK
| | - John S Beech
- School of Psychology and Centre for Brain Research, The University of Auckland , Auckland, New Zealand
| | - Steve C R Williams
- School of Psychology and Centre for Brain Research, The University of Auckland , Auckland, New Zealand
| | - Elaine Irving
- Value Evidence & Outcomes, GlaxoSmithKline R&D Ltd , Stevenage, UK
| | - Diana Cash
- School of Psychology and Centre for Brain Research, The University of Auckland , Auckland, New Zealand
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Aydin S, Fatihoğlu E, Koşar PN, Ergün E. Perfusion and permeability MRI in glioma grading. THE EGYPTIAN JOURNAL OF RADIOLOGY AND NUCLEAR MEDICINE 2020. [DOI: 10.1186/s43055-019-0127-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
Abstract
Background
MRI is successful in showing the anatomy of probable pathologies of the central nervous system. Although it may not be sufficient to reveal physiological and metabolic changes, advanced MRI techniques, such as perfusion and permeability MRI, are the key to overcoming these limitations. The aim of this study was to detect the efficacy of permeability and perfusion MRI techniques.
Results
The study included 38 patients with a pathology result of primary brain glioma. The permeability MRI (Ktrans, Ve), perfusion MRI values (CBV, CBF), and pathology results were evaluated. The high-grade group included 22 patients, and the low-grade group, 16 patients. Mean CBV and CBF, median Ktrans, and Ve values were higher in the high-grade group. All parameters tended to elevate with grade and had a positive correlation. CBV > 2.25, with sensitivity and specificity of 100%, CBF > 2.02, with sensitivity and specificity of 100%, Ktrans > 0.043, with sensitivity of 81.82% and specificity of 100%, and Ve > 0.255, with sensitivity and specificity of 100%, can predict high grade.
Conclusion
Perfusion and permeability MRI can be used safely for the differentiation of high- and low-grade gliomas and for the prediction of glioma grades.
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Shao X, Ma SJ, Casey M, D'Orazio L, Ringman JM, Wang DJJ. Mapping water exchange across the blood-brain barrier using 3D diffusion-prepared arterial spin labeled perfusion MRI. Magn Reson Med 2018; 81:3065-3079. [PMID: 30561821 DOI: 10.1002/mrm.27632] [Citation(s) in RCA: 74] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2018] [Revised: 10/19/2018] [Accepted: 11/17/2018] [Indexed: 01/22/2023]
Abstract
PURPOSE To present a novel MR pulse sequence and modeling algorithm to quantify the water exchange rate (kw ) across the blood-brain barrier (BBB) without contrast, and to evaluate its clinical utility in a cohort of elderly subjects at risk of cerebral small vessel disease (SVD). METHODS A diffusion preparation module with spoiling of non-Carr-Purcell-Meiboom-Gill signals was integrated with pseudo-continuous arterial spin labeling (pCASL) and 3D gradient and spin echo (GRASE) readout. The tissue/capillary fraction of the arterial spin labeling (ASL) signal was separated by appropriate diffusion weighting (b = 50 s/mm2 ). kw was quantified using a single-pass approximation (SPA) model with total generalized variation (TGV) regularization. Nineteen elderly subjects were recruited and underwent 2 MRIs to evaluate the reproducibility of the proposed technique. Correlation analysis was performed between kw and vascular risk factors, Clinical Dementia Rating (CDR) scale, neurocognitive assessments, and white matter hyperintensity (WMH). RESULTS The capillary/tissue fraction of ASL signal can be reliably differentiated with the diffusion weighting of b = 50 s/mm2 , given ~100-fold difference between the (pseudo-)diffusion coefficients of the 2 compartments. Good reproducibility of kw measurements (intraclass correlation coefficient = 0.75) was achieved. Average kw was 105.0 ± 20.6, 109.6 ± 18.9, and 94.1 ± 19.6 min-1 for whole brain, gray and white matter. kw was increased by 28.2%/19.5% in subjects with diabetes/hypercholesterolemia. Significant correlations between kw and vascular risk factors, CDR, executive/memory function, and the Fazekas scale of WMH were observed. CONCLUSION A diffusion prepared 3D GRASE pCASL sequence with TGV regularized SPA modeling was proposed to measure BBB water permeability noninvasively with good reproducibility. kw may serve as an imaging marker of cerebral SVD and associated cognitive impairment.
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Affiliation(s)
- Xingfeng Shao
- Laboratory of FMRI Technology (LOFT), Mark & Mary Stevens Neuroimaging and Informatics Institute, Keck School of Medicine, University of Southern California, Los Angeles, California
| | - Samantha J Ma
- Laboratory of FMRI Technology (LOFT), Mark & Mary Stevens Neuroimaging and Informatics Institute, Keck School of Medicine, University of Southern California, Los Angeles, California
| | - Marlene Casey
- Laboratory of FMRI Technology (LOFT), Mark & Mary Stevens Neuroimaging and Informatics Institute, Keck School of Medicine, University of Southern California, Los Angeles, California
| | - Lina D'Orazio
- Department of Neurology, Keck School of Medicine, University of Southern California, Los Angeles, California
| | - John M Ringman
- Department of Neurology, Keck School of Medicine, University of Southern California, Los Angeles, California
| | - Danny J J Wang
- Laboratory of FMRI Technology (LOFT), Mark & Mary Stevens Neuroimaging and Informatics Institute, Keck School of Medicine, University of Southern California, Los Angeles, California.,Department of Neurology, Keck School of Medicine, University of Southern California, Los Angeles, California
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7
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Brighi C, Puttick S, Rose S, Whittaker AK. The potential for remodelling the tumour vasculature in glioblastoma. Adv Drug Deliv Rev 2018; 136-137:49-61. [PMID: 30308226 DOI: 10.1016/j.addr.2018.10.001] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2018] [Revised: 10/04/2018] [Accepted: 10/07/2018] [Indexed: 12/19/2022]
Abstract
Despite significant improvements in the clinical management of glioblastoma, poor delivery of systemic therapies to the entire population of tumour cells remains one of the biggest challenges in the achievement of more effective treatments. On the one hand, the abnormal and dysfunctional tumour vascular network largely limits blood perfusion, resulting in an inhomogeneous delivery of drugs to the tumour. On the other hand, the presence of an intact blood-brain barrier (BBB) in certain regions of the tumour prevents chemotherapeutic drugs from permeating through the tumour vessels and reaching the diseased cells. In this review we analyse in detail the implications of the presence of a dysfunctional vascular network and the impenetrable BBB on drug transport. We discuss advantages and limitations of the currently available strategies for remodelling the tumour vasculature aiming to ameliorate the above mentioned limitations. Finally we review research methods for visualising vascular dysfunction and highlight the power of DCE- and DSC-MRI imaging to assess changes in blood perfusion and BBB permeability.
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8
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Thelin EP, Tajsic T, Zeiler FA, Menon DK, Hutchinson PJA, Carpenter KLH, Morganti-Kossmann MC, Helmy A. Monitoring the Neuroinflammatory Response Following Acute Brain Injury. Front Neurol 2017; 8:351. [PMID: 28775710 PMCID: PMC5517395 DOI: 10.3389/fneur.2017.00351] [Citation(s) in RCA: 79] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2017] [Accepted: 07/04/2017] [Indexed: 12/11/2022] Open
Abstract
Traumatic brain injury (TBI) and subarachnoid hemorrhage (SAH) are major contributors to morbidity and mortality. Following the initial insult, patients may deteriorate due to secondary brain damage. The underlying molecular and cellular cascades incorporate components of the innate immune system. There are different approaches to assess and monitor cerebral inflammation in the neuro intensive care unit. The aim of this narrative review is to describe techniques to monitor inflammatory activity in patients with TBI and SAH in the acute setting. The analysis of pro- and anti-inflammatory cytokines in compartments of the central nervous system (CNS), including the cerebrospinal fluid and the extracellular fluid, represent the most common approaches to monitor surrogate markers of cerebral inflammatory activity. Each of these compartments has a distinct biology that reflects local processes and the cross-talk between systemic and CNS inflammation. Cytokines have been correlated to outcomes as well as ongoing, secondary injury progression. Alongside the dynamic, focal assay of humoral mediators, imaging, through positron emission tomography, can provide a global in vivo measurement of inflammatory cell activity, which reveals long-lasting processes following the initial injury. Compared to the innate immune system activated acutely after brain injury, the adaptive immune system is likely to play a greater role in the chronic phase as evidenced by T-cell-mediated autoreactivity toward brain-specific proteins. The most difficult aspect of assessing neuroinflammation is to determine whether the processes monitored are harmful or beneficial to the brain as accumulating data indicate a dual role for these inflammatory cascades following injury. In summary, the inflammatory component of the complex injury cascade following brain injury may be monitored using different modalities. Using a multimodal monitoring approach can potentially aid in the development of therapeutics targeting different aspects of the inflammatory cascade and improve the outcome following TBI and SAH.
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Affiliation(s)
- Eric Peter Thelin
- Division of Neurosurgery, Department of Clinical Neurosciences, University of Cambridge, Cambridge, United Kingdom.,Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden
| | - Tamara Tajsic
- Division of Neurosurgery, Department of Clinical Neurosciences, University of Cambridge, Cambridge, United Kingdom
| | - Frederick Adam Zeiler
- Division of Anaesthesia, Department of Medicine, University of Cambridge, Cambridge, United Kingdom.,Rady Faculty of Health Sciences, Department of Surgery, University of Manitoba, Winnipeg, MB, Canada.,Clinician Investigator Program, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, MB, Canada
| | - David K Menon
- Division of Anaesthesia, Department of Medicine, University of Cambridge, Cambridge, United Kingdom.,Wolfson Brain Imaging Centre, Department of Clinical Neurosciences, University of Cambridge, Cambridge, United Kingdom
| | - Peter J A Hutchinson
- Division of Neurosurgery, Department of Clinical Neurosciences, University of Cambridge, Cambridge, United Kingdom.,Wolfson Brain Imaging Centre, Department of Clinical Neurosciences, University of Cambridge, Cambridge, United Kingdom
| | - Keri L H Carpenter
- Division of Neurosurgery, Department of Clinical Neurosciences, University of Cambridge, Cambridge, United Kingdom.,Wolfson Brain Imaging Centre, Department of Clinical Neurosciences, University of Cambridge, Cambridge, United Kingdom
| | - Maria Cristina Morganti-Kossmann
- Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden.,Department of Epidemiology and Preventive Medicine, Monash University, Melbourne, VIC, Australia.,Department of Child Health, Barrow Neurological Institute at Phoenix Children's Hospital, University of Arizona College of Medicine, Phoenix, Phoenix, AZ, United States
| | - Adel Helmy
- Division of Neurosurgery, Department of Clinical Neurosciences, University of Cambridge, Cambridge, United Kingdom
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9
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MRI/MRS in neuroinflammation: methodology and applications. Clin Transl Imaging 2015; 3:475-489. [PMID: 26705534 PMCID: PMC4679099 DOI: 10.1007/s40336-015-0142-y] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2015] [Accepted: 08/30/2015] [Indexed: 12/11/2022]
Abstract
Neuroinflammation encompasses a wide range of humoral and cellular responses, not only enabling the CNS to fight various noxious events, including infections and trauma, but also playing a critical role in autoimmune as well as in neurodegenerative diseases. The complex interactions of immune, endothelial, and neuronal cells that take place during inflammation require an equivalent complexity of imaging approaches to be appropriately explored in vivo. Magnetic Resonance provides several complementary techniques that allow to study most mechanisms underlying the brain/immune interaction. In this review, we discuss the MR approaches to the study of endothelial activation, blood-brain barrier permeability alterations, intercellular compartment modifications, immune cell trafficking, and of metabolic alterations linked to immune cell activity. The main advantages and limitations of these techniques are assessed, in view of their exploitation in the clinical arena, where the complementarity of the information that can be obtained has the potential to change our way of studying neuroinflammation, with implications for the management of several CNS diseases.
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10
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Snyder HM, Corriveau RA, Craft S, Faber JE, Greenberg SM, Knopman D, Lamb BT, Montine TJ, Nedergaard M, Schaffer CB, Schneider JA, Wellington C, Wilcock DM, Zipfel GJ, Zlokovic B, Bain LJ, Bosetti F, Galis ZS, Koroshetz W, Carrillo MC. Vascular contributions to cognitive impairment and dementia including Alzheimer's disease. Alzheimers Dement 2015; 11:710-7. [PMID: 25510382 PMCID: PMC4731036 DOI: 10.1016/j.jalz.2014.10.008] [Citation(s) in RCA: 413] [Impact Index Per Article: 45.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2014] [Revised: 08/22/2014] [Accepted: 10/02/2014] [Indexed: 02/07/2023]
Abstract
Scientific evidence continues to demonstrate the linkage of vascular contributions to cognitive impairment and dementia such as Alzheimer's disease. In December, 2013, the Alzheimer's Association, with scientific input from the National Institute of Neurological Disorders and Stroke and the National Heart, Lung and Blood Institute from the National Institutes of Health, convened scientific experts to discuss the research gaps in our understanding of how vascular factors contribute to Alzheimer's disease and related dementia. This manuscript summarizes the meeting and the resultant discussion, including an outline of next steps needed to move this area of research forward.
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Affiliation(s)
- Heather M Snyder
- Medical & Scientific Relations, Alzheimer's Association, Chicago, IL, USA.
| | - Roderick A Corriveau
- National Institute on Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA
| | - Suzanne Craft
- Department of Gerontology and Geriatric Medicine, Wake Forest University School of Medicine, Winston-Salem, NC, USA
| | - James E Faber
- Department of Cell Biology and Physiology, University of North Carolina School of Medicine, Chapel Hill, NC, USA
| | - Steven M Greenberg
- Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - David Knopman
- Department of Neurology, Mayo Clinic, Rochester, MN, USA
| | - Bruce T Lamb
- Department of Neurosciences, Cleveland Clinic, Cleveland, OH, USA
| | - Thomas J Montine
- Department of Pathology, University of Washington, Seattle, WA, USA
| | - Maiken Nedergaard
- Division of Glial Disease and Therapeutics, University of Rochester Medical Center, Rochester, NY, USA
| | - Chris B Schaffer
- Department of Biomedical Engineering, Cornell University, Ithaca, NY, USA
| | - Julie A Schneider
- Departments of Pathology and Neurological Sciences, Rush University Medical Center, Chicago, IL, USA
| | - Cheryl Wellington
- Department of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, BC, Canada
| | - Donna M Wilcock
- Department of Physiology, University of Kentucky, Lexington, KY, USA
| | - Gregory J Zipfel
- Departments of Neurological Surgery and Neurology, Washington University, St Louis, St Louis, MO, USA
| | - Berislav Zlokovic
- Department of Physiology, University of Southern California, Los Angeles, CA, USA
| | - Lisa J Bain
- Independent Science Writer, Elverson, PA, USA
| | - Francesca Bosetti
- National Institute on Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA
| | - Zorina S Galis
- National Institute of Heart, Lung and Blood, National Institutes of Health, Bethesda, MD, USA
| | - Walter Koroshetz
- National Institute on Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA
| | - Maria C Carrillo
- Medical & Scientific Relations, Alzheimer's Association, Chicago, IL, USA
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Abstract
While traditional computed tomography (CT) and magnetic resonance (MR) imaging illustrate the structural morphology of brain pathology, newer, dynamic imaging techniques are able to show the movement of contrast throughout the brain parenchyma and across the blood-brain barrier (BBB). These data, in combination with pharmacokinetic models, can be used to investigate BBB permeability, which has wide-ranging applications in the diagnosis and management of central nervous system (CNS) tumors in children. In the first part of this paper, we review the technical principles underlying four imaging modalities used to evaluate BBB permeability: PET, dynamic CT, dynamic T1-weighted contrast-enhanced MR imaging, and dynamic T2-weighted susceptibility contrast MR. We describe the data that can be derived from each method, provide some caveats to data interpretation, and compare the advantages and disadvantages of the different techniques. In the second part of this paper, we review the clinical applications that have been reported with permeability imaging data, including diagnosing the nature of a lesion found on imaging (neoplastic versus non-neoplastic, tumor type, tumor grade, recurrence versus pseudoprogression), predicting the natural history of a tumor, monitoring angiogenesis and tracking response to anti-angiogenic agents, optimizing chemotherapy agent selection, and aiding in the development of new antineoplastic drugs and methods to increase local delivery of chemotherapeutics.
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Affiliation(s)
- Sandi Lam
- 1 Department of Neurosurgery, Baylor College of Medicine, Texas Children's Hospital, Houston, Texas, USA ; 2 Functional and Stereotactic Neurosurgery, Department of Surgery, University of Chicago, Chicago, Illinois, USA
| | - Yimo Lin
- 1 Department of Neurosurgery, Baylor College of Medicine, Texas Children's Hospital, Houston, Texas, USA ; 2 Functional and Stereotactic Neurosurgery, Department of Surgery, University of Chicago, Chicago, Illinois, USA
| | - Peter C Warnke
- 1 Department of Neurosurgery, Baylor College of Medicine, Texas Children's Hospital, Houston, Texas, USA ; 2 Functional and Stereotactic Neurosurgery, Department of Surgery, University of Chicago, Chicago, Illinois, USA
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12
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Matthews PM, Comley R. Advances in the molecular imaging of multiple sclerosis. Expert Rev Clin Immunol 2014; 5:765-77. [DOI: 10.1586/eci.09.66] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
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13
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Chassidim Y, Veksler R, Lublinsky S, Pell GS, Friedman A, Shelef I. Quantitative imaging assessment of blood-brain barrier permeability in humans. Fluids Barriers CNS 2013; 10:9. [PMID: 23388348 PMCID: PMC3570379 DOI: 10.1186/2045-8118-10-9] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2012] [Accepted: 02/04/2013] [Indexed: 12/18/2022] Open
Abstract
The blood-brain barrier (BBB) is a functional and structural barrier separating the intravascular and neuropil compartments of the brain. It characterizes the vascular bed and is essential for normal brain functions. Dysfunction in the BBB properties have been described in most common neurological disorders, such as stroke, traumatic injuries, intracerebral hemorrhage, tumors, epilepsy and neurodegenerative disorders. It is now obvious that the BBB plays an important role in normal brain activity, stressing the need for applicable imaging and assessment methods. Recent advancements in imaging techniques now make it possible to establish sensitive and quantitative methods for the assessment of BBB permeability. However, most of the existing techniques require complicated and demanding dynamic scanning protocols that are impractical and cannot be fulfilled in some cases. We review existing methods for the evaluation of BBB permeability, focusing on quantitative magnetic resonance-based approaches and discuss their drawbacks and limitations. In light of those limitations we propose two new approaches for BBB assessment with less demanding imaging sequences: the "post-pre" and the "linear dynamic" methods, both allow semi-quantitative permeability assessment and localization of dysfunctional BBB with simple/partial dynamic imaging protocols and easy-to-apply analysis algorithms. We present preliminary results and show an example which compares these new methods with the existing standard assessment method. We strongly believe that the establishment of such "easy to use" and reliable imaging methods is essential before BBB assessment can become a routine clinical tool. Large clinical trials are awaited to fully understand the significance of BBB permeability as a biomarker and target for treatment in neurological disorders.
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Affiliation(s)
- Yoash Chassidim
- Departments of Physiology and Cell Biology & Biomedical Engineering, Faculty of Health Sciences, Zlotowski Center for Neuroscience, Ben-Gurion University of the Negev, Beer-Sheva, Israel.
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Wunder A, Schoknecht K, Stanimirovic DB, Prager O, Chassidim Y. Imaging blood-brain barrier dysfunction in animal disease models. Epilepsia 2013; 53 Suppl 6:14-21. [PMID: 23134491 DOI: 10.1111/j.1528-1167.2012.03698.x] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The blood-brain barrier (BBB) is a highly complex structure, which separates the extracellular fluid of the central nervous system (CNS) from the blood of CNS vessels. A wide range of neurologic conditions, including stroke, epilepsy, Alzheimer's disease, and brain tumors, are associated with perturbations of the BBB that contribute to their pathology. The common consequence of a BBB dysfunction is increased permeability, leading to extravasation of plasma constituents and vasogenic brain edema. The BBB impairment can persist for long periods, being involved in secondary inflammation and neuronal dysfunction, thus contributing to disease pathogenesis. Therefore, reliable imaging of the BBB impairment is of major importance in both clinical management of brain diseases and in experimental research. From landmark studies by Ehrlich and Goldman, the use of dyes (probes) has played a critical role in understanding BBB functions. In recent years methodologic advances in morphologic and functional brain imaging have provided insight into cellular and molecular interactions underlying BBB dysfunction in animal disease models. These imaging techniques, which range from in situ staining to noninvasive in vivo imaging, have different spatial resolution, sensitivity, and capacity for quantitative and kinetic measures of the BBB impairment. Despite significant advances, the translation of these techniques into clinical applications remains slow. This review outlines key recent advances in imaging techniques that have contributed to the understanding of BBB dysfunction in disease and discusses major obstacles and opportunities to advance these techniques into the clinical realm.
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Affiliation(s)
- Andreas Wunder
- Department of Experimental Neurology, Center for Stroke Research Berlin, Charité-University Medicine Berlin, Berlin, Germany.
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Patabendige A, Skinner RA, Abbott NJ. Establishment of a simplified in vitro porcine blood-brain barrier model with high transendothelial electrical resistance. Brain Res 2012; 1521:1-15. [PMID: 22789905 PMCID: PMC3694297 DOI: 10.1016/j.brainres.2012.06.057] [Citation(s) in RCA: 107] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2012] [Revised: 06/14/2012] [Accepted: 06/28/2012] [Indexed: 12/11/2022]
Abstract
Good in vitro blood-brain barrier (BBB) models that mimic the in vivo BBB phenotype are essential for studies on BBB functionality and for initial screening in drug discovery programmes, as many potential therapeutic drug candidates have poor BBB permeation. Difficulties associated with the availability of human brain tissue, coupled with the time and cost associated with using animals for this kind of research have led to the development of non-human cell culture models. However, most BBB models display a low transendothelial electrical resistance (TEER), which is a measure of the tightness of the BBB. To address these issues we have established and optimised a robust, simple to use in vitro BBB model using porcine brain endothelial cells (PBECs). The PBEC model gives high TEER without the need for co-culture with astrocytes (up to 1300 O cm(2) with a mean TEER of ~800 O cm(2)) with well organised tight junctions as shown by immunostaining for occludin and claudin-5. Functional assays confirmed the presence of high levels of alkaline phosphatase (ALP), and presence of the efflux transporter, P-glycoprotein (P-gp, ABCB1). Presence of the breast cancer resistance protein (BCRP, ABCG2) was confirmed by TaqMan real-time RT-PCR assay. Real-time RT-PCR assays for BCRP, occludin and claudin-5 demonstrated no significant differences between batches of PBECs, and also between primary and passage 1 PBECs. A permeability screen of 10 compounds demonstrated the usefulness of the model as a tool for drug permeability studies. Qualitative and quantitative results from this study confirm that this in vitro porcine BBB model is reliable and robust; it is also simpler to generate than most other BBB models. This article is part of a Special Issue entitled Electrical Synapses.
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Affiliation(s)
- Adjanie Patabendige
- King's College London, Institute of Pharmaceutical Science, BBB Group, Franklin Wilkins Building, 150 Stamford St, London SE1 9NH, UK
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Ergin A, Wang M, Zhang J, Bigio I, Joshi S. Noninvasive in vivo optical assessment of blood brain barrier permeability and brain tissue drug deposition in rabbits. JOURNAL OF BIOMEDICAL OPTICS 2012; 17:057008. [PMID: 22612147 PMCID: PMC3381026 DOI: 10.1117/1.jbo.17.5.057008] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/18/2011] [Revised: 02/28/2012] [Accepted: 03/01/2012] [Indexed: 06/01/2023]
Abstract
Osmotic disruption of the blood brain barrier (BBB) by intraarterial mannitol injection is sometimes the key step for the delivery of chemotherapeutic drugs to brain tissue. BBB disruption (BBBD) with mannitol, however, can be highly variable and could impact local drug deposition. We use optical pharmacokinetics, which is based on diffuse reflectance spectroscopy, to track in vivo brain tissue concentrations of indocyanine green (ICG), an optical reporter used to monitor BBBD, and mitoxantrone (MTX), a chemotherapy agent that does not deposit in brain tissue without BBBD, in anesthetized New Zealand white rabbits. Results show a significant increase in the tissue ICG concentrations with BBBD, and our method is able to track the animal-to-animal variation in tissue ICG and MTX concentrations after BBBD. The tissue concentrations of MTX increase with barrier disruption and are found to be correlated to the degree of disruption, as assessed by the ICG prior to the injection of the drug. These findings should encourage the development of tracers and optical methods capable of quantifying the degree of BBBD, with the goal of improving drug delivery.
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Affiliation(s)
- Aysegul Ergin
- Boston University, Department of Biomedical Engineering, 44 Cummington Street, Boston, Massachusetts 02215
| | - Mei Wang
- College of Physicians and Surgeons of Columbia University, Department of Anesthesiology, P&S Box 46, 630 West 168th Street, New York, New York 10032
| | - Jane Zhang
- Boston University, Department of Biomedical Engineering, 44 Cummington Street, Boston, Massachusetts 02215
| | - Irving Bigio
- Boston University, Department of Biomedical Engineering, Electrical Engineering, Physics and Medicine, 44 Cummington Street, Boston, Massachusetts 02215
| | - Shailendra Joshi
- College of Physicians and Surgeons of Columbia University, Department of Anesthesiology, P&S Box 46, 630 West 168th Street, New York, New York 10032
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Dake MD, Dantzker N, Bennett WL, Cooke JP. Endovascular correction of cerebrovenous anomalies in multiple sclerosis: a retrospective review of an uncontrolled case series. Vasc Med 2012; 17:131-7. [PMID: 22496109 DOI: 10.1177/1358863x12440125] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Endovascular intervention for obstruction to venous drainage of the head and neck is an established treatment for disorders such as superior vena cava syndrome. Some patients with multiple sclerosis have been observed to have anomalies of the veins draining the head and neck. It is possible that some symptoms associated with multiple sclerosis may be secondary to disturbed venous flow. In an uncontrolled clinical series of 40 patients who had been previously diagnosed with multiple sclerosis, anomalies of the venous drainage of the head and neck were observed, including venous stenoses of the internal jugular veins. In 38 of 40 patients, venous stents were placed with restoration of luminal dimensions and abrogation of the venous pressure gradient. The angiographic and hemodynamic improvement was associated with improvement in symptomatology, most particularly in cognitive and constitutional symptoms that may be related to cerebrovenous flow. Serious complications included death in one subject and stent embolization requiring open heart surgery in another. In conclusion, in this series, endovascular intervention to correct venous stenosis associated with multiple sclerosis was associated with improvement in symptoms possibly related to disturbed venous hemodynamics. However, given the serious adverse events in this small series, a randomized clinical trial is required to confirm these findings, and to determine if the procedure has any effect on the progression of multiple sclerosis, or untoward long-term adverse effects.
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Affiliation(s)
- Michael D Dake
- Department of Cardiothoracic Surgery, Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA 94305-5406, USA
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St Lawrence KS, Owen D, Wang DJJ. A two-stage approach for measuring vascular water exchange and arterial transit time by diffusion-weighted perfusion MRI. Magn Reson Med 2011; 67:1275-84. [PMID: 21858870 DOI: 10.1002/mrm.23104] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2011] [Revised: 06/13/2011] [Accepted: 06/27/2011] [Indexed: 01/01/2023]
Abstract
Changes in the exchange rate of water across the blood-brain barrier, denoted k(w), may indicate blood-brain barrier dysfunction before the leakage of large-molecule contrast agents is observable. A previously proposed approach for measuring k(w) is to use diffusion-weighted arterial spin labeling to measure the vascular and tissue fractions of labeled water, because the vascular-to-tissue ratio is related to k(w). However, the accuracy of diffusion-weighted arterial spin labeling is affected by arterial blood contributions and the arterial transit time (τ(a)). To address these issues, a two-stage method is proposed that uses combinations of diffusion-weighted gradient strengths and post-labeling delays to measure both τ(a) and k(w). The feasibility of this method was assessed by acquiring diffusion-weighted arterial spin labeling data from seven healthy volunteers. Repeat measurements and Monte Carlo simulations were conducted to determine the precision and accuracy of the k(w) estimates. Average grey and white matter k(w) values were 110 ± 18 and 126 ± 18 min(-1), respectively, which compare favorably to blood-brain barrier permeability measurements obtained with positron emission tomography. The intrasubject coefficient of variation was 26% ± 23% in grey matter and 21% ± 17% in white matter, indicating that reproducible k(w) measurements can be obtained.
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Lemasson B, Serduc R, Maisin C, Bouchet A, Coquery N, Robert P, Le Duc G, Troprès I, Rémy C, Barbier EL. Monitoring blood-brain barrier status in a rat model of glioma receiving therapy: dual injection of low-molecular-weight and macromolecular MR contrast media. Radiology 2010; 257:342-52. [PMID: 20829544 DOI: 10.1148/radiol.10092343] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
PURPOSE To evaluate the sequential injection of a low-molecular-weight (gadoterate meglumine [Gd-DOTA], 0.5 kDa) and a macromolecular (P846, 3.5 kDa) contrast media in monitoring the effect of antitumor therapies (antiangiogenic therapy and/or microbeam radiation therapy [MRT]) on healthy brain tissue and implanted tumors. MATERIALS AND METHODS Animal use was compliant with official French guidelines and was assessed by the local Internal Evaluation Committee for Animal Welfare and Rights. Eighty male rats bearing 9L gliosarcoma were randomized into four groups: untreated, antiangiogenic (sorafenib) therapy, MRT, and both treatments. Magnetic resonance (MR) imaging was performed 1 day before and 1, 5, and 8 days after the start of the treatment. At all time points, vascular integrity to a macromolecular contrast medium (P846) and, 11 minutes 30 seconds later, to low-molecular-weight contrast medium (Gd-DOTA) was evaluated by using a dynamic contrast material-enhanced MR imaging approach. To quantify vessel wall integrity, areas under the signal intensity curves were computed for each contrast medium. Unpaired t tests and one-way analysis of variance were used for statistical analyses. RESULTS Tumor vessels receiving antiangiogenic therapy became less permeable to the macromolecular contrast medium, but their permeability to the low-molecular-weight contrast medium remained unchanged. Healthy double-irradiated vessels became permeable to the low-molecular-weight contrast medium but not to the macromolecular contrast medium. CONCLUSION Antiangiogenic therapy and MRT generate different effects on the extravasation of contrast medium in tumoral and healthy tissues. This study indicates that the use of a low-molecular-weight contrast medium and a macromolecular contrast medium provides complementary information and suggests that the use of two contrast media within the same MR imaging session is feasible.
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Vlachos F, Tung YS, Konofagou EE. Permeability assessment of the focused ultrasound-induced blood-brain barrier opening using dynamic contrast-enhanced MRI. Phys Med Biol 2010; 55:5451-66. [PMID: 20736501 DOI: 10.1088/0031-9155/55/18/012] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Focused ultrasound (FUS) in conjunction with microbubbles has been shown to successfully open the blood-brain barrier (BBB) in the mouse brain. In this study, we compute the BBB permeability after opening in vivo. The spatial permeability of the BBB-opened region was assessed using dynamic contrast-enhanced MRI (DCE-MRI). The DCE-MR images were post-processed using the general kinetic model (GKM) and the reference region model (RRM). Permeability maps were generated and the K(trans) values were calculated for a predefined volume of interest in the sonicated and the control area for each mouse. The results demonstrated that K(trans) in the BBB-opened region (0.02 +/- 0.0123 for GKM and 0.03 +/- 0.0167 min(-1) for RRM) was at least two orders of magnitude higher when compared to the contra-lateral (control) side (0 and 8.5 x 10(-4) +/- 12 x 10(-4) min(-1), respectively). The permeability values obtained with the two models showed statistically significant agreement and excellent correlation (R(2) = 0.97). At histological examination, it was concluded that no macroscopic damage was induced. This study thus constitutes the first permeability assessment of FUS-induced BBB opening using DCE-MRI, supporting the fact that the aforementioned technique may constitute a safe, non-invasive and efficacious drug delivery method.
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Affiliation(s)
- F Vlachos
- Department of Biomedical Engineering, Columbia University, New York, NY 10027, USA
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de Graaf P, van der Valk P, Moll AC, Imhof SM, Schouten-van Meeteren AYN, Knol DL, Castelijns JA. Contrast-enhancement of the anterior eye segment in patients with retinoblastoma: correlation between clinical, MR imaging, and histopathologic findings. AJNR Am J Neuroradiol 2009; 31:237-45. [PMID: 19833805 DOI: 10.3174/ajnr.a1825] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
BACKGROUND AND PURPOSE AES contrast-enhancement is recognized in a substantial number of retinoblastoma-affected eyes. We retrospectively investigated the histopathologic basis of AES contrast-enhancement on MR images in retinoblastoma. MATERIALS AND METHODS Pretreatment contrast-enhanced MR images were obtained from 42 children with retinoblastoma. Forty-two enucleated eyes were included in this study, AES enhancement was evaluated by using a 3-point score, and these data were correlated with clinical, MR imaging, and histopathologic findings. Additionally, 14 specimens were immunohistochemically analyzed for CD31, VEGF, and Flt-1 expression. Statistical correlations with AES enhancement were assessed by using a linear-by-linear association test and univariate and multivariate ordinal regressions. RESULTS The degree of abnormal AES enhancement was moderate in 15 (36%) eyes and strong in 14 (33%) eyes, whereas 13 (31%) eyes showed normal AES enhancement. In multivariate analysis, the degree of AES enhancement showed statistically significant correlations with iris surface-vessel count (P = .05) and optic nerve invasion (P = .04) in the enucleated eye and with tumor volume (P = .02) as detected on MR imaging. No significant associations between AES enhancement and VEGF expression in the iris were observed. Flt-1 (P = .04) staining in iris stroma and IA as detected with CD31 staining (P = .009) both yielded a statistically significant positive correlation with abnormal AES enhancement. CONCLUSIONS The degree of abnormal AES enhancement on MR imaging in retinoblastoma reflects angiogenesis in the iris. AES enhancement is also a hallmark of advanced retinoblastoma because its degree correlates with tumor volume and optic nerve invasion.
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Affiliation(s)
- P de Graaf
- Departments of Radiology, VU University Medical Center, Amsterdam, the Netherlands.
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Abo-Ramadan U, Durukan A, Pitkonen M, Marinkovic I, Tatlisumak E, Pedrono E, Soinne L, Strbian D, Tatlisumak T. Post-ischemic leakiness of the blood–brain barrier: A quantitative and systematic assessment by Patlak plots. Exp Neurol 2009; 219:328-33. [DOI: 10.1016/j.expneurol.2009.06.002] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2009] [Revised: 05/07/2009] [Accepted: 06/02/2009] [Indexed: 11/16/2022]
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Noninvasive structural, functional, and molecular imaging in drug development. Curr Opin Chem Biol 2009; 13:360-71. [DOI: 10.1016/j.cbpa.2009.03.025] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2009] [Accepted: 03/30/2009] [Indexed: 11/19/2022]
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