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Wu YL. Cardiac MRI Assessment of Mouse Myocardial Infarction and Regeneration. Methods Mol Biol 2021; 2158:81-106. [PMID: 32857368 DOI: 10.1007/978-1-0716-0668-1_8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Small animal models are indispensable for cardiac regeneration research. Studies in mouse and rat models have provided important insights into the etiology and mechanisms of cardiovascular diseases and accelerated the development of therapeutic strategies. It is vitally important to be able to evaluate the therapeutic efficacy and have reliable surrogate markers for therapeutic development for cardiac regeneration research. Magnetic resonance imaging (MRI), a versatile and noninvasive imaging modality with excellent penetration depth, tissue coverage, and soft-tissue contrast, is becoming a more important tool in both clinical settings and research arenas. Cardiac MRI (CMR) is versatile, noninvasive, and capable of measuring many different aspects of cardiac functions, and, thus, is ideally suited to evaluate therapeutic efficacy for cardiac regeneration. CMR applications include assessment of cardiac anatomy, regional wall motion, myocardial perfusion, myocardial viability, cardiac function assessment, assessment of myocardial infarction, and myocardial injury. Myocardial infarction models in mice are commonly used model systems for cardiac regeneration research. In this chapter, we discuss various CMR applications to evaluate cardiac functions and inflammation after myocardial infarction.
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Affiliation(s)
- Yijen L Wu
- Department of Developmental Biology, Rangos Research Center Animal Imaging Core, School of Medicine, University of Pittsburgh, Pittsburgh, PA, USA.
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2
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Merkle CW, Zhu J, Bernucci MT, Srinivasan VJ. Dynamic Contrast Optical Coherence Tomography reveals laminar microvascular hemodynamics in the mouse neocortex in vivo. Neuroimage 2019; 202:116067. [PMID: 31394180 DOI: 10.1016/j.neuroimage.2019.116067] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2019] [Revised: 07/01/2019] [Accepted: 08/01/2019] [Indexed: 12/18/2022] Open
Abstract
Studies of flow-metabolism coupling often presume that microvessel architecture is a surrogate for blood flow. To test this assumption, we introduce an in vivo Dynamic Contrast Optical Coherence Tomography (DyC-OCT) method to quantify layer-resolved microvascular blood flow and volume across the full depth of the mouse neocortex, where the angioarchitecture has been previously described. First, we cross-validate average DyC-OCT cortical flow against conventional Doppler OCT flow. Next, with laminar DyC-OCT, we discover that layer 4 consistently exhibits the highest microvascular blood flow, approximately two-fold higher than the outer cortical layers. While flow differences between layers are well-explained by microvascular volume and density, flow differences between subjects are better explained by transit time. Finally, from layer-resolved tracer enhancement, we also infer that microvascular hematocrit increases in deep cortical layers, consistent with predictions of plasma skimming. Altogether, our results show that while the cortical blood supply derives mainly from the pial surface, laminar hemodynamics ensure that the energetic needs of individual cortical layers are met. The laminar trends reported here provide data that links predictions based on the cortical angioarchitecture to cerebrovascular physiology in vivo.
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Affiliation(s)
- Conrad W Merkle
- Department of Biomedical Engineering, University of California Davis, Davis, CA, 95616, USA
| | - Jun Zhu
- Department of Biomedical Engineering, University of California Davis, Davis, CA, 95616, USA
| | - Marcel T Bernucci
- Department of Biomedical Engineering, University of California Davis, Davis, CA, 95616, USA
| | - Vivek J Srinivasan
- Department of Biomedical Engineering, University of California Davis, Davis, CA, 95616, USA; Department of Ophthalmology and Vision Science, University of California Davis School of Medicine, Sacramento, CA, 95817, USA.
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Buck J, Larkin JR, Simard MA, Khrapitchev AA, Chappell MA, Sibson NR. Sensitivity of Multiphase Pseudocontinuous Arterial Spin Labelling (MP pCASL) Magnetic Resonance Imaging for Measuring Brain and Tumour Blood Flow in Mice. CONTRAST MEDIA & MOLECULAR IMAGING 2018; 2018:4580919. [PMID: 30532663 PMCID: PMC6247770 DOI: 10.1155/2018/4580919] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/14/2018] [Revised: 08/28/2018] [Accepted: 09/26/2018] [Indexed: 11/17/2022]
Abstract
Brain and tumour blood flow can be measured noninvasively using arterial spin labelling (ASL) magnetic resonance imaging (MRI), but reliable quantification in mouse models remains difficult. Pseudocontinuous ASL (pCASL) is recommended as the clinical standard for ASL and can be improved using multiphase labelling (MP pCASL). The aim of this study was to optimise and validate MP pCASL MRI for cerebral blood flow (CBF) measurement in mice and to assess its sensitivity to tumour perfusion. Following optimization of the MP pCASL sequence, CBF data were compared with gold-standard autoradiography, showing close agreement. Subsequently, MP pCASL data were acquired at weekly intervals in models of primary and secondary brain tumours, and tumour microvessel density was determined histologically. MP pCASL measurements in a secondary brain tumour model revealed a significant reduction in blood flow at day 35 after induction, despite a higher density of blood vessels. Tumour core regions also showed reduced blood flow compared with the tumour rim. Similarly, significant reductions in CBF were found in a model of glioma 28 days after tumour induction, together with an increased density of blood vessels. These findings indicate that MP pCASL MRI provides accurate and robust measurements of cerebral blood flow in naïve mice and is sensitive to changes in tumour perfusion.
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Affiliation(s)
- Jessica Buck
- Cancer Research UK and Medical Research Council Oxford Institute for Radiation Oncology, Department of Oncology, University of Oxford, OX3 7LE, Oxford, UK
| | - James R. Larkin
- Cancer Research UK and Medical Research Council Oxford Institute for Radiation Oncology, Department of Oncology, University of Oxford, OX3 7LE, Oxford, UK
| | - Manon A. Simard
- Cancer Research UK and Medical Research Council Oxford Institute for Radiation Oncology, Department of Oncology, University of Oxford, OX3 7LE, Oxford, UK
| | - Alexandre A. Khrapitchev
- Cancer Research UK and Medical Research Council Oxford Institute for Radiation Oncology, Department of Oncology, University of Oxford, OX3 7LE, Oxford, UK
| | - Michael A. Chappell
- Institute of Biomedical Engineering, University of Oxford, Old Road Campus Research Building, Oxford OX3 7DQ, Oxford, UK
| | - Nicola R. Sibson
- Cancer Research UK and Medical Research Council Oxford Institute for Radiation Oncology, Department of Oncology, University of Oxford, OX3 7LE, Oxford, UK
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Grandhi R, Peitz GW, Foley LM, Bonfield CM, Fellows-Mayle W, Hitchens TK, Mooney MP. The influence of suturectomy on age-related changes in cerebral blood flow in rabbits with familial bicoronal suture craniosynostosis: A quantitative analysis. PLoS One 2018; 13:e0197296. [PMID: 29856748 PMCID: PMC5983410 DOI: 10.1371/journal.pone.0197296] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2017] [Accepted: 04/30/2018] [Indexed: 11/23/2022] Open
Abstract
Background Coronal suture synostosis is a condition which can have deleterious physical and cognitive sequelae in humans if not corrected. A well-established animal model has previously demonstrated disruptions in intracranial pressure and developmental abnormalities in rabbits with congenital craniosynostosis compared to wild type rabbits. Objective The current study aimed to measure the cerebral blood flow (CBF) in developing rabbits with craniosynostosis who underwent suturectomy compared to those with no intervention and compared to wild type rabbits. Methods Rabbits with early onset coronal suture synostosis were assigned to have suturectomy at 10 days of age (EOCS-SU, n = 15) or no intervention (EOCS, n = 18). A subset of each group was randomly selected for measurement at 10 days of age, 25 days of age, and 42 days of age. Wild type rabbits (WT, n = 18) were also randomly assigned to measurement at each time point as controls. Cerebral blood flow at the bilateral hemispheres, cortices, thalami, and superficial cortices was measured in each group using arterial spin-labeling MRI. Results At 25 days of age, CBF at the superficial cortex was significantly higher in EOCS rabbits (192.6 ± 10.1 mL/100 mg/min on the left and 195 ± 9.5 mL/100 mg/min on the right) compared to WT rabbits (99.2 ± 29.1 mL/100 mg/min on the left and 96.2 ± 21.4 mL/100 mg/min on the right), but there was no significant difference in CBF between EOCS-SU (97.6 ± 11.3 mL/100 mg/min on the left and 99 ± 7.4 mL/100 mg/min on the right) and WT rabbits. By 42 days of age the CBF in EOCS rabbits was not significantly different than that of WT rabbits. Conclusion Suturectomy eliminated the abnormally increased CBF at the superficial cortex seen in EOCS rabbits at 25 days of age. This finding contributes to the evidence that suturectomy limits abnormalities of ICP and CBF associated with craniosynostosis.
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Affiliation(s)
- Ramesh Grandhi
- Department of Neurosurgery, University of Texas Health Science Center at San Antonio, San Antonio, TX, United States of America
- * E-mail:
| | - Geoffrey W. Peitz
- Department of Neurosurgery, University of Texas Health Science Center at San Antonio, San Antonio, TX, United States of America
| | - Lesley M. Foley
- Pittsburgh NMR Center for Biomedical Research, Carnegie Mellon University, Pittsburgh, PA, United States of America
- High Field Animal Imaging Center, University of Pittsburgh, Pittsburgh, PA, United States of America
| | - Christopher M. Bonfield
- Department of Neurosurgery, Vanderbilt University Medical Center, Nashville, TN, United States of America
| | - Wendy Fellows-Mayle
- Department of Neurological Surgery, University of Pittsburgh Medical Center, Pittsburgh, PA, United States of America
| | - T. Kevin Hitchens
- Pittsburgh NMR Center for Biomedical Research, Carnegie Mellon University, Pittsburgh, PA, United States of America
- High Field Animal Imaging Center, University of Pittsburgh, Pittsburgh, PA, United States of America
| | - Mark P. Mooney
- Departments of Oral Biology, University of Pittsburgh, Pittsburgh, PA, United States of America
- Department of Anthropology, University of Pittsburgh, Pittsburgh, PA, United States of America
- Deparment of Plastic Surgery, University of Pittsburgh, Pittsburgh, PA, United States of America
- Deparment of Orthodontics, University of Pittsburgh, Pittsburgh, PA, United States of America
- Department of Communication Science and Disorders, University of Pittsburgh, Pittsburgh, PA, United States of America
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Substantial Reduction of Parenchymal Cerebral Blood Flow in Mice with Bilateral Common Carotid Artery Stenosis. Sci Rep 2016; 6:32179. [PMID: 27535801 PMCID: PMC4989493 DOI: 10.1038/srep32179] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2016] [Accepted: 08/03/2016] [Indexed: 01/06/2023] Open
Abstract
The bilateral common carotid artery stenosis (BCAS) mouse model, which replicates chronic cerebral hypoperfusion and white matter ischemic lesions, is considered to model some aspects of vascular cognitive impairment. Cerebral blood flow (CBF) changes in the brain surface post-BCAS have been demonstrated by laser speckle flowmetry, but CBF levels in the brain parenchyma remain unknown. Adult C57BL/6J male mice were subjected to BCAS using external microcoils. Brain magnetic resonance angiography (MRA) was conducted to visualize the intracranial main arteries while arterial spin labeling (ASL) was used to measure cortical and subcortical parenchymal CBF levels before and after BCAS. Brain MRA showed anterior circulation flow was substantially decreased until 14 days post-BCAS, which gradually but incompletely recovered over the following 14 days, with probable growth of collaterals from the posterior cerebral artery. ASL showed that cortical and subcortical parenchymal CBF remained decreased at approximately 50% of the baseline level during 1 and 14 days post-BCAS, recovering to approximately 70% at day 28. CBF levels in the parenchyma were lower than the cortical superficial region in the BCAS model and remained decreased without recovery during the first 2 weeks post-BCAS. These results suggest that the BCAS model reliably replicates chronic cerebral hypoperfusion.
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Hong X, To XV, Teh I, Soh JR, Chuang KH. Evaluation of EPI distortion correction methods for quantitative MRI of the brain at high magnetic field. Magn Reson Imaging 2015; 33:1098-1105. [PMID: 26117700 DOI: 10.1016/j.mri.2015.06.010] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2015] [Accepted: 06/20/2015] [Indexed: 10/23/2022]
Abstract
High field MRI has been applied to high-resolution structural and functional imaging of the brain. Echo planar imaging (EPI) is an ultrafast acquisition technique widely used in diffusion imaging, functional MRI and perfusion imaging. However, it suffers from geometric and intensity distortions caused by static magnetic field inhomogeneity, which is worse at higher field strengths. Such susceptibility artifacts are particularly severe in relation to the small size of the mouse brain. In this study we compared different distortion correction methods, including nonlinear registration, field map-based, and reversed phase-encoding-based approaches, on quantitative imaging of T1 and perfusion in the mouse brain acquired by spin-echo EPI with inversion recovery and pseudo-continuous arterial spin labeling, respectively, at 7 T. Our results showed that the 3D reversed phase-encoding correction outperformed other methods in terms of geometric fidelity, and that conventional field map-based correction could be improved by combination with affine transformation to reduce the bias in the field map. Both methods improved quantification with smaller fitting error and regional variation. These approaches offer robust correction of EPI distortions at high field strengths and hence could lead to more accurate co-registration and quantification of imaging biomarkers in both clinical and preclinical applications.
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Affiliation(s)
- Xin Hong
- Magnetic Resonance Imaging Group, Singapore Bioimaging Consortium Agency for Science Technology and Research, 11 Biopolis Way, #01-02 Helios Building, Singapore, 138667
| | - Xuan Vinh To
- Magnetic Resonance Imaging Group, Singapore Bioimaging Consortium Agency for Science Technology and Research, 11 Biopolis Way, #01-02 Helios Building, Singapore, 138667
| | - Irvin Teh
- Clinical Imaging Research Centre, National University of Singapore, 14 Medical Drive, #B1-01, Singapore, 117599
| | - Jian Rui Soh
- Magnetic Resonance Imaging Group, Singapore Bioimaging Consortium Agency for Science Technology and Research, 11 Biopolis Way, #01-02 Helios Building, Singapore, 138667
| | - Kai-Hsiang Chuang
- Magnetic Resonance Imaging Group, Singapore Bioimaging Consortium Agency for Science Technology and Research, 11 Biopolis Way, #01-02 Helios Building, Singapore, 138667; Clinical Imaging Research Centre, National University of Singapore, 14 Medical Drive, #B1-01, Singapore, 117599; Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Block MD9, 2 Medical Drive #04-01, Singapore, 117597.
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Hafezi W, Hoerr V. In vivo visualization of encephalitic lesions in herpes simplex virus type 1 (HSV-1) infected mice by magnetic resonance imaging (MRI). Methods Mol Biol 2013; 1064:253-65. [PMID: 23996263 DOI: 10.1007/978-1-62703-601-6_18] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/16/2023]
Abstract
Herpes simplex encephalitis (HSE) is one of the most severe viral infections affecting the temporal lobes of the brain. Despite the improvements in diagnosis and antiviral drug treatment, one third of all patients fail to respond to therapy or subsequently suffer neurological relapse and develop long term neurological damage. Magnetic resonance imaging (MRI) is among the appropriate noninvasive tools for early diagnosis of viral central nervous system (CNS) infections. In this chapter we introduce a mouse model for HSE and describe a MRI protocol to characterize the pathogenesis of HSE over time.
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Affiliation(s)
- Wali Hafezi
- Institute of Medical Microbiology Clinical Virology, University Hospital Münster, Münster, Germany
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8
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Duhamel G, Prevost V, Girard OM, Callot V, Cozzone PJ. High-resolution mouse kidney perfusion imaging by pseudo-continuous arterial spin labeling at 11.75T. Magn Reson Med 2013; 71:1186-96. [DOI: 10.1002/mrm.24740] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Affiliation(s)
- Guillaume Duhamel
- Aix-Marseille Université, CNRS; CRMBM UMR 7339, 13385; Marseille France
| | - Valentin Prevost
- Aix-Marseille Université, CNRS; CRMBM UMR 7339, 13385; Marseille France
| | - Olivier M. Girard
- Aix-Marseille Université, CNRS; CRMBM UMR 7339, 13385; Marseille France
| | - Virginie Callot
- Aix-Marseille Université, CNRS; CRMBM UMR 7339, 13385; Marseille France
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MRI assessment of cerebral blood flow after experimental traumatic brain injury combined with hemorrhagic shock in mice. J Cereb Blood Flow Metab 2013; 33:129-36. [PMID: 23072750 PMCID: PMC3597358 DOI: 10.1038/jcbfm.2012.145] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Secondary insults such as hypotension or hemorrhagic shock (HS) can greatly worsen outcome after traumatic brain injury (TBI). We recently developed a mouse combined injury model of TBI and HS using a controlled cortical impact (CCI) model and showed that 90 minutes of HS can exacerbate neuronal death in hippocampus beneath the contusion. This combined injury model has three clinically relevant phases, a shock, pre hospital, and definitive care phases. Mice were randomly assigned to four groups, shams as well as a CCI only, an HS only, and a CCI+HS groups. The CCI and HS reduced cerebral blood flow (CBF) in multiple regions of interest (ROIs) in the hemisphere ipsilateral and contralateral to injury. Hemorrhagic shock to a level of ∼30 mm Hg exacerbated the CCI-induced CBF reductions in multiple ROIs ipsilateral to injury (hemisphere and thalamus) and in the hemisphere contralateral to injury (hemisphere, thalamus, hippocampus, and cortex, all P<0.05 versus CCI only, HS only or both). An important effect of HS duration was also seen after CCI with maximal CBF reduction seen at 90 minutes (P<0.0001 group-time effect in ipsilateral hippocampus). Given that neuronal death in hippocampus is exacerbated by 90 minutes of HS in this model, our data suggest an important role for exacerbation of posttraumatic ischemia in mediating the secondary injury in CCI plus HS. In conclusion, the serial, non invasive assessment of CBF using ASL-MRI (magnetic resonance imaging with arterial spin labeling) is feasible in mice even in the complex setting of combined CCI+HS. The impact of resuscitation therapies and various mutant mouse strains on CBF and other outcomes merits investigation in this model.
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Abstract
Perfusion MRI is a tool to assess the spatial distribution of microvascular blood flow. Arterial spin labeling (ASL) is shown here to be advantageous for quantification of cerebral microvascular blood flow (CBF) in rodents. This technique is today ready for assessment of a variety of murine models of human pathology including those associated with diffuse microvascular dysfunction. This chapter provides an introduction to the principles of CBF measurements by MRI along with a short overview over applications in which these measurements were found useful. The basics of commonly employed specific arterial spin-labeling techniques are described and theory is outlined in order to give the reader the ability to set up adequate post-processing tools. Three typical MR protocols for pulsed ASL on two different MRI systems are described in detail along with all necessary sequence parameters and technical requirements. The importance of the different parameters entering theory is discussed. Particular steps for animal preparation and maintenance during the experiment are given, since CBF regulation is sensitive to a number of experimental physiological parameters and influenced mainly by anesthesia and body temperature.
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Chugh BP, Bishop J, Zhou YQ, Wu J, Henkelman RM, Sled JG. Robust method for 3D arterial spin labeling in mice. Magn Reson Med 2011; 68:98-106. [PMID: 22102489 DOI: 10.1002/mrm.23209] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2011] [Revised: 08/15/2011] [Accepted: 08/16/2011] [Indexed: 11/12/2022]
Abstract
Arterial spin labeling is a versatile perfusion quantification methodology, which has the potential to provide accurate characterization of cerebral blood flow (CBF) in mouse models. However, a paucity of physiological data needed for accurate modeling, more stringent requirements for gradient performance, and strong artifacts introduced by magnetization transfer present special challenges for accurate CBF mapping in the mouse. This article describes robust mapping of CBF over three-dimensional brain regions using amplitude-modulated continuous arterial spin labeling. To provide physiological data for CBF modeling, the carotid artery blood velocity distribution was characterized using pulsed-wave Doppler ultrasound. These blood velocity measurements were used in simulations that optimize inversion efficiency for parameters meeting MRI gradient duty cycle constraints. A rapid slice positioning algorithm was developed and evaluated to provide accurate positioning of the labeling plane. To account for enhancement of T(1) due to magnetization transfer, a binary spin bath model of magnetization transfer was used to provide a more accurate estimate of CBF. Finally, a study of CBF was conducted on 10 mice with findings of highly reproducible inversion efficiency (mean ± standard-error-of-the-mean, 0.67 ± 0.03), statistically significant variation in CBF over 12 brain regions (P < 0.0001) and a mean ± standard-error-of-the-mean whole brain CBF of 219 ± 6 mL/100 g/min.
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Affiliation(s)
- Brige Paul Chugh
- Mouse Imaging Centre, The Hospital for Sick Children, Toronto, Ontario, Canada.
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12
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Duhamel G, Callot V, Tachrount M, Alsop DC, Cozzone PJ. Pseudo-continuous arterial spin labeling at very high magnetic field (11.75 T) for high-resolution mouse brain perfusion imaging. Magn Reson Med 2011; 67:1225-36. [DOI: 10.1002/mrm.23096] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2011] [Revised: 06/10/2011] [Accepted: 06/21/2011] [Indexed: 12/27/2022]
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Pino F, Roé N, Orero A, Falcón C, Rojas S, Benlloch JM, Ros D, Pavía J. Development of a variable-radius pinhole SPECT system with a portable gamma camera. ACTA ACUST UNITED AC 2011; 30:286-91. [PMID: 21640439 DOI: 10.1016/j.remn.2011.03.004] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2011] [Accepted: 03/02/2011] [Indexed: 11/25/2022]
Abstract
OBJECTIVE To develop a small-animal SPECT system using a low cost commercial portable gamma camera equipped with a pinhole collimator, a continuous scintillation crystal and a position-sensitive photomultiplier tube. MATERIAL AND METHODS The gamma camera was attached to a variable radius system, which enabled us to optimize sensitivity and resolution by adjusting the radius of rotation to the size of the object. To investigate the capability of the SPECT system for small animal imaging, the dependence of resolution and calibration parameters on radius was assessed and acquisitions of small phantoms and mice were carried out. RESULTS Resolution values, ranging from 1.0mm for a radius of 21.4mm and 1.4mm for a radius of 37.2mm were obtained, thereby justifying the interest of a variable radius SPECT system. CONCLUSIONS The image quality of phantoms and animals were satisfactory, thus confirming the usefulness of the system for small animal SPECT imaging.
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Affiliation(s)
- F Pino
- Unitat de Biofísica, Facultat de Medicina, Universitat de Barcelona, Spain.
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14
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Zheng B, Lee PTH, Golay X. High-sensitivity cerebral perfusion mapping in mice by kbGRASE-FAIR at 9.4 T. NMR IN BIOMEDICINE 2010; 23:1061-1070. [PMID: 20665907 DOI: 10.1002/nbm.1533] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
The combination of flow-sensitive alternating inversion recovery (FAIR) and single-shot k-space-banded gradient- and spin-echo (kbGRASE) is proposed here to measure perfusion in the mouse brain with high sensitivity and stability. Signal-to-noise ratio (SNR) analysis showed that kbGRASE-FAIR boosts image and temporal SNRs by 2.01 ± 0.08 and 2.50 ± 0.07 times, respectively, when compared with standard single-shot echo planar imaging (EPI)-FAIR implemented in our experimental systems, although the practically achievable spatial resolution was slightly reduced. The effects of varying physiological parameters on the precision and reproducibility of cerebral blood flow (CBF) measurements were studied following changes in anesthesia regime, capnia and body temperature. The functional MRI time courses with kbGRASE-FAIR showed a more stable response to 5% CO(2) than did those with EPI-FAIR. The results establish kbGRASE-FAIR as a practical and robust protocol for quantitative CBF measurements in mice at 9.4 T.
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Affiliation(s)
- Bingwen Zheng
- Singapore Bioimaging Consortium, Agency for Science, Technology and Research, Biopolis, Singapore.
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15
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Leithner C, Müller S, Füchtemeier M, Lindauer U, Dirnagl U, Royl G. Determination of the brain-blood partition coefficient for water in mice using MRI. J Cereb Blood Flow Metab 2010; 30:1821-4. [PMID: 20842161 PMCID: PMC3023928 DOI: 10.1038/jcbfm.2010.160] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Cerebral blood flow (CBF) quantification is a valuable tool in stroke research. Mice are of special interest because of the potential of genetic engineering. Magnetic resonance imaging (MRI) provides repetitive, noninvasive CBF quantification. Many MRI techniques require the knowledge of the brain-blood partition coefficient (BBPC) for water. Adopting an MRI protocol described by Roberts et al (1996) in humans, we determined the BBPC for water in 129S6/SvEv mice from proton density measurements of brain and blood, calibrated with deuterium oxide/water phantoms. The average BBPC for water was 0.89 ± 0.03 mL/g, with little regional variation within the mouse brain.
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Affiliation(s)
- Christoph Leithner
- Department of Experimental Neurology, Charité-Universitätsmedizin, Center for Stroke Research Berlin, Berlin, Germany.
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16
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What is the optimal anesthetic protocol for measurements of cerebral autoregulation in spontaneously breathing mice? Exp Brain Res 2010; 207:249-58. [DOI: 10.1007/s00221-010-2447-4] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2010] [Accepted: 09/30/2010] [Indexed: 11/27/2022]
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Foley LM, Hitchens TK, Ho C, Janesko-Feldman KL, Melick JA, Bayir H, Kochanek PM. Magnetic resonance imaging assessment of macrophage accumulation in mouse brain after experimental traumatic brain injury. J Neurotrauma 2009; 26:1509-19. [PMID: 19663686 DOI: 10.1089/neu.2008.0747] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Macrophages contribute to secondary damage and repair after central nervous system (CNS) injury. Micron-sized paramagnetic iron oxide (MPIO) particles can label macrophages in situ, facilitating three-dimensional (3D) mapping of macrophage accumulation following traumatic brain injury (TBI), via ex vivo magnetic resonance microscopy (MRM) and in vivo monitoring with magnetic resonance imaging (MRI). MPIO particles were injected intravenously (iv; 4.5 mg Fe/Kg) in male C57BL/6J mice (n = 21). A controlled cortical impact (CCI) was delivered to the left parietal cortex. Five protocols were used in naive and injured mice to assess feasibility, specificity, and optimal labeling time. In vivo imaging was carried out at 4.7 Tesla (T). Brains were then excised for 3D MRM at 11.7 T. Triple-label immunofluorescence (MPIO via Dragon Green, macrophages via F480, and nuclei via 4,6-diamidino-2-phenylindole [DAPI]) of brain sections confirmed MPIO particles within macrophages. MRM of naives showed an even distribution of a small number of MPIO-labeled macrophages in the brain. MRM at 48-72 h after CCI and MPIO injection revealed MPIO-labeled macrophages accumulated in the trauma region. When MPIO particles were injected 6 days before CCI, MRM 48 h after CCI also revealed labeled cells at the injury site. In vivo studies of macrophage accumulation by MRI suggest that this approach is feasible, but requires additional optimization. We conclude that MPIO labeling and ex vivo MRM mapping of macrophage accumulation for assessment of TBI is readily accomplished. This new technique could serve as an adjunct to conventional MR approaches by defining inflammatory mechanisms and therapeutic efficacy of anti-inflammatory agents in experimental TBI.
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Affiliation(s)
- Lesley M Foley
- Pittsburgh NMR Center for Biomedical Research, Carnegie Mellon University, Pittsburgh, Pennsylvania, USA
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Duhamel G, Callot V, Decherchi P, Le Fur Y, Marqueste T, Cozzone PJ, Kober F. Mouse lumbar and cervical spinal cord blood flow measurements by arterial spin labeling: Sensitivity optimization and first application. Magn Reson Med 2009; 62:430-9. [DOI: 10.1002/mrm.22015] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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19
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Muir ER, Shen Q, Duong TQ. Cerebral blood flow MRI in mice using the cardiac-spin-labeling technique. Magn Reson Med 2009; 60:744-8. [PMID: 18727091 DOI: 10.1002/mrm.21721] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Continuous arterial spin labeling MRI with a separate neck labeling coil provides a highly sensitive method to image cerebral blood flow (CBF). In mice, however, this has not been possible because the proximity of the neck coil to the brain uses the neck coil to significantly saturate the brain signal. To overcome this limitation the cardiac spin labeling (CSL) technique is introduced in which the labeling coil is placed at the heart position. To demonstrate its utility, CSL CBF was applied to image quantitative basal CBF and hypercapnia-induced CBF changes. This approach provides a practical means to image CBF with high sensitivity in small animals, compares favorably to existing mouse CBF imaging techniques, and could broaden CBF applications in mice where many brain disease and transgenic models are widely available.
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Affiliation(s)
- Eric R Muir
- Department of Neurology, Yerkes Imaging Center, Emory University, Atlanta, Georgia 30329, USA
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Manole MD, Foley LM, Hitchens TK, Kochanek PM, Hickey RW, Bayir H, Alexander H, Ho C, Clark RSB. Magnetic resonance imaging assessment of regional cerebral blood flow after asphyxial cardiac arrest in immature rats. J Cereb Blood Flow Metab 2009; 29:197-205. [PMID: 18827831 PMCID: PMC2613172 DOI: 10.1038/jcbfm.2008.112] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Cerebral blood flow (CBF) alterations after asphyxial cardiac arrest (CA) are not defined in developmental animal models or humans. We characterized regional and temporal changes in CBF from 5 to 150 mins after asphyxial CA of increasing duration (8.5, 9, 12 min) in postnatal day (PND) 17 rats using the noninvasive method of arterial spin-labeled magnetic resonance imaging (ASL-MRI). We also assessed blood-brain barrier (BBB) permeability, and evaluated the relationship between CBF and mean arterial pressure after resuscitation. After all durations of asphyxia CBF alterations were region dependent. After 8.5- and 9-min asphyxia, intense subcortical hyperemia at 5 min was followed by return of CBF to baseline values by 10 mins. After 12-min asphyxia, hyperemia was absent and hypoperfusion reached a nadir of 38% to 65% of baselines with the lowest values in the cortex. BBB was impermeable to gadoteridol 150 mins after CA. CBF in the 12-min CA group was blood pressure passive at 60 min assessed via infusion of epinephrine. ASL-MRI assessment of CBF after asphyxial CA in PND 17 rats reveals marked duration and region-specific reperfusion patterns and identifies possible new therapeutic targets.
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Affiliation(s)
- Mioara D Manole
- Division of Pediatric Emergency Medicine, Department of Pediatrics, Children's Hospital of Pittsburgh, Pittsburgh, Pennsylvania 15213-2583, USA.
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Kober F, Duhamel G, Cozzone PJ. Experimental comparison of four FAIR arterial spin labeling techniques for quantification of mouse cerebral blood flow at 4.7 T. NMR IN BIOMEDICINE 2008; 21:781-792. [PMID: 18384177 DOI: 10.1002/nbm.1253] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Pulsed arterial spin labeling (ASL) is an attractive and robust method for quantification of rodent cerebral blood flow (CBF) in particular, although there is a need for sensitivity optimization. Look-Locker flow-sensitive alternating inversion recovery (FAIR) echo planar imaging (EPI) (LLFAIREPI) was expected to be a likely candidate for assessing sensitivity, although it has not yet been applied to rodents. In this study, the performance of two FAIR techniques and two Look-Locker FAIR techniques were compared in mouse brain at 4.7 T. FAIR-EPI (single inversion time, FAIREPI-1TI), FAIR-EPI (eight inversion times, FAIREPI-8TI), LLFAIREPI and Look-Locker FAIR gradient echo (LLFAIRGE) sequences were implemented with equal spatial resolution and equal FAIR preparation modules. Measurements were carried out sequentially on the brain in 10 healthy mice, and quantitative CBF maps were obtained after different acquisition times up to 23 min. All methods gave similar group variability in CBF. Especially at shorter acquisition times, LLFAIREPI gave lower relative variations in CBF within selected brain regions than the other techniques at the same acquisition time. The Look-Locker techniques, however, overestimated CBF compared with classical FAIR-EPI, which was attributed to bulk flow in arterioles and T(2) effects. The image quality with LLFAIREPI was less reproducible within the group. Both FAIREPI-1TI and LLFAIREPI appear to be good candidates for serial rapid measurement of CBF, but LLFAIREPI has the additional advantage that apparent T(1) can be measured simultaneously with CBF.
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Affiliation(s)
- Frank Kober
- Centre de Résonance Magnétique Biologique et Médicale (CRMBM), UMR CNRS no. 6612, Faculté de Médecine, Université de la Méditerranée, Marseille, France.
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22
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Duhamel G, Callot V, Cozzone PJ, Kober F. Spinal cord blood flow measurement by arterial spin labeling. Magn Reson Med 2008; 59:846-54. [PMID: 18383283 DOI: 10.1002/mrm.21567] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The assessment of spinal cord (SC) hemodynamics, and especially SC blood flow (SCBF), plays a key role in the pathophysiological description and understanding of many SC diseases such as ischemia, or spinal cord injury. SCBF has been previously measured in animals with invasive techniques such as autoradiography or labeled microspheres; no MR technique, however, has been proposed so far. The possibility of quantitatively measuring SCBF in mice using MRI was investigated using a presaturated FAIR (flow-sensitive alternating inversion recovery) arterial spin labeling (ASL) technique. SCBF measurements were performed at the cervical level of the mouse as well as on the brain so as to use cerebral blood flow (CBF) values as internal references. With a spatial resolution of 133 x 133 microm(2) for the SCBF maps, absolute regional perfusion values could be measured within the different structures of the SC (gray matter, white matter, and cerebrospinal fluid area). Similar perfusion values were found in SC gray matter (330+/-90 mL/100g/min) and in brain (295+/-22 mL/100g/min for thalamus). This result, in agreement with SCBF/CBF measurements performed with non-MR techniques, opens new perspectives for noninvasive longitudinal and in vivo animal studies. Application to human experiments may also be possible.
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Affiliation(s)
- Guillaume Duhamel
- Centre de Résonance Magnétique Biologique et Médicale, Faculté de Médecine de Marseille, Université de la Méditerranée, Marseille, France.
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Foley LM, Hitchens TK, Melick JA, Bayir H, Ho C, Kochanek PM. Effect of Inducible Nitric Oxide Synthase on Cerebral Blood Flow after Experimental Traumatic Brain Injury in Mice. J Neurotrauma 2008; 25:299-310. [DOI: 10.1089/neu.2007.0471] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- Lesley M. Foley
- Pittsburgh NMR Center for Biomedical Research, Carnegie Mellon University, Pittsburgh, Pennsylvania
| | - T. Kevin Hitchens
- Pittsburgh NMR Center for Biomedical Research, Carnegie Mellon University, Pittsburgh, Pennsylvania
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, Pennsylvania
| | - John A. Melick
- Safar Center for Resuscitation Research, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
| | - Hülya Bayir
- Safar Center for Resuscitation Research, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
- Department of Critical Care Medicine, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
| | - Chien Ho
- Pittsburgh NMR Center for Biomedical Research, Carnegie Mellon University, Pittsburgh, Pennsylvania
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, Pennsylvania
| | - Patrick M. Kochanek
- Safar Center for Resuscitation Research, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
- Department of Critical Care Medicine, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
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Leithner C, Gertz K, Schröck H, Priller J, Prass K, Steinbrink J, Villringer A, Endres M, Lindauer U, Dirnagl U, Royl G. A flow sensitive alternating inversion recovery (FAIR)-MRI protocol to measure hemispheric cerebral blood flow in a mouse stroke model. Exp Neurol 2008; 210:118-27. [DOI: 10.1016/j.expneurol.2007.10.003] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2007] [Revised: 09/21/2007] [Accepted: 10/10/2007] [Indexed: 10/22/2022]
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Hossmann KA, Traystman RJ. Cerebral blood flow and the ischemic penumbra. HANDBOOK OF CLINICAL NEUROLOGY 2008; 92:67-92. [PMID: 18790270 DOI: 10.1016/s0072-9752(08)01904-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
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Brockmann MA, Kemmling A, Groden C. Current issues and perspectives in small rodent magnetic resonance imaging using clinical MRI scanners. Methods 2007; 43:79-87. [PMID: 17720566 DOI: 10.1016/j.ymeth.2007.07.001] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2007] [Accepted: 07/10/2007] [Indexed: 12/16/2022] Open
Abstract
Small rodents such as mice and rats are frequently used in animal experiments for several reasons. In the past, animal experiments were frequently associated with invasive methods and groups of animals had to be killed to perform longitudinal studies. Today's modern imaging techniques such as magnetic resonance imaging (MRI) allow non-invasive longitudinal monitoring of multiple parameters. Although only a few institutions have access to dedicated small animal MR scanners, most institutions carrying out animal experiments have access to clinical MR scanners. Technological advances and the increasing field strength of clinical scanners make MRI a broadly available and viable technique in preclinical in vivo research. This review provides an overview of current concepts, limitations, and recent studies dealing with small animal imaging using clinical MR scanners.
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Affiliation(s)
- Marc A Brockmann
- Department of Neuroradiology, Medical Faculty Mannheim, University of Heidelberg, Theodor-Kutzer-Ufer 1-3, 61867 Mannheim, Germany.
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