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Research paper thumbnail of In vivo MRI effectively monitors onset and progression of bleomycin-induced lung fibrosis in free-breathing mice

Proc. Intl. Soc. Mag. Reson. Med., May 1, 2014

PURPOSE Lung fibrosis, either idiopathic or secondary to diseases such as systemic sclerosis, is ... more PURPOSE Lung fibrosis, either idiopathic or secondary to diseases such as systemic sclerosis, is a devastating and life threatening disorder for which effective treatment is still lacking . As the course of fibrosis progression in rodent models shows substantial interindividual variation, non-invasive techniques are indispensable to dynamically monitor initial lung inflammation and progression of fibrosis to establish the appropriate time window for anti-fibrotic treatment and its effects for each animal individually. This is important because improvement of our understanding of pathological mechanisms and treatment effects in preclinical models is likely to improve predictability of clinical outcome of experimental treatment, where real anti-fibrotic treatments will be most relevant for clinical applicability. Non-invasive MRI of progression of lung disease in bleomycin-instilled mice may provide a sensitive and valuable tool to assess onset and progression of lung fibrosis in free-breathing mice, without radiotoxicity concerns or elaborate invasive endpoint measurements. Therefore, we evaluated and compared the potential of respiratory gated ultra short echo time (UTE) and self-gated MRI approaches with a conventional respiratory triggered pulse sequence in the bleomycin-induced lung fibrosis mouse model. We validated the MRI results with in vivo micro-computed tomography (μCT) 2 and ex vivo histology as golden standard histochemical readouts for lung fibrosis.

Research paper thumbnail of In vivo T2 relaxometry to assess inflamamtion and fibrosis in a murine model of inflammatory bowel diseases

Journal of Crohns & Colitis, 2011

Research paper thumbnail of Biomechanical properties of bovine knee cartilage under compressive loading: A study at high field MRI (9.4T) using T1, T2 and T1rho relaxometry combined with DENSE-FID

Research paper thumbnail of Cerebrovascular alterations in an animal model of Alzmeimer’s disease expressing human mutant APP and Tau

Research paper thumbnail of The importance of total lung volume changes detected by microMR and microCT imaging in experimental models of pulmonary aspergillosis and pulmonary cryptococcosis

Research paper thumbnail of Visualizing stem cells by MRI: sensitivity and potential adverse effects on cell phenotype using paramagnetic nanoparticles

Research paper thumbnail of In vitro and in vivo 19-fluorine magnetic resonance imaging (MRI) of beta-cells and pancreatic using GLUT-2 specific contrast agents

Introduction The assessment of the β-cell mass in experimental models of diabetes and ultimately ... more Introduction The assessment of the β-cell mass in experimental models of diabetes and ultimately in patients is a hallmark to understand the relationship between reduced β-cell mass/function and the onset of diabetes. Several attempts have been made to visualize β-cells in vivo using targeted nanoparticles and MRI. However due to the small size of fenestra in pancreatic islets, not all β-cells can be reached, preventing quantitative assessment of β-cell mass. F MRI has emerged as a new alternative method for MRI cell tracking [1] because it provides potential non-invasive localization and quantification of labeled cells. The purpose of this project is to validate β-cell and pancreatic islet imaging by using fluorinated, GLUT-2 targeting mannoheptulose derivatives (FMH) in vivo. It has been shown before that the GLUT-2 transporter is highly expressed in both βcells and hepatocytes and that mannoheptulose has high uptake specificity for the GLUT-2 transporter [2-4]. Methods Contrast a...

Research paper thumbnail of Combination of MRI experiments and finite element modelling for interpretation of water profiles in pears during postharvest conditions

Research paper thumbnail of Non-invasive visualization of invasive pulmonary aspergillosis in mice by using a multimodal imaging approach

Research paper thumbnail of Multipotent Adult Progenitor Cells Support Lymphatic Regeneration at Multiple Anatomical Levels during Wound Healing and Lymphedema

Scientific Reports, 2018

Lymphatic capillary growth is an integral part of wound healing, yet, the combined effectiveness ... more Lymphatic capillary growth is an integral part of wound healing, yet, the combined effectiveness of stem/progenitor cells on lymphatic and blood vascular regeneration in wounds needs further exploration. Stem/progenitor cell transplantation also emerged as an approach to cure lymphedema, a condition caused by lymphatic system deficiency. While lymphedema treatment requires lymphatic system restoration from the capillary to the collector level, it remains undetermined whether stem/progenitor cells support a complex regenerative response across the entire anatomical spectrum of the system. Here, we demonstrate that, although multipotent adult progenitor cells (MAPCs) showed potential to differentiate down the lymphatic endothelial lineage, they mainly trophically supported lymphatic endothelial cell behaviour in vitro. In vivo, MAPC transplantation supported blood vessel and lymphatic capillary growth in wounds and restored lymph drainage across skin flaps by stimulating capillary and...

Research paper thumbnail of Core Breakdown 'Conference' Pears: A Problem of Respiration and Diffusion

Research paper thumbnail of Characterization of a photothrombotic stroke model by MRI: implications for stem cell transplantation

Research paper thumbnail of PET and MRI for evaluation of long term vascular remodeling resulting from chronic cerebral hypoperfusion

Research paper thumbnail of In vitro and in vivo study of gold synthetic antiferromagnetic nanoparticles as bimodal contrast agents in MRI and CT

Research paper thumbnail of In vivo quantification of particle based and gene based MRI reporters in the rodent brain

INTRODUCTION: MRI reporters for in vivo labelling and visualization of endogenous progenitor stem... more INTRODUCTION: MRI reporters for in vivo labelling and visualization of endogenous progenitor stem cells (eNPCs) in the adult rodent brain, such as iron oxide particles or reporter genes (e.g. ferritin), result in hypo-intense contrast in high resolution 3D T2*-weighted MR images that can be quantified using suitable image processing tools. We have previously demonstrated that the assessment of lentiviral (LV) and adeno-associated viral (AAV) vector induced expression of the ferritin reporter gene with MRI is confounded by unspecific background contrast at the site-of-injection of the vector in the subventricular zone (SVZ) and around the injection tract (1). However, as the labeled eNPCs migrate away from the SVZ towards the olfactory bulb (OB), LV or AAV mediated MR reporter gene labeling of stem cells still holds potential for neural progenitor cell tracking with MRI. In (2), we quantitatively compared the use of ferritin reporter gene based and micron-sized iron oxide particle (MPIO) based labeling for visualization of the migrated cells in OB using high resolution ex vivo MRI. Here, we demonstrate the potential of this methodology for regional quantification of MRI reporter contrast from in vivo MRI, which could enable longitudinal analysis of regional particle based and reporter gene based MRI contrast changes over time in the same animal.

Research paper thumbnail of Assessment of variability within small animal stereotactic neurosurgery and inclusion of vasculature information for planning neuro-anatomical surgery in the rodent brain

OF VASCULATURE INFORMATION FOR PLANNING NEURO-ANATOMICAL SURGERY IN THE RODENT BRAIN Janaki Raman... more OF VASCULATURE INFORMATION FOR PLANNING NEURO-ANATOMICAL SURGERY IN THE RODENT BRAIN Janaki Raman Rangarajan, Greetje VandeVelde, Kris van Kuyck, Maarten Depypere, Friso van Gent, Tom Dresselaers, Uwe Himmelreich, and Frederik Maes Medical image Computing -ESAT/PSI, K.U. Leuven, Leuven, Belgium, IBBT-K.U.Leuven Future Health Department, K.U. Leuven, Leuven, Belgium, Biomedical NMR unit, Department of Medical Diagnostic Sciences, Faculty of Medicine, K.U. Leuven, Belgium, Molecular Small Animal Imaging Center (MoSAIC), Faculty of Medicine, K.U. Leuven, Laboratory for Experimental Functional Neurosurgery, Dept. of Neurosciences, K.U. Leuven, Medical image Computing -ESAT/PSI, K.U. Leuven, Belgium, Medical image Computing -ESAT/PSI, K.U. Leuven, Leuven, Flanders, Belgium

Research paper thumbnail of Longitudinal mouse colon T2 monitoring of chronically relapsing inflammation induced by repeated cycles of DSS

Annual meeting of the ISMRM Benelux Chapter, Jan 16, 2012

Research paper thumbnail of Longitudinal T2 relaxometry to monitor repeated cycles of DSS inducing a chronically relapsing inflammation

International Society for Magnetic Resonance in Medicine, May 5, 2012

Research paper thumbnail of Robustness of T1 and ECV mapping radiomics features: a between-session evaluation in young athletes

European Heart Journal - Cardiovascular Imaging

Funding Acknowledgements Type of funding sources: None. Introduction Radiomics of cardiac MRI T1,... more Funding Acknowledgements Type of funding sources: None. Introduction Radiomics of cardiac MRI T1, T2 and extracellular volume (ECV) maps has the potential to add biomarkers that can aid in the detection and diagnosis of myocardial diseases. Recently, the feasibility of CMR mapping based radiomics to classify various myocardial diseases was demonstrated [1-6]. However, reproducibility studies have reported sensitivity of radiomics to acquisition parameters and processing steps involved concluding that only a limited number of features may be reproducible [7-8]. As CMR mapping guidelines recommend to use site-specific normal values [9], radiomics features derived likely also need careful site-specific evaluation to benchmark disease-related feature alterations. Purpose We aimed to assess the between-session reproducibility of radiomics features in a longitudinal dataset of MOLLI T1 and ECV maps obtained in young athletes at 1.5T. Materials and methods This study included data from 17 ...

Research paper thumbnail of Additional file 1: Figure S1. of Assessment of bystander killing-mediated therapy of malignant brain tumors using a multimodal imaging approach

High magnification images from brain sections of representative animals for all groups and subgro... more High magnification images from brain sections of representative animals for all groups and subgroups. Masssonâ s Trichrome staining (top) of sham-operated and PBS-injected, control animals showed very large tumors with some bleeding. Prussian blue (bottom) staining was also performed, which indicated presence of iron (*) in PBS-injected, control animals that did not respond to treatment. For these animals, positive iron staining was seen both at the tumor border (left Prussian blue staining) and inside the tumor mass (right Prussian blue staining). GCV-treated responders showed high iron content as the cells remained more localized around the much smaller tumor lesions. The presence of high amounts of iron is an indication for the presence of SPIO from engrafted, labeled stem cells. Finally, Iba1 staining (middle) was performed which showed microglial activation in the GCV-treated responding group. Microglial activation was also pronounced around the tumor in sham-operated and PBS-i...

Research paper thumbnail of In vivo MRI effectively monitors onset and progression of bleomycin-induced lung fibrosis in free-breathing mice

Proc. Intl. Soc. Mag. Reson. Med., May 1, 2014

PURPOSE Lung fibrosis, either idiopathic or secondary to diseases such as systemic sclerosis, is ... more PURPOSE Lung fibrosis, either idiopathic or secondary to diseases such as systemic sclerosis, is a devastating and life threatening disorder for which effective treatment is still lacking . As the course of fibrosis progression in rodent models shows substantial interindividual variation, non-invasive techniques are indispensable to dynamically monitor initial lung inflammation and progression of fibrosis to establish the appropriate time window for anti-fibrotic treatment and its effects for each animal individually. This is important because improvement of our understanding of pathological mechanisms and treatment effects in preclinical models is likely to improve predictability of clinical outcome of experimental treatment, where real anti-fibrotic treatments will be most relevant for clinical applicability. Non-invasive MRI of progression of lung disease in bleomycin-instilled mice may provide a sensitive and valuable tool to assess onset and progression of lung fibrosis in free-breathing mice, without radiotoxicity concerns or elaborate invasive endpoint measurements. Therefore, we evaluated and compared the potential of respiratory gated ultra short echo time (UTE) and self-gated MRI approaches with a conventional respiratory triggered pulse sequence in the bleomycin-induced lung fibrosis mouse model. We validated the MRI results with in vivo micro-computed tomography (μCT) 2 and ex vivo histology as golden standard histochemical readouts for lung fibrosis.

Research paper thumbnail of In vivo T2 relaxometry to assess inflamamtion and fibrosis in a murine model of inflammatory bowel diseases

Journal of Crohns & Colitis, 2011

Research paper thumbnail of Biomechanical properties of bovine knee cartilage under compressive loading: A study at high field MRI (9.4T) using T1, T2 and T1rho relaxometry combined with DENSE-FID

Research paper thumbnail of Cerebrovascular alterations in an animal model of Alzmeimer’s disease expressing human mutant APP and Tau

Research paper thumbnail of The importance of total lung volume changes detected by microMR and microCT imaging in experimental models of pulmonary aspergillosis and pulmonary cryptococcosis

Research paper thumbnail of Visualizing stem cells by MRI: sensitivity and potential adverse effects on cell phenotype using paramagnetic nanoparticles

Research paper thumbnail of In vitro and in vivo 19-fluorine magnetic resonance imaging (MRI) of beta-cells and pancreatic using GLUT-2 specific contrast agents

Introduction The assessment of the β-cell mass in experimental models of diabetes and ultimately ... more Introduction The assessment of the β-cell mass in experimental models of diabetes and ultimately in patients is a hallmark to understand the relationship between reduced β-cell mass/function and the onset of diabetes. Several attempts have been made to visualize β-cells in vivo using targeted nanoparticles and MRI. However due to the small size of fenestra in pancreatic islets, not all β-cells can be reached, preventing quantitative assessment of β-cell mass. F MRI has emerged as a new alternative method for MRI cell tracking [1] because it provides potential non-invasive localization and quantification of labeled cells. The purpose of this project is to validate β-cell and pancreatic islet imaging by using fluorinated, GLUT-2 targeting mannoheptulose derivatives (FMH) in vivo. It has been shown before that the GLUT-2 transporter is highly expressed in both βcells and hepatocytes and that mannoheptulose has high uptake specificity for the GLUT-2 transporter [2-4]. Methods Contrast a...

Research paper thumbnail of Combination of MRI experiments and finite element modelling for interpretation of water profiles in pears during postharvest conditions

Research paper thumbnail of Non-invasive visualization of invasive pulmonary aspergillosis in mice by using a multimodal imaging approach

Research paper thumbnail of Multipotent Adult Progenitor Cells Support Lymphatic Regeneration at Multiple Anatomical Levels during Wound Healing and Lymphedema

Scientific Reports, 2018

Lymphatic capillary growth is an integral part of wound healing, yet, the combined effectiveness ... more Lymphatic capillary growth is an integral part of wound healing, yet, the combined effectiveness of stem/progenitor cells on lymphatic and blood vascular regeneration in wounds needs further exploration. Stem/progenitor cell transplantation also emerged as an approach to cure lymphedema, a condition caused by lymphatic system deficiency. While lymphedema treatment requires lymphatic system restoration from the capillary to the collector level, it remains undetermined whether stem/progenitor cells support a complex regenerative response across the entire anatomical spectrum of the system. Here, we demonstrate that, although multipotent adult progenitor cells (MAPCs) showed potential to differentiate down the lymphatic endothelial lineage, they mainly trophically supported lymphatic endothelial cell behaviour in vitro. In vivo, MAPC transplantation supported blood vessel and lymphatic capillary growth in wounds and restored lymph drainage across skin flaps by stimulating capillary and...

Research paper thumbnail of Core Breakdown 'Conference' Pears: A Problem of Respiration and Diffusion

Research paper thumbnail of Characterization of a photothrombotic stroke model by MRI: implications for stem cell transplantation

Research paper thumbnail of PET and MRI for evaluation of long term vascular remodeling resulting from chronic cerebral hypoperfusion

Research paper thumbnail of In vitro and in vivo study of gold synthetic antiferromagnetic nanoparticles as bimodal contrast agents in MRI and CT

Research paper thumbnail of In vivo quantification of particle based and gene based MRI reporters in the rodent brain

INTRODUCTION: MRI reporters for in vivo labelling and visualization of endogenous progenitor stem... more INTRODUCTION: MRI reporters for in vivo labelling and visualization of endogenous progenitor stem cells (eNPCs) in the adult rodent brain, such as iron oxide particles or reporter genes (e.g. ferritin), result in hypo-intense contrast in high resolution 3D T2*-weighted MR images that can be quantified using suitable image processing tools. We have previously demonstrated that the assessment of lentiviral (LV) and adeno-associated viral (AAV) vector induced expression of the ferritin reporter gene with MRI is confounded by unspecific background contrast at the site-of-injection of the vector in the subventricular zone (SVZ) and around the injection tract (1). However, as the labeled eNPCs migrate away from the SVZ towards the olfactory bulb (OB), LV or AAV mediated MR reporter gene labeling of stem cells still holds potential for neural progenitor cell tracking with MRI. In (2), we quantitatively compared the use of ferritin reporter gene based and micron-sized iron oxide particle (MPIO) based labeling for visualization of the migrated cells in OB using high resolution ex vivo MRI. Here, we demonstrate the potential of this methodology for regional quantification of MRI reporter contrast from in vivo MRI, which could enable longitudinal analysis of regional particle based and reporter gene based MRI contrast changes over time in the same animal.

Research paper thumbnail of Assessment of variability within small animal stereotactic neurosurgery and inclusion of vasculature information for planning neuro-anatomical surgery in the rodent brain

OF VASCULATURE INFORMATION FOR PLANNING NEURO-ANATOMICAL SURGERY IN THE RODENT BRAIN Janaki Raman... more OF VASCULATURE INFORMATION FOR PLANNING NEURO-ANATOMICAL SURGERY IN THE RODENT BRAIN Janaki Raman Rangarajan, Greetje VandeVelde, Kris van Kuyck, Maarten Depypere, Friso van Gent, Tom Dresselaers, Uwe Himmelreich, and Frederik Maes Medical image Computing -ESAT/PSI, K.U. Leuven, Leuven, Belgium, IBBT-K.U.Leuven Future Health Department, K.U. Leuven, Leuven, Belgium, Biomedical NMR unit, Department of Medical Diagnostic Sciences, Faculty of Medicine, K.U. Leuven, Belgium, Molecular Small Animal Imaging Center (MoSAIC), Faculty of Medicine, K.U. Leuven, Laboratory for Experimental Functional Neurosurgery, Dept. of Neurosciences, K.U. Leuven, Medical image Computing -ESAT/PSI, K.U. Leuven, Belgium, Medical image Computing -ESAT/PSI, K.U. Leuven, Leuven, Flanders, Belgium

Research paper thumbnail of Longitudinal mouse colon T2 monitoring of chronically relapsing inflammation induced by repeated cycles of DSS

Annual meeting of the ISMRM Benelux Chapter, Jan 16, 2012

Research paper thumbnail of Longitudinal T2 relaxometry to monitor repeated cycles of DSS inducing a chronically relapsing inflammation

International Society for Magnetic Resonance in Medicine, May 5, 2012

Research paper thumbnail of Robustness of T1 and ECV mapping radiomics features: a between-session evaluation in young athletes

European Heart Journal - Cardiovascular Imaging

Funding Acknowledgements Type of funding sources: None. Introduction Radiomics of cardiac MRI T1,... more Funding Acknowledgements Type of funding sources: None. Introduction Radiomics of cardiac MRI T1, T2 and extracellular volume (ECV) maps has the potential to add biomarkers that can aid in the detection and diagnosis of myocardial diseases. Recently, the feasibility of CMR mapping based radiomics to classify various myocardial diseases was demonstrated [1-6]. However, reproducibility studies have reported sensitivity of radiomics to acquisition parameters and processing steps involved concluding that only a limited number of features may be reproducible [7-8]. As CMR mapping guidelines recommend to use site-specific normal values [9], radiomics features derived likely also need careful site-specific evaluation to benchmark disease-related feature alterations. Purpose We aimed to assess the between-session reproducibility of radiomics features in a longitudinal dataset of MOLLI T1 and ECV maps obtained in young athletes at 1.5T. Materials and methods This study included data from 17 ...

Research paper thumbnail of Additional file 1: Figure S1. of Assessment of bystander killing-mediated therapy of malignant brain tumors using a multimodal imaging approach

High magnification images from brain sections of representative animals for all groups and subgro... more High magnification images from brain sections of representative animals for all groups and subgroups. Masssonâ s Trichrome staining (top) of sham-operated and PBS-injected, control animals showed very large tumors with some bleeding. Prussian blue (bottom) staining was also performed, which indicated presence of iron (*) in PBS-injected, control animals that did not respond to treatment. For these animals, positive iron staining was seen both at the tumor border (left Prussian blue staining) and inside the tumor mass (right Prussian blue staining). GCV-treated responders showed high iron content as the cells remained more localized around the much smaller tumor lesions. The presence of high amounts of iron is an indication for the presence of SPIO from engrafted, labeled stem cells. Finally, Iba1 staining (middle) was performed which showed microglial activation in the GCV-treated responding group. Microglial activation was also pronounced around the tumor in sham-operated and PBS-i...