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Kiessling F, Schulz V. Perspectives of Evidence-Based Therapy Management. Nuklearmedizin 2023; 62:314-322. [PMID: 37802059 DOI: 10.1055/a-2159-6949] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/08/2023]
Abstract
BACKGROUND Therapeutics that specifically address biological processes often require a much finer selection of patients and subclassification of diseases. Thus, diagnostic procedures must describe the diseases in sufficient detail to allow selection of appropriate therapy and to sensitively track therapy response. Anatomical features are often not sufficient for this purpose and there is a need to image molecular and pathophysiological processes. METHOD Two imaging strategies can be pursued: molecular imaging attempts to image a few biomarkers that play key roles in pathological processes. Alternatively, patterns describing a biological process can be identified from the synopsis of multiple (non-specific) imaging markers, possibly in combination with omics and other clinical findings. Here, AI-based methods are increasingly being used. RESULTS Both strategies of evidence-based therapy management are explained in this review article and examples and clinical successes are presented. In this context, reviews of clinically approved molecular diagnostics and decision support systems are listed. Furthermore, since reliable, representative, and sufficiently large datasets are further important prerequisites for AI-assisted multiparametric analyses, concepts are presented to make data available in a structured way, e. g., using Generative Adversarial Networks to complement databases with virtual cases and to build completely anonymous reference databases. CONCLUSION Molecular imaging and computer-assisted cluster analysis of diagnostic data are complementary methods to describe pathophysiological processes. Both methods have the potential to improve (evidence-based) the future management of therapies, partly on their own but also in combined approaches. KEY POINTS · Molecular imaging and radiomics provide valuable complementary disease biomarkers.. · Data-driven, model-based, and hybrid model-based integrated diagnostics advance precision medicine.. · Synthetic data generation may become essential in the development process of future AI methods..
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Affiliation(s)
- Fabian Kiessling
- Universitätsklinikum Aachen, Lehrstuhl für Experimentelle Molekulare Bildgebung, Aachen, Germany
- Group Aachen, Fraunhofer-Institut für Digitale Medizin MEVIS, Bremen, Germany
| | - Volkmar Schulz
- Universitätsklinikum Aachen, Lehrstuhl für Experimentelle Molekulare Bildgebung, Aachen, Germany
- Group Aachen, Fraunhofer-Institut für Digitale Medizin MEVIS, Bremen, Germany
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Kiessling F, Schulz V. Perspectives of Evidence-Based Therapy Management. ROFO-FORTSCHR RONTG 2022; 194:728-736. [PMID: 35545101 DOI: 10.1055/a-1752-0839] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
BACKGROUND Therapeutics that specifically address biological processes often require a much finer selection of patients and subclassification of diseases. Thus, diagnostic procedures must describe the diseases in sufficient detail to allow selection of appropriate therapy and to sensitively track therapy response. Anatomical features are often not sufficient for this purpose and there is a need to image molecular and pathophysiological processes. METHOD Two imaging strategies can be pursued: molecular imaging attempts to image a few biomarkers that play key roles in pathological processes. Alternatively, patterns describing a biological process can be identified from the synopsis of multiple (non-specific) imaging markers, possibly in combination with omics and other clinical findings. Here, AI-based methods are increasingly being used. RESULTS Both strategies of evidence-based therapy management are explained in this review article and examples and clinical successes are presented. In this context, reviews of clinically approved molecular diagnostics and decision support systems are listed. Furthermore, since reliable, representative, and sufficiently large datasets are further important prerequisites for AI-assisted multiparametric analyses, concepts are presented to make data available in a structured way, e. g., using Generative Adversarial Networks to complement databases with virtual cases and to build completely anonymous reference databases. CONCLUSION Molecular imaging and computer-assisted cluster analysis of diagnostic data are complementary methods to describe pathophysiological processes. Both methods have the potential to improve (evidence-based) the future management of therapies, partly on their own but also in combined approaches. KEY POINTS · Molecular imaging and radiomics provide valuable complementary disease biomarkers.. · Data-driven, model-based, and hybrid model-based integrated diagnostics advance precision medicine.. · Synthetic data generation may become essential in the development process of future AI methods.. CITATION FORMAT · Kiessling F, Schulz V, . Perspectives of Evidence-Based Therapy Management. Fortschr Röntgenstr 2022; DOI: 10.1055/a-1752-0839.
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Affiliation(s)
- Fabian Kiessling
- Universitätsklinikum Aachen, Lehrstuhl für Experimentelle Molekulare Bildgebung, Aachen, Germany.,Group Aachen, Fraunhofer-Institut für Digitale Medizin MEVIS, Bremen, Germany
| | - Volkmar Schulz
- Universitätsklinikum Aachen, Lehrstuhl für Experimentelle Molekulare Bildgebung, Aachen, Germany.,Group Aachen, Fraunhofer-Institut für Digitale Medizin MEVIS, Bremen, Germany
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Evaluation of different grafting materials for alveolar cleft repair in the context of orthodontic tooth movement in rats. Sci Rep 2021; 11:13586. [PMID: 34193933 PMCID: PMC8245488 DOI: 10.1038/s41598-021-93033-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2021] [Accepted: 06/09/2021] [Indexed: 12/05/2022] Open
Abstract
To minimize the postoperative risks posed by grafting autologous transplants for cleft repair, efforts are being made to improve grafting materials for use as potential alternatives. The aim of this study was to compare the bone graft quality of different bone substitutes including the gold standard autografts during the healing processes after cleft repair in the context of orthodontic treatment. In 21 Wistar rats, a complete, continuity-interrupting cleft was created. After 4 weeks, cleft repair was performed using autografts from the hips’ ischial tuberosity, human xenografts, or synthetic bone substitutes [beta-tricalcium phosphate (β-TCP)/hydroxyapatite (HA)]. After another 4 weeks, the first molar movement was initiated in the reconstructed jaw for 8 weeks. The bone remodeling was analyzed in vivo using micro-computed tomography (bone mineral density and bone volume fraction) and histology (new bone formation). All the grafting materials were statistically different in bone morphology, which changed during the treatment period. The β-TCP/HA substitute demonstrated less resorption compared to the autologous and xenogeneic/human bone, and the autografts led to a stronger reaction in the surrounding bone. Histologically, the highest level of new bone formation was found in the human xenografts, and the lowest was found in the β-TCP/HA substitute. The differences between the two bone groups and the synthetic materials were statistically significant. Autografts were confirmed to be the gold standard in cleft repair with regard to graft integration. However, parts of the human xenograft seemed comparable to the autografts. Thus, this substitute could perhaps be used as an alternative after additional tissue-engineered modification.
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Kniha K, Bock A, Peters F, Magnuska ZA, Gremse F, Möhlhenrich SC, Hölzle F, Modabber A. Microstructural volumetric analysis of the jaw following dental implantation under systemic bisphosphonate delivery: An in vivo and ex vivo rat study. J Periodontol 2020; 92:66-75. [PMID: 33258110 DOI: 10.1002/jper.20-0547] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2020] [Revised: 09/29/2020] [Accepted: 10/27/2020] [Indexed: 11/06/2022]
Abstract
BACKGROUND Because of bisphosphonate medication, dental implantation with a subsequent infection poses a relevant risk factor to suffer from medication-related osteonecrosis of the jaw. This rat study evaluated different implant materials under systemic bisphosphonate delivery using micro-computed tomography (μCT) images. METHODS Fifty-four rats were randomly allocated into a control group 1, test group 2 with intravenous drug application of zoledronic acid and test group 3 with a subcutaneous application of alendronic acid. After 4 weeks of drug delivery, the first molar on each side of the upper jaw was extracted, and either a zirconia or a titanium implant was immediately inserted. Radiological examinations at four timepoints before the operation, 1 week later, 6 weeks later and after 12 weeks of follow up included μCT measurements of the in vivo peri-implant bone loss. μCT measurements of the ex vivo peri-implant bony structure after 12 weeks follow-up covered the bone mineral density, -volume, -trabecular thickness and -separation. RESULTS Both test groups showed a significant increase in bone loss over time (P < 0.05). The clinical observations of exposed bone revealed that most cases occurred under alendronic acid delivery. Exposed bone was recorded only in the test groups around both titanium and zirconia implants. Regarding the peri-implant bony structure, no significant differences were found between both materials. CONCLUSIONS Systemic bisphosphonate delivery led to increased peri-implant bone loss over time after immediate implant insertion. In terms of bone resorption and bone quality parameters, no implant material was superior to the other.
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Affiliation(s)
- Kristian Kniha
- Private clinic for oral and maxillofacial surgery, Kniha, Schlegel and colleagues, Munich, Germany.,Department of Oral and Cranio-Maxillofacial Surgery, University Hospital RWTH Aachen, Aachen, Germany
| | - Anna Bock
- Department of Oral and Cranio-Maxillofacial Surgery, University Hospital RWTH Aachen, Aachen, Germany
| | - Florian Peters
- Department of Oral and Cranio-Maxillofacial Surgery, University Hospital RWTH Aachen, Aachen, Germany
| | - Zuzanna Anna Magnuska
- Department of Experimental Molecular Imaging, RWTH Aachen University, Aachen, Germany
| | - Felix Gremse
- Department of Experimental Molecular Imaging, RWTH Aachen University, Aachen, Germany
| | | | - Frank Hölzle
- Department of Oral and Cranio-Maxillofacial Surgery, University Hospital RWTH Aachen, Aachen, Germany
| | - Ali Modabber
- Department of Oral and Cranio-Maxillofacial Surgery, University Hospital RWTH Aachen, Aachen, Germany
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Steinman DA, Pereira VM. How patient specific are patient-specific computational models of cerebral aneurysms? An overview of sources of error and variability. Neurosurg Focus 2020; 47:E14. [PMID: 31261118 DOI: 10.3171/2019.4.focus19123] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2019] [Accepted: 04/12/2019] [Indexed: 01/20/2023]
Abstract
Computational modeling of cerebral aneurysms, derived from clinical 3D angiography, has become widespread over the past 15 years. While such "image-based" or "patient-specific" models have shown promise for the assessment of rupture risk, much debate remains about their reliability in light of necessary modeling assumptions and incomplete or uncertain model input parameters derived from the clinic. The aims of this review were to walk through the various steps of this so-called patient-specific modeling pipeline and to highlight evidence supporting those steps that we can or cannot rely on. The relative importance of the different sources of error and variability on hemodynamic predictions is summarized, with recommendations to standardize for those that can be avoided and to pay closer attention those to that cannot.
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Affiliation(s)
- David A Steinman
- 1Department of Mechanical and Industrial Engineering and Institute of Biomaterials and Biomedical Engineering, University of Toronto; and
| | - Vitor M Pereira
- 2Divisions of Neuroradiology and Neurosurgery, Toronto Western Hospital, University Health Network, Toronto, Ontario, Canada
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Abstract
The objective of the current study was to compare the three-dimensional (3D) morphometric microstructure in human cadaveric bone specimens taken from various commonly utilized donor sites for autogenous bone grafting. Autogenous bone grafts can be harvested from various anatomic sites and express heterogeneous bone quality with a specific 3D microstructure for each site. The long-term structural integrity and susceptibility to resorption of the graft depend on the selected donor bone. Micro-computed tomography generates high-resolution datasets of bone structures and calcifications making this modality versatile for microarchitecture analysis and quantification of the bone. Six bone specimens, 10 mm in length, where anatomically possible, were obtained from various anatomical sites from 10 human dentate cadavers (4 men, 6 women, mean age 69.5 years). Specimens were scanned using a micro-computed tomography device and volumetrically reconstructed. A virtual cylindrical inclusion was reconstructed to analyze the bone mineral density and structural morphometric analysis using bone indices: relative bone volume, surface density, trabecular thicknesses, and trabecular separation. Calvarial bone specimens showed the highest mineral density, followed by the chin, then mandibular ramus then the tibia, whereas iliac crest and maxillary tuberosity had lower bone mineral densities. The pairwise comparison revealed statistically significant differences in the bone mineral density and relative bone volume index in the calvaria, mandibular ramus, mandibular symphysis groups when compared with those in the iliac crest and maxillary tuberosity, suggesting higher bone quality in the former groups than in the latter; tibial specimens expressed variable results.
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A preclinical micro-computed tomography database including 3D whole body organ segmentations. Sci Data 2018; 5:180294. [PMID: 30561432 PMCID: PMC6298256 DOI: 10.1038/sdata.2018.294] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2018] [Accepted: 10/31/2018] [Indexed: 12/13/2022] Open
Abstract
The gold-standard of preclinical micro-computed tomography (μCT) data processing is still manual delineation of complete organs or regions by specialists. However, this method is time-consuming, error-prone, has limited reproducibility, and therefore is not suitable for large-scale data analysis. Unfortunately, robust and accurate automated whole body segmentation algorithms are still missing. In this publication, we introduce a database containing 225 murine 3D whole body μCT scans along with manual organ segmentation of most important organs including heart, liver, lung, trachea, spleen, kidneys, stomach, intestine, bladder, thigh muscle, bone, as well as subcutaneous tumors. The database includes native and contrast-enhanced, regarding spleen and liver, μCT data. All scans along with organ segmentation are freely accessible at the online repository Figshare. We encourage researchers to reuse the provided data to evaluate and improve methods and algorithms for accurate automated organ segmentation which may reduce manual segmentation effort, increase reproducibility, and even reduce the number of required laboratory animals by reducing a source of variability and having access to a reliable reference group.
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Abstract
The tumor vasculature is a chaotic mixture of abnormal, hierarchically disorganized vessels that differ from those of normal tissues with respect to organization, structure and function. Firstly, tumor vessel wall structure is abnormal and heterogeneous within the tumor. Besides contractile wall components, the perivascular compartment is often lacking pericytes, what makes the tumor vessels fragile and leaky. Secondly, another group of abnormalities involves distortions in angioarchitecture and vasculature as network. Common features of tumor vessels, irrespective of their origin, size and growth pattern, are absence of hierarchical organization, formation of vessels with irregular contours and their heterogeneous distribution within the tumor.
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Rosenhain S, Al Rawashdeh W, Kiessling F, Gremse F. Sensitivity and accuracy of hybrid fluorescence-mediated tomography in deep tissue regions. JOURNAL OF BIOPHOTONICS 2017; 10:1208-1216. [PMID: 27868394 DOI: 10.1002/jbio.201600232] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/04/2016] [Revised: 10/27/2016] [Accepted: 10/28/2016] [Indexed: 06/06/2023]
Abstract
Fluorescence-mediated tomography (FMT) enables noninvasive assessment of the three-dimensional distribution of near-infrared fluorescence in mice. The combination with micro-computed tomography (µCT) provides anatomical data, enabling improved fluorescence reconstruction and image analysis. The aim of our study was to assess sensitivity and accuracy of µCT-FMT under realistic in vivo conditions in deeply-seated regions. Accordingly, we acquired fluorescence reflectance images (FRI) and µCT-FMT scans of mice which were prepared with rectal insertions with different amounts of fluorescent dye. Default and high-sensitivity scans were acquired and background signal was analyzed for three FMT channels (670 nm, 745 nm, and 790 nm). Analysis was performed for the original and an improved FMT reconstruction using the µCT data. While FRI and the original FMT reconstruction could detect 100 pmol, the improved FMT reconstruction could detect 10 pmol and significantly improved signal localization. By using a finer sampling grid and increasing the exposure time, the sensitivity could be further improved to detect 0.5 pmol. Background signal was highest in the 670 nm channel and most prominent in the gastro-intestinal tract and in organs with high relative amounts of blood. In conclusion, we show that µCT-FMT allows sensitive and accurate assessment of fluorescence in deep tissue regions.
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Affiliation(s)
- Stefanie Rosenhain
- Experimental Molecular Imaging, RWTH Aachen University Clinic, Aachen, Germany
| | - Wa'el Al Rawashdeh
- Experimental Molecular Imaging, RWTH Aachen University Clinic, Aachen, Germany
| | - Fabian Kiessling
- Experimental Molecular Imaging, RWTH Aachen University Clinic, Aachen, Germany
| | - Felix Gremse
- Experimental Molecular Imaging, RWTH Aachen University Clinic, Aachen, Germany
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Quantification of Hepatic Vascular and Parenchymal Regeneration in Mice. PLoS One 2016; 11:e0160581. [PMID: 27494255 PMCID: PMC4975469 DOI: 10.1371/journal.pone.0160581] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2016] [Accepted: 07/21/2016] [Indexed: 01/13/2023] Open
Abstract
BACKGROUND Liver regeneration consists of cellular proliferation leading to parenchymal and vascular growth. This study complements previous studies on cellular proliferation and weight recovery by (1) quantitatively describing parenchymal and vascular regeneration, and (2) determining their relationship. Both together are needed to (3) characterize the underlying growth pattern. METHODS Specimens were created by injecting a polymerizing contrast agent in either portal or hepatic vein in normal or regenerating livers after 70% partial hepatectomy. 3D image data were obtained through micro-CT scanning. Parenchymal growth was assessed by determining weight and volume of the regenerating liver. Vascular growth was described by manually determined circumscribed parameters (maximal vessel length and radius of right inferior portal/hepatic vein), automatically determined cumulative parameters (total edge length and total vascular volume), and parameters describing vascular density (total edge length/volume, vascular volume fraction). The growth pattern was explored by comparing the relative increase of these parameters to the increase expected in case of isotropic expansion. RESULTS Liver volume recovery paralleled weight recovery and reached 90% of the original liver volume within 7 days. Comparing radius-related vascular parameters immediately after surgical resection and after virtual resection in-silico revealed a slight increase, possibly reflecting the effect of resection-induced portal hyperperfusion. Comparing length-related parameters between post-operative day 7 and after virtual resection showed similar vascular growth in both vascular systems investigated. In contrast, radius-related parameters increased slightly more in the portal vein. Despite the seemingly homogeneous 3D growth, the observed vascular parameters were not compatible with the hypothesis of isotropic expansion of liver parenchyma and vascular structures. CONCLUSION We present an approach for the quantitative analysis of the vascular systems of regenerating mouse livers. We applied this technique for assessing the hepatic growth pattern. Prospectively, this approach can be used to investigate hepatic vascular regeneration under different conditions.
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Bartneck M, Fech V, Ehling J, Govaere O, Warzecha KT, Hittatiya K, Vucur M, Gautheron J, Luedde T, Trautwein C, Lammers T, Roskams T, Jahnen-Dechent W, Tacke F. Histidine-rich glycoprotein promotes macrophage activation and inflammation in chronic liver disease. Hepatology 2016; 63:1310-24. [PMID: 26699087 DOI: 10.1002/hep.28418] [Citation(s) in RCA: 65] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/23/2015] [Accepted: 12/20/2015] [Indexed: 01/07/2023]
Abstract
UNLABELLED Pathogen- and injury-related danger signals as well as cytokines released by immune cells influence the functional differentiation of macrophages in chronic inflammation. Recently, the liver-derived plasma protein, histidine-rich glycoprotein (HRG), was demonstrated, in mouse tumor models, to mediate the transition of alternatively activated (M2) to proinflammatory (M1) macrophages, which limit tumor growth and metastasis. We hypothesized that liver-derived HRG is a critical endogenous modulator of hepatic macrophage functionality and investigated its implications for liver inflammation and fibrosis by comparing C57BL/6N wild-type (WT) and Hrg(-/-) mice. In homeostatic conditions, hepatic macrophages were overall reduced and preferentially polarized toward the anti-inflammatory M2 subtype in Hrg(-/-) mice. Upon chronic liver damage induced by CCl4 or methionine-choline-deficient (MCD) diet, liver injury and fibrosis were attenuated in Hrg(-/-) , compared to WT, mice. Macrophage populations were reduced and skewed toward M2 polarization in injured livers of Hrg(-/-) mice. Moreover, HRG-deficient mice showed significantly enhanced hepatic vascularization by micro-computed tomography and histology, corroborating proangiogenic activities of M2-polarized liver macrophages. Purified HRG protein induced, but HRG-deficient serum prevented, M1 macrophage differentiation in vitro. Accordingly, Hrg(-/-) mice transplanted with Hrg(+/+) bone marrow, but not Hrg(-/-) -transplanted Hrg(+/+) mice, remained protected from experimental steatohepatitis. Consistent with these findings, patients with chronic hepatitis C and nonalcoholic steatohepatitis significantly up-regulated hepatocytic HRG expression, which was associated with M1 polarization of adjacent macrophages. CONCLUSIONS Liver-derived HRG, similar to alarmins, appears to be an endogenous molecular factor promoting polarization of hepatic macrophages toward the M1 phenotype, thereby promoting chronic liver injury and fibrosis progression, but limiting angiogenesis. Therefore, controlling tissue levels of HRG or PGF might be a promising strategy in chronic inflammatory liver diseases.
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Affiliation(s)
- Matthias Bartneck
- Department of Medicine III, Helmholtz Institute for Biomedical Engineering, RWTH University-Hospital Aachen, Aachen, Germany
| | - Viktor Fech
- Department of Medicine III, Helmholtz Institute for Biomedical Engineering, RWTH University-Hospital Aachen, Aachen, Germany
| | - Josef Ehling
- Department of Experimental Molecular Imaging, Helmholtz Institute for Biomedical Engineering, RWTH University-Hospital Aachen, Aachen, Germany
| | - Olivier Govaere
- Translational Cell & Tissue Research Unit, Department of Imaging & Pathology, KU Leuven, Belgium
| | - Klaudia Theresa Warzecha
- Department of Medicine III, Helmholtz Institute for Biomedical Engineering, RWTH University-Hospital Aachen, Aachen, Germany
| | | | - Mihael Vucur
- Department of Medicine III, Helmholtz Institute for Biomedical Engineering, RWTH University-Hospital Aachen, Aachen, Germany
| | - Jérémie Gautheron
- Department of Medicine III, Helmholtz Institute for Biomedical Engineering, RWTH University-Hospital Aachen, Aachen, Germany
| | - Tom Luedde
- Department of Medicine III, Helmholtz Institute for Biomedical Engineering, RWTH University-Hospital Aachen, Aachen, Germany
| | - Christian Trautwein
- Department of Medicine III, Helmholtz Institute for Biomedical Engineering, RWTH University-Hospital Aachen, Aachen, Germany
| | - Twan Lammers
- Department of Experimental Molecular Imaging, Helmholtz Institute for Biomedical Engineering, RWTH University-Hospital Aachen, Aachen, Germany.,Department of Targeted Therapeutics, MIRA Institute for Biomedical Technology and Technical Medicine, University of Twente, Enschede, The Netherlands.,Department of Pharmaceutics, Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Utrecht, The Netherlands
| | - Tania Roskams
- Translational Cell & Tissue Research Unit, Department of Imaging & Pathology, KU Leuven, Belgium
| | - Willi Jahnen-Dechent
- Helmholtz-Institute for Biomedical Engineering, Biointerface Laboratory, RWTH Aachen, Germany
| | - Frank Tacke
- Department of Medicine III, Helmholtz Institute for Biomedical Engineering, RWTH University-Hospital Aachen, Aachen, Germany
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Dziewiecki D, van de Loo S, Gremse F, Kloss-Brandstätter A, Kloss F, Offermanns V, Yamauchi K, Kessler P, Lethaus B. Osteoneogenesis due to periosteal elevation with degradable and nondegradable devices in Göttingen Minipigs. J Craniomaxillofac Surg 2016; 44:318-24. [DOI: 10.1016/j.jcms.2015.12.011] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2015] [Revised: 11/23/2015] [Accepted: 12/23/2015] [Indexed: 02/07/2023] Open
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Brinkmann M, Rizzo LY, Lammers T, Gremse F, Schiwy S, Kiessling F, Hollert H. Micro-computed tomography (μCT) as a novel method in ecotoxicology--determination of morphometric and somatic data in rainbow trout (Oncorhynchus mykiss). THE SCIENCE OF THE TOTAL ENVIRONMENT 2016; 543:135-139. [PMID: 26580735 DOI: 10.1016/j.scitotenv.2015.11.020] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2015] [Revised: 11/03/2015] [Accepted: 11/03/2015] [Indexed: 06/05/2023]
Abstract
Fish are important sentinel organisms for the assessment of water quality and play a central role in ecotoxicological research. Of particular importance to the assessment of health and fitness of fish stocks in response to environmental conditions or pollution are morphometric (e.g. Fulton's condition index) and somatic indices (e.g. hepatosomatic, and gonadosomatic index). Standard measurements of somatic indices are invasive and require, by definition, the sacrifice of examined animals, thus prohibiting longitudinal studies and relocation of animals captured in the field. As a potential solution, in the present study, we propose the use of micro-computed tomography (μCT) as imaging modality to non-invasively tomographically image rainbow trout (Oncorhynchus mykiss) exposed to different sediment suspensions. We here demonstrate that μCT can be used as a tool to reliably measure the volumes of different organs, which could then be applied as a substitute of their weights in calculation of somatic indices. To the best of our knowledge, this study is the first to report the results of μCT analyses in the context of ecotoxicological research in rainbow trout. It has the potential to greatly increase the information value of experiments conducted with fish and also to potentially reduce the number of animals required for studying temporal effects through facilitating longitudinal studies within the same individuals.
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Affiliation(s)
- Markus Brinkmann
- Department of Ecosystem Analysis, Institute for Environmental Research, RWTH Aachen University, Worringerweg 1, 52074 Aachen, Germany.
| | - Larissa Y Rizzo
- Department of Experimental Molecular Imaging, Helmholtz Institute for Biomedical Engineering, RWTH Aachen University, Aachen, Germany
| | - Twan Lammers
- Department of Experimental Molecular Imaging, Helmholtz Institute for Biomedical Engineering, RWTH Aachen University, Aachen, Germany
| | - Felix Gremse
- Department of Experimental Molecular Imaging, Helmholtz Institute for Biomedical Engineering, RWTH Aachen University, Aachen, Germany
| | - Sabrina Schiwy
- Department of Ecosystem Analysis, Institute for Environmental Research, RWTH Aachen University, Worringerweg 1, 52074 Aachen, Germany
| | - Fabian Kiessling
- Department of Experimental Molecular Imaging, Helmholtz Institute for Biomedical Engineering, RWTH Aachen University, Aachen, Germany
| | - Henner Hollert
- Department of Ecosystem Analysis, Institute for Environmental Research, RWTH Aachen University, Worringerweg 1, 52074 Aachen, Germany; College of Resources and Environmental Science, Chongqing University, 1 Tiansheng Road Beibei, Chongqing 400715, China; College of Environmental Science and Engineering, State Key Laboratory of Pollution Control and Resource Reuse, Tongji University, 1239 Siping Road, Shanghai, China; State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, China.
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Gremse F, Stärk M, Ehling J, Menzel JR, Lammers T, Kiessling F. Imalytics Preclinical: Interactive Analysis of Biomedical Volume Data. Am J Cancer Res 2016; 6:328-41. [PMID: 26909109 PMCID: PMC4737721 DOI: 10.7150/thno.13624] [Citation(s) in RCA: 81] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2015] [Accepted: 09/25/2015] [Indexed: 12/21/2022] Open
Abstract
A software tool is presented for interactive segmentation of volumetric medical data sets. To allow interactive processing of large data sets, segmentation operations, and rendering are GPU-accelerated. Special adjustments are provided to overcome GPU-imposed constraints such as limited memory and host-device bandwidth. A general and efficient undo/redo mechanism is implemented using GPU-accelerated compression of the multiclass segmentation state. A broadly applicable set of interactive segmentation operations is provided which can be combined to solve the quantification task of many types of imaging studies. A fully GPU-accelerated ray casting method for multiclass segmentation rendering is implemented which is well-balanced with respect to delay, frame rate, worst-case memory consumption, scalability, and image quality. Performance of segmentation operations and rendering are measured using high-resolution example data sets showing that GPU-acceleration greatly improves the performance. Compared to a reference marching cubes implementation, the rendering was found to be superior with respect to rendering delay and worst-case memory consumption while providing sufficiently high frame rates for interactive visualization and comparable image quality. The fast interactive segmentation operations and the accurate rendering make our tool particularly suitable for efficient analysis of multimodal image data sets which arise in large amounts in preclinical imaging studies.
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Analysis of Endothelial Adherence of Bartonella henselae and Acinetobacter baumannii Using a Dynamic Human Ex Vivo Infection Model. Infect Immun 2015; 84:711-22. [PMID: 26712205 DOI: 10.1128/iai.01502-15] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2015] [Accepted: 12/14/2015] [Indexed: 12/22/2022] Open
Abstract
Bacterial adherence determines the virulence of many human-pathogenic bacteria. Experimental approaches elucidating this early infection event in greater detail have been performed using mainly methods of cellular microbiology. However, in vitro infections of cell monolayers reflect the in vivo situation only partially, and animal infection models are not available for many human-pathogenic bacteria. Therefore, ex vivo infection of human organs might represent an attractive method to overcome these limitations. We infected whole human umbilical cords ex vivo with Bartonella henselae or Acinetobacter baumannii under dynamic flow conditions mimicking the in vivo infection situation of human endothelium. For this purpose, methods for quantifying endothelium-adherent wild-type and trimeric autotransporter adhesin (TAA)-deficient bacteria were set up. Data revealed that (i) A. baumannii binds in a TAA-dependent manner to endothelial cells, (ii) this organ infection model led to highly reproducible adherence rates, and furthermore, (iii) this model allowed to dissect the biological function of TAAs in the natural course of human infections. These findings indicate that infection models using ex vivo human tissue samples ("organ microbiology") might be a valuable tool in analyzing bacterial pathogenicity with the capacity to replace animal infection models at least partially.
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Kakinuma R, Moriyama N, Muramatsu Y, Gomi S, Suzuki M, Nagasawa H, Kusumoto M, Aso T, Muramatsu Y, Tsuchida T, Tsuta K, Maeshima AM, Tochigi N, Watanabe SI, Sugihara N, Tsukagoshi S, Saito Y, Kazama M, Ashizawa K, Awai K, Honda O, Ishikawa H, Koizumi N, Komoto D, Moriya H, Oda S, Oshiro Y, Yanagawa M, Tomiyama N, Asamura H. Ultra-High-Resolution Computed Tomography of the Lung: Image Quality of a Prototype Scanner. PLoS One 2015; 10:e0137165. [PMID: 26352144 PMCID: PMC4564227 DOI: 10.1371/journal.pone.0137165] [Citation(s) in RCA: 82] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2014] [Accepted: 08/14/2015] [Indexed: 12/21/2022] Open
Abstract
Purpose The image noise and image quality of a prototype ultra-high-resolution computed tomography (U-HRCT) scanner was evaluated and compared with those of conventional high-resolution CT (C-HRCT) scanners. Materials and Methods This study was approved by the institutional review board. A U-HRCT scanner prototype with 0.25 mm x 4 rows and operating at 120 mAs was used. The C-HRCT images were obtained using a 0.5 mm x 16 or 0.5 mm x 64 detector-row CT scanner operating at 150 mAs. Images from both scanners were reconstructed at 0.1-mm intervals; the slice thickness was 0.25 mm for the U-HRCT scanner and 0.5 mm for the C-HRCT scanners. For both scanners, the display field of view was 80 mm. The image noise of each scanner was evaluated using a phantom. U-HRCT and C-HRCT images of 53 images selected from 37 lung nodules were then observed and graded using a 5-point score by 10 board-certified thoracic radiologists. The images were presented to the observers randomly and in a blinded manner. Results The image noise for U-HRCT (100.87 ± 0.51 Hounsfield units [HU]) was greater than that for C-HRCT (40.41 ± 0.52 HU; P < .0001). The image quality of U-HRCT was graded as superior to that of C-HRCT (P < .0001) for all of the following parameters that were examined: margins of subsolid and solid nodules, edges of solid components and pulmonary vessels in subsolid nodules, air bronchograms, pleural indentations, margins of pulmonary vessels, edges of bronchi, and interlobar fissures. Conclusion Despite a larger image noise, the prototype U-HRCT scanner had a significantly better image quality than the C-HRCT scanners.
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Affiliation(s)
- Ryutaro Kakinuma
- Division of Cancer Screening, National Cancer Center, Research Center for Cancer Prevention and Screening, Chuo-ku, Tokyo, Japan
- Department of Radiology, National Cancer Center Hospital, Chuo-ku, Tokyo, Japan
- * E-mail:
| | - Noriyuki Moriyama
- Division of Cancer Screening, National Cancer Center, Research Center for Cancer Prevention and Screening, Chuo-ku, Tokyo, Japan
| | - Yukio Muramatsu
- Division of Cancer Screening, National Cancer Center, Research Center for Cancer Prevention and Screening, Chuo-ku, Tokyo, Japan
| | - Shiho Gomi
- Department of Radiology, National Cancer Center Hospital, Chuo-ku, Tokyo, Japan
| | - Masahiro Suzuki
- Department of Radiology, National Cancer Center Hospital, Chuo-ku, Tokyo, Japan
| | - Hirobumi Nagasawa
- Department of Radiology, National Cancer Center Hospital, Chuo-ku, Tokyo, Japan
| | - Masahiko Kusumoto
- Department of Radiology, National Cancer Center Hospital, Chuo-ku, Tokyo, Japan
- Department of Radiology, National Cancer Center Hospital East, Kashiwa, Chiba, Japan
| | - Tomohiko Aso
- Department of Radiology, National Cancer Center Hospital, Chuo-ku, Tokyo, Japan
| | - Yoshihisa Muramatsu
- Department of Radiology, National Cancer Center Hospital East, Kashiwa, Chiba, Japan
| | - Takaaki Tsuchida
- Department of Endoscopy, Respiratory Endoscopy Division, National Cancer Center Hospital, Chuo-ku, Tokyo, Japan
| | - Koji Tsuta
- Division of Pathology, National Cancer Center Hospital, Chuo-ku, Tokyo, Japan
| | | | - Naobumi Tochigi
- Division of Pathology, National Cancer Center Hospital, Chuo-ku, Tokyo, Japan
| | - Shun-ichi Watanabe
- Department of Thoracic Surgery, National Cancer Center Hospital, Chuo-ku, Tokyo, Japan
| | - Naoki Sugihara
- Department of CT Systems Division, Toshiba Medical Systems Corporation, Otawara, Tochigi, Japan
| | - Shinsuke Tsukagoshi
- Department of CT Systems Division, Toshiba Medical Systems Corporation, Otawara, Tochigi, Japan
| | - Yasuo Saito
- Department of CT Systems Division, Toshiba Medical Systems Corporation, Otawara, Tochigi, Japan
| | - Masahiro Kazama
- Department of CT Systems Division, Toshiba Medical Systems Corporation, Otawara, Tochigi, Japan
| | - Kazuto Ashizawa
- Department of Clinical Oncology, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Nagasaki, Japan
| | - Kazuo Awai
- Department of Diagnostic Radiology, Hiroshima University, Institute and Graduate School of Biomedical Sciences, Hiroshima, Hiroshima, Japan
| | - Osamu Honda
- Department of Radiology, Osaka University Graduate School of Medicine, Suita, Osaka, Japan
| | - Hiroyuki Ishikawa
- Department of Radiology, Niigata University Medical and Dental Hospital, Niigata, Niigata, Japan
| | - Naoya Koizumi
- Department of Radiology, Niigata Cancer Center Hospital, Niigata, Niigata, Japan
| | - Daisuke Komoto
- Department of Diagnostic Radiology, Hiroshima University, Institute and Graduate School of Biomedical Sciences, Hiroshima, Hiroshima, Japan
| | - Hiroshi Moriya
- Department of Radiology, Ohara General Hospital, Fukushima, Fukushima, Japan
| | - Seitaro Oda
- Department of Diagnostic Radiology, Kumamoto University, Faculty of Life Sciences, Kumamoto, Kumamoto, Japan
| | - Yasuji Oshiro
- Department of Radiology, National Hospital Organization Okinawa National Hospital, Ginowan, Okinawa, Japan
| | - Masahiro Yanagawa
- Department of Radiology, Osaka University Graduate School of Medicine, Suita, Osaka, Japan
| | - Noriyuki Tomiyama
- Department of Radiology, Osaka University Graduate School of Medicine, Suita, Osaka, Japan
| | - Hisao Asamura
- Department of Thoracic Surgery, National Cancer Center Hospital, Chuo-ku, Tokyo, Japan
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Quantitative Spectral K-Edge Imaging in Preclinical Photon-Counting X-Ray Computed Tomography. Invest Radiol 2015; 50:297-304. [DOI: 10.1097/rli.0000000000000126] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Schürmann C, Gremse F, Jo H, Kiessling F, Brandes RP. Micro-CT Technique Is Well Suited for Documentation of Remodeling Processes in Murine Carotid Arteries. PLoS One 2015; 10:e0130374. [PMID: 26086218 PMCID: PMC4472757 DOI: 10.1371/journal.pone.0130374] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2014] [Accepted: 05/20/2015] [Indexed: 01/08/2023] Open
Abstract
BACKGROUND The pathomechanisms of atherosclerosis and vascular remodelling are under intense research. Only a few in vivo tools to study these processes longitudinally in animal experiments are available. Here, we evaluated the potential of micro-CT technology. METHODS Lumen areas of the common carotid arteries (CCA) in the ApoE-/- partial carotid artery ligation mouse model were compared between in vivo and ex vivo micro-CT technique and serial histology in a total of 28 animals. AuroVist-15 nm nanoparticles were used as in vivo blood pool contrast agent in a Skyscan 1176 micro-CT at resolution of 18 μmeter voxel size and a mean x-ray dose of 0.5 Gy. For ex vivo imaging, animals were perfused with MicroFil and imaged at 9 μmeter voxel size. Lumen area was evaluated at postoperative days 7, 14, and 28 first by micro-CT followed by histology. RESULTS In vivo micro-CT and histology revealed lumen loss starting at day 14. The lumen profile highly correlated (r = 0.79, P<0.0001) between this two methods but absolute lumen values obtained by histology were lower than those obtained by micro-CT. Comparison of in vivo and ex vivo micro-CT imaging revealed excellent correlation (r = 0.83, P<0.01). Post mortem micro-CT yielded a higher resolution than in vivo micro-CT but there was no statistical difference of lumen measurements in the partial carotid artery ligation model. CONCLUSION These data demonstrate that in vivo micro-CT is a feasible and accurate technique with low animal stress to image remodeling processes in the murine carotid artery.
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Affiliation(s)
- Christoph Schürmann
- Institut für Kardiovaskuläre Physiologie, Fachbereich Medizin der Goethe-Universität, Theodor-Stern-Kai 7, Frankfurt am Main, Germany; German Center for Cardiovascular Research (DZHK), Partner site RheinMain, Frankfurt, Germany
| | - Felix Gremse
- Experimental Molecular Imaging, University Clinic Aachen, RWTH Aachen University, Aachen, Germany
| | - Hanjoong Jo
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, Georgia, United States of America
| | - Fabian Kiessling
- Experimental Molecular Imaging, University Clinic Aachen, RWTH Aachen University, Aachen, Germany
| | - Ralf P Brandes
- Institut für Kardiovaskuläre Physiologie, Fachbereich Medizin der Goethe-Universität, Theodor-Stern-Kai 7, Frankfurt am Main, Germany; German Center for Cardiovascular Research (DZHK), Partner site RheinMain, Frankfurt, Germany
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Schwen LO, Wei W, Gremse F, Ehling J, Wang L, Dahmen U, Preusser T. Algorithmically generated rodent hepatic vascular trees in arbitrary detail. J Theor Biol 2014; 365:289-300. [PMID: 25451523 DOI: 10.1016/j.jtbi.2014.10.026] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2014] [Revised: 10/16/2014] [Accepted: 10/22/2014] [Indexed: 12/13/2022]
Abstract
Physiologically realistic geometric models of the vasculature in the liver are indispensable for modelling hepatic blood flow, the main connection between the liver and the organism. Current in vivo imaging techniques do not provide sufficiently detailed vascular trees for many simulation applications, so it is necessary to use algorithmic refinement methods. The method of Constrained Constructive Optimization (CCO) (Schreiner et al., 2006) is well suited for this purpose. Its results after calibration have been previously compared to experimentally acquired human vascular trees (Schwen and Preusser, 2012). The goal of this paper is to extend this calibration to the case of rodents (mice and rats), the most commonly used animal models in liver research. Based on in vivo and ex vivo micro-CT scans of rodent livers and their vasculature, we performed an analysis of various geometric features of the vascular trees. Starting from pruned versions of the original vascular trees, we applied the CCO procedure and compared these algorithmic results to the original vascular trees using a suitable similarity measure. The calibration of the postprocessing improved the algorithmic results compared to those obtained using standard CCO. In terms of angular features, the average similarity increased from 0.27 to 0.61, improving the total similarity from 0.28 to 0.40. Finally, we applied the calibrated algorithm to refine measured vascular trees to the (higher) level of detail desired for specific applications. Having successfully adapted the CCO algorithm to the rodent model organism, the resulting individual-specific refined hepatic vascular trees can now be used for advanced modeling involving, e.g., detailed blood flow simulations.
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Affiliation(s)
- Lars Ole Schwen
- Fraunhofer MEVIS, Universitätsallee 29, 28359 Bremen, Germany.
| | - Weiwei Wei
- Department of General, Visceral and Vascular Surgery, University Hospital Jena, Drackendorfer Str. 1, 07747 Jena, Germany.
| | - Felix Gremse
- Experimental Molecular Imaging, RWTH Aachen University, Pauwelsstrasse 30, 52074 Aachen, Germany.
| | - Josef Ehling
- Experimental Molecular Imaging, RWTH Aachen University, Pauwelsstrasse 30, 52074 Aachen, Germany.
| | - Lei Wang
- Fraunhofer MEVIS, Universitätsallee 29, 28359 Bremen, Germany.
| | - Uta Dahmen
- Department of General, Visceral and Vascular Surgery, University Hospital Jena, Drackendorfer Str. 1, 07747 Jena, Germany.
| | - Tobias Preusser
- Fraunhofer MEVIS, Universitätsallee 29, 28359 Bremen, Germany; School of Engineering and Science, Jacobs University, Campus Ring 1, 28759 Bremen, Germany.
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Gremse F, Theek B, Kunjachan S, Lederle W, Pardo A, Barth S, Lammers T, Naumann U, Kiessling F. Absorption reconstruction improves biodistribution assessment of fluorescent nanoprobes using hybrid fluorescence-mediated tomography. Theranostics 2014; 4:960-71. [PMID: 25157277 PMCID: PMC4142290 DOI: 10.7150/thno.9293] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2014] [Accepted: 05/27/2014] [Indexed: 11/25/2022] Open
Abstract
Aim: Fluorescence-mediated tomography (FMT) holds potential for accelerating diagnostic and theranostic drug development. However, for proper quantitative fluorescence reconstruction, knowledge on optical scattering and absorption, which are highly heterogeneous in different (mouse) tissues, is required. We here describe methods to assess these parameters using co-registered micro Computed Tomography (µCT) data and nonlinear whole-animal absorption reconstruction, and evaluate their importance for assessment of the biodistribution and target site accumulation of fluorophore-labeled drug delivery systems. Methods: Besides phantoms with varying degrees of absorption, mice bearing A431 tumors were imaged 15 min and 48 h after i.v. injection of a fluorophore-labeled polymeric drug carrier (pHPMA-Dy750) using µCT-FMT. The outer shape of mice and a scattering map were derived using automated segmentation of the µCT data. Furthermore, a 3D absorption map was reconstructed from the trans-illumination data. We determined the absorption of five interactively segmented regions (heart, liver, kidney, muscle, tumor). Since blood is the main near-infrared absorber in vivo, the absorption was also estimated from the relative blood volume (rBV), determined by contrast-enhanced µCT. We compared the reconstructed absorption with the rBV-based values and analyzed the effect of using the absorption map on the fluorescence reconstruction. Results: Phantom experiments demonstrated that absorption reconstruction is possible and necessary for quantitative fluorescence reconstruction. In vivo, the reconstructed absorption showed high values in strongly blood-perfused organs such as the heart, liver and kidney. The absorption values correlated strongly with the rBV-based absorption values, confirming the accuracy of the absorption reconstruction. Usage of homogenous absorption instead of the reconstructed absorption map resulted in reduced values in the heart, liver and kidney, by factors of 3.5, 2.1 and 1.4, respectively. For muscle and subcutaneous tumors, which have a much lower rBV and absorption, absorption reconstruction was less important. Conclusion: Quantitative whole-animal absorption reconstruction is possible and can be validated in vivo using the rBV. Usage of an absorption map is important when quantitatively assessing the biodistribution of fluorescently labeled drugs and drug delivery systems, to avoid a systematic underestimation of fluorescence in strongly absorbing organs, such as the heart, liver and kidney.
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22
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Gremse F, Krone O, Thamm M, Kiessling F, Tolba RH, Rieger S, Gremse C. Performance of lead-free versus lead-based hunting ammunition in ballistic soap. PLoS One 2014; 9:e102015. [PMID: 25029572 PMCID: PMC4100882 DOI: 10.1371/journal.pone.0102015] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2014] [Accepted: 06/12/2014] [Indexed: 12/02/2022] Open
Abstract
Background Lead-free hunting bullets are an alternative to lead-containing bullets which cause health risks for humans and endangered scavenging raptors through lead ingestion. However, doubts concerning the effectiveness of lead-free hunting bullets hinder the wide-spread acceptance in the hunting and wildlife management community. Methods We performed terminal ballistic experiments under standardized conditions with ballistic soap as surrogate for game animal tissue to characterize dimensionally stable, partially fragmenting, and deforming lead-free bullets and one commonly used lead-containing bullet. The permanent cavities created in soap blocks are used as a measure for the potential wound damage. The soap blocks were imaged using computed tomography to assess the volume and shape of the cavity and the number of fragments. Shots were performed at different impact speeds, covering a realistic shooting range. Using 3D image segmentation, cavity volume, metal fragment count, deflection angle, and depth of maximum damage were determined. Shots were repeated to investigate the reproducibility of ballistic soap experiments. Results All bullets showed an increasing cavity volume with increasing deposited energy. The dimensionally stable and fragmenting lead-free bullets achieved a constant conversion ratio while the deforming copper and lead-containing bullets showed a ratio, which increases linearly with the total deposited energy. The lead-containing bullet created hundreds of fragments and significantly more fragments than the lead-free bullets. The deflection angle was significantly higher for the dimensionally stable bullet due to its tumbling behavior and was similarly low for the other bullets. The deforming bullets achieved higher reproducibility than the fragmenting and dimensionally stable bullets. Conclusion The deforming lead-free bullet closely resembled the deforming lead-containing bullet in terms of energy conversion, deflection angle, cavity shape, and reproducibility, showing that similar terminal ballistic behavior can be achieved. Furthermore, the volumetric image processing allowed superior analysis compared to methods that involve cutting of the soap blocks.
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Affiliation(s)
- Felix Gremse
- Experimental Molecular Imaging, University Hospital, RWTH Aachen University, Aachen, Germany
| | - Oliver Krone
- Leibniz Institute for Zoo and Wildlife Research, Berlin, Germany
| | - Mirko Thamm
- Experimental Molecular Imaging, University Hospital, RWTH Aachen University, Aachen, Germany
| | - Fabian Kiessling
- Experimental Molecular Imaging, University Hospital, RWTH Aachen University, Aachen, Germany
| | - René Hany Tolba
- Laboratory Animal Science, University Hospital, RWTH Aachen University, Aachen, Germany
| | - Siegfried Rieger
- Wildlife Biology, Management and Hunting Practice, HNE Eberswalde, Eberswalde, Germany
| | - Carl Gremse
- Wildlife Biology, Management and Hunting Practice, HNE Eberswalde, Eberswalde, Germany
- * E-mail:
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Duttenhoefer F, Mertens ME, Vizkelety J, Gremse F, Stadelmann VA, Sauerbier S. Magnetic resonance imaging in zirconia‐based dental implantology. Clin Oral Implants Res 2014; 26:1195-202. [DOI: 10.1111/clr.12430] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/03/2014] [Indexed: 11/30/2022]
Affiliation(s)
- Fabian Duttenhoefer
- Department of Oral and Craniomaxillofacial Surgery University Hospital Freiburg Freiburg Germany
| | - Marianne E. Mertens
- Department of Experimental Molecular Imaging Helmholtz‐Institute for Biomedical Engineering RWTH‐Aachen University Aachen Germany
| | - Josef Vizkelety
- Department of Oral and Craniomaxillofacial Surgery University Hospital Freiburg Freiburg Germany
| | - Felix Gremse
- Department of Experimental Molecular Imaging Helmholtz‐Institute for Biomedical Engineering RWTH‐Aachen University Aachen Germany
| | | | - Sebastian Sauerbier
- Department of Oral and Craniomaxillofacial Surgery University Hospital Freiburg Freiburg Germany
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Schwen LO, Krauss M, Niederalt C, Gremse F, Kiessling F, Schenk A, Preusser T, Kuepfer L. Spatio-temporal simulation of first pass drug perfusion in the liver. PLoS Comput Biol 2014; 10:e1003499. [PMID: 24625393 PMCID: PMC3952820 DOI: 10.1371/journal.pcbi.1003499] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2013] [Accepted: 01/21/2014] [Indexed: 01/21/2023] Open
Abstract
The liver is the central organ for detoxification of xenobiotics in the body. In pharmacokinetic modeling, hepatic metabolization capacity is typically quantified as hepatic clearance computed as degradation in well-stirred compartments. This is an accurate mechanistic description once a quasi-equilibrium between blood and surrounding tissue is established. However, this model structure cannot be used to simulate spatio-temporal distribution during the first instants after drug injection. In this paper, we introduce a new spatially resolved model to simulate first pass perfusion of compounds within the naive liver. The model is based on vascular structures obtained from computed tomography as well as physiologically based mass transfer descriptions obtained from pharmacokinetic modeling. The physiological architecture of hepatic tissue in our model is governed by both vascular geometry and the composition of the connecting hepatic tissue. In particular, we here consider locally distributed mass flow in liver tissue instead of considering well-stirred compartments. Experimentally, the model structure corresponds to an isolated perfused liver and provides an ideal platform to address first pass effects and questions of hepatic heterogeneity. The model was evaluated for three exemplary compounds covering key aspects of perfusion, distribution and metabolization within the liver. As pathophysiological states we considered the influence of steatosis and carbon tetrachloride-induced liver necrosis on total hepatic distribution and metabolic capacity. Notably, we found that our computational predictions are in qualitative agreement with previously published experimental data. The simulation results provide an unprecedented level of detail in compound concentration profiles during first pass perfusion, both spatio-temporally in liver tissue itself and temporally in the outflowing blood. We expect our model to be the foundation of further spatially resolved models of the liver in the future.
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Affiliation(s)
| | - Markus Krauss
- Computational Systems Biology, Bayer Technology Services, Leverkusen, Germany
- Aachen Institute for Advanced Study in Computational Engineering Sciences, RWTH Aachen University, Aachen, Germany
| | - Christoph Niederalt
- Computational Systems Biology, Bayer Technology Services, Leverkusen, Germany
| | - Felix Gremse
- Experimental Molecular Imaging, RWTH Aachen University, Aachen, Germany
| | - Fabian Kiessling
- Experimental Molecular Imaging, RWTH Aachen University, Aachen, Germany
| | | | - Tobias Preusser
- Fraunhofer MEVIS, Bremen, Germany
- School of Engineering and Science, Jacobs University, Bremen, Germany
| | - Lars Kuepfer
- Computational Systems Biology, Bayer Technology Services, Leverkusen, Germany
- Institute of Applied Microbiology, RWTH Aachen University, Aachen, Germany
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MicroRNA-126-5p promotes endothelial proliferation and limits atherosclerosis by suppressing Dlk1. Nat Med 2014; 20:368-76. [PMID: 24584117 DOI: 10.1038/nm.3487] [Citation(s) in RCA: 489] [Impact Index Per Article: 48.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2013] [Accepted: 01/29/2014] [Indexed: 12/14/2022]
Abstract
Atherosclerosis, a hyperlipidemia-induced chronic inflammatory process of the arterial wall, develops preferentially at sites where disturbed laminar flow compromises endothelial cell (EC) function. Here we show that endothelial miR-126-5p maintains a proliferative reserve in ECs through suppression of the Notch1 inhibitor delta-like 1 homolog (Dlk1) and thereby prevents atherosclerotic lesion formation. Endothelial recovery after denudation was impaired in Mir126(-/-) mice because lack of miR-126-5p, but not miR-126-3p, reduced EC proliferation by derepressing Dlk1. At nonpredilection sites, high miR-126-5p levels in endothelial cells confer a proliferative reserve that compensates for the antiproliferative effects of hyperlipidemia, such that atherosclerosis was exacerbated in Mir126(-/-) mice. In contrast, downregulation of miR-126-5p by disturbed flow abrogated EC proliferation at predilection sites in response to hyperlipidemic stress through upregulation of Dlk1 expression. Administration of miR-126-5p rescued EC proliferation at predilection sites and limited atherosclerosis, introducing a potential therapeutic approach.
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Micro-CT imaging of tumor angiogenesis: quantitative measures describing micromorphology and vascularization. THE AMERICAN JOURNAL OF PATHOLOGY 2013; 184:431-41. [PMID: 24262753 DOI: 10.1016/j.ajpath.2013.10.014] [Citation(s) in RCA: 99] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2013] [Revised: 10/25/2013] [Accepted: 10/28/2013] [Indexed: 02/08/2023]
Abstract
Angiogenesis is a hallmark of cancer, and its noninvasive visualization and quantification are key factors for facilitating translational anticancer research. Using four tumor models characterized by different degrees of aggressiveness and angiogenesis, we show that the combination of functional in vivo and anatomical ex vivo X-ray micro-computed tomography (μCT) allows highly accurate quantification of relative blood volume (rBV) and highly detailed three-dimensional analysis of the vascular network in tumors. Depending on the tumor model, rBV values determined using in vivo μCT ranged from 2.6% to 6.0%, and corresponds well with the values assessed using IHC. Using ultra-high-resolution ex vivo μCT, blood vessels as small as 3.4 μm and vessel branches up to the seventh order could be visualized, enabling a highly detailed and quantitative analysis of the three-dimensional micromorphology of tumor vessels. Microvascular parameters such as vessel size and vessel branching correlated very well with tumor aggressiveness and angiogenesis. In rapidly growing and highly angiogenic A431 tumors, the majority of vessels were small and branched only once or twice, whereas in slowly growing A549 tumors, the vessels were much larger and branched four to seven times. Thus, we consider that combining highly accurate functional with highly detailed anatomical μCT is a useful tool for facilitating high-throughput, quantitative, and translational (anti-) angiogenesis and antiangiogenesis research.
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Vascular diameter measurement in CT angiography: comparison of model-based iterative reconstruction and standard filtered back projection algorithms in vitro. AJR Am J Roentgenol 2013; 200:652-7. [PMID: 23436858 DOI: 10.2214/ajr.12.8689] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
OBJECTIVE The purpose of this study was to evaluate the performance of model-based iterative reconstruction (MBIR) in measurement of the inner diameter of models of blood vessels and compare performance between MBIR and a standard filtered back projection (FBP) algorithm. MATERIALS AND METHODS Vascular models with wall thicknesses of 0.5, 1.0, and 1.5 mm were scanned with a 64-MDCT unit and densities of contrast material yielding 275, 396, and 542 HU. Images were reconstructed images by MBIR and FBP, and the mean diameter of each model vessel was measured by software automation. Twenty separate measurements were repeated for each vessel, and variance among the repeated measures was analyzed for determination of measurement error. For all nine model vessels, CT attenuation profiles were compared along a line passing through the luminal center on axial images reconstructed with FBP and MBIR, and the 10-90% edge rise distances at the boundary between the vascular wall and the lumen were evaluated. RESULTS For images reconstructed with FBP, measurement errors were smallest for models with 1.5-mm wall thickness, except those filled with 275-HU contrast material, and errors grew as the density of the contrast material decreased. Measurement errors with MBIR were comparable to or less than those with FBP. In CT attenuation profiles of images reconstructed with MBIR, the 10-90% edge rise distances at the boundary between the lumen and vascular wall were relatively short for each vascular model compared with those of the profile curves of FBP images. CONCLUSION MBIR is better than standard FBP for reducing reconstruction blur and improving the accuracy of diameter measurement at CT angiography.
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Ehling J, Lammers T, Kiessling F. Non-invasive imaging for studying anti-angiogenic therapy effects. Thromb Haemost 2013; 109:375-90. [PMID: 23407722 DOI: 10.1160/th12-10-0721] [Citation(s) in RCA: 71] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2012] [Accepted: 12/28/2012] [Indexed: 12/14/2022]
Abstract
Noninvasive imaging plays an emerging role in preclinical and clinical cancer research and has high potential to improve clinical translation of new drugs. This article summarises and discusses tools and methods to image tumour angiogenesis and monitor anti-angiogenic therapy effects. In this context, micro-computed tomography (µCT) is recommended to visualise and quantify the micro-architecture of functional tumour vessels. Contrast-enhanced ultrasound (US) and magnetic resonance imaging (MRI) are favourable tools to assess functional vascular parameters, such as perfusion and relative blood volume. These functional parameters have been shown to indicate anti-angiogenic therapy response at an early stage, before changes in tumour size appear. For tumour characterisation, the imaging of the molecular characteristics of tumour blood vessels, such as receptor expression, might have an even higher diagnostic potential and has been shown to be highly suitable for therapy monitoring as well. In this context, US using targeted microbubbles is currently evaluated in clinical trials as an important tool for the molecular characterisation of the angiogenic endothelium. Other modalities, being preferably used for molecular imaging of vessels and their surrounding stroma, are photoacoustic imaging (PAI), near-infrared fluorescence optical imaging (OI), MRI, positron emission tomography (PET) and single photon emission computed tomography (SPECT). The latter two are particularly useful if very high sensitivity is needed, and/or if the molecular target is difficult to access. Carefully considering the pros and cons of different imaging modalities in a multimodal imaging setup enables a comprehensive longitudinal assessment of the (micro)morphology, function and molecular regulation of tumour vessels.
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Affiliation(s)
- Josef Ehling
- Department of Experimental Molecular Imaging, Medical Faculty and Helmholtz Institute for Biomedical Engineering, Pauwelsstraße 30, 52074 Aachen, Germany
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Adaptive Statistical Iterative Reconstruction Algorithm for Measurement of Vascular Diameter on Computed Tomographic Angiography In Vitro. J Comput Assist Tomogr 2013; 37:311-6. [DOI: 10.1097/rct.0b013e3182811127] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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30
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Nazari-Jahantigh M, Wei Y, Noels H, Akhtar S, Zhou Z, Koenen RR, Heyll K, Gremse F, Kiessling F, Grommes J, Weber C, Schober A. MicroRNA-155 promotes atherosclerosis by repressing Bcl6 in macrophages. J Clin Invest 2012; 122:4190-202. [PMID: 23041630 DOI: 10.1172/jci61716] [Citation(s) in RCA: 406] [Impact Index Per Article: 33.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2011] [Accepted: 08/20/2012] [Indexed: 12/14/2022] Open
Abstract
Macrophages in atherosclerotic plaques drive inflammatory responses, degrade lipoproteins, and phagocytose dead cells. MicroRNAs (miRs) control the differentiation and activity of macrophages by regulating the signaling of key transcription factors. However, the functional role of macrophage-related miRs in the immune response during atherogenesis is unknown. Here, we report that miR-155 is specifically expressed in atherosclerotic plaques and proinflammatory macrophages, where it was induced by treatment with mildly oxidized LDL (moxLDL) and IFN-γ. Leukocyte-specific Mir155 deficiency reduced plaque size and number of lesional macrophages after partial carotid ligation in atherosclerotic (Apoe-/-) mice. In macrophages stimulated with moxLDL/IFN-γ in vitro, and in lesional macrophages, loss of Mir155 reduced the expression of the chemokine CCL2, which promotes the recruitment of monocytes to atherosclerotic plaques. Additionally, we found that miR-155 directly repressed expression of BCL6, a transcription factor that attenuates proinflammatory NF-κB signaling. Silencing of Bcl6 in mice harboring Mir155-/- macrophages enhanced plaque formation and CCL2 expression. Taken together, these data demonstrated that miR-155 plays a key role in atherogenic programming of macrophages to sustain and enhance vascular inflammation.
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