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Melbourne A, Schabel MC, David AL, Roberts VHJ. Magnetic resonance imaging of placental Intralobule structure and function in a pre-clinical nonhuman primate model. Biol Reprod 2024:ioae035. [PMID: 38442734 DOI: 10.1093/biolre/ioae035] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/07/2024] Open
Abstract
The placenta has a critical role in delivery of oxygen and an array of nutrients, hormones, antibodies and other biochemicals to the fetus, as well as the elimination of carbon dioxide and other waste products from the fetal circulation. Interrogating placental function is therefore essential for assessment of fetal and maternal health during gestation. Although the central role of adequate blood flow and oxygen delivery is clear, the lack of optimized imaging modalities to study placental structure has impeded our understanding of its vascular function. MRI is increasingly being applied in this field, but gaps in knowledge remain and further MRI methodological developments are needed. In particular, the ability to distinguish maternal from fetal placental perfusion, and the understanding of how individual placental lobules are functioning is lacking. The potential clinical benefits of developing noninvasive tools for the in vivo assessment of blood flow and oxygenation, two key determinants of placental function, are tremendous. Here we summarize a number of structural and functional MRI techniques that have been developed and applied in animal models and studies of human pregnancy over the past decade. We briefly discuss potential applications and limitations for these approaches. Their combination provides a novel source of contrast to allow analysis of placental structure and function at the level of the lobule. We outline physiological mechanisms of placental T2 and T2* decay and devise a model of how tissue composition affects the observed relaxation properties. We apply this modelling to longitudinal MRI data obtained from a pre-clinical pregnant nonhuman primate (NHP) model to provide initial proof-of-concept data for this methodology which quantifies oxygen transfer and placental structure across and between lobules. This method has the potential to improve our understanding and clinical management of placental insufficiency once validation in a larger NHP cohort is complete.
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Affiliation(s)
- Andrew Melbourne
- School of Biomedical Engineering and Imaging Sciences, King's College London, London, UK
- Elizabeth Garrett Anderson Institute for Women's Health, University College London, London, UK
| | - Matthias C Schabel
- Advanced Imaging Research Center, Oregon Health and Science University (OHSU), Portland, OR, USA
- Utah Center for Advanced Imaging Research, University of Utah, Salt Lake City, Utah, USA
| | - Anna L David
- Elizabeth Garrett Anderson Institute for Women's Health, University College London, London, UK
| | - Victoria H J Roberts
- Division of Reproductive and Developmental Sciences, Oregon National Primate Research Center (ONPRC), OHSU, Portland, OR, USA
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2
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Lo JO, Schabel MC, Gaffney J, Lewandowski KS, Kroenke CD, Roberts CT, Scottoline BP, Frias AE, Sullivan EL, Roberts VHJ. Impaired placental hemodynamics and function in a non-human primate model of gestational protein restriction. Sci Rep 2023; 13:841. [PMID: 36646824 PMCID: PMC9842719 DOI: 10.1038/s41598-023-28051-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2022] [Accepted: 01/11/2023] [Indexed: 01/18/2023] Open
Abstract
Maternal malnutrition increases fetal and neonatal morbidity, partly by affecting placental function and morphology, but its impact on placental hemodynamics are unknown. Our objective was to define the impact of maternal malnutrition on placental oxygen reserve and perfusion in vivo in a rhesus macaque model of protein restriction (PR) using advanced imaging. Animals were fed control (CON, 26% protein), 33% PR diet (17% protein), or a 50% PR diet (13% protein, n = 8/group) preconception and throughout pregnancy. Animals underwent Doppler ultrasound and fetal biometry followed by MRI at gestational days 85 (G85) and 135 (G135; term is G168). Pregnancy loss rates were 0/8 in CON, 1/8 in 33% PR, and 3/8 in 50% PR animals. Fetuses of animals fed a 50% PR diet had a smaller abdominal circumference (G135, p < 0.01). On MRI, placental blood flow was decreased at G135 (p < 0.05) and placental oxygen reserve was reduced (G85, p = 0.05; G135, p = 0.01) in animals fed a 50% PR diet vs. CON. These data demonstrate that a 50% PR diet reduces maternal placental perfusion, decreases fetal oxygen availability, and increases fetal mortality. These alterations in placental hemodynamics may partly explain human growth restriction and stillbirth seen with severe PR diets in the developing world.
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Affiliation(s)
- Jamie O Lo
- Department of Obstetrics and Gynecology, Oregon Health and Science University, 3181 SW Sam Jackson Park Road, Mail Code L458, Portland, OR, 97239, USA. .,Division of Reproductive and Developmental Sciences, Oregon National Primate Research Center, Oregon Health and Science University, Beaverton, OR, USA.
| | - Matthias C Schabel
- Advanced Imaging Research Center, Oregon Health and Science University, Portland, OR, USA
| | - Jessica Gaffney
- Division of Reproductive and Developmental Sciences, Oregon National Primate Research Center, Oregon Health and Science University, Beaverton, OR, USA
| | - Katherine S Lewandowski
- Division of Reproductive and Developmental Sciences, Oregon National Primate Research Center, Oregon Health and Science University, Beaverton, OR, USA
| | - Christopher D Kroenke
- Advanced Imaging Research Center, Oregon Health and Science University, Portland, OR, USA.,Division of Neuroscience, Oregon National Primate Research Center, Oregon Health and Science University, Beaverton, OR, USA
| | - Charles T Roberts
- Division of Reproductive and Developmental Sciences, Oregon National Primate Research Center, Oregon Health and Science University, Beaverton, OR, USA.,Division of Cardiometabolic Health, Oregon National Primate Research Center, Oregon Health and Science University, Beaverton, OR, USA
| | - Brian P Scottoline
- Division of Reproductive and Developmental Sciences, Oregon National Primate Research Center, Oregon Health and Science University, Beaverton, OR, USA.,Department of Pediatrics, Oregon Health and Science University, Portland, OR, USA
| | - Antonio E Frias
- Department of Obstetrics and Gynecology, Oregon Health and Science University, 3181 SW Sam Jackson Park Road, Mail Code L458, Portland, OR, 97239, USA
| | - Elinor L Sullivan
- Division of Neuroscience, Oregon National Primate Research Center, Oregon Health and Science University, Beaverton, OR, USA.,Department of Psychiatry, Oregon Health and Science University, Portland, OR, USA
| | - Victoria H J Roberts
- Division of Reproductive and Developmental Sciences, Oregon National Primate Research Center, Oregon Health and Science University, Beaverton, OR, USA
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3
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Roberts VHJ, Schabel MC, Boniface ER, D’Mello RJ, Morgan TK, Terrobias JJD, Graham JA, Borgelt LM, Grant KA, Sullivan EL, Lo JO. Chronic prenatal delta-9-tetrahydrocannabinol exposure adversely impacts placental function and development in a rhesus macaque model. Sci Rep 2022; 12:20260. [PMID: 36424495 PMCID: PMC9691736 DOI: 10.1038/s41598-022-24401-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2022] [Accepted: 11/15/2022] [Indexed: 11/27/2022] Open
Abstract
Cannabis use in pregnancy is associated with adverse perinatal outcomes, which are likely mediated by the placenta. However, the underlying mechanisms and specific vasoactive effects of cannabis on the placenta are unknown. Our objective was to determine the impact of chronic prenatal delta-tetrahydrocannabinol (THC, main psychoactive component of cannabis) exposure on placental function and development in a rhesus macaque model using advanced imaging. Animals were divided into two groups, control (CON, n = 5) and THC-exposed (THC, n = 5). THC-exposed animals received a THC edible daily pre-conception and throughout pregnancy. Animals underwent serial ultrasound and MRI at gestational days 85 (G85), G110, G135 and G155 (full term is ~ G168). Animals underwent cesarean delivery and placental collection at G155 for histologic and RNA-Seq analysis. THC-exposed pregnancies had significantly decreased amniotic fluid volume (p < 0.001), placental perfusion (p < 0.05), and fetal oxygen availability (p < 0.05), all indicators of placental insufficiency. Placental histological analysis demonstrated evidence of ischemic injury with microinfarctions present in THC-exposed animals only. Bulk RNA-seq demonstrated that THC alters the placental transcriptome and pathway analysis suggests dysregulated vasculature development and angiogenesis pathways. The longer-term consequences of these adverse placental findings are unknown, but they suggest that use of THC during pregnancy may deleteriously impact offspring development.
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Affiliation(s)
- Victoria H. J. Roberts
- grid.5288.70000 0000 9758 5690Division of Reproductive and Developmental Sciences, Oregon National Primate Research Center, Oregon Health & Science University, Beaverton, OR USA
| | - Matthias C. Schabel
- grid.5288.70000 0000 9758 5690Advanced Imaging Research Center, Oregon Health & Science University, Portland, OR USA
| | - Emily R. Boniface
- grid.5288.70000 0000 9758 5690Department of Obstetrics and Gynecology, Oregon Health & Science University, 3181 SW Sam Jackson Park Road, Mail Code L458, Portland, OR 97239 USA
| | - Rahul J. D’Mello
- grid.5288.70000 0000 9758 5690Division of Reproductive and Developmental Sciences, Oregon National Primate Research Center, Oregon Health & Science University, Beaverton, OR USA ,grid.5288.70000 0000 9758 5690Department of Obstetrics and Gynecology, Oregon Health & Science University, 3181 SW Sam Jackson Park Road, Mail Code L458, Portland, OR 97239 USA
| | - Terry K. Morgan
- grid.5288.70000 0000 9758 5690Department of Pathology, Oregon Health & Science University, Portland, OR USA
| | - Juanito Jose D. Terrobias
- grid.5288.70000 0000 9758 5690Division of Reproductive and Developmental Sciences, Oregon National Primate Research Center, Oregon Health & Science University, Beaverton, OR USA
| | - Jason A. Graham
- grid.5288.70000 0000 9758 5690Division of Reproductive and Developmental Sciences, Oregon National Primate Research Center, Oregon Health & Science University, Beaverton, OR USA ,grid.5288.70000 0000 9758 5690Division of Neuroscience, Oregon National Primate Research Center, Oregon Health & Science University, Beaverton, OR USA
| | - Laura M. Borgelt
- grid.430503.10000 0001 0703 675XDepartment of Clinical Pharmacy and Family Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO USA
| | - Kathleen A. Grant
- grid.5288.70000 0000 9758 5690Division of Neuroscience, Oregon National Primate Research Center, Oregon Health & Science University, Beaverton, OR USA
| | - Elinor L. Sullivan
- grid.5288.70000 0000 9758 5690Division of Neuroscience, Oregon National Primate Research Center, Oregon Health & Science University, Beaverton, OR USA ,grid.5288.70000 0000 9758 5690Department of Psychiatry, Oregon Health & Science University, Portland, OR USA
| | - Jamie O. Lo
- grid.5288.70000 0000 9758 5690Division of Reproductive and Developmental Sciences, Oregon National Primate Research Center, Oregon Health & Science University, Beaverton, OR USA ,grid.5288.70000 0000 9758 5690Department of Obstetrics and Gynecology, Oregon Health & Science University, 3181 SW Sam Jackson Park Road, Mail Code L458, Portland, OR 97239 USA
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Schabel MC, Roberts VHJ, Gibbins KJ, Rincon M, Gaffney JE, Streblow AD, Wright AM, Lo JO, Park B, Kroenke CD, Szczotka K, Blue NR, Page JM, Harvey K, Varner MW, Silver RM, Frias AE. Quantitative longitudinal T2* mapping for assessing placental function and association with adverse pregnancy outcomes across gestation. PLoS One 2022; 17:e0270360. [PMID: 35853003 PMCID: PMC9295947 DOI: 10.1371/journal.pone.0270360] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2022] [Accepted: 06/09/2022] [Indexed: 11/21/2022] Open
Abstract
Existing methods for evaluating in vivo placental function fail to reliably detect pregnancies at-risk for adverse outcomes prior to maternal and/or fetal morbidity. Here we report the results of a prospective dual-site longitudinal clinical study of quantitative placental T2* as measured by blood oxygen-level dependent magnetic resonance imaging (BOLD-MRI). The objectives of this study were: 1) to quantify placental T2* at multiple time points across gestation, and its consistency across sites, and 2) to investigate the association between placental T2* and adverse outcomes. 797 successful imaging studies, at up to three time points between 11 and 38 weeks of gestation, were completed in 316 pregnancies. Outcomes were stratified into three groups: (UN) uncomplicated/normal pregnancy, (PA) primary adverse pregnancy, which included hypertensive disorders of pregnancy, birthweight <5th percentile, and/or stillbirth or fetal death, and (SA) secondary abnormal pregnancy, which included abnormal prenatal conditions not included in the PA group such as spontaneous preterm birth or fetal anomalies. Of the 316 pregnancies, 198 (62.6%) were UN, 70 (22.2%) PA, and 48 (15.2%) SA outcomes. We found that the evolution of placental T2* across gestation was well described by a sigmoid model, with T2* decreasing continuously from a high plateau level early in gestation, through an inflection point around 30 weeks, and finally approaching a second, lower plateau in late gestation. Model regression revealed significantly lower T2* in the PA group than in UN pregnancies starting at 15 weeks and continuing through 33 weeks. T2* percentiles were computed for individual scans relative to UN group regression, and z-scores and receiver operating characteristic (ROC) curves calculated for association of T2* with pregnancy outcome. Overall, differences between UN and PA groups were statistically significant across gestation, with large effect sizes in mid- and late- pregnancy. The area under the curve (AUC) for placental T2* percentile and PA pregnancy outcome was 0.71, with the strongest predictive power (AUC of 0.76) at the mid-gestation time period (20–30 weeks). Our data demonstrate that placental T2* measurements are strongly associated with pregnancy outcomes often attributed to placental insufficiency. Trial registration: ClinicalTrials.gov: NCT02749851.
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Affiliation(s)
- Matthias C. Schabel
- Advanced Imaging Research Center, Oregon Health and Science University (OHSU), Portland, Oregon, United States of America
| | - Victoria H. J. Roberts
- Division of Reproductive and Developmental Sciences, Oregon National Primate Research Center (ONPRC), OHSU, Portland, Oregon, United States of America
- * E-mail:
| | - Karen J. Gibbins
- Department of Obstetrics and Gynecology, OHSU, Portland, Oregon, United States of America
| | - Monica Rincon
- Department of Obstetrics and Gynecology, OHSU, Portland, Oregon, United States of America
| | - Jessica E. Gaffney
- Division of Reproductive and Developmental Sciences, Oregon National Primate Research Center (ONPRC), OHSU, Portland, Oregon, United States of America
| | - Aaron D. Streblow
- Division of Reproductive and Developmental Sciences, Oregon National Primate Research Center (ONPRC), OHSU, Portland, Oregon, United States of America
| | - Adam M. Wright
- Division of Reproductive and Developmental Sciences, Oregon National Primate Research Center (ONPRC), OHSU, Portland, Oregon, United States of America
| | - Jamie O. Lo
- Division of Reproductive and Developmental Sciences, Oregon National Primate Research Center (ONPRC), OHSU, Portland, Oregon, United States of America
- Department of Obstetrics and Gynecology, OHSU, Portland, Oregon, United States of America
| | - Byung Park
- Biostatistics Shared Resource, Knight Cancer Institute, OHSU, Portland, Oregon, United States of America
| | - Christopher D. Kroenke
- Advanced Imaging Research Center, Oregon Health and Science University (OHSU), Portland, Oregon, United States of America
- Division of Neuroscience, ONPRC, OHSU, Portland, Oregon, United States of America
| | - Kathryn Szczotka
- Department of Obstetrics and Gynecology, University of Utah, Salt Lake City, Utah, United States of America
| | - Nathan R. Blue
- Department of Obstetrics and Gynecology, University of Utah, Salt Lake City, Utah, United States of America
| | - Jessica M. Page
- Department of Obstetrics and Gynecology, University of Utah, Salt Lake City, Utah, United States of America
| | - Kathy Harvey
- Department of Obstetrics and Gynecology, University of Utah, Salt Lake City, Utah, United States of America
| | - Michael W. Varner
- Department of Obstetrics and Gynecology, University of Utah, Salt Lake City, Utah, United States of America
| | - Robert M. Silver
- Department of Obstetrics and Gynecology, University of Utah, Salt Lake City, Utah, United States of America
| | - Antonio E. Frias
- Department of Obstetrics and Gynecology, OHSU, Portland, Oregon, United States of America
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5
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Abstract
Prenatal exposure to marijuana may lead to epigenetic alterations in the placenta and fetal brain, affecting short- and long-term offspring health. This Viewpoint addresses the critical need to study and characterize the impact of maternal marijuana use and consequences of in utero exposure on later development and health. We highlight the development of new PET imaging tools and the opportunity for longitudinal in vivo non-human primate studies to help elucidate epigenetic changes resulting from prenatal marijuana exposure throughout gestation.
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Affiliation(s)
- Nicole R. Zürcher
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Charlestown, Massachusetts, USA
| | - Victoria HJ. Roberts
- Division of Reproductive & Developmental Sciences, Oregon National Primate Research Center, Oregon Health & Science University, Beaverton, Oregon, USA
| | - Matthias C. Schabel
- Advanced Imaging Research Center, Oregon Health & Science University, Portland, OR, USA
| | - Andrea G. Edlow
- Department of Obstetrics and Gynecology, Division of Maternal-Fetal Medicine, Massachusetts General Hospital; Harvard Medical School, Boston, Massachusetts, USA
| | - Jacob M. Hooker
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Charlestown, Massachusetts, USA
| | - Jamie O. Lo
- Division of Reproductive & Developmental Sciences, Oregon National Primate Research Center, Oregon Health & Science University, Beaverton, Oregon, USA,Department of Obstetrics and Gynecology, Division of Maternal Fetal Medicine, Oregon Health & Science University, Portland, Oregon, USA
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Steins A, Klaassen R, Jacobs I, Schabel MC, van Lier MGJTB, Ebbing EA, Hectors SJ, Tas SW, Maracle CX, Punt CJA, Siebes M, Bergman JJGHM, Medema JP, Wilmink JW, Mathot RAA, Strijkers GJ, Bijlsma MF, van Laarhoven HWM. Rapid stromal remodeling by short-term VEGFR2 inhibition increases chemotherapy delivery in esophagogastric adenocarcinoma. Mol Oncol 2020; 14:704-720. [PMID: 31733011 PMCID: PMC7138404 DOI: 10.1002/1878-0261.12599] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2019] [Revised: 10/30/2019] [Accepted: 11/13/2019] [Indexed: 12/11/2022] Open
Abstract
Anti-angiogenic agents combined with chemotherapy is an important strategy for the treatment of solid tumors. However, survival benefit is limited, urging the improvement of combination therapies. We aimed to clarify the effects of vascular endothelial growth factor receptor 2 (VEGFR2) targeting on hemodynamic function and penetration of drugs in esophagogastric adenocarcinoma (EAC). Patient-derived xenograft (PDX) models of EAC were subjected to long-term and short-term treatment with anti-VEGFR2 therapy followed by chemotherapy injection or multi-agent dynamic contrast-enhanced (DCE-) MRI and vascular casting. Long-term anti-VEGFR2-treated tumors showed a relatively lower flow and vessel density resulting in reduced chemotherapy uptake. On the contrary, short-term VEGFR2 targeting resulted in relatively higher flow, rapid vasodilation, and improved chemotherapy delivery. Assessment of the extracellular matrix (ECM) revealed that short-term anti-angiogenic treatment drastically remodels the tumor stroma by inducing nitric oxide synthesis and hyaluronan degradation, thereby dilating the vasculature and improving intratumoral chemotherapy delivery. These previously unrecognized beneficial effects could not be maintained by long-term VEGFR2 inhibition. As the identified mechanisms are targetable, they offer direct options to enhance the treatment efficacy of anti-angiogenic therapy combined with chemotherapy in EAC patients.
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Affiliation(s)
- Anne Steins
- Laboratory for Experimental Oncology and Radiobiology, Center for Experimental and Molecular Medicine, Cancer Center Amsterdam, Amsterdam UMC, University of Amsterdam, The Netherlands.,Department of Medical Oncology, Amsterdam UMC, University of Amsterdam, The Netherlands.,Oncode Institute, Amsterdam UMC, University of Amsterdam, The Netherlands
| | - Remy Klaassen
- Laboratory for Experimental Oncology and Radiobiology, Center for Experimental and Molecular Medicine, Cancer Center Amsterdam, Amsterdam UMC, University of Amsterdam, The Netherlands.,Department of Medical Oncology, Amsterdam UMC, University of Amsterdam, The Netherlands
| | - Igor Jacobs
- Department of Biomedical Engineering, Biomedical NMR, Eindhoven, The Netherlands.,Oncology Solutions, Philips Research, Eindhoven, The Netherlands
| | - Matthias C Schabel
- Advanced Imaging Research Center, Oregon Health and Science University, Portland, OR, USA
| | - Monique G J T B van Lier
- Department of Biomedical Engineering and Physics, Amsterdam UMC, University of Amsterdam, The Netherlands
| | - Eva A Ebbing
- Laboratory for Experimental Oncology and Radiobiology, Center for Experimental and Molecular Medicine, Cancer Center Amsterdam, Amsterdam UMC, University of Amsterdam, The Netherlands
| | - Stefanie J Hectors
- Translational and Molecular Imaging Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Sander W Tas
- Department of Rheumatology and Immunology, Amsterdam UMC, University of Amsterdam, The Netherlands.,Department of Experimental Immunology, Amsterdam UMC, University of Amsterdam, The Netherlands
| | - Chrissta X Maracle
- Department of Rheumatology and Immunology, Amsterdam UMC, University of Amsterdam, The Netherlands.,Department of Experimental Immunology, Amsterdam UMC, University of Amsterdam, The Netherlands
| | - Cornelis J A Punt
- Department of Medical Oncology, Amsterdam UMC, University of Amsterdam, The Netherlands
| | - Maria Siebes
- Department of Biomedical Engineering and Physics, Amsterdam UMC, University of Amsterdam, The Netherlands
| | - Jacques J G H M Bergman
- Department of Gastroenterology and Hepatology, Amsterdam UMC, University of Amsterdam, The Netherlands
| | - Jan Paul Medema
- Laboratory for Experimental Oncology and Radiobiology, Center for Experimental and Molecular Medicine, Cancer Center Amsterdam, Amsterdam UMC, University of Amsterdam, The Netherlands.,Oncode Institute, Amsterdam UMC, University of Amsterdam, The Netherlands
| | - Johanna W Wilmink
- Department of Medical Oncology, Amsterdam UMC, University of Amsterdam, The Netherlands
| | - Ron A A Mathot
- Department of Hospital Pharmacy, Amsterdam UMC, University of Amsterdam, The Netherlands
| | - Gustav J Strijkers
- Department of Biomedical Engineering and Physics, Amsterdam UMC, University of Amsterdam, The Netherlands
| | - Maarten F Bijlsma
- Laboratory for Experimental Oncology and Radiobiology, Center for Experimental and Molecular Medicine, Cancer Center Amsterdam, Amsterdam UMC, University of Amsterdam, The Netherlands.,Oncode Institute, Amsterdam UMC, University of Amsterdam, The Netherlands
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Roberts VH, Gaffney JE, Lewandowski KS, Schabel MC, Morgan TK, Frias AE. A standardized method for collection of human placenta samples in the age of functional magnetic resonance imaging. Biotechniques 2019; 67:45-49. [PMID: 31184493 PMCID: PMC7027198 DOI: 10.2144/btn-2019-0029] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Current methods for placental tissue collection assess a delivered organ without direct functional correlates; therefore, the four-quadrant biopsy protocol utilized by many researchers may provide reasonable representation of tissue across a large organ, and offer a snapshot for molecular analysis of the placenta. However, the recent impetus to understand the placenta in real time, and the use of functional imaging to comprehend placental biology, warrants a different sampling approach. Here we present a method to standardize placental tissue collection in a format designed to facilitate correlation of in vivo function with ex vivo assessments. Additionally, we draw comparisons to the quadrant biopsy regimen, and highlight a pathological case of placental infarction detected by in utero imaging.
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Affiliation(s)
- Victoria Hj Roberts
- Division of Reproductive & Developmental Sciences, Oregon National Primate Research Center, Oregon Health & Science University, Beaverton, OR 97006, USA
| | - Jessica E Gaffney
- Division of Reproductive & Developmental Sciences, Oregon National Primate Research Center, Oregon Health & Science University, Beaverton, OR 97006, USA
| | - Katherine S Lewandowski
- Division of Reproductive & Developmental Sciences, Oregon National Primate Research Center, Oregon Health & Science University, Beaverton, OR 97006, USA
| | - Matthias C Schabel
- Advanced Imaging Research Center, Oregon Health & Science University, Portland, OR 97239, USA
| | - Terry K Morgan
- Department of Pathology, Oregon Health & Science University, Portland, OR 97239, USA.,Department of Obstetrics & Gynecology, Oregon Health & Science University, Portland, OR 97239, USA
| | - Antonio E Frias
- Division of Reproductive & Developmental Sciences, Oregon National Primate Research Center, Oregon Health & Science University, Beaverton, OR 97006, USA.,Department of Obstetrics & Gynecology, Oregon Health & Science University, Portland, OR 97239, USA
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8
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Salati JA, Roberts VHJ, Schabel MC, Lo JO, Kroenke CD, Lewandowski KS, Lindner JR, Grove KL, Frias AE. Maternal high-fat diet reversal improves placental hemodynamics in a nonhuman primate model of diet-induced obesity. Int J Obes (Lond) 2018; 43:906-916. [PMID: 30006583 PMCID: PMC6330251 DOI: 10.1038/s41366-018-0145-7] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/08/2018] [Revised: 05/16/2018] [Accepted: 05/27/2018] [Indexed: 12/17/2022]
Abstract
BACKGROUND In a Japanese macaque model of diet-induced obesity, we have previously demonstrated that consumption of a high-fat, "Western-style" diet (WSD) is associated with placental dysfunction and adverse pregnancy outcomes, independent of an obese maternal phenotype. Specifically, we have reported decreased uterine placental blood flow and increased inflammation with maternal WSD consumption. We also previously investigated the use of a promising therapeutic intervention that mitigated the adverse placental effects of a WSD but had unexpected detrimental effects on fetal pancreatic development. Thus, the objective of the current study was to determine whether simple preconception diet reversal (REV) would improve placental function. METHODS Female Japanese macaques were divided into three groups: REV animals (n = 5) were switched from a chronic WSD (36% fat) to a low fat, CON diet (14% fat) prior to conception and throughout pregnancy. The CON (n = 6) and WSD (n = 6) cohorts were maintained on their respective diets throughout pregnancy. Maternal body weight and composition were regularly assessed and advanced noninvasive imaging was performed at midgestation (gestational day 90, G90, or 0.5 of gestation, where full term is G175), and G129, 1 day prior to C-section delivery at G130 (0.75 of gestation). Imaging studies comprised Doppler ultrasound (US), contrast-enhanced US, and dynamic contrast-enhanced magnetic resonance imaging to assess uteroplacental hemodynamics and maternal-side placental perfusion. RESULTS Dietary intervention resulted in significant maternal weight loss prior to pregnancy, and improved lean to fat mass ratio. By advanced imaging we demonstrated that a chronic WSD led to decreased blood flow velocity in the intervillous space, delayed blood flow transfer through the maternal spiral arteries, and reduced total placental blood flow compared to CON fed animals. Dietary reversal ameliorated these concerning derangements, restoring these hemodynamic parameters to CON levels. CONCLUSIONS Preconception dietary modification has beneficial effects on the maternal metabolic phenotype, and results in improved placental hemodynamics.
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Affiliation(s)
- Jennifer A Salati
- Department of Obstetrics & Gynecology, Oregon Health & Science University, 3181 S W Sam Jackson Park Rd, Portland, OR, 97239, USA
| | - Victoria H J Roberts
- Division of Reproductive and Developmental Sciences, Oregon National Primate Research Center, Oregon Health & Science University, 505 NW 185th Ave, Beaverton, OR, 97006, USA.
| | - Matthias C Schabel
- Advanced Imaging Research Center, Oregon Health & Science University, 3181 S W Sam Jackson Park Rd, Portland, OR, 97239, USA.,Utah Center for Advanced Imaging Research, University of Utah, Salt Lake City, UT, 84112, USA
| | - Jamie O Lo
- Department of Obstetrics & Gynecology, Oregon Health & Science University, 3181 S W Sam Jackson Park Rd, Portland, OR, 97239, USA
| | - Christopher D Kroenke
- Advanced Imaging Research Center, Oregon Health & Science University, 3181 S W Sam Jackson Park Rd, Portland, OR, 97239, USA.,Division of Neuroscience, Oregon National Primate Research Center, Oregon Health & Science University, Beaverton, 505 NW 185th Ave, Beaverton, OR, 97006, USA
| | - Katherine S Lewandowski
- Division of Reproductive and Developmental Sciences, Oregon National Primate Research Center, Oregon Health & Science University, 505 NW 185th Ave, Beaverton, OR, 97006, USA
| | - Jonathan R Lindner
- Knight Cardiovascular Institute, Oregon Health & Science University, 3303 S W Bond Ave., Portland, OR, 97239, USA.,Division of Cardiometabolic Health, Oregon National Primate Research Center, Oregon Health & Science University, 505 NW 185th Ave, Beaverton, OR, 97006, USA
| | - Kevin L Grove
- Novo Nordisk Research Center, 530 Fairview Ave N #5000, Seattle, WA, 98109, USA
| | - Antonio E Frias
- Department of Obstetrics & Gynecology, Oregon Health & Science University, 3181 S W Sam Jackson Park Rd, Portland, OR, 97239, USA.,Division of Reproductive and Developmental Sciences, Oregon National Primate Research Center, Oregon Health & Science University, 505 NW 185th Ave, Beaverton, OR, 97006, USA
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Hectors SJ, Jacobs I, Lok J, Peters J, Bussink J, Hoeben FJ, Keizer HM, Janssen HM, Nicolay K, Schabel MC, Strijkers GJ. Improved Evaluation of Antivascular Cancer Therapy Using Constrained Tracer-Kinetic Modeling for Multiagent Dynamic Contrast-Enhanced MRI. Cancer Res 2018; 78:1561-1570. [PMID: 29317433 DOI: 10.1158/0008-5472.can-17-2569] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2017] [Revised: 11/10/2017] [Accepted: 01/03/2018] [Indexed: 11/16/2022]
Abstract
Dynamic contrast-enhanced MRI (DCE-MRI) is a promising technique for assessing the response of tumor vasculature to antivascular therapies. Multiagent DCE-MRI employs a combination of low and high molecular weight contrast agents, which potentially improves the accuracy of estimation of tumor hemodynamic and vascular permeability parameters. In this study, we used multiagent DCE-MRI to assess changes in tumor hemodynamics and vascular permeability after vascular-disrupting therapy. Multiagent DCE-MRI (sequential injection of G5 dendrimer, G2 dendrimer, and Gd-DOTA) was performed in tumor-bearing mice before, 2 and 24 hours after treatment with vascular disrupting agent DMXAA or placebo. Constrained DCE-MRI gamma capillary transit time modeling was used to estimate flow F, blood volume fraction vb, mean capillary transit time tc, bolus arrival time td, extracellular extravascular fraction ve, vascular heterogeneity index α-1 (all identical between agents) and extraction fraction E (reflective of permeability), and transfer constant Ktrans (both agent-specific) in perfused pixels. F, vb, and α-1 decreased at both time points after DMXAA, whereas tc increased. E (G2 and G5) showed an initial increase, after which, both parameters restored. Ktrans (G2 and Gd-DOTA) decreased at both time points after treatment. In the control, placebo-treated animals, only F, tc, and Ktrans Gd-DOTA showed significant changes. Histologic perfused tumor fraction was significantly lower in DMXAA-treated versus control animals. Our results show how multiagent tracer-kinetic modeling can accurately determine the effects of vascular-disrupting therapy by separating simultaneous changes in tumor hemodynamics and vascular permeability.Significance: These findings describe a new approach to measure separately the effects of antivascular therapy on tumor hemodynamics and vascular permeability, which could help more rapidly and accurately assess the efficacy of experimental therapy of this class. Cancer Res; 78(6); 1561-70. ©2018 AACR.
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Affiliation(s)
- Stefanie J Hectors
- Department of Biomedical Engineering, Biomedical NMR, Eindhoven, the Netherlands.,Translational and Molecular Imaging Institute, Icahn School of Medicine at Mount Sinai, New York, New York
| | - Igor Jacobs
- Department of Biomedical Engineering, Biomedical NMR, Eindhoven, the Netherlands.,Oncology Solutions, Philips Research, Eindhoven, the Netherlands
| | - Jasper Lok
- Department of Radiation Oncology, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Johannes Peters
- Department of Radiation Oncology, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Johan Bussink
- Department of Radiation Oncology, Radboud University Medical Center, Nijmegen, the Netherlands
| | | | | | | | - Klaas Nicolay
- Department of Biomedical Engineering, Biomedical NMR, Eindhoven, the Netherlands
| | - Matthias C Schabel
- Advanced Imaging Research Center, Oregon Health and Science University, Portland, Oregon
| | - Gustav J Strijkers
- Department of Biomedical Engineering, Biomedical NMR, Eindhoven, the Netherlands. .,Biomedical Engineering and Physics, Academic Medical Center, University of Amsterdam, Amsterdam, the Netherlands
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10
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Lo JO, Roberts VHJ, Schabel MC, Wang X, Morgan TK, Liu Z, Studholme C, Kroenke CD, Frias AE. Novel Detection of Placental Insufficiency by Magnetic Resonance Imaging in the Nonhuman Primate. Reprod Sci 2018; 25:64-73. [PMID: 28330415 PMCID: PMC5993076 DOI: 10.1177/1933719117699704] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
The placenta is a vital organ necessary for healthy fetal development. Placental insufficiency creates an in utero environment where the fetus is at risk of insufficient oxygen or nutrient exchange. This is primarily caused by impairment of either maternal or fetal circulation or vascular thrombosis such as placental infarction. As a result of placental dysfunction, affected fetuses may be growth restricted, neurologically impaired, and at risk of increased morbidity and mortality. In a cohort of 4 pregnant Rhesus macaques, we describe antenatal detection of naturally occurring intrauterine growth restriction (IUGR) and aberrant fetal neurodevelopment in 1 animal. Abnormal growth parameters were detected by Doppler ultrasound, and vascular insufficiency in the intervillous space was characterized by dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI). Furthermore, placental oxygen reserve was shown to be reduced compared to control animals by measurements of placental water T2*. To characterize the effects of IUGR on fetal brain development, T2 and diffusion anisotropy images of the fetal brain were acquired in utero. Reduced brain volume and cerebral cortical surface area were apparent macroscopically. Microstructural abnormalities within the developing white matter and cerebral cortex were also observed through analysis of water diffusion anisotropy. After delivery by cesarean section, pathological examination confirmed placental insufficiency with hypoxia. These findings exemplify how DCE-MRI and T2*-based measurements of blood oxygenation within the placenta can provide noninvasive imaging methods for assessing in vivo placental health to potentially identify pregnancies affected by placental insufficiency and abnormal fetal neurodevelopment prior to the onset of fetal and neonatal distress.
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Affiliation(s)
- Jamie O. Lo
- Department of Obstetrics and Gynecology, Oregon Health & Science University, Portland, OR, USA
| | - Victoria H. J. Roberts
- Division of Reproductive & Developmental Sciences, Oregon National Primate Research Center, Beaverton, OR, USA
| | - Matthias C. Schabel
- Advanced Imaging Research Center, Oregon Health & Science University, Portland, OR, USA
| | - Xiaojie Wang
- Division of Neuroscience, Oregon National Primate Research Center, Portland, OR, USA
| | - Terry K. Morgan
- Department of Pathology, Oregon Health & Science University, Portland, OR, USA
| | - Zheng Liu
- Division of Neuroscience, Oregon National Primate Research Center, Portland, OR, USA
| | - Colin Studholme
- Division of Neonatology, University of Washington, Seattle, WA, USA
| | - Christopher D. Kroenke
- Advanced Imaging Research Center, Oregon Health & Science University, Portland, OR, USA
- Department of Behavioral Neuroscience, Oregon Health & Science University, Portland, OR, USA
| | - Antonio E. Frias
- Department of Obstetrics and Gynecology, Oregon Health & Science University, Portland, OR, USA
- Division of Reproductive & Developmental Sciences, Oregon National Primate Research Center, Beaverton, OR, USA
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11
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Lo JO, Schabel MC, Roberts VHJ, Wang X, Lewandowski KS, Grant KA, Frias AE, Kroenke CD. First trimester alcohol exposure alters placental perfusion and fetal oxygen availability affecting fetal growth and development in a non-human primate model. Am J Obstet Gynecol 2017; 216:302.e1-302.e8. [PMID: 28153658 PMCID: PMC5334435 DOI: 10.1016/j.ajog.2017.01.016] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2016] [Revised: 12/22/2016] [Accepted: 01/13/2017] [Indexed: 10/20/2022]
Abstract
BACKGROUND Prenatal alcohol exposure leads to impaired fetal growth, brain development, and stillbirth. Placental impairment likely contributes to these adverse outcomes, but the mechanisms and specific vasoactive effects of alcohol that links altered placental function to impaired fetal development remain areas of active research. OBJECTIVE Recently, we developed magnetic resonance imaging techniques in nonhuman primates to characterize placental blood oxygenation through measurements of T2* and perfusion using dynamic contrast-enhanced magnetic resonance imaging. The objective of this study was to evaluate the effects of first-trimester alcohol exposure on macaque placental function and to characterize fetal brain development in vivo. STUDY DESIGN Timed-pregnant Rhesus macaques (n=12) were divided into 2 groups: control (n=6) and ethanol exposed (n=6). Animals were trained to self-administer orally either 1.5 g/kg/d of a 4% ethanol solution (equivalent to 6 drinks/d) or an isocaloric control fluid from preconception until gestational day 60 (term is G168). All animals underwent Doppler ultrasound scanning followed by magnetic resonance imaging that consisted of T2* and dynamic contrast-enhanced measurements. Doppler ultrasound scanning was used to measure uterine artery and umbilical vein velocimetry and diameter to calculate uterine artery volume blood flow and placental volume blood flow. After noninvasive imaging, animals underwent cesarean delivery for placenta collection and fetal necropsy at gestational day 110 (n=6) or 135 (n=6). RESULTS Fetal weight and biparietal diameter were significantly smaller in ethanol-exposed animals compared with control animals at gestational day 110. By Doppler ultrasound scanning, placental volume blood flow was significantly lower (P=.04) at gestational day 110 in ethanol-exposed vs control animals. A significant reduction in placental blood flow was evident by dynamic contrast-enhanced magnetic resonance imaging. As we demonstrated recently, T2* values vary throughout the placenta and reveal gradients in blood deoxyhemoglobin concentration that range from highly oxygenated blood (long T2*) proximal to spiral arteries to highly deoxygenated blood (short T2*). Distributions of T2*throughout the placenta show significant global reduction in T2* (and hence high blood deoxyhemoglobin concentration) in ethanol-exposed vs control animals at gestational day 110 (P=.02). Fetal brain measurements indicated impaired growth and development at gestational day 110, but less so at gestational day 135 in ethanol-exposed vs control animals. CONCLUSION Chronic first-trimester ethanol exposure significantly reduces placental perfusion and oxygen supply to the fetal vasculature later in pregnancy. These perturbations of placental function are associated with fetal growth impairments. However, differences between ethanol-exposed and control animals in placental function and fetal developmental outcomes were smaller at gestational day 135 than at gestational day 110. These findings are consistent with placental adaptation to early perturbations that allow for compensated placental function and maintenance of fetal growth.
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Affiliation(s)
- Jamie O Lo
- Department of Obstetrics and Gynecology, Oregon Health & Science University, Portland, OR.
| | - Matthias C Schabel
- Advanced Imaging Research Center, Oregon Health & Science University, Portland, OR
| | - Victoria H J Roberts
- Division of Reproductive & Developmental Sciences, Oregon National Primate Research Center, Oregon Health & Science University, Beaverton, OR
| | - Xiaojie Wang
- Division of Neuroscience, Oregon National Primate Research Center, Oregon Health & Science University, Beaverton, OR
| | - Katherine S Lewandowski
- Division of Reproductive & Developmental Sciences, Oregon National Primate Research Center, Oregon Health & Science University, Beaverton, OR
| | - Kathleen A Grant
- Division of Neuroscience, Oregon National Primate Research Center, Oregon Health & Science University, Beaverton, OR
| | - Antonio E Frias
- Department of Obstetrics and Gynecology, Oregon Health & Science University, Portland, OR; Division of Reproductive & Developmental Sciences, Oregon National Primate Research Center, Oregon Health & Science University, Beaverton, OR
| | - Christopher D Kroenke
- Advanced Imaging Research Center, Oregon Health & Science University, Portland, OR; Division of Neuroscience, Oregon National Primate Research Center, Oregon Health & Science University, Beaverton, OR
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12
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Lobo MR, Kukino A, Tran H, Schabel MC, Springer CS, Gillespie GY, Grafe MR, Woltjer RL, Pike MM. Synergistic Antivascular and Antitumor Efficacy with Combined Cediranib and SC6889 in Intracranial Mouse Glioma. PLoS One 2015; 10:e0144488. [PMID: 26645398 PMCID: PMC4672903 DOI: 10.1371/journal.pone.0144488] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2015] [Accepted: 11/19/2015] [Indexed: 12/20/2022] Open
Abstract
Prognosis remains extremely poor for malignant glioma. Targeted therapeutic approaches, including single agent anti-angiogenic and proteasome inhibition strategies, have not resulted in sustained anti-glioma clinical efficacy. We tested the anti-glioma efficacy of the anti-angiogenic receptor tyrosine kinase inhibitor cediranib and the novel proteasome inhibitor SC68896, in combination and as single agents. To assess anti-angiogenic effects and evaluate efficacy we employed 4C8 intracranial mouse glioma and a dual-bolus perfusion MRI approach to measure Ktrans, relative cerebral blood flow and volume (rCBF, rCBV), and relative mean transit time (rMTT) in combination with anatomical MRI measurements of tumor growth. While single agent cediranib or SC68896 treatment did not alter tumor growth or survival, combined cediranib/SC68896 significantly delayed tumor growth and increased median survival by 2-fold, compared to untreated. This was accompanied by substantially increased tumor necrosis in the cediranib/SC68896 group (p<0.01), not observed with single agent treatments. Mean vessel density was significantly lower, and mean vessel lumen area was significantly higher, for the combined cediranib/SC68896 group versus untreated. Consistent with our previous findings, cediranib alone did not significantly alter mean tumor rCBF, rCBV, rMTT, or Ktrans. In contrast, SC68896 reduced rCBF in comparison to untreated, but without concomitant reductions in rCBV, rMTT, or Ktrans. Importantly, combined cediranib/SC68896 substantially reduced rCBF, rCBV. rMTT, and Ktrans. A novel analysis of Ktrans/rCBV suggests that changes in Ktrans with time and/or treatment are related to altered total vascular surface area. The data suggest that combined cediranib/SC68896 induced potent anti-angiogenic effects, resulting in increased vascular efficiency and reduced extravasation, consistent with a process of vascular normalization. The study represents the first demonstration that the combination of cediranib with a proteasome inhibitor substantially increases the anti-angiogenic efficacy produced from either agent alone, and synergistically slows glioma tumor growth and extends survival, suggesting a promising treatment which warrants further investigation.
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Affiliation(s)
- Merryl R. Lobo
- Advanced Imaging Research Center, Oregon Health and Science University, Portland, Oregon, United States of America
- Department of Biomedical Engineering, Oregon Health and Science University, Portland, Oregon, United States of America
| | - Ayaka Kukino
- Advanced Imaging Research Center, Oregon Health and Science University, Portland, Oregon, United States of America
| | - Huong Tran
- Department of Pathology, Oregon Health and Science University, Portland, Oregon, United States of America
| | - Matthias C. Schabel
- Advanced Imaging Research Center, Oregon Health and Science University, Portland, Oregon, United States of America
| | - Charles S. Springer
- Advanced Imaging Research Center, Oregon Health and Science University, Portland, Oregon, United States of America
| | - G. Yancey Gillespie
- Department of Surgery, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
| | - Marjorie R. Grafe
- Department of Pathology, Oregon Health and Science University, Portland, Oregon, United States of America
| | - Randall L. Woltjer
- Department of Pathology, Oregon Health and Science University, Portland, Oregon, United States of America
| | - Martin M. Pike
- Advanced Imaging Research Center, Oregon Health and Science University, Portland, Oregon, United States of America
- Department of Biomedical Engineering, Oregon Health and Science University, Portland, Oregon, United States of America
- * E-mail:
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13
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Schabel MC, Roberts VHJ, Lo JO, Platt S, Grant KA, Frias AE, Kroenke CD. Functional imaging of the nonhuman primate Placenta with endogenous blood oxygen level-dependent contrast. Magn Reson Med 2015; 76:1551-1562. [PMID: 26599502 DOI: 10.1002/mrm.26052] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2015] [Revised: 10/22/2015] [Accepted: 10/23/2015] [Indexed: 02/05/2023]
Abstract
PURPOSE To characterize spatial patterns of T2* in the placenta of the rhesus macaque (Macaca mulatta), to correlate these patterns with placental perfusion determined using dynamic contrast-enhanced MRI (DCE-MRI), and to evaluate the potential for using the blood oxygen level-dependent effect to quantify placental perfusion without the use of exogenous contrast reagent. METHODS MRI was performed on three pregnant rhesus macaques at gestational day 110. Multiecho spoiled gradient echo measurements were used to compute maps of T2*. Spatial maxima in these maps were compared with foci of early enhancement determined by DCE-MRI. RESULTS Local maxima in T2* maps were strongly correlated with spiral arteries identified by DCE-MRI, with mean spatial separations ranging from 2.34 to 6.11 mm in the three animals studied. Spatial patterns of R2* ( = 1/ T2*) within individual placental lobules can be quantitatively analyzed using a simple model to estimate fetal arterial oxyhemoglobin concentration [Hbo,f] and a parameter viPS/Φ, reflecting oxygen transport to the fetus. Estimated mean values of [Hbo,f] ranged from 4.25 mM to 4.46 mM, whereas viPS/Φ ranged from 2.80 × 105 cm-3 to 1.61 × 106 cm-3 . CONCLUSIONS Maternal spiral arteries show strong spatial correlation with foci of extended T2* observed in the primate placenta. A simple model of oxygen transport accurately describes the spatial dependence of R2* within placental lobules and enables assessment of placental function and oxygenation without requiring administration of an exogenous contrast reagent. Magn Reson Med 76:1551-1562, 2016. © 2015 International Society for Magnetic Resonance in Medicine.
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Affiliation(s)
- M C Schabel
- Advanced Imaging Research Center, Oregon Health & Science University.,Utah Center for Advanced Imaging Research, University of Utah
| | - V H J Roberts
- Division of Diabetes, Obesity & Metabolism, Oregon Health & Science University
| | - J O Lo
- Division of Diabetes, Obesity & Metabolism, Oregon Health & Science University
| | - S Platt
- Division of Neuroscience, Oregon National Primate Research Center
| | - K A Grant
- Division of Neuroscience, Oregon National Primate Research Center.,Department of Behavioral Neuroscience, Oregon Health & Science University
| | - A E Frias
- Division of Diabetes, Obesity & Metabolism, Oregon Health & Science University.,Division of Developmental & Reproductive Sciences, Oregon National Primate Research Center.,Department of Obstetrics & Gynecology, Oregon Health & Science University
| | - C D Kroenke
- Advanced Imaging Research Center, Oregon Health & Science University.,Division of Neuroscience, Oregon National Primate Research Center.,Department of Behavioral Neuroscience, Oregon Health & Science University
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14
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Jacobs I, Hectors SJCG, Schabel MC, Grüll H, Strijkers GJ, Nicolay K. Cluster analysis of DCE-MRI data identifies regional tracer-kinetic changes after tumor treatment with high intensity focused ultrasound. NMR Biomed 2015; 28:1443-1454. [PMID: 26390040 DOI: 10.1002/nbm.3406] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2014] [Revised: 07/27/2015] [Accepted: 08/14/2015] [Indexed: 06/05/2023]
Abstract
Evaluation of high intensity focused ultrasound (HIFU) treatment with MRI is generally based on assessment of the non-perfused volume from contrast-enhanced T1-weighted images. However, the vascular status of tissue surrounding the non-perfused volume has not been extensively investigated with MRI. In this study, cluster analysis of the transfer constant K(trans) and extravascular extracellular volume fraction ve , derived from dynamic contrast-enhanced MRI (DCE-MRI) data, was performed in tumor tissue surrounding the non-perfused volume to identify tumor subregions with distinct contrast agent uptake kinetics. DCE-MRI was performed in CT26.WT colon carcinoma-bearing BALB/c mice before (n = 12), directly after (n = 12) and 3 days after (n = 6) partial tumor treatment with HIFU. In addition, a non-treated control group (n = 6) was included. The non-perfused volume was identified based on the level of contrast enhancement. Quantitative comparison between non-perfused tumor fractions and non-viable tumor fractions derived from NADH-diaphorase histology showed a stronger agreement between these fractions 3 days after treatment (R(2) to line of identity = 0.91) compared with directly after treatment (R(2) = 0.74). Next, k-means clustering with four clusters was applied to K(trans) and ve parameter values of all significantly enhanced pixels. The fraction of pixels within two clusters, characterized by a low K(trans) and either a low or high ve , significantly increased after HIFU. Changes in composition of these clusters were considered to be HIFU induced. Qualitative H&E histology showed that HIFU-induced alterations in these clusters may be associated with hemorrhage and structural tissue disruption. Combined microvasculature and hypoxia staining suggested that these tissue changes may affect blood vessel functionality and thereby tumor oxygenation. In conclusion, it was demonstrated that, in addition to assessment of the non-perfused tumor volume, the presented methodology gives further insight into HIFU-induced effects on tumor vascular status. This method may aid in assessment of the consequences of vascular alterations for the fate of the tissue.
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Affiliation(s)
- Igor Jacobs
- Biomedical NMR, Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands
| | - Stefanie J C G Hectors
- Biomedical NMR, Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands
- Translational and Molecular Imaging Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Matthias C Schabel
- Imaging Research Center, Oregon Health and Science University, Portland, OR, USA
- Utah Center for Advanced Imaging Research, University of Utah, Salt Lake City, UT, USA
| | - Holger Grüll
- Biomedical NMR, Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands
- Oncology solutions, Philips Research, Eindhoven, The Netherlands
| | - Gustav J Strijkers
- Biomedical NMR, Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands
- Biomedical Engineering and Physics, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Klaas Nicolay
- Biomedical NMR, Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands
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15
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Oh KY, Roberts VHJ, Schabel MC, Grove KL, Woods M, Frias AE. Gadolinium Chelate Contrast Material in Pregnancy: Fetal Biodistribution in the Nonhuman Primate. Radiology 2015; 276:110-8. [PMID: 25763829 PMCID: PMC4485748 DOI: 10.1148/radiol.15141488] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
PURPOSE To determine the extent to which gadolinium chelate is found in nonhuman primate fetal tissues and amniotic fluid at 19-45 hours after intravenous injection of a weight-appropriate maternal dose of the contrast agent gadoteridol. MATERIALS AND METHODS Gravid Japanese macaques (n = 14) were maintained as approved by the institutional animal care and utilization committee. In the 3rd trimester of pregnancy, the macaques were injected with gadoteridol (0.1 mmol per kilogram of maternal weight). Fetuses were delivered by means of cesarean section within 24 hours of maternal injection (range, 19-21 hours; n = 11) or 45 hours after injection (n = 3). Gadolinium chelate levels in the placenta, fetal tissues, and amniotic fluid were obtained by using inductively coupled plasma mass spectrometry. The Wilcoxon rank sum test was used for quantitative comparisons. RESULTS Gadoteridol was present in the fetoplacental circulation at much lower quantities than in the mother. At both time points, the distribution of gadolinium chelate in the fetus was comparable to that expected in an adult. The highest concentration of the injected dose (ID) was found in the fetal kidney (0.0161% ID per gram in the 19-21-hour group). The majority of the in utero gadolinium chelate was found in the amniotic fluid and the placenta (mean, 0.1361% ID per organ ± 0.076 [standard deviation] and 0.0939% ID per organ ± 0.0494, respectively). Data acquired 45 hours after injection showed a significant decrease in the gadolinium chelate concentration in amniotic fluid compared with that in the 19-21-hour group (from 0.0017% to 0.0007% ID per gram; P = .01). CONCLUSION Amounts of gadolinium chelate in the fetal tissues and amniotic fluid were minimal compared with the maternal ID. This may impact future clinical studies on the safety of gadolinium contrast agent use in pregnancy.
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Affiliation(s)
- Karen Y. Oh
- From the Department of Radiology (K.Y.O.), Advanced Imaging Research Center (M.C.S., M.W.), and Department of Obstetrics and Gynecology, Division of Maternal Fetal Medicine (A.E.F.), Oregon Health and Science University, 3181 SW Sam Jackson Park Rd, MC L340, Portland, OR 97239; Division of Diabetes, Obesity and Metabolism, Oregon National Primate Research Center, Oregon Health and Science University, Beaverton, Ore (V.H.J.R., K.L.G., A.E.F.); and Department of Chemistry, Portland State University, Portland, Ore (M.W.)
| | - Victoria H. J. Roberts
- From the Department of Radiology (K.Y.O.), Advanced Imaging Research Center (M.C.S., M.W.), and Department of Obstetrics and Gynecology, Division of Maternal Fetal Medicine (A.E.F.), Oregon Health and Science University, 3181 SW Sam Jackson Park Rd, MC L340, Portland, OR 97239; Division of Diabetes, Obesity and Metabolism, Oregon National Primate Research Center, Oregon Health and Science University, Beaverton, Ore (V.H.J.R., K.L.G., A.E.F.); and Department of Chemistry, Portland State University, Portland, Ore (M.W.)
| | - Matthias C. Schabel
- From the Department of Radiology (K.Y.O.), Advanced Imaging Research Center (M.C.S., M.W.), and Department of Obstetrics and Gynecology, Division of Maternal Fetal Medicine (A.E.F.), Oregon Health and Science University, 3181 SW Sam Jackson Park Rd, MC L340, Portland, OR 97239; Division of Diabetes, Obesity and Metabolism, Oregon National Primate Research Center, Oregon Health and Science University, Beaverton, Ore (V.H.J.R., K.L.G., A.E.F.); and Department of Chemistry, Portland State University, Portland, Ore (M.W.)
| | - Kevin L. Grove
- From the Department of Radiology (K.Y.O.), Advanced Imaging Research Center (M.C.S., M.W.), and Department of Obstetrics and Gynecology, Division of Maternal Fetal Medicine (A.E.F.), Oregon Health and Science University, 3181 SW Sam Jackson Park Rd, MC L340, Portland, OR 97239; Division of Diabetes, Obesity and Metabolism, Oregon National Primate Research Center, Oregon Health and Science University, Beaverton, Ore (V.H.J.R., K.L.G., A.E.F.); and Department of Chemistry, Portland State University, Portland, Ore (M.W.)
| | - Mark Woods
- From the Department of Radiology (K.Y.O.), Advanced Imaging Research Center (M.C.S., M.W.), and Department of Obstetrics and Gynecology, Division of Maternal Fetal Medicine (A.E.F.), Oregon Health and Science University, 3181 SW Sam Jackson Park Rd, MC L340, Portland, OR 97239; Division of Diabetes, Obesity and Metabolism, Oregon National Primate Research Center, Oregon Health and Science University, Beaverton, Ore (V.H.J.R., K.L.G., A.E.F.); and Department of Chemistry, Portland State University, Portland, Ore (M.W.)
| | - Antonio E. Frias
- From the Department of Radiology (K.Y.O.), Advanced Imaging Research Center (M.C.S., M.W.), and Department of Obstetrics and Gynecology, Division of Maternal Fetal Medicine (A.E.F.), Oregon Health and Science University, 3181 SW Sam Jackson Park Rd, MC L340, Portland, OR 97239; Division of Diabetes, Obesity and Metabolism, Oregon National Primate Research Center, Oregon Health and Science University, Beaverton, Ore (V.H.J.R., K.L.G., A.E.F.); and Department of Chemistry, Portland State University, Portland, Ore (M.W.)
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16
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Jacobs I, Strijkers GJ, Keizer HM, Janssen HM, Nicolay K, Schabel MC. A novel approach to tracer-kinetic modeling for (macromolecular) dynamic contrast-enhanced MRI. Magn Reson Med 2015; 75:1142-53. [PMID: 25846802 DOI: 10.1002/mrm.25704] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2014] [Revised: 02/26/2015] [Accepted: 02/26/2015] [Indexed: 12/21/2022]
Abstract
PURPOSE To develop a novel tracer-kinetic modeling approach for multi-agent dynamic contrast-enhanced MRI (DCE-MRI) that facilitates separate estimation of parameters characterizing blood flow and microvascular permeability within one individual. METHODS Monte Carlo simulations were performed to investigate the performance of the constrained multi-agent model. Subsequently, multi-agent DCE-MRI was performed on tumor-bearing mice (n = 5) on a 7T Bruker scanner on three measurement days, in which two dendrimer-based contrast agents having high and intermediate molecular weight, respectively, along with gadoterate meglumine, were sequentially injected within one imaging session. Multi-agent data were simultaneously fit with the gamma capillary transit time model. Blood flow, mean capillary transit time, and bolus arrival time were constrained to be identical between the boluses, while extraction fractions and washout rate constants were separately determined for each agent. RESULTS Simulations showed that constrained multi-agent model regressions led to less uncertainty and bias in estimated tracer-kinetic parameters compared with single-bolus modeling. The approach was successfully applied in vivo, and significant differences in the extraction fraction and washout rate constant between the agents, dependent on their molecular weight, were consistently observed. CONCLUSION A novel multi-agent tracer-kinetic modeling approach that enforces self-consistency of model parameters and can robustly characterize tumor vascular status was demonstrated.
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Affiliation(s)
- Igor Jacobs
- Biomedical NMR, Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, Netherlands
| | - Gustav J Strijkers
- Biomedical NMR, Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, Netherlands.,Biomedical Engineering and Physics, Academic Medical Center, University of Amsterdam, Amsterdam, Netherlands
| | | | | | - Klaas Nicolay
- Biomedical NMR, Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, Netherlands
| | - Matthias C Schabel
- Advanced Imaging Research Center, Oregon Health & Science University, Portland, Oregon, USA.,Utah Center for Advanced Imaging Research, University of Utah, Salt Lake City, Utah, USA
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Frias AE, Schabel MC, Roberts VHJ, Tudorica A, Grigsby PL, Oh KY, Kroenke CD. Using dynamic contrast-enhanced MRI to quantitatively characterize maternal vascular organization in the primate placenta. Magn Reson Med 2014; 73:1570-8. [PMID: 24753177 DOI: 10.1002/mrm.25264] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2013] [Revised: 04/02/2014] [Accepted: 04/03/2014] [Indexed: 11/09/2022]
Abstract
PURPOSE The maternal microvasculature of the primate placenta is organized into 10-20 perfusion domains that are functionally optimized to facilitate nutrient exchange to support fetal growth. This study describes a dynamic contrast-enhanced magnetic resonance imaging method for identifying vascular domains and quantifying maternal blood flow in them. METHODS A rhesus macaque on the 133rd day of pregnancy (G133, term = 165 days) underwent Doppler ultrasound procedures, dynamic contrast-enhanced magnetic resonance imaging and Cesarean-section delivery. Serial T1 -weighted images acquired throughout intravenous injection of a contrast reagent bolus were analyzed to obtain contrast reagent arrival time maps of the placenta. RESULTS Watershed segmentation of the arrival time map identified 16 perfusion domains. The number and location of these domains corresponded to anatomical cotyledonary units observed following delivery. Analysis of the contrast reagent wave front through each perfusion domain enabled determination of volumetric flow, which ranged from 9.03 to 44.9 mL/s (25.2 ± 10.3 mL/s). These estimates are supported by Doppler ultrasound results. CONCLUSIONS The dynamic contrast-enhanced magnetic resonance imaging analysis described here provides quantitative estimates of the number of maternal perfusion domains in a primate placenta and estimates flow within each domain. Anticipated extensions of this technique are to the study placental function in non-human primate models of obstetric complications.
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Affiliation(s)
- Antonio E Frias
- Division of Diabetes, Obesity and Metabolism, Oregon National Primate Research Center, Beaverton, Oregon, USA; Division of Developmental and Reproductive Sciences, Oregon National Primate Research Center, Beaverton, Oregon, USA; Department of Obstetrics and Gynecology, Oregon National Primate Research Center, Beaverton, Oregon, USA
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Jensen RL, Mumert ML, Gillespie DL, Kinney AY, Schabel MC, Salzman KL. Preoperative dynamic contrast-enhanced MRI correlates with molecular markers of hypoxia and vascularity in specific areas of intratumoral microenvironment and is predictive of patient outcome. Neuro Oncol 2013; 16:280-91. [PMID: 24305704 DOI: 10.1093/neuonc/not148] [Citation(s) in RCA: 78] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND Measures of tumor vascularity and hypoxia have been correlated with glioma grade and outcome. Dynamic contrast-enhanced (DCE) MRI can noninvasively map tumor blood flow, vascularity, and permeability. In this prospective observational cohort pilot study, preoperative imaging was correlated with molecular markers of hypoxia, vascularity, proliferation, and progression-free and overall patient survival. METHODS Pharmacokinetic modeling methods were used to generate maps of tumor blood flow, extraction fraction, permeability-surface area product, transfer constant, washout rate, interstitial volume, blood volume, capillary transit time, and capillary heterogeneity from preoperative DCE-MRI data in human glioma patients. Tissue was obtained from areas of peritumoral edema, active tumor, hypoxic penumbra, and necrotic core and evaluated for vascularity, proliferation, and expression of hypoxia-regulated molecules. DCE-MRI parameter values were correlated with hypoxia-regulated protein expression at tissue sample sites. RESULTS Patient survival correlated with DCE parameters in 2 cases: capillary heterogeneity in active tumor and interstitial volume in areas of peritumoral edema. Statistically significant correlations were observed between several DCE parameters and tissue markers. In addition, MIB-1 index was predictive of overall survival (P = .044) and correlated with vascular endothelial growth factor expression in hypoxic penumbra (r = 0.7933, P = .0071) and peritumoral edema (r = 0.4546). Increased microvessel density correlated with worse patient outcome (P = .026). CONCLUSIONS Our findings suggest that DCE-MRI may facilitate noninvasive preoperative predictions of areas of tumor with increased hypoxia and proliferation. Both imaging and hypoxia biomarkers are predictive of patient outcome. This has the potential to allow unprecedented prognostic decisions and to guide therapies to specific tumor areas.
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Affiliation(s)
- Randy L Jensen
- Corresponding author: Randy L. Jensen, MD, PhD, Huntsman Cancer Institute and Departments of Neurosurgery, Radiation Oncology, Oncological Sciences, Clinical Neuroscience Center, University of Utah, 175 North Medical Drive, Salt Lake City, Utah 84132.
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Lobo MR, Green SC, Schabel MC, Gillespie GY, Woltjer RL, Pike MM. Quinacrine synergistically enhances the antivascular and antitumor efficacy of cediranib in intracranial mouse glioma. Neuro Oncol 2013; 15:1673-83. [PMID: 24092859 DOI: 10.1093/neuonc/not119] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND Despite malignant glioma vascularity, anti-angiogenic therapy is largely ineffective. We hypothesize that efficacy of the antiangiogenic agent cediranib is synergistically enhanced in intracranial glioma via combination with the late-stage autophagy inhibitor quinacrine. METHODS Relative cerebral blood flow and volume (rCBF, rCBV), vascular permeability (K(trans)), and tumor volume were assessed in intracranial 4C8 mouse glioma using a dual-bolus perfusion MRI approach. Tumor necrosis and tumor mean vessel density (MVD) were assessed immunohistologically. Autophagic vacuole accumulation and apoptosis were assessed via Western blot in 4C8 glioma in vitro. RESULTS Cediranib or quinacrine treatment alone did not alter tumor growth. Survival was only marginally improved by cediranib and unchanged by quinacrine. In contrast, combined cediranib/quinacrine reduced tumor growth by >2-fold (P < .05) and increased median survival by >2-fold, compared with untreated controls (P < .05). Cediranib or quinacrine treatment alone did not significantly alter mean tumor rCBF or K(trans) compared with untreated controls, while combined cediranib/quinacrine substantially reduced both (P < .05), indicating potent tumor devascularization. MVD and necrosis were unchanged by cediranib or quinacrine treatment. In contrast, MVD was reduced by nearly 2-fold (P < .01), and necrosis increased by 3-fold (P < .05, one-tailed), in cediranib + quinacrine treated vs untreated groups. Autophagic vacuole accumulation was induced by cediranib and quinacrine in vitro. Combined cediranib/quinacrine treatment under hypoxic conditions induced further accumulation and apoptosis. CONCLUSION Combined cediranib/quinacrine treatment synergistically increased antivascular/antitumor efficacy in intracranial 4C8 mouse glioma, suggesting a promising and facile treatment strategy for malignant glioma. Modulations in the autophagic pathway may play a role in the increased efficacy.
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Affiliation(s)
- Merryl R Lobo
- Corresponding Author: Martin M. Pike, PhD, Advanced Imaging Research Center, 3181SW Sam Jackson Park Rd, L452 Portland, OR 97239-3098.
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Abstract
PURPOSE To determine the feasibility of three-dimensional (3D) hybrid radial (stack-of-stars) MRI with spatiotemporal total variation (TV) constrained reconstruction for dynamic contrast enhanced myocardial perfusion imaging. METHODS An ECG-triggered saturation recovery turboFLASH sequence with undersampled stack-of-stars sampling with spatiotemporal TV constrained reconstruction was developed for dynamic contrast enhanced myocardial perfusion imaging. Simulations were performed to study the dependence of the approach to steady state on flip angle and saturation recovery time for this stack-of-stars acquisition. Phantom studies were used to show the effect of the flip angle selection and imperfect spoiling on image qualities. Studies were done in three humans to test the feasibility of the approach for myocardial perfusion imaging. RESULTS The simulation and phantom studies showed that imperfect spoiling and magnetization changes during the readout were a function of flip angle and nonoptimized selection of flip angle could degrade the images. Low flip angle acquisitions in the human subjects result in images with good quality similar to multislice radial 2D images. CONCLUSIONS 3D stack-of-stars sampling with spatiotemporal TV constrained reconstruction provides a promising alternative for myocardial perfusion imaging.
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Affiliation(s)
- Liyong Chen
- Department of Bioengineering, University of Utah, Salt Lake City, Utah 84108, USA
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Fluckiger JU, Schabel MC, Dibella EVR. The effect of temporal sampling on quantitative pharmacokinetic and three-time-point analysis of breast DCE-MRI. Magn Reson Imaging 2012; 30:934-43. [PMID: 22513074 DOI: 10.1016/j.mri.2012.02.011] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2011] [Revised: 02/15/2012] [Accepted: 02/17/2012] [Indexed: 01/28/2023]
Abstract
The effects of temporal sampling on the previously published three-time-point (3TP) method are compared with those of a Tofts-Kety model using an arterial input function from the alternating minimization with model (AMM) method. Computer simulations are done to estimate the expected error in both the 3TP and Tofts-Kety models as a function of the temporal sampling rate of the data. The error in the 3TP model parameters remained essentially constant with respect to temporal sampling. The Tofts-Kety model showed a linear increase in parameter error with respect to temporal sampling. Both analysis methods were also applied to 87 clinically acquired breast scans. These scans were downsampled in time by a factor of 2 and 4, and the methods were reapplied. The spatial resolution was held constant throughout this study. At temporal resolutions less than 19.4 s, the Tofts-Kety model outperformed the 3TP model using receiver operating characteristic curve analysis (area under the ROC curve [AUC] of 0.94 compared to 0.91). As the temporal sampling rate decreased, the 3TP model outperformed the Tofts-Kety model (AUC of 0.89 versus 0.85). When the temporal sampling rate of the data was less than 20 s, the Tofts-Kety model with the AMM method had lower parameter error than the 3TP method.
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Affiliation(s)
- Jacob U Fluckiger
- Department of Radiology, Utah Center for Advanced Imaging Research, University of Utah, Salt Lake City, UT 84108, USA
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Lobo MR, Huang ET, Kurre P, Schabel MC, Gillespie GY, Pike MM. Abstract 1905: Autophagy inhibitor quinacrine synergistically enhances anti-angiogenic efficacy of Cediranib in intracranial mouse glioma. Cancer Res 2012. [DOI: 10.1158/1538-7445.am2012-1905] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Abstract
Despite robust vascularity of malignant gliomas, anti-angiogenic therapy (AAT), largely fails to induce durable responses. We hypothesized that AAT efficacy in treating glioma could be increased by disrupting adaptive mechanisms that enable tumors to survive AAT alone. Hypoxic/nutrient stress conditions, such as those induced by AAT, can activate autophagy in tumor cells, a degradative catabolic pathway that promotes cellular survival during metabolic stress. The anti-malarial agent quinacrine induces late-stage autophagic inhibition, which can induce cell death. We determined whether the angiogenic/anti-tumor efficacy of Cediranib, a VEGF/PDGF receptor tyrosine kinase inhibitor, could be synergistically enhanced through combined administration of quinacrine. A noninvasive, dual bolus perfusion MRI approach was used to assess tumor growth and vascular parameters in the syngeneic 4C8 mouse model of intracranial glioma. Dynamic contrast enhanced (DCE) MRI, provided high resolution maps of Ktrans, an index of vascular permeability. At the same time, dynamic susceptibility contrast (DSC) MRI determined cerebral blood flow (CBF). Once tumor growth was documented by MRI, mice were randomized to untreated (U), Cediranib (C, 6 mg/kg daily), quinacrine (Q, 50mg/kg daily), or Cediranib plus quinacrine (C+Q) groups. Tumor growth rate (days−1, mean±SE) was moderately decreased for C (0.17±0.01) in comparison to U (0.22±0.01) and Q (0.21±0.01) (p<0.05). Tumor growth rate was reduced substantially, with C+Q (0.11±0.004) (p<0.01 versus other groups). Consistent with this, survival (days from tumor growth initiation) was greatly increased for C+Q, 25.3±1.8, versus other groups (p<0.01): 11.0 ± 1.6 (U), 11.5 ± 1.2 (Q), and, 14.3 ± 0.7 (C). Perfusion MRI indicated that mean tumor Ktrans for C (0.13±0.01 min−1) was moderately reduced in comparison to U (0.21±0.04) and Q (0.20±0.2), during the 2nd treatment week (P<0.05). Dramatically reduced Ktrans was observed with C+Q (0.07±0.01; p<0.05 vs U, C, and Q). Consistent with this, mean tumor CBF relative to contralateral brain CBF during the 2nd treatment week, was dramatically lower for C+Q, 1.61±0.06 (p<0.05) compared to other groups: 3.06 ± 0.15 (U), 2.55±0.24 (Q), 3.07±0.47 (C). In vitro MTS cell viability assays of 4C8 glioma cells indicated markedly increased efficacy for combined C+Q under hypoxic conditions: 1μM C/2.5μM Q decreased cell viability by 76±6% and 33±1% with 0.5 and 21% O2, respectively. Combination indices (CI) indicated less than additive effects for C and Q with normal O2, while synergism (CI<1) was observed under hypoxic conditions (CI=0.58, 0.75μM C/1μM Q). In conclusion, the autophagy inhibitor quinacrine synergistically increases the anti-angiogenic/anti-tumor effect of Cediranib in 4C8 mouse glioma. Tumor microenvironment conditions such as hypoxia may play a role in the synergistic interaction.
Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 1905. doi:1538-7445.AM2012-1905
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Affiliation(s)
- Merryl R. Lobo
- 1Advanced Imaging Research Center, Oregon Health and Science University, Portland, OR
| | - Elaine T. Huang
- 2Department of Pediatrics, Oregon Health and Science University, Portland, OR
| | - Peter Kurre
- 2Department of Pediatrics, Oregon Health and Science University, Portland, OR
| | - Matthias C. Schabel
- 1Advanced Imaging Research Center, Oregon Health and Science University, Portland, OR
| | | | - Martin M. Pike
- 1Advanced Imaging Research Center, Oregon Health and Science University, Portland, OR
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Schabel MC. A unified impulse response model for DCE-MRI. Magn Reson Med 2012; 68:1632-46. [DOI: 10.1002/mrm.24162] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2011] [Revised: 12/15/2011] [Accepted: 12/21/2011] [Indexed: 01/13/2023]
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DiBella EVR, Chen L, Schabel MC, Adluru G, McGann CJ. Myocardial perfusion acquisition without magnetization preparation or gating. Magn Reson Med 2011; 67:609-13. [PMID: 22190332 DOI: 10.1002/mrm.23318] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2011] [Revised: 11/10/2011] [Accepted: 11/14/2011] [Indexed: 01/13/2023]
Abstract
Current myocardial perfusion MRI acquisitions are performed with a saturation recovery sequence, in large part to minimize sensitivity to arrhythmia. A new approach is proposed here where the images are acquired ungated at steady state without use of a saturation pulse. The data are acquired continuously and reach steady state after the first few images. A confluence of advances has made this new paradigm of an ungated steady-state acquisition possible-very rapid undersampled readouts with new reconstruction technologies permit enough measurements that continuous acquisition becomes a feasible approach. Gating can be applied retrospectively from a logged electrocardiogram (ECG) or with self-gating methods. In this work, simulations and measurements in a concentration phantom are used to demonstrate that similar contrast and signal can be obtained with the standard saturation recovery and the proposed spoiled gradient echo (SPGR) acquisition. Specifically, for a flip angle of 14° and a saturation recovery time of 80 ms, similar signals are acquired over a range of T(1) s that reflect realistic myocardial tissue concentrations. Preliminary results in one subject are presented to show the potential of this new approach. The method may allow for cine cardiac perfusion and more signal-to-noise ratio-efficient acquisitions.
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Affiliation(s)
- Edward V R DiBella
- Utah Center for Advanced Imaging Research, Department of Radiology, University of Utah, Salt Lake City, Utah, USA.
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Carney CE, Tran AD, Wang J, Schabel MC, Sherry AD, Woods M. Towards the rational design of MRI contrast agents: δ-substitution of lanthanide(III) NB-DOTA-tetraamide chelates influences but does not control coordination geometry. Chemistry 2011; 17:10372-8. [PMID: 21837722 DOI: 10.1002/chem.201101007] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2011] [Indexed: 11/12/2022]
Abstract
LnDOTA-tetraamide chelates (DOTA=1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid) have received considerable recent attention as a result of their potential to act as PARACEST contrast agents for magnetic resonance imaging (MRI). Although PARACEST agents afford several advantages over conventional contrast agents they suffer from substantially higher detection limits; thus, improving the effectiveness of LnDOTA-tetraamide chelates is an important goal. In this study we investigate the potential to extend conformational control of LnDOTA-type ligands to those applicable to PARACEST. Furthermore, the question of whether δ- rather than α-substitution of the pendant arms could be used to control the chelate coordination geometry is addressed. Although δ-substitution does influence coordination geometry it does not afford control. However, it can play an important role in governing the conformation of the amide substituent relative to the chelate in such as way that suggests a PARACEST agent could be designed that has detection limits at least as low as a conventional MRI contrast agent.
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Affiliation(s)
- Christiane E Carney
- Department of Chemistry, Portland State University, 1719 SW 10th Ave, Portland, OR 97201, USA
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Tsimberidou AM, Akerley W, Schabel MC, Hong DS, Uehara C, Chhabra A, Warren T, Mather GG, Evans BA, Woodland DP, Swabb EA, Kurzrock R. Phase I clinical trial of MPC-6827 (Azixa), a microtubule destabilizing agent, in patients with advanced cancer. Mol Cancer Ther 2011; 9:3410-9. [PMID: 21159616 DOI: 10.1158/1535-7163.mct-10-0516] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
MPC-6827 (Azixa) is a small-molecule microtubule-destabilizing agent that binds to the same (or nearby) sites on β-tubulin as colchicine. This phase I study was designed to determine the dose-limiting toxicities (DLT), maximum tolerated dose (MTD), and pharmacokinetics (PK) of MPC-6827 in patients with solid tumors. Patients with advanced/metastatic cancer were treated with once-weekly, 1- to 2-hour intravenous administration of MPC-6827 for 3 consecutive weeks every 28 days (1 cycle). Dose escalation began with 0.3, 0.6, 1, and 1.5 mg/m(2), with subsequent increments of 0.6 mg/m(2) until the MTD was determined. A 3 + 3 design was used. Pharmacokinetics of MPC-6827 and its metabolite MPI-0440627 were evaluated. Forty-eight patients received therapy; 79 cycles were completed (median, 1; range, 1-10). The most common adverse events were nausea, fatigue, flushing, and hyperglycemia. The DLT was nonfatal grade 3 myocardial infarction at 3.9 mg/m(2) (1/6 patients) and at 4.5 mg/m(2) (1/7 patients). The MTD was determined to be 3.3 mg/m(2) (0/13 patients had a DLT). Five (10.4%) of the 48 patients achieved stable disease (Response Evaluation Criteria in Solid Tumors) for 4 months or greater. MPC-6827 has a high volume of distribution and clearance. Half-life ranged from 3.8 to 7.5 hours. In conclusion, MPC-6827 administered intravenously over 2 hours at a dose of 3.3 mg/m(2) once weekly for 3 weeks every 28 days was safe in patients with heavily pretreated cancer. Clinical trials with MPC-6827 and chemotherapy are ongoing.
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Affiliation(s)
- Apostolia-Maria Tsimberidou
- Phase I Clinical Trials Program, Department of Investigational Cancer Therapeutics, The University of Texas MD Anderson Cancer Center, Houston, Texas 77030, USA.
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Fluckiger JU, Schabel MC, DiBella EVR. Constrained estimation of the arterial input function for myocardial perfusion cardiovascular magnetic resonance. Magn Reson Med 2011; 66:419-27. [PMID: 21446030 DOI: 10.1002/mrm.22809] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2010] [Revised: 12/02/2010] [Accepted: 12/10/2010] [Indexed: 12/21/2022]
Abstract
Accurate quantification of myocardial perfusion remains challenging due to saturation of the arterial input function at high contrast concentrations. A method for estimating the arterial input function directly from tissue curves in the myocardium that avoids these difficulties is presented. In this constrained alternating minimization with model (CAMM) algorithm, a portion of the left ventricular blood pool signal is also used to constrain the estimation process. Extensive computer simulations assessing the accuracy of kinetic parameter estimation were performed. In 5000 noise realizations, the use of the AIF given by the estimation method returned kinetic parameters with mean Ktrans error of -2% and mean kep error of 0.4%. Twenty in vivo resting perfusion datasets were also processed with this method, and pharmacokinetic parameter values derived from the blind AIF were compared with those derived from a dual-bolus measured AIF. For 17 of the 20 datasets, there were no statistically significant differences in Ktrans estimates, and in aggregate the kinetic parameters were not significantly different from the dual-bolus method. The cardiac constrained alternating minimization with model method presented here provides a promising approach to quantifying perfusion of myocardial tissue with a single injection of contrast agent and without a special pulse sequence though further work is needed to validate the approach in a clinical setting.
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Affiliation(s)
- Jacob U Fluckiger
- Utah Center for Advanced Imaging Research, Department of Radiology, University of Utah, Salt Lake City, Utah 84108, USA
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Adluru G, Tasdizen T, Schabel MC, DiBella EVR. Reconstruction of 3D dynamic contrast-enhanced magnetic resonance imaging using nonlocal means. J Magn Reson Imaging 2011; 32:1217-27. [PMID: 21031528 DOI: 10.1002/jmri.22358] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
PURPOSE To develop and test a nonlocal means-based reconstruction algorithm for undersampled 3D dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI) of tumors. MATERIALS AND METHODS We propose a reconstruction technique that is based on the recently proposed nonlocal means (NLM) filter which can relax trade-offs in spatial and temporal resolutions in dynamic imaging. Unlike the original application of NLM for image denoising, the MR reconstruction framework here can offer high-quality images from undersampled k-space data. The method is based on enforcing similarity constraints in terms of neighborhoods of pixels rather than individual pixels. The method was applied on undersampled 3D DCE imaging of breast and brain tumor datasets and the results were compared to sliding window reconstructions and to a compressed sensing method using total variation constraints on the images. RESULTS Undersampling factors of up to five were obtained with the proposed approach while preserving the spatial and temporal characteristics. The NLM reconstruction method offered improved performance over the sliding window and the total variation constrained reconstruction techniques. CONCLUSION The reconstruction framework here can give high-quality images from undersampled DCE MRI data and has the potential to improve the quality of DCE tumor imaging.
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Affiliation(s)
- Ganesh Adluru
- UCAIR, Department of Radiology, University of Utah, Salt Lake City, Utah 84108, USA.
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Abstract
PURPOSE To present a method for estimating the local arterial input function (AIF) within a dynamic contrast-enhanced MRI scan, based on the alternating minimization with model (AMM) method. MATERIALS AND METHODS This method clusters a subset of data into representative curves, which are then input to the AMM algorithm to return a parameterized AIF and pharmacokinetic parameters. Computer simulations are used to investigate the accuracy with which the AMM is able to estimate the true AIF as a function of the input tissue curves. RESULTS Simulations show that a power law relates uncertainty in kinetic parameters and SNR and heterogeneity of the input. Kinetic parameters calculated with the measured AIF are significantly different from those calculated with either a global (P < 0.005) or a local input function (P = 0.0). The use of local AIFs instead of measured AIFs yield mean lesion-averaged parameter changes: K(trans): +24% [+15%, +70%], k(ep): +13% [-36%, +300%]. Globally estimated input functions yield mean lesion-averaged changes: K(trans): +9% [-38%, +65%], k(ep): +13% [-100%, +400%]. The observed improvement in fit quality with local AIFs was found to be significant when additional free parameters were accounted for using the Akaike information criterion. CONCLUSION Local AIFs result in significantly different kinetic parameter values. The statistically significant improvement in fit quality suggests that changes in parameter estimates using local AIFs reflect differences in underlying tissue physiology.
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Affiliation(s)
- Jacob U Fluckiger
- Utah Center for Advanced Imaging Research, Department of Radiology, University of Utah, Salt Lake City, Utah, USA
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Schabel MC, Morrell GR, Oh KY, Walczak CA, Barlow RB, Neumayer LA. Pharmacokinetic mapping for lesion classification in dynamic breast MRI. J Magn Reson Imaging 2010; 31:1371-8. [PMID: 20512889 DOI: 10.1002/jmri.22179] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
PURPOSE To prospectively investigate whether a rapid dynamic MRI protocol, in conjunction with pharmacokinetic modeling, could provide diagnostically useful information for discriminating biopsy-proven benign lesions from malignancies. MATERIALS AND METHODS Patients referred to breast biopsy based on suspicious screening findings were eligible. After anatomic imaging, patients were scanned using a dynamic protocol with complete bilateral breast coverage. Maps of pharmacokinetic parameters representing transfer constant (K(trans)), efflux rate constant (k(ep)), blood plasma volume fraction (v(p)), and extracellular extravascular volume fraction (v(e)) were averaged over lesions and used, with biopsy results, to generate receiver operating characteristic curves for linear classifiers using one, two, or three parameters. RESULTS Biopsy and imaging results were obtained from 93 lesions in 74 of 78 study patients. Classification based on K(trans) and k(ep) gave the greatest accuracy, with an area under the receiver operating characteristic curve of 0.915, sensitivity of 91%, and specificity of 85%, compared with values of 88% and 68%, respectively, obtained in a recent study of clinical breast MRI in a similar patient population. CONCLUSION Pharmacokinetic classification of breast lesions is practical on modern MRI hardware and provides significant accuracy for identification of malignancies. Sensitivity of a two-parameter linear classifier is comparable to that reported in a recent multicenter study of clinical breast MRI, while specificity is significantly higher.
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Affiliation(s)
- Matthias C Schabel
- University of Utah Department of Radiology, Salt Lake City, Utah 84132, USA.
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Schabel MC, DiBella EVR, Jensen RL, Salzman KL. A model-constrained Monte Carlo method for blind arterial input function estimation in dynamic contrast-enhanced MRI: II. In vivo results. Phys Med Biol 2010; 55:4807-23. [PMID: 20679695 DOI: 10.1088/0031-9155/55/16/012] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Accurate quantification of pharmacokinetic model parameters in tracer kinetic imaging experiments requires correspondingly accurate determination of the arterial input function (AIF). Despite significant effort expended on methods of directly measuring patient-specific AIFs in modalities as diverse as dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI), dynamic positron emission tomography (PET), and perfusion computed tomography (CT), fundamental and technical difficulties have made consistent and reliable achievement of that goal elusive. Here, we validate a new algorithm for AIF determination, the Monte Carlo blind estimation (MCBE) method (which is described in detail and characterized by extensive simulations in a companion paper), by comparing AIFs measured in DCE-MRI studies of eight brain tumor patients with results of blind estimation. Blind AIFs calculated with the MCBE method using a pool of concentration-time curves from a region of normal brain tissue were found to be quite similar to the measured AIFs, with statistically significant decreases in fit residuals observed in six of eight patients. Biases between the blind and measured pharmacokinetic parameters were the dominant source of error. Averaged over all eight patients, the mean biases were +7% in K(trans), 0% in k(ep), -11% in v(p) and +10% in v(e). Corresponding uncertainties (median absolute deviation from the best fit line) were 0.0043 min(-1) in K(trans), 0.0491 min(-1) in k(ep), 0.29% in v(p) and 0.45% in v(e). The use of a published population-averaged AIF resulted in larger mean biases in three of the four parameters (-23% in K(trans), -22% in k(ep), -63% in v(p)), with the bias in v(e) unchanged, and led to larger uncertainties in all four parameters (0.0083 min(-1) in K(trans), 0.1038 min(-1) in k(ep), 0.31% in v(p) and 0.95% in v(e)). When blind AIFs were calculated from a region of tumor tissue, statistically significant decreases in fit residuals were observed in all eight patients despite larger deviations of these blind AIFs from the measured AIFs. The observed decrease in root-mean-square fit residuals between the normal brain and tumor tissue blind AIFs suggests that the local blood supply in tumors is measurably different from that in normal brain tissue and that the proposed method is able to discriminate between the two. We have shown the feasibility of applying the MCBE algorithm to DCE-MRI data acquired in brain, finding generally good agreement with measured AIFs and decreased biases and uncertainties relative to the use of a population-averaged AIF. These results demonstrate that the MCBE algorithm is a useful alternative to direct AIF measurement in cases where acquisition of high-quality arterial input function data is difficult or impossible.
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Affiliation(s)
- Matthias C Schabel
- Utah Center for Advanced Imaging Research, Department of Radiology, University of Utah Health Sciences Center, 729 Arapeen Drive, Salt Lake City, UT 84108-1218, USA.
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Schabel MC, Fluckiger JU, DiBella EVR. A model-constrained Monte Carlo method for blind arterial input function estimation in dynamic contrast-enhanced MRI: I. Simulations. Phys Med Biol 2010; 55:4783-806. [PMID: 20679691 DOI: 10.1088/0031-9155/55/16/011] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Widespread adoption of quantitative pharmacokinetic modeling methods in conjunction with dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) has led to increased recognition of the importance of obtaining accurate patient-specific arterial input function (AIF) measurements. Ideally, DCE-MRI studies use an AIF directly measured in an artery local to the tissue of interest, along with measured tissue concentration curves, to quantitatively determine pharmacokinetic parameters. However, the numerous technical and practical difficulties associated with AIF measurement have made the use of population-averaged AIF data a popular, if sub-optimal, alternative to AIF measurement. In this work, we present and characterize a new algorithm for determining the AIF solely from the measured tissue concentration curves. This Monte Carlo blind estimation (MCBE) algorithm estimates the AIF from the subsets of D concentration-time curves drawn from a larger pool of M candidate curves via nonlinear optimization, doing so for multiple (Q) subsets and statistically averaging these repeated estimates. The MCBE algorithm can be viewed as a generalization of previously published methods that employ clustering of concentration-time curves and only estimate the AIF once. Extensive computer simulations were performed over physiologically and experimentally realistic ranges of imaging and tissue parameters, and the impact of choosing different values of D and Q was investigated. We found the algorithm to be robust, computationally efficient and capable of accurately estimating the AIF even for relatively high noise levels, long sampling intervals and low diversity of tissue curves. With the incorporation of bootstrapping initialization, we further demonstrated the ability to blindly estimate AIFs that deviate substantially in shape from the population-averaged initial guess. Pharmacokinetic parameter estimates for K(trans), k(ep), v(p) and v(e) all showed relative biases and uncertainties of less than 10% for measurements having a temporal sampling rate of 4 s and a concentration measurement noise level of sigma = 0.04 mM. A companion paper discusses the application of the MCBE algorithm to DCE-MRI data acquired in eight patients with malignant brain tumors.
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Affiliation(s)
- Matthias C Schabel
- Utah Center for Advanced Imaging Research, Department of Radiology, University of Utah Health Sciences Center, 729 Arapeen Drive, Salt Lake City, UT 84108-1218, USA.
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Chen L, Schabel MC, DiBella EVR. Reconstruction of dynamic contrast enhanced magnetic resonance imaging of the breast with temporal constraints. Magn Reson Imaging 2010; 28:637-45. [PMID: 20392585 DOI: 10.1016/j.mri.2010.03.001] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2009] [Revised: 01/15/2010] [Accepted: 03/02/2010] [Indexed: 10/19/2022]
Abstract
A number of methods using temporal and spatial constraints have been proposed for reconstruction of undersampled dynamic magnetic resonance imaging (MRI) data. The complex data can be constrained or regularized in a number of different ways, for example, the time derivative of the magnitude and phase image voxels can be constrained separately or jointly. Intuitively, the performance of different regularizations will depend on both the data and the chosen temporal constraints. Here, a complex temporal total variation (TV) constraint was compared to the use of separate real and imaginary constraints, and to a magnitude constraint alone. Projection onto Convex Sets (POCS) with a gradient descent method was used to implement the diverse temporal constraints in reconstructions of DCE MRI data. For breast DCE data, serial POCS with separate real and imaginary TV constraints was found to give relatively poor results while serial/parallel POCS with a complex temporal TV constraint and serial POCS with a magnitude-only temporal TV constraint performed well with an acceleration factor as large as R=6. In the tumor area, the best method was found to be parallel POCS with complex temporal TV constraint. This method resulted in estimates for the pharmacokinetic parameters that were linearly correlated to those estimated from the fully-sampled data, with K(trans,R=6)=0.97 K(trans,R=1)+0.00 with correlation coefficient r=0.98, k(ep,R=6)=0.95 k(ep,R=1)+0.00 (r=0.85). These results suggest that it is possible to acquire highly undersampled breast DCE-MRI data with improved spatial and/or temporal resolution with minimal loss of image quality.
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Affiliation(s)
- Liyong Chen
- Department of Bioengineering, University of Utah, Salt Lake City, UT 84108, USA
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Fluckiger JU, Schabel MC, Dibella EVR. Model-based blind estimation of kinetic parameters in dynamic contrast enhanced (DCE)-MRI. Magn Reson Med 2010; 62:1477-86. [PMID: 19859949 DOI: 10.1002/mrm.22101] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
A method to simultaneously estimate the arterial input function (AIF) and pharmacokinetic model parameters from dynamic contrast-enhanced (DCE)-MRI data was developed. This algorithm uses a parameterized functional form to model the AIF and k-means clustering to classify tissue time-concentration measurements into a set of characteristic curves. An iterative blind estimation algorithm alternately estimated parameters for the input function and the pharmacokinetic model. Computer simulations were used to investigate the algorithm's sensitivity to noise and initial estimates. In 12 patients with sarcomas, pharmacokinetic parameter estimates were compared with "truth" obtained from model regression using a measured AIF. When arterial voxels were included in the blind estimation algorithm, the resulting AIF was similar to the measured input function. The "true" K(trans) values in tumor regions were not significantly different than the estimated values, 0.99 +/- 0.41 and 0.86 +/- 0.40 min(-1), respectively, P = 0.27. "True" k(ep) values also matched closely, 0.70 +/- 0.24 and 0.65 +/- 0.25 min(-1), P = 0.08. When only tissue curves free of significant vascular contribution are used (v(p) < 0.05), the resulting AIF showed substantial delay and dispersion consistent with a more local AIF such as has been observed in dynamic susceptibility contrast imaging in the brain.
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Affiliation(s)
- Jacob U Fluckiger
- Utah Center for Advanced Imaging Research, Department of Radiology, University of Utah, Salt Lake City, Utah, USA.
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Abstract
Propagation of errors, in conjunction with the theoretical signal equation for spoiled gradient echo pulse sequences, is used to derive a theoretical expression for uncertainty in quantitative variable flip angle T(1) mapping using two flip angles. This expression is then minimized to derive a rigorous expression for optimal flip angles that elucidates a commonly used empirical result. The theoretical expressions for uncertainty and optimal flip angles are combined to derive a lower bound on the achievable uncertainty for a given set of pulse sequence parameters and signal-to-noise ratio (SNR). These results provide a means of quantitatively determining the effect of changing acquisition parameters on T(1) uncertainty.
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Affiliation(s)
- Matthias C Schabel
- Utah Center for Advanced Imaging Research, Department of Radiology, University of Utah Health Sciences Center, 729 Arapeen Drive, Salt Lake City, UT 84108-1218, USA.
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Abstract
Dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) is a widely used technique for assessing tissue physiology. Spoiled gradient echo (SPGR) pulse sequences are one of the most common methods for acquisition of DCE-MRI data, providing high temporal and spatial resolution with strong T(1)-weighting. Conversion of SPGR signal to concentration is briefly reviewed, and a new closed-form expression for concentration measurement uncertainty for finite signal-to-noise ratio (SNR) and baseline scan time is derived. This result is applicable to arbitrary concentration-dependent relaxation rate and is valid over the same domain as the theoretical SPGR signal equation. Expressions for the lower and upper bounds on measurable concentration are also derived. The existence of a concentration- and tissue-dependent optimal flip angle that minimizes concentration uncertainty is demonstrated and it is shown that, for clinically relevant pulse sequence parameters, this optimal flip angle is significantly larger than the corresponding Ernst angle. Analysis of three pulse sequences from the DCE-MRI literature shows that optimization of flip angle using the methods discussed here leads to potential improvements of 10-1166% in effective SNR over the 0.5-5.0 mM concentration range with minimal or no loss of measurement accuracy down to 0.1 mM. In vivo data from three study patients provide further support for our theoretical expression for concentration measurement uncertainty, with predicted and experimental estimates agreeing to within +/- 30%. Equations for concentration bias resulting from biases in flip angle and from pre-contrast relaxation time and contrast relaxivity (both longitudinal and transverse) are also derived in closed-form. The resulting equations show the potential for significant contributions to bias in concentration measurement arising from even relatively small mis-specification of flip angle and/or pre-contrast longitudinal relaxation time, particularly at high contrast concentrations.
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Affiliation(s)
- Matthias C Schabel
- Utah Center for Advanced Imaging Research, Department of Radiology, University of Utah Health Sciences Center, Salt Lake City, UT 84108-1218, USA.
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Abstract
PURPOSE To assess the accuracy of a model-based approach for registration of myocardial dynamic contrast-enhanced (DCE)-MRI corrupted by respiratory motion. MATERIALS AND METHODS Ten patients were scanned for myocardial perfusion on 3T or 1.5T scanners, and short- and long-axis slices were acquired. Interframe registration was done using an iterative model-based method in conjunction with a mean square difference metric. The method was tested by comparing the absolute motion before and after registration, as determined from manually registered images. Regional flow indices of myocardium calculated from the manually registered data were compared with those obtained with the model-based registration technique. RESULTS The mean absolute motion of the heart for the short-axis data sets over all the time frames decreased from 5.3+/-5.2 mm (3.3+/-3.1 pixels) to 0.8+/-1.3 mm (0.5+/-0.7 pixels) in the vertical direction, and from 3.0+/-3.7 mm (1.7+/-2.1 pixels) to 0.9+/-1.2 mm (0.5+/-0.7 pixels) in the horizontal direction. A mean absolute improvement of 77% over all the data sets was observed in the estimation of the regional perfusion flow indices of the tissue as compared to those obtained from manual registration. Similar results were obtained with two-chamber-view long-axis data sets. CONCLUSION The model-based registration method for DCE cardiac data is comparable to manual registration and offers a unique registration method that reduces errors in the quantification of myocardial perfusion parameters as compared to those obtained from manual registration.
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Affiliation(s)
- Ganesh Adluru
- Electrical and Computer Engineering Department, University of Utah, Salt Lake City, Utah 84108, USA
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Harris JM, Shen Z, White PJ, Marshall DS, Schabel MC, Eckstein JN, Bozovic I. Anomalous superconducting state gap size versus Tc behavior in underdoped Bi2Sr2Ca1-xDyxCu2O8+ delta. Phys Rev B Condens Matter 1996; 54:R15665-R15668. [PMID: 9985728 DOI: 10.1103/physrevb.54.r15665] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Biegelsen DK, Bringans RD, Northrup JE, Schabel MC, Swartz L. Arsenic termination of the Si(110) surface. Phys Rev B Condens Matter 1993; 47:9589-9596. [PMID: 10005025 DOI: 10.1103/physrevb.47.9589] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Northrup JE, Schabel MC, Karlsson CJ, Uhrberg RI. Structure of low-coverage phases of Al, Ga, and In on Si(100). Phys Rev B Condens Matter 1991; 44:13799-13802. [PMID: 9999594 DOI: 10.1103/physrevb.44.13799] [Citation(s) in RCA: 76] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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