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Xiong LQ, Ma LL, Shi LY, Pan NN, Ai K, Zhao JX, He DL, Hang G. Functional magnetic resonance imaging for staging chronic kidney disease: a systematic review and meta-analysis. Int Urol Nephrol 2024:10.1007/s11255-024-04055-z. [PMID: 38632173 DOI: 10.1007/s11255-024-04055-z] [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] [Received: 12/11/2023] [Accepted: 04/08/2024] [Indexed: 04/19/2024]
Abstract
INTRODUCTION The commonly used clinical indicators are not sensitive and comprehensive enough to evaluate the early staging of chronic kidney disease (CKD). This study aimed to evaluate the differences in arterial spin labeling (ASL) and blood oxygenation level-dependent functional magnetic resonance imaging (BOLD-MRI) parameter values among patients at various stages of chronic kidney disease and healthy individuals. METHODS Electronic databases PubMed, Web of Science, Cochrane, and Embase were searched from inception to March 29, 2024, to identify relevant studies on ASL and BOLD in CKD. The renal blood flow (RBF) and apparent relaxation rate (R2*) values were obtained from healthy individuals and patients with various stages of CKD. The meta-analysis was conducted using STATA version 12.0. The random-effects model was used to obtain estimates of the effects, and the results were expressed as 95% confidence intervals (CIs) and mean differences (MDs) of continuous variables. RESULTS A total of 18 published studies were included in this meta-analysis. The cortical RBF and R2* values and medulla RBF values were considerably distinct between patients with various stages of CKD and healthy controls (MD, - 78.162; 95% CI, - 85.103 to - 71.221; MD, 2.440; 95% CI, 1.843 to 3.037; and MD, - 36.787; 95% CI, - 47.107 to - 26.468, respectively). No obvious difference in medulla R2* values was noted between patients with various stages of CKD and healthy controls (MD, - 1.475; 95% CI, - 4.646 to 1.696). CONCLUSION ASL and BOLD may provide complementary and distinct information regarding renal function and could potentially be used together to gain a more comprehensive understanding of renal physiology.
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Affiliation(s)
- Lian Qiu Xiong
- First Clinical School of Medicine, Gansu University of Chinese Medicine, Lanzhou, China
| | - Li Li Ma
- First Clinical School of Medicine, Gansu University of Chinese Medicine, Lanzhou, China
| | - Liu Yan Shi
- First Clinical School of Medicine, Gansu University of Chinese Medicine, Lanzhou, China
| | - Ni Ni Pan
- First Clinical School of Medicine, Gansu University of Chinese Medicine, Lanzhou, China
| | - Kai Ai
- Philip Healthcare, Xi'an, China
| | - Jian Xin Zhao
- First Clinical School of Medicine, Gansu University of Chinese Medicine, Lanzhou, China
| | - Di Liang He
- First Clinical School of Medicine, Gansu University of Chinese Medicine, Lanzhou, China
| | - Gang Hang
- Department of Radiology, Gansu Provincial Hospital, Lanzhou, 730000, China.
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Francis ST, Selby NM, Taal MW. Magnetic Resonance Imaging to Evaluate Kidney Structure, Function, and Pathology: Moving Toward Clinical Application. Am J Kidney Dis 2023; 82:491-504. [PMID: 37187282 DOI: 10.1053/j.ajkd.2023.02.007] [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] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2022] [Accepted: 02/20/2023] [Indexed: 05/17/2023]
Abstract
Recent advances in multiparametric magnetic resonance imaging (MRI) allow multiple quantitative measures to assess kidney morphology, tissue microstructure, oxygenation, kidney blood flow, and perfusion to be collected in a single scan session. Animal and clinical studies have investigated the relationship between the different MRI measures and biological processes, although their interpretation can be complex due to variations in study design and generally small participant numbers. However, emerging themes include the apparent diffusion coefficient derived from diffusion-weighted imaging, T1 and T2 mapping parameters, and cortical perfusion being consistently associated with kidney damage and predicting kidney function decline. Blood oxygen level-dependent (BOLD) MRI has shown inconsistent associations with kidney damage markers but has been predictive of kidney function decline in several studies. Therefore, multiparametric MRI of the kidneys has the potential to address the limitations of existing diagnostic methods to provide a noninvasive, noncontrast, and radiation-free method to assess whole kidney structure and function. Barriers to be overcome to facilitate widespread clinical application include improved understanding of biological factors that impact MRI measures, development of a larger evidence base for clinical utility, standardization of MRI protocols, automation of data analysis, determining optimal combination of MRI measures, and health economic evaluation.
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Affiliation(s)
- Susan T Francis
- Sir Peter Mansfield Imaging Centre, School of Physics & Astronomy, University of Nottingham, Nottingham; NIHR Nottingham Biomedical Research Centre, Nottingham University Hospitals NHS Trust, University of Nottingham, Nottingham
| | - Nicholas M Selby
- Centre for Kidney Research and Innovation, Academic Unit for Translational Medical Sciences, School of Medicine, University of Nottingham, Nottingham; Department of Renal Medicine, University Hospitals of Derby and Burton NHS Foundation Trust, Derby, United Kingdom
| | - Maarten W Taal
- Centre for Kidney Research and Innovation, Academic Unit for Translational Medical Sciences, School of Medicine, University of Nottingham, Nottingham; Department of Renal Medicine, University Hospitals of Derby and Burton NHS Foundation Trust, Derby, United Kingdom.
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Ton C, Salehi S, Abasi S, Aggas JR, Liu R, Brandacher G, Guiseppi-Elie A, Grayson WL. Methods of ex vivo analysis of tissue status in vascularized composite allografts. J Transl Med 2023; 21:609. [PMID: 37684651 PMCID: PMC10492401 DOI: 10.1186/s12967-023-04379-x] [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] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2023] [Accepted: 07/21/2023] [Indexed: 09/10/2023] Open
Abstract
Vascularized composite allotransplantation can improve quality of life and restore functionality. However, the complex tissue composition of vascularized composite allografts (VCAs) presents unique clinical challenges that increase the likelihood of transplant rejection. Under prolonged static cold storage, highly damage-susceptible tissues such as muscle and nerve undergo irreversible degradation that may render allografts non-functional. Skin-containing VCA elicits an immunogenic response that increases the risk of recipient allograft rejection. The development of quantitative metrics to evaluate VCAs prior to and following transplantation are key to mitigating allograft rejection. Correspondingly, a broad range of bioanalytical methods have emerged to assess the progression of VCA rejection and characterize transplantation outcomes. To consolidate the current range of relevant technologies and expand on potential for development, methods to evaluate ex vivo VCA status are herein reviewed and comparatively assessed. The use of implantable physiological status monitoring biochips, non-invasive bioimpedance monitoring to assess edema, and deep learning algorithms to fuse disparate inputs to stratify VCAs are identified.
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Affiliation(s)
- Carolyn Ton
- Department of Biomedical Engineering, Johns Hopkins University, 400 North Broadway, Smith Building 5023, Baltimore, MD, 21231, USA
- Translational Tissue Engineering Center, Johns Hopkins University, 400 North Broadway, Smith Building 5023, Baltimore, MD, 21231, USA
| | - Sara Salehi
- Department of Biomedical Engineering, Johns Hopkins University, 400 North Broadway, Smith Building 5023, Baltimore, MD, 21231, USA
- Translational Tissue Engineering Center, Johns Hopkins University, 400 North Broadway, Smith Building 5023, Baltimore, MD, 21231, USA
| | - Sara Abasi
- Department of Biomedical Engineering, Center for Bioelectronics, Biosensors and Biochips (C3B®), Texas A&M University, Emerging Technologies Building 3120, 101 Bizzell St, College Station, TX, 77843, USA
- Department of Electrical and Computer Engineering, Center for Bioelectronics, Biosensors and Biochips (C3B®), Texas A&M University, Emerging Technologies Building 3120, 101 Bizzell St, College Station, TX, 77843, USA
- Media and Metabolism, Wildtype, Inc., 2325 3rd St., San Francisco, CA, 94107, USA
| | - John R Aggas
- Department of Biomedical Engineering, Center for Bioelectronics, Biosensors and Biochips (C3B®), Texas A&M University, Emerging Technologies Building 3120, 101 Bizzell St, College Station, TX, 77843, USA
- Department of Electrical and Computer Engineering, Center for Bioelectronics, Biosensors and Biochips (C3B®), Texas A&M University, Emerging Technologies Building 3120, 101 Bizzell St, College Station, TX, 77843, USA
- Test Development, Roche Diagnostics, 9115 Hague Road, Indianapolis, IN, 46256, USA
| | - Renee Liu
- Department of Biomedical Engineering, Johns Hopkins University, 400 North Broadway, Smith Building 5023, Baltimore, MD, 21231, USA
- Translational Tissue Engineering Center, Johns Hopkins University, 400 North Broadway, Smith Building 5023, Baltimore, MD, 21231, USA
| | - Gerald Brandacher
- Department of Plastic and Reconstructive Surgery, Vascularized Composite Allotransplantation (VCA) Laboratory, Reconstructive Transplantation Program, Center for Advanced Physiologic Modeling (CAPM), Johns Hopkins University, Ross Research Building/Suite 749D, 720 Rutland Avenue, Baltimore, MD, 21205, USA.
| | - Anthony Guiseppi-Elie
- Department of Biomedical Engineering, Center for Bioelectronics, Biosensors and Biochips (C3B®), Texas A&M University, Emerging Technologies Building 3120, 101 Bizzell St, College Station, TX, 77843, USA.
- Department of Electrical and Computer Engineering, Center for Bioelectronics, Biosensors and Biochips (C3B®), Texas A&M University, Emerging Technologies Building 3120, 101 Bizzell St, College Station, TX, 77843, USA.
- Department of Cardiovascular Sciences, Houston Methodist Institute for Academic Medicine and Houston Methodist Research Institute, 6670 Bertner Ave., Houston, TX, USA.
- ABTECH Scientific, Inc., Biotechnology Research Park, 800 East Leigh Street, Richmond, VA, USA.
| | - Warren L Grayson
- Department of Biomedical Engineering, Johns Hopkins University, 400 North Broadway, Smith Building 5023, Baltimore, MD, 21231, USA.
- Translational Tissue Engineering Center, Johns Hopkins University, 400 North Broadway, Smith Building 5023, Baltimore, MD, 21231, USA.
- Department of Chemical and Biomolecular Engineering, Johns Hopkins University, Baltimore, MD, USA.
- Department of Materials Science and Engineering, Johns Hopkins University, Baltimore, MD, USA.
- Institute for Nanobiotechnology, Johns Hopkins University, Baltimore, MD, USA.
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Zhao S, Hartanto J, Joseph R, Wu CH, Zhao Y, Chen YS. Hybrid photoacoustic and fast super-resolution ultrasound imaging. Nat Commun 2023; 14:2191. [PMID: 37072402 PMCID: PMC10113238 DOI: 10.1038/s41467-023-37680-w] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2022] [Accepted: 03/28/2023] [Indexed: 04/20/2023] Open
Abstract
The combination of photoacoustic (PA) imaging and ultrasound localization microscopy (ULM) with microbubbles has great potential in various fields such as oncology, neuroscience, nephrology, and immunology. Here we developed an interleaved PA/fast ULM imaging technique that enables super-resolution vascular and physiological imaging in less than 2 seconds per frame in vivo. By using sparsity-constrained (SC) optimization, we accelerated the frame rate of ULM up to 37 times with synthetic data and 28 times with in vivo data. This allows for the development of a 3D dual imaging sequence with a commonly used linear array imaging system, without the need for complicated motion correction. Using the dual imaging scheme, we demonstrated two in vivo scenarios challenging to image with either technique alone: the visualization of a dye-labeled mouse lymph node showing nearby microvasculature, and a mouse kidney microangiography with tissue oxygenation. This technique offers a powerful tool for mapping tissue physiological conditions and tracking the contrast agent biodistribution non-invasively.
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Affiliation(s)
- Shensheng Zhao
- Department of Electrical and Computer Engineering, University of Illinois Urbana-Champaign, Urbana, IL, USA
- Beckman Institute for Advanced Science and Technology, University of Illinois Urbana-Champaign, Urbana, IL, USA
- Holonyak Micro and Nanotechnology Laboratory, University of Illinois Urbana-Champaign, Urbana, IL, USA
| | - Jonathan Hartanto
- Department of Chemical and Biomolecular Engineering, University of Illinois Urbana-Champaign, Urbana, IL, USA
| | - Ritin Joseph
- Department of Materials Science and Engineering, University of Illinois Urbana-Champaign, Urbana, IL, USA
| | | | - Yang Zhao
- Department of Electrical and Computer Engineering, University of Illinois Urbana-Champaign, Urbana, IL, USA
- Holonyak Micro and Nanotechnology Laboratory, University of Illinois Urbana-Champaign, Urbana, IL, USA
- Department of Bioengineering, University of Illinois Urbana-Champaign, Urbana, IL, USA
| | - Yun-Sheng Chen
- Department of Electrical and Computer Engineering, University of Illinois Urbana-Champaign, Urbana, IL, USA.
- Beckman Institute for Advanced Science and Technology, University of Illinois Urbana-Champaign, Urbana, IL, USA.
- Holonyak Micro and Nanotechnology Laboratory, University of Illinois Urbana-Champaign, Urbana, IL, USA.
- Department of Bioengineering, University of Illinois Urbana-Champaign, Urbana, IL, USA.
- Department of Biomedical and Translational Sciences, Carle Illinois College of Medicine, University of Illinois Urbana-Champaign, Urbana, IL, USA.
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Rasmussen CW, Bøgh N, Bech SK, Thorsen TH, Hansen ESS, Bertelsen LB, Laustsen C. Fibrosis imaging with multiparametric proton and sodium MRI in pig injury models. NMR Biomed 2023; 36:e4838. [PMID: 36151711 PMCID: PMC10078455 DOI: 10.1002/nbm.4838] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Revised: 09/10/2022] [Accepted: 09/12/2022] [Indexed: 05/10/2023]
Abstract
Chronic kidney disease (CKD) is common and has huge implications for health and mortality. It is aggravated by intrarenal fibrosis, but the assessment of fibrosis is limited to kidney biopsies, which carry a risk of complications and sampling errors. This calls for a noninvasive modality for diagnosing and staging intrarenal fibrosis. The current, exploratory study evaluates a multiparametric MRI protocol including sodium imaging (23 Na-MRI) to determine the opportunities within this modality to assess kidney injury as a surrogate endpoint of fibrosis. The study includes 43 pigs exposed to ischemia-reperfusion injury (IRI) or unilateral ureteral obstruction (UUO), or serving as healthy controls. Fibrosis was determined using gene expression analysis of collagen. The medulla/cortex ratio of 23 Na-MRI decreased in the injured kidney in the IRI pigs, but not in the UUO pigs (p = 0.0180, p = 0.0754). To assess the combination of MRI parameters in estimating fibrosis, we created a linear regression model consisting of the cortical apparent diffusion coefficient, ΔR2*, ΔT1, the 23 Na medulla/cortex ratio, and plasma creatinine (R2 = 0.8009, p = 0.0117). The 23 Na medulla/cortex ratio only slightly improved the fibrosis prediction model, leaving 23 Na-MRI in an ambiguous place for evaluation of intrarenal fibrosis. Use of multiparametric MRI in combination with plasma creatinine shows potential for the estimation of fibrosis in human kidney disease, but more translational and clinical work is warranted before MRI can contribute to earlier diagnosis and evaluation of treatment for acute kidney injury and CKD.
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Affiliation(s)
- Camilla W. Rasmussen
- The MR Research Center, Department of Clinical MedicineAarhus UniversityAarhusDenmark
| | - Nikolaj Bøgh
- The MR Research Center, Department of Clinical MedicineAarhus UniversityAarhusDenmark
| | - Sabrina K. Bech
- The MR Research Center, Department of Clinical MedicineAarhus UniversityAarhusDenmark
| | - Thomas H. Thorsen
- The MR Research Center, Department of Clinical MedicineAarhus UniversityAarhusDenmark
| | - Esben S. S. Hansen
- The MR Research Center, Department of Clinical MedicineAarhus UniversityAarhusDenmark
| | - Lotte B. Bertelsen
- The MR Research Center, Department of Clinical MedicineAarhus UniversityAarhusDenmark
| | - Christoffer Laustsen
- The MR Research Center, Department of Clinical MedicineAarhus UniversityAarhusDenmark
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Copur S, Yavuz F, Sag AA, Tuttle KR, Kanbay M. Future of kidney imaging: Functional magnetic resonance imaging and kidney disease progression. Eur J Clin Invest 2022; 52:e13765. [PMID: 35267195 DOI: 10.1111/eci.13765] [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] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/10/2022] [Revised: 03/01/2022] [Accepted: 03/05/2022] [Indexed: 11/26/2022]
Abstract
INTRODUCTION Chronic kidney disease (CKD) which is a common cause of death has an increasing trend, but there is no established approach for predicting CKD progression yet. Functional magnetic resonance imaging (fMRI) studies such as blood oxygenation level-dependent MRI (BOLD-MRI), diffusion-weighted MRI (DWI-MRI), diffusion-tensor MRI (DTI-MRI) and arterial spin labelling MRI (ASL-MRI) are rising methods for the assessment of kidney functions in native and transplanted kidneys as well as the estimation of CKD progression. METHODS Systematic literature review was performed through the Embase (Elsevier), Cochrane Central Register of Controlled Trials (Wiley), PubMed/Medline and Web of Science databases, and studies investigating the role of fMRI methods assessing kidney functions in native and transplanted kidneys, as well as the value of fMRI methods to predict CKD progression, were included. Working mechanisms, advantages and limitations of the fMRI modalities were reviewed, and three studies investigating the role of fMRI studies in kidney functions were analysed. RESULTS AND CONCLUSION BOLD-MRI signal was found to be inversely correlated with annual eGFR change, and DWI/ADC (apparent diffusion coefficient map) values were shown to be correlated with annual eGFR decline. fMRI methods which are currently used for other systems can be utilized to provide more detailed information about kidney functions, and doctors should be ready to interpret kidney MRIs.
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Affiliation(s)
- Sidar Copur
- Department of Medicine, Koc University School of Medicine, Istanbul, Turkey
| | - Furkan Yavuz
- Department of Medicine, Koc University School of Medicine, Istanbul, Turkey
| | - Alan A Sag
- Department of Radiology, Division of Vascular and Interventional Radiology, Duke University Medical Center, Durham, North Carolina, USA
| | - Kathherine R Tuttle
- Division of Nephrology, University of Washington, Seattle, Washington, USA.,Providence Medical Research Center, Providence Health Care, Washington, District of Columbia, USA
| | - Mehmet Kanbay
- Department of Medicine, Division of Nephrology, Koc University School of Medicine, Istanbul, Turkey
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Seah JM, Botterill E, MacIsaac RJ, Milne M, Ekinci EI, Lim RP. Functional MRI in assessment of diabetic kidney disease in people with type 1 diabetes. J Diabetes Complications 2022; 36:108076. [PMID: 34802902 DOI: 10.1016/j.jdiacomp.2021.108076] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/10/2021] [Revised: 10/05/2021] [Accepted: 10/07/2021] [Indexed: 12/16/2022]
Abstract
AIMS To compare levels of renal hypoxia measured by Blood Oxygen Level Dependent (BOLD) magnetic resonance imaging (MRI) with measured transverse relaxation rate (R2*) and renal structural changes including apparent diffusion coefficient (ADC) and fractional anisotropy (FA) in patients with type 1 diabetes and healthy controls. METHODS Cohort study comparing MRI metrics in type 1 diabetes (n = 32, GFR 105 (77, 120) ml/min.1.73m2) and controls (n = 10). Renal function and selected inflammatory renal biomarkers were also measured. RESULTS For BOLD, we found reduced cortical [14.7 (13.7,15.8) (1/s) vs 15.7 (15.1,16.6) (1/s), p < 0.001] and medullary [24.8 (21.8,28.2) (1/s) vs. 29.3 (24.3,32.4) (1/s), p < 0.001] R2*, indicating more oxygenated parenchyma, in type 1 diabetes vs. controls, respectively. We observed reduced cortical FA, indicating decreased structural integrity in type 1 diabetes -0.04 (-0.07, -0.01), (p = 0.02). We found reduced cortical ADC, reflecting reduced water diffusion, in non-hyperfiltering [2.40 (2.29,2.53) (103mm2/s)] versus hyperfiltering [2.61 (2.53,2.74) (103mm2/s)] type 1 diabetes patients. MRI parameters correlated with renal function and inflammatory renal biomarkers. CONCLUSIONS MRI derived indices of renal function and structure differed between (i) type 1 diabetes and healthy controls, and (ii) between non-hyperfiltering and hyperfiltering type 1 diabetes patients, providing insight into the role of hypoxia and renal structural, and functional changes in DKD.
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Affiliation(s)
- Jas-Mine Seah
- Department of Endocrinology and Diabetes, Austin Health, Heidelberg, VIC, Australia; Department of Medicine, The University of Melbourne, Parkville, VIC, Australia
| | - Elissa Botterill
- Department of Radiology and Surgery, Austin Health, Heidelberg, VIC, Australia
| | - Richard J MacIsaac
- Department of Medicine, The University of Melbourne, Parkville, VIC, Australia; Department of Endocrinology and Diabetes, St Vincent's Hospital Melbourne, Fitzroy, VIC, Australia
| | - Michele Milne
- Department of Medicine, The University of Melbourne, Parkville, VIC, Australia
| | - Elif I Ekinci
- Department of Endocrinology and Diabetes, Austin Health, Heidelberg, VIC, Australia; Department of Medicine, The University of Melbourne, Parkville, VIC, Australia.
| | - Ruth P Lim
- Department of Medicine, The University of Melbourne, Parkville, VIC, Australia; Department of Radiology and Surgery, Austin Health, Heidelberg, VIC, Australia
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Lee SK, Lee J, Jang S, Lee E, Jeon CY, Lim KS, Jin YB, Choi J. Quantification of renal T2 relaxation rate by use of blood oxygen level-dependent magnetic resonance imaging before and after furosemide administration in healthy Beagles. Am J Vet Res 2021; 82:880-889. [PMID: 34669496 DOI: 10.2460/ajvr.82.11.880] [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: 11/20/2022]
Abstract
OBJECTIVE To assess the feasibility of blood oxygen level-dependent (BOLD) MRI for measurement of the renal T2* relaxation rate (R2*; proxy for renal oxygenation) before and after furosemide administration and to evaluate the reliability and repeatability of those measurements in healthy dogs. ANIMALS 8 healthy adult Beagles (4 males and 4 females). PROCEDURES Each dog was anesthetized and underwent BOLD MRI before (baseline) and 3 minutes after administration of furosemide (1 mg/kg, IV) twice, with a 1-week interval between scanning sessions. Mapping software was used to process MRI images and measure R2* and the difference in R2* (ΔR2*) before and after furosemide administration. The intraclass correlation coefficient was calculated to assess measurement reliability, and the coefficient of variation and Bland-Altman method were used to assess measurement repeatability. RESULTS Mean ± SD baseline R2* in the renal medulla (24.5 ± 3.8 seconds-1) was significantly greater than that in the renal cortex (20.6 ± 2.7 seconds-1). Mean R2* in the renal cortex (18.6 ± 2.6 seconds-1) and medulla (17.8 ± 1.5 seconds-1) decreased significantly after furosemide administration. Mean ΔR2* in the medulla (6.7 ± 2.4 seconds-1) was significantly greater than that in the renal cortex (2.1 ± 0.7 seconds-1). All R2* and ΔR2* values had good or excellent reliability and repeatability, except the cortical ΔR2*, which had poor repeatability. CONCLUSIONS AND CLINICAL RELEVANCE Results suggested that BOLD MRI, when performed before and after furosemide administration, was noninvasive and highly reliable and repeatable for dynamic evaluation of renal oxygenation in healthy dogs.
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Affiliation(s)
- Sang-Kwon Lee
- From the College of Veterinary Medicine, Kyungpook National University, Daegu 41566, South Korea
| | - Juryeong Lee
- the College of Veterinary Medicine and BK21 Plus Project Team, Chonnam National University, Gwangju 61186, Republic of Korea
| | - Seolyn Jang
- the College of Veterinary Medicine and BK21 Plus Project Team, Chonnam National University, Gwangju 61186, Republic of Korea
| | - Eunji Lee
- the College of Veterinary Medicine and BK21 Plus Project Team, Chonnam National University, Gwangju 61186, Republic of Korea
| | - Chang-Yeop Jeon
- National Primate Research Center and Futuristic Animal Resource and Research Center, Korea Research Institute of Bioscience and Biotechnology, Cheongju 28116, Republic of Korea
| | - Kyung-Seob Lim
- National Primate Research Center and Futuristic Animal Resource and Research Center, Korea Research Institute of Bioscience and Biotechnology, Cheongju 28116, Republic of Korea
| | - Yeung Bae Jin
- the College of Veterinary Medicine, Gyeongsang National University, Jinju 52828, Republic of Korea
| | - Jihye Choi
- the Department of Veterinary Medical Imaging, College of Veterinary Medicine, Seoul National University, Seoul 08826, South Korea
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Jiang Z, Wang Y, Ding J, Yu S, Zhang J, Zhou H, Di J, Xing W. Susceptibility weighted imaging (SWI) for evaluating renal dysfunction in type 2 diabetes mellitus: a preliminary study using SWI parameters and SWI-based texture features. Ann Transl Med 2021; 8:1673. [PMID: 33490185 PMCID: PMC7812222 DOI: 10.21037/atm-20-7121] [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] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Background Susceptibility weighted imaging (SWI) could reflect tissue blood oxygen levels, and then whether it could be used to evaluate renal injury remains to be further studied. This study aimed to examine the performance of SWI parameters and SWI-based texture features in evaluating renal dysfunction of type 2 diabetes mellitus (T2DM). Methods Forty-five patients with T2DM were included. With the estimated glomerular filtration rate (eGFR), the patients were divided into non-moderate-severe renal injured group (non-msRI, eGFR >60 mL/min/1.73 m2) and moderate-severe renal injured group (msRI, eGFR ≤60 mL/min/1.73 m2). The 3 SWI parameters and 16 SWI-based texture features between non-msRI and msRI were compared. The correlation between the parameters and BUN, Scr was analyzed. Results The signal intensity ratio of the medulla to psoas muscle (MPswi) was significantly lower than the signal intensity ratio of the cortex to psoas muscle (CPswi) in non-msRI and msRI group (t=8.619, 3.483, respectively, P<0.05). MPswi was higher, and the signal intensity ratio of the cortex to the medulla (CMswi), Skewness, Correlation were lower in msRI than in non-msRI (P<0.05). These parameters showed similar diagnostic efficacies for msRI (P>0.05), and AUCs were 0.703–0.854. CMswi was an independent protective factor for msRI (OR =0.026, P=0.003). MPswi and CMswi were correlated with BUN (r=0.416, −0.545, P<0.05). CMswi and Correlation were correlated with Scr (r=−0.645, −0.411, P<0.05). Conclusions SWI was valuable for assessing renal dysfunction, which may be helpful for the evaluation of moderate-severe renal injured patients with T2DM.
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Affiliation(s)
- Zhenxing Jiang
- Department of Radiology, The Third Affiliated Hospital of Soochow University, Changzhou, China
| | - Yu Wang
- Department of Radiology, The Third Affiliated Hospital of Soochow University, Changzhou, China
| | - Jiule Ding
- Department of Radiology, The Third Affiliated Hospital of Soochow University, Changzhou, China
| | - Shengnan Yu
- Department of Radiology, The Third Affiliated Hospital of Soochow University, Changzhou, China
| | - Jinggang Zhang
- Department of Radiology, The Third Affiliated Hospital of Soochow University, Changzhou, China
| | - Hua Zhou
- Department of Nephrology, The Third Affiliated Hospital of Soochow University, Changzhou, China
| | - Jia Di
- Department of Nephrology, The Third Affiliated Hospital of Soochow University, Changzhou, China
| | - Wei Xing
- Department of Radiology, The Third Affiliated Hospital of Soochow University, Changzhou, China
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Abstract
Magnetic Resonance Imaging (MRI) has been actively explored in the last several decades for assessing renal function by providing several physiological information, including glomerular filtration rate, renal plasma flow, tissue oxygenation and water diffusion. Within MRI, the developing field of chemical exchange saturation transfer (CEST) has potential to provide further functional information for diagnosing kidney diseases. Both endogenous produced molecules as well as exogenously administered CEST agents have been exploited for providing functional information related to kidney diseases in preclinical studies. In particular, CEST MRI has been exploited for assessing the acid-base homeostasis in the kidney and for monitoring pH changes in several disease models. This review summarizes several CEST MRI procedures for assessing kidney functionality and pH, for monitoring renal pH changes in different kidney injury models and for evaluating renal allograft rejection.This chapter is based upon work from the COST Action PARENCHIMA, a community-driven network funded by the European Cooperation in Science and Technology (COST) program of the European Union, which aims to improve the reproducibility and standardization of renal MRI biomarkers. This introduction chapter is complemented by two separate chapters describing the experimental procedure and data analysis.
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Affiliation(s)
- Dario Livio Longo
- Institute of Biostructures and Bioimaging (IBB), Italian National Research Council (CNR), Torino, Italy.
| | - Pietro Irrera
- University of Campania "Luigi Vanvitelli", Napoli, Italy
| | - Lorena Consolino
- Department of Molecular Biotechnology and Health Sciences, University of Torino, Torino, Italy
| | - Phillip Zhe Sun
- Yerkes Imaging Center, Yerkes National Primate Research Center, Emory University, Atlanta, GA, USA
- Department of Radiology and Imaging Sciences, Emory University School of Medicine, Atlanta, GA, USA
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA, USA
| | - Michael T McMahon
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, USA
- Division of MR Research, The Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
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11
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Irrera P, Consolino L, Cutrin JC, Zöllner FG, Longo DL. Dual assessment of kidney perfusion and pH by exploiting a dynamic CEST-MRI approach in an acute kidney ischemia-reperfusion injury murine model. NMR Biomed 2020; 33:e4287. [PMID: 32153058 DOI: 10.1002/nbm.4287] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [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: 05/14/2019] [Revised: 02/03/2020] [Accepted: 02/18/2020] [Indexed: 06/10/2023]
Abstract
Several factors can lead to acute kidney injury, but damage following ischemia and reperfusion injuries is the main risk factor and usually develops into chronic disease. MRI has often been proposed as a method with which to assess renal function. It does so by measuring the renal perfusion of an injected Gd-based contrast agent. The use of pH-responsive agents as part of the CEST (chemical exchange saturation transfer)-MRI technique has recently shown that pH homeostasis is also an important indicator of kidney functionality. However, there is still a need for methods that can provide more than one type of information following the injection of a single contrast agent for the characterization of renal function. Herein we propose, for the first time, dynamic CEST acquisition following iopamidol injection to quantify renal function by assessing both perfusion and pH homeostasis. The aim of this study is to assess renal functionality in a murine unilateral ischemia-reperfusion injury model at two time points (3 and 7 days) after acute kidney injury. The renal-perfusion estimates measured with iopamidol were compared with those obtained with a gadolinium-based agent, via a dynamic contrast enhanced (DCE)-MRI approach, to validate the proposed method. Compared with the contralateral kidneys, the clamped ones showed a significant decrease in renal perfusion, as measured using the DCE-MRI approach, which is consistent with reduced filtration capability. Dynamic CEST-MRI findings provided similar results, indicating that the clamped kidneys displayed significantly reduced renal filtration that persisted up to 7 days after the damage. In addition, CEST-MRI pH imaging showed that the clamped kidneys displayed significantly increased pH values, reflecting the disturbance to pH homeostasis. Our results demonstrate that a single CEST-MRI contrast agent can provide multiple types of information related to renal function and can discern healthy kidneys from pathological ones by combining perfusion measurements with renal pH mapping.
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Affiliation(s)
- Pietro Irrera
- Università degli Studi della Campania "Luigi Vanvitelli", Napoli, Italy
- Istituto di Biostrutture e Bioimmagini (IBB), Consiglio Nazionale delle Ricerche (CNR), Torino, Italy
| | - Lorena Consolino
- Centro di Imaging Molecolare, Dipartimento di Biotecnologie Molecolari e Scienze per la Salute, Università degli Studi di Torino, Torino, Italy
| | - Juan Carlos Cutrin
- Centro di Imaging Molecolare, Dipartimento di Biotecnologie Molecolari e Scienze per la Salute, Università degli Studi di Torino, Torino, Italy
| | - Frank G Zöllner
- Computer Assisted Clinical Medicine, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
| | - Dario Livio Longo
- Istituto di Biostrutture e Bioimmagini (IBB), Consiglio Nazionale delle Ricerche (CNR), Torino, Italy
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12
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Wang C, Zhang B, Wang H, Kong H, Gao F, Wang X, Yang M, Zhang J. A feasibility study of using noninvasive renal oxygenation imaging for the early assessment of ischemic acute kidney injury in an embolization model. Magn Reson Imaging 2019; 63:178-184. [PMID: 31425814 DOI: 10.1016/j.mri.2019.08.027] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [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: 01/15/2019] [Revised: 06/18/2019] [Accepted: 08/15/2019] [Indexed: 12/15/2022]
Abstract
PURPOSE To investigate the feasibility of using MRI based oxygenation imaging for early assessment of ischemic acute kidney injury (AKI) in an embolization model. METHODS Ischemic AKI model was induced in 40 rabbits by injection of microspheres into the right renal arteries. Animals were grouped according to the dose of microspheres: Severe AKI group, 2.0 mg (N = 10); Moderate AKI group, 1.0 mg (N = 10); Mild AKI group, 0.5 mg (N = 10); Control group, saline without microspheres (N = 10). A serial MRI examination was performed at intervals of 1 h, 1 day, 1 week and 4 weeks to evaluate the deterioration of renal function. A multi-echo ASE sequence was implemented for renal oxygenation measurement 1 h after surgery. Pathological examinations were performed 4 weeks after the surgery. RESULTS In renal cortex, renal oxygen extraction fraction (OEF) raised significantly after embolization procedures in all experimental groups (severe AKI: 0.39 ± 0.05, P < 0.05; moderate AKI: 0.36 ± 0.03, P < 0.05; mild AKI: 0.34 ± 0.02, P < 0.05) compared to the control group (0.29 ± 0.02). In outer medulla, significant difference was observed between control group (0.29 ± 0.03) and severe AKI group (0.35 ± 0.03, P < 0.05), and between control group and moderate AKI group (0.34 ± 0.04, P < 0.05). Corresponding lesions were found in pathological examinations 4 weeks after the procedure. CONCLUSION This study demonstrates the feasibility of using oxygenation imaging to assess the embolization induced ischemic AKI at an early stage.
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Affiliation(s)
- Chengyan Wang
- Human Phenome Institute, Fudan University, Shanghai, China; Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China
| | - Bihui Zhang
- Department of Interventional Radiology and Vascular Surgery, Peking University First Hospital, Beijing, China
| | - Haochen Wang
- Department of Interventional Radiology, Beijing Friendship Hospital, Beijing, China
| | - Hanjing Kong
- Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China
| | - Fei Gao
- College of Engineering, Peking University, Beijing, China
| | - Xiaoying Wang
- Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China; Department of Radiology, Peking University First Hospital, Beijing, China
| | - Min Yang
- Department of Interventional Radiology and Vascular Surgery, Peking University First Hospital, Beijing, China.
| | - Jue Zhang
- Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China; College of Engineering, Peking University, Beijing, China.
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13
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Zha T, Ren X, Xing Z, Zhang J, Tian X, Du Y, Xing W, Chen J. Evaluating Renal Fibrosis with R2* Histogram Analysis of the Whole Cortex in a Unilateral Ureteral Obstruction Model. Acad Radiol 2019; 26:e202-e207. [PMID: 30111497 DOI: 10.1016/j.acra.2018.07.010] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2018] [Revised: 07/19/2018] [Accepted: 07/19/2018] [Indexed: 12/15/2022]
Abstract
RATIONALE AND OBJECTIVES The aim of this study was to use histogram analysis to assess the correlation between blood oxygen-level dependent magnetic resonance imaging (BOLD-MRI) and renal fibrosis induced by unilateral ureteral obstruction (UUO) in an animal model for a long experimental period. MATERIALS AND METHODS The rabbits were randomly divided into a control group (n = 6) and a UUO group (n = 30). The rabbits in the UUO group underwent left ureteral obstruction surgery. BOLD-MRI examinations were performed at 2, 4, 6, and 8 weeks after ligation. After the examinations, nephrectomy was performed for histologic evaluation. Histogram analysis of the left renal cortex (C) R2* values was performed to measure the mean, median, 10th percentile, 90th percentile, skewness, and kurtosis for all kidneys. Masson trichrome staining was used to assess the percentage of fibrotic area. RESULTS The histogram R2* values of the mean, median, 10th percentile, and 90th percentile at week 2 were all lower than those at baseline. Over the course of UUO progression, there were statistical differences between the histogram R2* values at any other two time points, except between weeks 4 and 6, and weeks 6 and 8. A close correlation was found between the percentage of fibrotic area and R2* values (mean: F = 21.49, p = 0.0001, R2 = 0.49, median: F = 30.07, p < 0.0001, R2 = 0.58, 10th percentile: F = 31.02, p < 0.0001, R2 = 0.59, 90th percentile: F = 24.13, p < 0.0001, R2 = 0.52). CONCLUSION BOLD-MRI could reflect the formation and progression of renal fibrosis in a rabbit UUO model; however, the value of BOLD-MRI in the long-term evaluation of fibrosis is limited.
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14
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Chen NT, Barth ED, Lee TH, Chen CT, Epel B, Halpern HJ, Lo LW. Highly sensitive electron paramagnetic resonance nanoradicals for quantitative intracellular tumor oxymetric images. Int J Nanomedicine 2019; 14:2963-2971. [PMID: 31118615 PMCID: PMC6503311 DOI: 10.2147/ijn.s194779] [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] [Received: 11/15/2018] [Accepted: 03/11/2019] [Indexed: 01/25/2023] Open
Abstract
Purpose: Tumor oxygenation is a critical parameter influencing the efficacy of cancer therapy. Low levels of oxygen in solid tumor have been recognized as an indicator of malignant progression and metastasis, as well as poor response to chemo- and radiation therapy. Being able to measure oxygenation for an individual's tumor would provide doctors with a valuable way of identifying optimal treatments for patients. Methods: Electron paramagnetic resonance imaging (EPRI) in combination with an oxygen-measuring paramagnetic probe was performed to measure tumor oxygenation in vivo. Triarylmethyl (trityl) radical exhibits high specificity, sensitivity, and resolution for quantitative measurement of O2 concentration. However, its in vivo applications in previous studies have been limited by the required high dosage, its short half-life, and poor intracellular permeability. To address these limitations, we developed high-capacity nanoformulated radicals that employed fluorescein isothiocyanate-labeled mesoporous silica nanoparticles (FMSNs) as trityl radical carriers. The high surface area nanostructure and easy surface modification of physiochemical properties of FMSNs enable efficient targeted delivery of highly concentrated, nonself-quenched trityl radicals, protected from environmental degradation and dilution. Results: We successfully designed and synthesized a tumor-targeted nanoplatform as a carrier for trityl. In addition, the nanoformulated trityl does not affect oxygen-sensing capacity by a self-relaxation or broadening effect. The FMSN-trityl exhibited high sensitivity/response to oxygen in the partial oxygen pressure range from 0 to 155 mmHg. Furthermore, MSN-trityl displayed outstanding intracellular oxygen mapping in both in vitro and in vivo animal studies. Conclusion: The highly sensitive nanoformulated trityl spin probe can profile intracellular oxygen distributions of tumor in a real-time and quantitative manner using in vivo EPRI.
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Affiliation(s)
- Nai-Tzu Chen
- Institute of New Drug Development, China Medical University, Taichung 40402, Taiwan
| | - Eugene D Barth
- Department of Radiation and Cellular Oncology, University of Chicago, Chicago, IL 60637, USA.,Center for EPR Imaging In Vivo Physiology, University of Chicago, Chicago, IL 60637, USA
| | - Tsung-Hsi Lee
- Department of Biological Science and Technology, China Medical University, Taichung 40402, Taiwan
| | - Chin-Tu Chen
- Department of Radiology, University of Chicago, Chicago, IL 60637 USA
| | - Boris Epel
- Department of Radiation and Cellular Oncology, University of Chicago, Chicago, IL 60637, USA.,Center for EPR Imaging In Vivo Physiology, University of Chicago, Chicago, IL 60637, USA
| | - Howard J Halpern
- Department of Radiation and Cellular Oncology, University of Chicago, Chicago, IL 60637, USA.,Center for EPR Imaging In Vivo Physiology, University of Chicago, Chicago, IL 60637, USA
| | - Leu-Wei Lo
- Department of Radiology, University of Chicago, Chicago, IL 60637 USA.,Institute of Biomedical Engineering and Nanomedicine, National Health Research Institutes, Zhunan 35053, Taiwan
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15
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Abumoawad A, Saad A, Ferguson CM, Eirin A, Woollard JR, Herrmann SM, Hickson LJ, Bendel EC, Misra S, Glockner J, Lerman LO, Textor SC. Tissue hypoxia, inflammation, and loss of glomerular filtration rate in human atherosclerotic renovascular disease. Kidney Int 2019; 95:948-957. [PMID: 30904069 PMCID: PMC6738340 DOI: 10.1016/j.kint.2018.11.039] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [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: 09/04/2018] [Revised: 11/15/2018] [Accepted: 11/29/2018] [Indexed: 12/18/2022]
Abstract
The relationships between renal blood flow (RBF), tissue oxygenation, and inflammatory injury in atherosclerotic renovascular disease (ARVD) are poorly understood. We sought to correlate RBF and tissue hypoxia with glomerular filtration rate (GFR) in 48 kidneys from patients with ARVD stratified by single kidney iothalamate GFR (sGFR). Oxygenation was assessed by blood oxygenation level dependent magnetic resonance imaging (BOLD MRI), which provides an index for the levels of deoxyhemoglobin within a defined volume of tissue (R2*). sGFR correlated with RBF and with the severity of vascular stenosis as estimated by duplex velocities. Higher cortical R2* and fractional hypoxia and higher levels of renal vein neutrophil-gelatinase-associated-lipocalin (NGAL) and monocyte-chemoattractant protein-1 (MCP-1) were observed at lower GFR, with an abrupt inflection below 20 ml/min. Renal vein MCP-1 levels correlated with cortical R2* and with fractional hypoxia. Correlations between cortical R2* and RBF in the highest sGFR stratum (mean sGFR 51 ± 12 ml/min; R = -0.8) were degraded in the lowest sGFR stratum (mean sGFR 8 ± 3 ml/min; R = -0.1). Changes in fractional hypoxia after furosemide were also absent in the lowest sGFR stratum. These data demonstrate relative stability of renal oxygenation with moderate reductions in RBF and GFR but identify a transition to overt hypoxia and inflammatory cytokine release with severely reduced GFR. Tissue oxygenation and RBF were less correlated in the setting of reduced sGFR, consistent with variable oxygen consumption or a shift to alternative mechanisms of tissue injury. Identifying transitions in tissue oxygenation may facilitate targeted therapy in ARVD.
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Affiliation(s)
| | - Ahmed Saad
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, Minnesota, USA; Department of Family Medicine, Creighton University, Omaha, Nebraska, USA
| | | | - Alfonso Eirin
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, Minnesota, USA
| | - John R Woollard
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, Minnesota, USA
| | - Sandra M Herrmann
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, Minnesota, USA
| | - LaTonya J Hickson
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, Minnesota, USA
| | - Emily C Bendel
- Department of Radiology, Mayo Clinic, Rochester, Minnesota, USA
| | - Sanjay Misra
- Department of Radiology, Mayo Clinic, Rochester, Minnesota, USA
| | - James Glockner
- Department of Radiology, Mayo Clinic, Rochester, Minnesota, USA
| | - Lilach O Lerman
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, Minnesota, USA
| | - Stephen C Textor
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, Minnesota, USA.
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16
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Sugiyama K, Inoue T, Kozawa E, Ishikawa M, Shimada A, Kobayashi N, Tanaka J, Okada H. Reduced oxygenation but not fibrosis defined by functional magnetic resonance imaging predicts the long-term progression of chronic kidney disease. Nephrol Dial Transplant 2018; 35:964-970. [DOI: 10.1093/ndt/gfy324] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2018] [Accepted: 09/12/2018] [Indexed: 12/14/2022] Open
Abstract
Abstract
Background
Although chronic hypoxia and fibrosis may be a key to the progression of chronic kidney disease (CKD), a noninvasive means of measuring these variables is not yet available. Here, using blood oxygen level–dependent (BOLD) and diffusion-weighted (DW) magnetic resonance imaging (MRI), we assessed changes in renal tissue oxygenation and fibrosis, respectively, and evaluated their correlation with prognosis for renal function.
Methods
The study was conducted under a single-center, longitudinal, retrospective observational design. We examined the prognostic significance of T2* values of BOLD-MRI and apparent diffusion coefficient (ADC) values on DW-MRI and other clinical parameters. The rate of decline in estimated glomerular filtration rate (eGFR) was calculated by linear regression analysis using changes in eGFR during the observation period.
Results
A total of 91 patients were enrolled, with a mean age of 55.8 ± 15.6 years. Among patients, 51 (56.0%) were males and 38 (41.8%) had diabetes mellitus. The mean eGFR was 49.2 ± 28.9 mL/min/1.73 m2 and the mean observation period was 5.13 years. ADC values of DW-MRI but not T2* values of BOLD-MRI were well correlated with eGFR at the initial time point. The mean annual rate of decline in eGFR during the 5-year observation period was −1.92 ± 3.00 mL/min/1.73 m2. On multiple linear regression analysis, the rate of decline in eGFR was significantly correlated with eGFR at the start point, period average amount of proteinuria and T2* values, but not with ADC values (t = 2.980, P = 0.004).
Conclusions
Reduced oxygenation as determined by low T2* values on BOLD-MRI is a clinically useful marker of CKD progression.
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Affiliation(s)
- Kei Sugiyama
- Department of Nephrology, Faculty of Medicine, Saitama Medical University, Saitama, Japan
| | - Tsutomu Inoue
- Department of Nephrology, Faculty of Medicine, Saitama Medical University, Saitama, Japan
| | - Eito Kozawa
- Department of Radiology, Faculty of Medicine, Saitama Medical University, Saitama, Japan
| | - Masahiro Ishikawa
- School of Clinical Engineering, Faculty of Health and Medical Care, Saitama Medical University, Saitama, Japan
| | - Akira Shimada
- Department of Endocrinology and Diabetes, Faculty of Medicine, Saitama Medical University, Saitama, Japan
| | - Naoki Kobayashi
- School of Clinical Engineering, Faculty of Health and Medical Care, Saitama Medical University, Saitama, Japan
| | - Junji Tanaka
- Department of Radiology, Faculty of Medicine, Saitama Medical University, Saitama, Japan
| | - Hirokazu Okada
- Department of Nephrology, Faculty of Medicine, Saitama Medical University, Saitama, Japan
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Abstract
Metabolic syndrome (MetS) is the constellation of metabolic risk factors that might foster development of type 2 diabetes and cardiovascular disease. Abdominal obesity and insulin resistance play a prominent role among all metabolic traits of MetS. Because intervention including weight loss can reduce these morbidity and mortality in MetS, early detection of the severity and complications of MetS could be useful. Recent advances in imaging modalities have provided significant insight into the development and progression of abdominal obesity and insulin resistance, as well as target organ injuries. The purpose of this review is to summarize advances in diagnostic imaging modalities in MetS that can be applied for evaluating each components and target organs. This may help in early detection, monitoring target organ injury, and in turn developing novel therapeutic target to alleviate and avert them.
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Affiliation(s)
- Seo Rin Kim
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, Minn
| | - Lilach O Lerman
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, Minn.
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18
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Ren K, Wang Y. Response to "Interpretation of functional renal MRI findings: Where physiology and imaging sciences need to talk across domains". J Magn Reson Imaging 2018; 47:1142. [PMID: 28758281 DOI: 10.1002/jmri.25828] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2017] [Accepted: 07/20/2017] [Indexed: 11/09/2022] Open
Affiliation(s)
- Ke Ren
- Department of Radiology, First Hospital of China Medical University, Shenyang, Liaoning, P.R. China
| | - Yi Wang
- Department of Radiology, First Hospital of China Medical University, Shenyang, Liaoning, P.R. China.,Key Laboratory of Imaging Diagnosis and Interventional Radiology of Liaoning Province, Shenyang, Liaoning, P.R. China
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Abstract
Blood oxygen level-dependent magnetic resonance imaging (BOLD MRI) has recently been utilized as a noninvasive tool for evaluating renal oxygenation. Several methods have been proposed for analyzing BOLD images. Regional ROI selection is the earliest and most widely used method for BOLD analysis. In the last 20 years, many investigators have used this method to evaluate cortical and medullary oxygenation in patients with ischemic nephropathy, hypertensive nephropathy, diabetic nephropathy, chronic kidney disease (CKD), acute kidney injury and renal allograft rejection. However, clinical trials of BOLD MRI using regional ROI selection revealed that it was difficult to distinguish the renal cortico-medullary zones with this method, and that it was susceptible to observer variability. To overcome these deficiencies, several new methods were proposed for analyzing BOLD images, including the compartmental approach, fractional hypoxia method, concentric objects (CO) method and twelve-layer concentric objects (TLCO) method. The compartmental approach provides an algorithm to judge whether the pixel belongs to the cortex or medulla. Fractional kidney hypoxia, measured by using BOLD MRI, was negatively correlated with renal blood flow, tissue perfusion and glomerular filtration rate (GFR) in patients with atherosclerotic renal artery stenosis. The CO method divides the renal parenchyma into six or twelve layers of thickness in each coronal slice of BOLD images and provides a R2* radial profile curve. The slope of the R2* curve associated positively with eGFR in CKD patients. Indeed, each method invariably has advantages and disadvantages, and there is generally no consensus method so far. Undoubtedly, analytic approaches for BOLD MRI with better reproducibility would assist clinicians in monitoring the degree of kidney hypoxia and thus facilitating timely reversal of tissue hypoxia.
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Affiliation(s)
- Fen Chen
- Department of Nephrology, Xuzhou Medical University, Xuzhou, China
| | - Shulin Li
- Department of Nephrology, Xuzhou Medical University, Xuzhou, China.,Department of Nephrology, Affiliated Hospital of Xuzhou Medical University, Xuzhou, China
| | - Dong Sun
- Department of Nephrology, Xuzhou Medical University, Xuzhou, China.,Department of Nephrology, Affiliated Hospital of Xuzhou Medical University, Xuzhou, China
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20
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Mahmoud H, Buchanan C, Francis ST, Selby NM. Imaging the kidney using magnetic resonance techniques: structure to function. Curr Opin Nephrol Hypertens 2016; 25:487-93. [PMID: 27636770 DOI: 10.1097/MNH.0000000000000266] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
PURPOSE OF REVIEW MRI can noninvasively assess the structure and function of the kidney in a single MRI scan session. This review summarizes recent advancements in functional renal MRI techniques, with a particular focus on clinical applications. RECENT FINDINGS A number of MRI techniques now provide measures of relevance to the pathophysiology of kidney disease. Diffusion-weighted imaging, used in chronic kidney disease and renal transplantation, shows promise as a measure of renal fibrosis. Longitudinal relaxation time (T1) mapping has been utilized in cardiac MRI to measure fibrosis and oedema; recent work shows its potential in the kidney. Blood oxygen-level-dependent MRI to measure renal oxygenation has been extensively studied, but a number of other factors affect results making it hard to draw definite conclusions as to its utility as an independent measure. Phase contrast and arterial spin labelling can measure renal artery blood flow and renal perfusion without exogenous contrast, as opposed to dynamic contrast-enhanced studies. In general, current data on clinical use of functional renal MRI are restricted to cross-sectional studies. SUMMARY Renal MRI has seen significant recent advances. Current evidence demonstrates its potential, and next steps include wider evaluation of its clinical application.
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21
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Shved N, Warsow G, Eichinger F, Hoogewijs D, Brandt S, Wild P, Kretzler M, Cohen CD, Lindenmeyer MT. Transcriptome-based network analysis reveals renal cell type-specific dysregulation of hypoxia-associated transcripts. Sci Rep 2017; 7:8576. [PMID: 28819298 DOI: 10.1038/s41598-017-08492-y] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2017] [Accepted: 07/10/2017] [Indexed: 12/19/2022] Open
Abstract
Accumulating evidence suggests that dysregulation of hypoxia-regulated transcriptional mechanisms is involved in development of chronic kidney diseases (CKD). However, it remains unclear how hypoxia-induced transcription factors (HIFs) and subsequent biological processes contribute to CKD development and progression. In our study, genome-wide expression profiles of more than 200 renal biopsies from patients with different CKD stages revealed significant correlation of HIF-target genes with eGFR in glomeruli and tubulointerstitium. These correlations were positive and negative and in part compartment-specific. Microarrays of proximal tubular cells and podocytes with stable HIF1α and/or HIF2α suppression displayed cell type-specific HIF1/HIF2-dependencies as well as dysregulation of several pathways. WGCNA analysis identified gene sets that were highly coregulated within modules. Characterization of the modules revealed common as well as cell group- and condition-specific pathways, GO-Terms and transcription factors. Gene expression analysis of the hypoxia-interconnected pathways in patients with different CKD stages revealed an increased dysregulation with loss of renal function. In conclusion, our data clearly point to a compartment- and cell type-specific dysregulation of hypoxia-associated gene transcripts and might help to improve the understanding of hypoxia, HIF dysregulation, and transcriptional program response in CKD.
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22
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Lee CJ, Gardiner BS, Ngo JP, Kar S, Evans RG, Smith DW. Accounting for oxygen in the renal cortex: a computational study of factors that predispose the cortex to hypoxia. Am J Physiol Renal Physiol 2017; 313:F218-F236. [DOI: 10.1152/ajprenal.00657.2016] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2016] [Revised: 03/24/2017] [Accepted: 04/05/2017] [Indexed: 12/21/2022] Open
Abstract
We develop a pseudo-three-dimensional model of oxygen transport for the renal cortex of the rat, incorporating both the axial and radial geometry of the preglomerular circulation and quantitative information regarding the surface areas and transport from the vasculature and renal corpuscles. The computational model was validated by simulating four sets of published experimental studies of renal oxygenation in rats. Under the control conditions, the predicted cortical tissue oxygen tension ([Formula: see text]) or microvascular oxygen tension (µPo2) were within ±1 SE of the mean value observed experimentally. The predicted [Formula: see text] or µPo2 in response to ischemia-reperfusion injury, acute hemodilution, blockade of nitric oxide synthase, or uncoupling mitochondrial respiration, were within ±2 SE observed experimentally. We performed a sensitivity analysis of the key model parameters to assess their individual or combined impact on the predicted [Formula: see text] and µPo2. The model parameters analyzed were as follows: 1) the major determinants of renal oxygen delivery ([Formula: see text]) (arterial blood Po2, hemoglobin concentration, and renal blood flow); 2) the major determinants of renal oxygen consumption (V̇o2) [glomerular filtration rate (GFR) and the efficiency of oxygen utilization for sodium reabsorption (β)]; and 3) peritubular capillary surface area (PCSA). Reductions in PCSA by 50% were found to profoundly increase the sensitivity of [Formula: see text] and µPo2 to the major the determinants of [Formula: see text] and V̇o2. The increasing likelihood of hypoxia with decreasing PCSA provides a potential explanation for the increased risk of acute kidney injury in some experimental animals and for patients with chronic kidney disease.
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Affiliation(s)
- Chang-Joon Lee
- Faculty of Engineering and Mathematical Sciences, The University of Western Australia, Perth, Western Australia, Australia
| | - Bruce S. Gardiner
- School of Engineering and Information Technology, Murdoch University, Perth, Western Australia, Australia; and
| | - Jennifer P. Ngo
- Cardiovascular Disease Program, Biosciences Discovery Institute and Department of Physiology, Monash University, Melbourne, Sydney, Australia
| | - Saptarshi Kar
- Faculty of Engineering and Mathematical Sciences, The University of Western Australia, Perth, Western Australia, Australia
| | - Roger G. Evans
- Cardiovascular Disease Program, Biosciences Discovery Institute and Department of Physiology, Monash University, Melbourne, Sydney, Australia
| | - David W. Smith
- Faculty of Engineering and Mathematical Sciences, The University of Western Australia, Perth, Western Australia, Australia
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Longo DL, Cutrin JC, Michelotti F, Irrera P, Aime S. Noninvasive evaluation of renal pH homeostasis after ischemia reperfusion injury by CEST-MRI. NMR Biomed 2017; 30:e3720. [PMID: 28370530 DOI: 10.1002/nbm.3720] [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] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2016] [Revised: 02/06/2017] [Accepted: 02/06/2017] [Indexed: 06/07/2023]
Abstract
Acute kidney injury (AKI) in mice caused by sustained ischemia followed by reperfusion is associated with acute tubular necrosis and renal dysfunctional blood flow. Although the principal role of the kidney is the maintenance of acid-base balance, current imaging approaches are unable to assess this important parameter, and clinical biomarkers are not robust enough in evaluating the severity of kidney damage. Therefore, novel noninvasive imaging approaches are needed to assess the acid-base homeostasis in vivo. This study investigates the usefulness of MRI-chemical exchange saturation transfer (CEST) pH imaging (through iopamidol injection) in characterizing moderate and severe AKI in mice following unilateral ischemia reperfusion injury. Moderate (20 min) and severe (40 min) ischemia were induced in Balb/C mice, which were imaged at several time points thereafter (Days 0, 1, 2, 7). A significant increase of renal pH values was observed as early as one day after the ischemia reperfusion damage for both moderate and severe ischemia. MRI-CEST pH imaging distinguished the evolution of moderate from severe AKI. A recovery of normal renal pH values was observed for moderate AKI, whereas a persisting renal pH increase was observed for severe AKI on Day 7. Renal filtration fraction was significantly lower for clamped kidneys (0.54-0.57) in comparison to contralateral kidneys (0.84-0.86) following impairment of glomerular filtration. The severe AKI group showed a reduced filtration fraction even after 7 days (0.38 for the clamped kidneys). Notably, renal pH values were significantly correlated with the histopathological score. In conclusion, MRI-CEST pH mapping is a valid tool for the noninvasive evaluation of both acid-base balance and renal filtration in patients with ischemia reperfusion injury.
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Affiliation(s)
- Dario Livio Longo
- Istituto di Biostrutture e Bioimmagini (CNR), c/o Centro di Biotecnologie Molecolari, Torino, Italy
- Dipartimento di Biotecnologie Molecolari e Scienze per la Salute, Università degli Studi di Torino, Torino, Italy
| | - Juan Carlos Cutrin
- Dipartimento di Biotecnologie Molecolari e Scienze per la Salute, Università degli Studi di Torino, Torino, Italy
| | - Filippo Michelotti
- Dipartimento di Biotecnologie Molecolari e Scienze per la Salute, Università degli Studi di Torino, Torino, Italy
| | - Pietro Irrera
- Dipartimento di Biotecnologie Molecolari e Scienze per la Salute, Università degli Studi di Torino, Torino, Italy
| | - Silvio Aime
- Dipartimento di Biotecnologie Molecolari e Scienze per la Salute, Università degli Studi di Torino, Torino, Italy
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van Eijs MJM, van Zuilen AD, de Boer A, Froeling M, Nguyen TQ, Joles JA, Leiner T, Verhaar MC. Innovative Perspective: Gadolinium-Free Magnetic Resonance Imaging in Long-Term Follow-Up after Kidney Transplantation. Front Physiol 2017; 8:296. [PMID: 28559850 PMCID: PMC5432553 DOI: 10.3389/fphys.2017.00296] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [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: 01/09/2017] [Accepted: 04/24/2017] [Indexed: 12/23/2022] Open
Abstract
Since the mid-1980s magnetic resonance imaging (MRI) has been investigated as a non- or minimally invasive tool to probe kidney allograft function. Despite this long-standing interest, MRI still plays a subordinate role in daily practice of transplantation nephrology. With the introduction of new functional MRI techniques, administration of exogenous gadolinium-based contrast agents has often become unnecessary and true non-invasive assessment of allograft function has become possible. This raises the question why application of MRI in the follow-up of kidney transplantation remains restricted, despite promising results. Current literature on kidney allograft MRI is mainly focused on assessment of (sub) acute kidney injury after transplantation. The aim of this review is to survey whether MRI can provide valuable diagnostic information beyond 1 year after kidney transplantation from a mechanistic point of view. The driving force behind chronic allograft nephropathy is believed to be chronic hypoxia. Based on this, techniques that visualize kidney perfusion and oxygenation, scarring, and parenchymal inflammation deserve special interest. We propose that functional MRI mechanistically provides tools for diagnostic work-up in long-term follow-up of kidney allografts.
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Affiliation(s)
- Mick J M van Eijs
- Department of Nephrology and Hypertension, University Medical Center UtrechtUtrecht, Netherlands
| | - Arjan D van Zuilen
- Department of Nephrology and Hypertension, University Medical Center UtrechtUtrecht, Netherlands
| | - Anneloes de Boer
- Department of Radiology, University Medical Center UtrechtUtrecht, Netherlands
| | - Martijn Froeling
- Department of Radiology, University Medical Center UtrechtUtrecht, Netherlands
| | - Tri Q Nguyen
- Department of Pathology, University Medical Center UtrechtUtrecht, Netherlands
| | - Jaap A Joles
- Department of Nephrology and Hypertension, University Medical Center UtrechtUtrecht, Netherlands
| | - Tim Leiner
- Department of Radiology, University Medical Center UtrechtUtrecht, Netherlands
| | - Marianne C Verhaar
- Department of Nephrology and Hypertension, University Medical Center UtrechtUtrecht, Netherlands
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25
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Deux JF, Audard V, Brugières P, Habibi A, Manea EM, Guillaud-Danis C, Godeau B, Galactéros F, Stehlé T, Lang P, Grimbert P, Audureau E, Rahmouni A, Bartolucci P. Magnetic Resonance Imaging Assessment of Kidney Oxygenation and Perfusion During Sickle Cell Vaso-occlusive Crises. Am J Kidney Dis 2017; 69:51-59. [DOI: 10.1053/j.ajkd.2016.07.027] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2016] [Accepted: 07/18/2016] [Indexed: 12/25/2022]
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26
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Chehade H, Milani B, Ansaloni A, Anex C, Bassi I, Piskunowicz M, Stuber M, Cachat F, Burnier M, Pruijm M. Renal tissue oxygenation in children with chronic kidney disease due to vesicoureteral reflux. Pediatr Nephrol 2016; 31:2103-11. [PMID: 27230512 DOI: 10.1007/s00467-016-3419-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/23/2016] [Revised: 05/10/2016] [Accepted: 05/11/2016] [Indexed: 10/21/2022]
Abstract
BACKGROUND Vesicoureteral reflux (VUR) is a frequent cause of chronic kidney disease (CKD) in children. Using blood oxygenation level-dependent magnetic resonance imaging (BOLD-MRI), we measured cortical and medullary oxygenation in children with CKD due to VUR and compared the results to those obtained on healthy controls. METHOD The study population comprised 37 children (19 with CKD due to VUR and 18 healthy age-matched controls). BOLD-MRI was performed before and after furosemide treatment. MR images were analyzed with the region-of-interest (ROI) technique to assess the mean R2* values (=1/T2*) of the cortex and medulla of each kidney and with the concentric object (CO) technique that divides renal parenchyma in 12 equal layers. RESULTS R2* values were significantly lower (corresponding to higher oxygenation) in the cortex and medulla of kidneys of children with CKD due to VUR than in those of the healthy controls (cortex 16.4 ± 1.4 vs. 17.2 ± 1.6 s(-1) , respectively; medulla 28.4 ± 3.2 vs. 30.3 ± 1.9 s(-1) , respectively; P < 0.05), and furosemide-induced changes in medullary R2* were smaller in the former than in the latter (-5.7 ± 3.0 vs. -6.9 ± 3.4 s(-1), respectively; P < 0.05). Similar results were found with the CO technique. In children with a history of unilateral reflux (n = 9), the non-affected contralateral kidneys presented similar R2* values as the diseased kidneys, but their response to furosemide was significantly larger (-7.4 ± 3.2 vs. -5.7 ± 3.0, respectively; P = 0.05). CONCLUSIONS Chronic kidney disease due to VUR is not associated with kidney tissue hypoxia in children. The significantly larger furosemide-induced decrease in medullary R2* levels in the healthy group and unaffected contralateral kidneys of the VUR group points towards more intense renal sodium transport in these kidneys.
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27
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Gradzik M, Niemczyk M, Gołębiowski M, Pączek L. Diagnostic Imaging of Autosomal Dominant Polycystic Kidney Disease. Pol J Radiol 2016; 81:441-453. [PMID: 27733888 PMCID: PMC5031169 DOI: 10.12659/pjr.894482] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [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: 04/28/2015] [Accepted: 02/19/2016] [Indexed: 12/21/2022] Open
Abstract
Autosomal dominant polycystic kidney disease (ADPKD) is one of the most common genetic disorders caused by a single gene mutation. The disease usually manifests itself at the age of 30-40 years and is characterized by formation of renal cysts along with the enlargement of kidneys and deterioration of their function, eventually leading to renal insufficiency. Imaging studies (sonography, computed tomography, magnetic resonance imaging) play an important role in the diagnostics of the disease, the monitoring of its progression, and the detection of complications. Imaging is also helpful in detecting extrarenal manifestations of ADPKD, most significant of which include intracranial aneurysms and cystic liver diseases.
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Affiliation(s)
- Monika Gradzik
- Department of Clinical Radiology, Medical University of Warsaw, Warsaw, Poland
| | - Mariusz Niemczyk
- Department of Immunology, Transplant Medicine and Internal Diseases, Medical University of Warsaw, Warsaw, Poland
| | - Marek Gołębiowski
- Department of Clinical Radiology, Medical University of Warsaw, Warsaw, Poland
| | - Leszek Pączek
- Department of Immunology, Transplant Medicine and Internal Diseases, Medical University of Warsaw, Warsaw, Poland
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28
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Mudaliar S, Alloju S, Henry RR. Can a Shift in Fuel Energetics Explain the Beneficial Cardiorenal Outcomes in the EMPA-REG OUTCOME Study? A Unifying Hypothesis. Diabetes Care 2016; 39:1115-22. [PMID: 27289124 DOI: 10.2337/dc16-0542] [Citation(s) in RCA: 424] [Impact Index Per Article: 53.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/11/2016] [Accepted: 03/29/2016] [Indexed: 02/03/2023]
Abstract
Type 2 diabetes mellitus causes excessive morbidity and premature cardiovascular (CV) mortality. Although tight glycemic control improves microvascular complications, its effects on macrovascular complications are unclear. The recent publication of the EMPA-REG OUTCOME study documenting impressive benefits with empagliflozin (a sodium-glucose cotransporter 2 [SGLT2] inhibitor) on CV and all-cause mortality and hospitalization for heart failure without any effects on classic atherothrombotic events is puzzling. More puzzling is that the curves for heart failure hospitalization, renal outcomes, and CV mortality begin to separate widely within 3 months and are maintained for >3 years. Modest improvements in glycemic, lipid, or blood pressure control unlikely contributed significantly to the beneficial cardiorenal outcomes within 3 months. Other known effects of SGLT2 inhibitors on visceral adiposity, vascular endothelium, natriuresis, and neurohormonal mechanisms are also unlikely major contributors to the CV/renal benefits. We postulate that the cardiorenal benefits of empagliflozin are due to a shift in myocardial and renal fuel metabolism away from fat and glucose oxidation, which are energy inefficient in the setting of the type 2 diabetic heart and kidney, toward an energy-efficient super fuel like ketone bodies, which improve myocardial/renal work efficiency and function. Even small beneficial changes in energetics minute to minute translate into large differences in efficiency, and improved cardiorenal outcomes over weeks to months continue to be sustained. Well-planned physiologic and imaging studies need to be done to characterize fuel energetics-based mechanisms for the CV/renal benefits.
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Affiliation(s)
- Sunder Mudaliar
- Veterans Affairs Medical Center and University of California, San Diego School of Medicine, San Diego, CA
| | - Sindura Alloju
- Veterans Affairs Medical Center and University of California, San Diego School of Medicine, San Diego, CA
| | - Robert R Henry
- Veterans Affairs Medical Center and University of California, San Diego School of Medicine, San Diego, CA
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29
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30
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van der Bel R, Coolen BF, Nederveen AJ, Potters WV, Verberne HJ, Vogt L, Stroes ESG, Krediet CTP. Magnetic Resonance Imaging-Derived Renal Oxygenation and Perfusion During Continuous, Steady-State Angiotensin-II Infusion in Healthy Humans. J Am Heart Assoc 2016; 5:e003185. [PMID: 27021686 PMCID: PMC4943284 DOI: 10.1161/jaha.115.003185] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Background The role of kidney hypoxia is considered pivotal in the progression of chronic kidney disease. A widely used method to assess kidney oxygenation is blood oxygen level dependent (BOLD)–magnetic resonance imaging (MRI), but its interpretation remains problematic. The BOLD‐MRI signal is the result of kidney oxygen consumption (a proxy of glomerular filtration) and supply (ie, glomerular perfusion). Therefore, we hypothesized that with pharmacological modulation of kidney blood flow, renal oxygenation, as assessed by BOLD‐MRI, correlates to filtration fraction (ie, glomerular filtration rate/effective renal plasma flow) in healthy humans. Methods and Results Eight healthy volunteers were subjected to continuous angiotensin‐II infusion at 0.3, 0.9, and 3.0 ng/kg per minute. At each dose, renal oxygenation and blood flow were assessed using BOLD and phase‐contrast MRI. Subsequently, “gold standard” glomerular filtration rate/effective renal plasma flow measurements were performed under the same conditions. Renal plasma flow decreased dose dependently from 660±146 to 467±103 mL/min per 1.73 m2 (F[3, 21]=33.3, P<0.001). Glomerular filtration rate decreased from 121±23 to 110±18 mL/min per 1.73 m2 (F[1.8, 2.4]=6.4, P=0.013). Cortical transverse relaxation rate (R2*; increases in R2* represent decreases in oxygenation) increased by 7.2±3.8% (F[3, 21]=7.37, P=0.001); medullar R2* did not change. Cortical R2* related to filtration fraction (R2 0.46, P<0.001). Conclusions By direct comparison between “gold standard” kidney function measurements and BOLD MRI, we showed that cortical oxygenation measured by BOLD MRI relates poorly to glomerular filtration rate but is associated with filtration fraction. For future studies, there may be a need to include renal plasma flow measurements when employing renal BOLD‐MRI.
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Affiliation(s)
- René van der Bel
- Department of Internal Medicine, Academic Medical Center at the University of Amsterdam, The Netherlands
| | - Bram F Coolen
- Department of Radiology, Academic Medical Center at the University of Amsterdam, The Netherlands
| | - Aart J Nederveen
- Department of Radiology, Academic Medical Center at the University of Amsterdam, The Netherlands
| | - Wouter V Potters
- Department of Radiology, Academic Medical Center at the University of Amsterdam, The Netherlands
| | - Hein J Verberne
- Department of Nuclear Medicine, Academic Medical Center at the University of Amsterdam, The Netherlands
| | - Liffert Vogt
- Department of Internal Medicine, Academic Medical Center at the University of Amsterdam, The Netherlands
| | - Erik S G Stroes
- Department of Internal Medicine, Academic Medical Center at the University of Amsterdam, The Netherlands
| | - C T Paul Krediet
- Department of Internal Medicine, Academic Medical Center at the University of Amsterdam, The Netherlands
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31
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Abstract
PURPOSE OF REVIEW Over the past decade, a variety of MRI methods have been developed and applied to many kidney diseases. These MRI techniques show great promise, enabling the noninvasive assessment of renal structure, function and injury in individuals. This review will highlight the current applications of functional MRI techniques for the assessment of renal disease and discuss future directions. RECENT FINDINGS Many pathological (functional and structural) changes or factors in renal disease can be assessed by advanced MRI techniques. These include renal vascular structure and function (contrast-enhanced MRI, arterial spin labelling), tissue oxygenation (blood oxygen level dependent MRI), renal tissue injury and fibrosis (diffusion or magnetization transfer imaging, magnetic resonance elastography), renal metabolism (chemical exchange saturation transfer, spectroscopic imaging), nephron endowment (cationic-contrast imaging), sodium concentration (23Na-MRI) and molecular events (targeted-contrast imaging). SUMMARY Current advances in MRI techniques have enabled the noninvasive investigation of renal disease. Further development, evaluation and application of the MRI techniques should facilitate better understanding and assessment of renal disease, and the development of new imaging biomarkers, enabling the intensified treatment of high-risk populations and a more rapid interrogation of novel therapeutic agents and protocols.
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Abstract
Early diagnosis of kidney allograft injury contributes to proper decisions regarding treatment strategy and promotes the long-term survival of both the recipients and the allografts. Although biopsy remains the gold standard, non-invasive methods of kidney allograft evaluation are required for clinical practice. Recently, novel ultrasonic technologies have been applied in the evaluation and diagnosis of kidney allograft status, including tissue elasticity quantification using acoustic radiation force impulse (ARFI) and contrast-enhanced ultrasonography (CEUS). In this review, we discuss current opinions on the application of ARFI and CEUS for evaluating kidney allograft function and their possible influencing factors, advantages and limitations. We also compare these two technologies with other non-invasive diagnostic methods, including nuclear medicine and radiology. While the role of novel non-invasive ultrasonic technologies in the assessment of kidney allografts requires further investigation, the use of such technologies remains highly promising.
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Affiliation(s)
- Cheng Yang
- Department of Urology, Zhongshan Hospital, Fudan University, Shanghai Key Laboratory of Organ Transplantation, Shanghai, China
| | - Mushuang Hu
- Department of Urology, Zhongshan Hospital, Fudan University, Shanghai Key Laboratory of Organ Transplantation, Shanghai, China
| | - Tongyu Zhu
- Department of Urology, Zhongshan Hospital, Fudan University, Shanghai Key Laboratory of Organ Transplantation, Shanghai, China
| | - Wanyuan He
- Department of Ultrasound, Zhongshan Hospital, Fudan University, Shanghai Institute of Imaging Medicine, Shanghai, China
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Abstract
PURPOSE OF REVIEW Over the past decade, a variety of MRI methods have been developed and applied to many kidney diseases. These MRI techniques show great promise, enabling the noninvasive assessment of renal structure, function and injury in individuals. This review will highlight the current applications of functional MRI techniques for the assessment of renal disease and discuss future directions. RECENT FINDINGS Many pathological (functional and structural) changes or factors in renal disease can be assessed by advanced MRI techniques. These include renal vascular structure and function (contrast-enhanced MRI, arterial spin labelling), tissue oxygenation (blood oxygen level dependent MRI), renal tissue injury and fibrosis (diffusion or magnetization transfer imaging, magnetic resonance elastography), renal metabolism (chemical exchange saturation transfer, spectroscopic imaging), nephron endowment (cationic-contrast imaging), sodium concentration (23Na-MRI) and molecular events (targeted-contrast imaging). SUMMARY Current advances in MRI techniques have enabled the noninvasive investigation of renal disease. Further development, evaluation and application of the MRI techniques should facilitate better understanding and assessment of renal disease, and the development of new imaging biomarkers, enabling the intensified treatment of high-risk populations and a more rapid interrogation of novel therapeutic agents and protocols.
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Affiliation(s)
- Takamune Takahashi
- aDivision of Nephrology and Hypertension bDepartment of Radiology and Radiological Sciences cVanderbilt University Institute of Imaging Science, Vanderbilt University School of Medicine, Nashville, Tennessee, USA
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