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Hillaert A, Sanmiguel Serpa LC, Xu Y, Hesta M, Bogaert S, Vanderperren K, Pullens P. Optimization of Fair Arterial Spin Labeling Magnetic Resonance Imaging (ASL-MRI) for Renal Perfusion Quantification in Dogs: Pilot Study. Animals (Basel) 2024; 14:1810. [PMID: 38929429 PMCID: PMC11201026 DOI: 10.3390/ani14121810] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2024] [Revised: 06/11/2024] [Accepted: 06/12/2024] [Indexed: 06/28/2024] Open
Abstract
Arterial spin labeling (ASL) MRI allows non-invasive quantification of renal blood flow (RBF) and shows great potential for renal assessment. To our knowledge, renal ASL-MRI has not previously been performed in dogs. The aim of this pilot study was to determine parameters essential for ALS-MRI-based quantification of RBF in dogs: T1, blood (longitudinal relaxation time), λ (blood tissue partition coefficient) and TI (inversion time). A Beagle was scanned at 3T with a multi-TI ASL sequence, with TIs ranging from 250 to 2500 ms, to determine the optimal TI value. The T1 of blood for dogs was determined by scanning a blood sample with a 2D IR TSE sequence. The water content of the dog's kidney was determined by analyzing kidney samples from four dogs with a moisture analyzer and was subsequently used to calculate λ. The optimal TI and the measured values for T1,blood, and λ were 2000 ms, 1463 ms and 0.91 mL/g, respectively. These optimized parameters for dogs resulted in lower RBF values than those obtained from inline generated RBF maps. In conclusion, this study determined preliminary parameters essential for ALS-MRI-based RBF quantification in dogs. Further research is needed to confirm these values, but it may help guide future research.
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Affiliation(s)
- Amber Hillaert
- Department of Morphology, Imaging, Orthopedics, Rehabilitation and Nutrition, Faculty of Veterinary Medicine, Ghent University, 9820 Merelbeke, Belgium; (A.H.)
| | - Luis Carlos Sanmiguel Serpa
- Department of Medical Imaging, Ghent University Hospital, 9000 Ghent, Belgium
- Ghent Institute for Functional and Metabolic Imaging, Ghent University, 9000 Ghent, Belgium
- Department of Diagnostic Sciences, Faculty of Medicine and Health Sciences, Ghent University, 9000 Ghent, Belgium
| | - Yangfeng Xu
- Department of Morphology, Imaging, Orthopedics, Rehabilitation and Nutrition, Faculty of Veterinary Medicine, Ghent University, 9820 Merelbeke, Belgium; (A.H.)
| | - Myriam Hesta
- Department of Morphology, Imaging, Orthopedics, Rehabilitation and Nutrition, Faculty of Veterinary Medicine, Ghent University, 9820 Merelbeke, Belgium; (A.H.)
| | - Stephanie Bogaert
- Department of Medical Imaging, Ghent University Hospital, 9000 Ghent, Belgium
- Ghent Institute for Functional and Metabolic Imaging, Ghent University, 9000 Ghent, Belgium
| | - Katrien Vanderperren
- Department of Morphology, Imaging, Orthopedics, Rehabilitation and Nutrition, Faculty of Veterinary Medicine, Ghent University, 9820 Merelbeke, Belgium; (A.H.)
| | - Pim Pullens
- Department of Medical Imaging, Ghent University Hospital, 9000 Ghent, Belgium
- Ghent Institute for Functional and Metabolic Imaging, Ghent University, 9000 Ghent, Belgium
- Institute of Biomedical Engineering and Technology (IBiTech)—MEDISP, Faculty of Engineering and Architecture, Ghent University, 9000 Ghent, Belgium
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2
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Wang R, Lin Z, Quan S, Yang X, Zhao K, Sui X, Kong H, Wang X, Su T. Evaluation of renal tubular function by multiparametric functional MRI in early diabetes. Magn Reson Imaging 2024; 109:100-107. [PMID: 38494095 DOI: 10.1016/j.mri.2024.03.016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2023] [Revised: 03/13/2024] [Accepted: 03/13/2024] [Indexed: 03/19/2024]
Abstract
Purpose To evaluate the tubular function in an alloxan-induced type 1 diabetes mellitus (DM) rabbit model measured by renal oxygenation (R2*), oxygen extraction fraction (OEF), and renal blood flow (RBF) using blood oxygenation level dependent, asymmetric spin echo, and arterial spin labeling MRI. Methods Twenty-six rabbits were randomized into the 3-day DM group (n = 13) and the 7-day DM group (n = 13). We performed pairs of multiparametric MRIs (before and after furosemide injection) at baseline and 3/7 days post-DM, and scored pathological kidney injury. We performed statistical analyses using non-parametric, chi-square, and Spearman correlation tests. Results At baseline, medullary R2* significantly decreased by 24.97% and 16.74% in the outer and inner stripes of the outer medulla (OS and IS, p = 0.006 and 0.003, respectively) after furosemide administration. While the corresponding OEF decreased by 15.91% for OS and 16.67% for IS (both p = 0.003), and no significant change in medullary RBF was observed (p > 0.05). In the 3-day DM group, the decrease of medullary R2* and OEF post-furosemide became unremarkable, suggesting tubular dysfunction. We noticed similar changes in the 7-day DM group. Correlation analysis showed pathological tubular injury score significantly correlated with medullary ∆R2* (post-furosemide - pre-furosemide difference, r = 0.82 for OS and 0.82 for IS) and ∆OEF (r = 0.82 for OS and 0.82 for IS) (p < 0.001, respectively). Conclusion: The combination of medullary OEF and R2* in response to furosemide could detect renal tubular dysfunction in early DM.
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Affiliation(s)
- Rui Wang
- Department of Radiology, Peking University First Hospital, Beijing, China
| | - Zhiyong Lin
- Department of Radiology, Peking University First Hospital, Beijing, China
| | - Shuo Quan
- Department of Radiology, Peking University First Hospital, Beijing, China
| | - Xuedong Yang
- Department of Radiology, China Academy of Chinese Medical Sciences Guanganmen Hospital, Beijing, China
| | - Kai Zhao
- Department of Radiology, Peking University First Hospital, Beijing, China
| | - Xueqing Sui
- Department of Radiology, The Affiliated Hospital of Qingdao University, Qingdao, China
| | - Hanjing Kong
- UIH Group, Beijing United Imaging Research Institute of Intelligent Imaging, Beijing, China
| | - Xiaoying Wang
- Department of Radiology, Peking University First Hospital, Beijing, China.
| | - Tao Su
- Department of Nephrology, Peking University First Hospital, Beijing, China.
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3
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Alhummiany B, Sharma K, Buckley DL, Soe KK, Sourbron SP. Physiological confounders of renal blood flow measurement. MAGMA (NEW YORK, N.Y.) 2023:10.1007/s10334-023-01126-7. [PMID: 37971557 DOI: 10.1007/s10334-023-01126-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2023] [Revised: 09/26/2023] [Accepted: 10/12/2023] [Indexed: 11/19/2023]
Abstract
OBJECTIVES Renal blood flow (RBF) is controlled by a number of physiological factors that can contribute to the variability of its measurement. The purpose of this review is to assess the changes in RBF in response to a wide range of physiological confounders and derive practical recommendations on patient preparation and interpretation of RBF measurements with MRI. METHODS A comprehensive search was conducted to include articles reporting on physiological variations of renal perfusion, blood and/or plasma flow in healthy humans. RESULTS A total of 24 potential confounders were identified from the literature search and categorized into non-modifiable and modifiable factors. The non-modifiable factors include variables related to the demographics of a population (e.g. age, sex, and race) which cannot be manipulated but should be considered when interpreting RBF values between subjects. The modifiable factors include different activities (e.g. food/fluid intake, exercise training and medication use) that can be standardized in the study design. For each of the modifiable factors, evidence-based recommendations are provided to control for them in an RBF-measurement. CONCLUSION Future studies aiming to measure RBF are encouraged to follow a rigorous study design, that takes into account these recommendations for controlling the factors that can influence RBF results.
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Affiliation(s)
- Bashair Alhummiany
- Department of Biomedical Imaging Sciences, University of Leeds, Leeds, LS2 9NL, UK.
| | - Kanishka Sharma
- Department of Imaging, Infection, Immunity and Cardiovascular Disease, The University of Sheffield, Sheffield, UK
| | - David L Buckley
- Department of Biomedical Imaging Sciences, University of Leeds, Leeds, LS2 9NL, UK
| | - Kywe Kywe Soe
- Department of Imaging, Infection, Immunity and Cardiovascular Disease, The University of Sheffield, Sheffield, UK
| | - Steven P Sourbron
- Department of Imaging, Infection, Immunity and Cardiovascular Disease, The University of Sheffield, Sheffield, UK.
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4
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Li X, Wang W, Cheng D, Yu Y, Wu Q, Ni X, Chen J, Zhang L, Wen J. Perfusion and oxygenation in allografts with transplant renal artery stenosis: Evaluation with functional magnetic resonance imaging. Clin Transplant 2022; 36:e14806. [PMID: 36029202 DOI: 10.1111/ctr.14806] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2022] [Revised: 08/21/2022] [Accepted: 08/22/2022] [Indexed: 12/15/2022]
Abstract
BACKGROUND Transplant renal artery stenosis (TRAS) has been shown to reduce kidney perfusion leading to post-operative hypertension. We aimed to measure the perfusion and oxygenation changes in TRAS with arterial spin labeling (ASL) and blood oxygen level-dependent (BOLD) imaging, respectively. METHODS In this single-center prospective study, a total of seven patients with TRAS and seven age- and sex-matched normal kidney transplant recipients underwent both ASL and BOLD imaging. Moreover, measurements of ASL and BOLD were also performed in five patients after successful angioplasty for TRAS. RESULTS Allograft cortical perfusion as measured by ASL in the TRAS group was significantly decreased as compared with normal control group (129.9 ± 46.6 ml/100 g vs. 202.4 ± 47.7 ml/100 g, P = .01). Interestingly, allograft oxygenation as indicated by R2* derived from BOLD in both the cortex (16.42 ± 1.90 Hz vs. 18.25 ± 4.34 Hz, P = .33) and the medulla (30.34 ± 2.35 Hz vs. 30.43 ± 6.85 Hz, P = .97) showed no statistical difference between the TRAS and normal control group. In addition, both cortical and medullary oxygenation remained unchanged despite significantly improved cortical perfusion in those undergone successful angioplasty. CONCLUSION Cortical and medullary oxygenation were preserved in the presence of reduced allograft perfusion in clinically significant TRAS. Prospective larger studies are needed to conclusively establish perfusion and oxygenation changes in TRAS.
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Affiliation(s)
- Xue Li
- National Clinical Research Center of Kidney Disease, Jinling Hospital, Medical School of Nanjing University, Nanjing, Jiangsu Province, China
| | - Wei Wang
- Department of Nephrology, Shanghai Tenth People's Hospital, Shanghai, China.,Center for Nephrology and Metabolomics, Tongji University School of Medicine, Shanghai, China
| | - Dongrui Cheng
- National Clinical Research Center of Kidney Disease, Jinling Hospital, Medical School of Nanjing University, Nanjing, Jiangsu Province, China
| | - Yuanmeng Yu
- Department of Medical Imaging, Jinling Hospital, Southern Medical University Clinical Medical College, Nanjing, Jiangsu Province, China.,Department of MRI, The First People's Hospital of Yunnan Province, The Affiliated Hospital of Kunming University of Science and Technology, Kunming, Yunnan, China
| | - Qianqian Wu
- National Clinical Research Center of Kidney Disease, Jinling Hospital, Medical School of Nanjing University, Nanjing, Jiangsu Province, China
| | - Xuefeng Ni
- National Clinical Research Center of Kidney Disease, Jinling Hospital, Medical School of Nanjing University, Nanjing, Jiangsu Province, China
| | - Jinsong Chen
- National Clinical Research Center of Kidney Disease, Jinling Hospital, Medical School of Nanjing University, Nanjing, Jiangsu Province, China
| | - Longjiang Zhang
- Department of Medical Imaging, Jinling Hospital, Medical School of Nanjing University, Nanjing, Jiangsu Province, China
| | - Jiqiu Wen
- National Clinical Research Center of Kidney Disease, Jinling Hospital, Medical School of Nanjing University, Nanjing, Jiangsu Province, China
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An J, Zhang J, Dong F, Yin J, Feng F, Guo W, Huang S, Wang D, Dang J, Zhang J, Cheng H. Arterial Labeling Ultrasound Subtraction Angiography (ALUSA) Based on Acoustic Phase-Change Nanodroplets. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2022; 18:e2105989. [PMID: 35088522 DOI: 10.1002/smll.202105989] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Revised: 12/15/2021] [Indexed: 06/14/2023]
Abstract
Biomedical imaging technology (like digital subtraction angiography (DSA)) based on contrast agents has been widely employed in the diagnosis of vascular-related diseases. While the DSA achieves the high-resolution observation of specified vessels and their downstream perfusion at the cost of invasive, radioactive operation and hepatorenal toxicity. To address those problems, this study develops arterial labeling ultrasound (US) subtraction angiography (ALUSA) based on a new perfluorobutane (PFB) nanodroplets with a lower vaporization threshold through spontaneous nucleation. The nanodroplets can be selectively vaporized to microbubbles, indicating a highly echogenic signal at B-mode images only using a diagnostic transducer. By labeling a single blood vessel for nanodroplets vaporization and tracking its downstream blood perfusion in segmental renal arteries at a frame rate of 500 Hz. The results demonstrate the color-coded super-resolution ALUSA image, exhibiting the downstream arcuate and interlobular arteries of each segmental renal artery with a resolution of 36 µm in a rabbit kidney. Furthermore, ALUSA could offer the vascular structures, blood flow velocity, and direction of their primary supply vessels in the mouse breast tumor. ALUSA fills the gap of noninvasive labeling angiography in US and opens a broad vista in the diagnosis and treatment of tumor and vascular-related diseases.
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Affiliation(s)
- Jian An
- Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, 100871, China
| | - Jiabin Zhang
- State Key Laboratory of Membrane Biology, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Peking-Tsinghua Center for Life Sciences, College of Future Technology, Peking University, Beijing, 100871, China
| | - Feihong Dong
- State Key Laboratory of Membrane Biology, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Peking-Tsinghua Center for Life Sciences, College of Future Technology, Peking University, Beijing, 100871, China
| | - Jingyi Yin
- Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, 100871, China
| | - Feng Feng
- Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, 100871, China
| | - Wenyu Guo
- Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, 100871, China
| | - Shuo Huang
- Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, 100871, China
| | - Di Wang
- Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, 100871, China
| | - Jie Dang
- Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, 100871, China
| | - Jue Zhang
- Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, 100871, China
- College of Engineering, Peking University, Beijing, 100871, China
- National Biomedical Imaging Center, Peking University, Beijing, 100871, China
| | - Heping Cheng
- National Biomedical Imaging Center, Peking University, Beijing, 100871, China
- Research Unit of Mitochondria in Brain Diseases, Chinese Academy of Medical Sciences, PKU-Nanjing Institute of Translational Medicine, Nanjing, 210031, China
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6
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Hwang M, Tierradentro-García LO, Haddad S, Poznick L, Kilbaugh T, Chiotos K. Feasibility of Contrast-Enhanced Ultrasound for Assessing Cardiac and Renal Microvascular Flow in Patients With Multisystem Inflammatory Syndrome in Children. Clin Pediatr (Phila) 2022; 61:241-247. [PMID: 35081803 DOI: 10.1177/00099228211073288] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- Misun Hwang
- Children's Hospital of Philadelphia, Philadelphia, PA, USA.,University of Pennsylvania Health System, Philadelphia, PA, USA
| | | | - Sophie Haddad
- Children's Hospital of Philadelphia, Philadelphia, PA, USA
| | - Laura Poznick
- Children's Hospital of Philadelphia, Philadelphia, PA, USA
| | - Todd Kilbaugh
- Children's Hospital of Philadelphia, Philadelphia, PA, USA.,University of Pennsylvania Health System, Philadelphia, PA, USA
| | - Kathleen Chiotos
- Children's Hospital of Philadelphia, Philadelphia, PA, USA.,University of Pennsylvania Health System, Philadelphia, PA, USA
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7
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Bones IK, Bos C, Moonen C, Hendrikse J, van Stralen M. Workflow for automatic renal perfusion quantification using ASL-MRI and machine learning. Magn Reson Med 2021; 87:800-809. [PMID: 34672029 PMCID: PMC9297892 DOI: 10.1002/mrm.29016] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2021] [Revised: 08/31/2021] [Accepted: 09/01/2021] [Indexed: 11/07/2022]
Abstract
PURPOSE Clinical applicability of renal arterial spin labeling (ASL) MRI is hampered because of time consuming and observer dependent post-processing, including manual segmentation of the cortex to obtain cortical renal blood flow (RBF). Machine learning has proven its value in medical image segmentation, including the kidneys. This study presents a fully automatic workflow for renal cortex perfusion quantification by including machine learning-based segmentation. METHODS Fully automatic workflow was achieved by construction of a cascade of 3 U-nets to replace manual segmentation in ASL quantification. All 1.5T ASL-MRI data, including M0 , T1 , and ASL label-control images, from 10 healthy volunteers was used for training (dataset 1). Trained cascade performance was validated on 4 additional volunteers (dataset 2). Manual segmentations were generated by 2 observers, yielding reference and second observer segmentations. To validate the intended use of the automatic segmentations, manual and automatic RBF values in mL/min/100 g were compared. RESULTS Good agreement was found between automatic and manual segmentations on dataset 1 (dice score = 0.78 ± 0.04), which was in line with inter-observer variability (dice score = 0.77 ± 0.02). Good agreement was confirmed on dataset 2 (dice score = 0.75 ± 0.03). Moreover, similar cortical RBF was obtained with automatic or manual segmentations, on average and at subject level; with 211 ± 31 mL/min/100 g and 208 ± 31 mL/min/100 g (P < .05), respectively, with narrow limits of agreement at -11 and 4.6 mL/min/100 g. RBF accuracy with automated segmentations was confirmed on dataset 2. CONCLUSION Our proposed method automates ASL quantification without compromising RBF accuracy. With quick processing and without observer dependence, renal ASL-MRI is more attractive for clinical application as well as for longitudinal and multi-center studies.
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Affiliation(s)
- Isabell K Bones
- Center for Image Sciences, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Clemens Bos
- Center for Image Sciences, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Chrit Moonen
- Center for Image Sciences, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Jeroen Hendrikse
- Department of Radiology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Marijn van Stralen
- Center for Image Sciences, University Medical Center Utrecht, Utrecht, The Netherlands
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8
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Mani LY, Seif M, Nikles F, Tshering Vogel DW, Diserens G, Martirosian P, Burnier M, Vogt B, Vermathen P. Hip Position Acutely Affects Oxygenation and Perfusion of Kidney Grafts as Measured by Functional Magnetic Resonance Imaging Methods-The Bent Knee Study. Front Med (Lausanne) 2021; 8:697055. [PMID: 34447762 PMCID: PMC8384256 DOI: 10.3389/fmed.2021.697055] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2021] [Accepted: 07/12/2021] [Indexed: 12/16/2022] Open
Abstract
Background: Kidney perfusion and oxygenation are two important determinants of kidney graft function. In kidney transplantation, repeated graft hypoperfusion may occur during hip flexion, for example in the sitting position, due to the progressive development of fibrotic tissue around iliac arteries. The aim of this study was to assess the changes in oxygenation and perfusion of kidney grafts during hip flexion and extension using a new functional magnetic resonance imaging (fMRI) protocol. Methods: Nineteen kidney graft recipients prospectively underwent MRI on a 3T scanner including diffusion-weighted, blood oxygenation level dependent (BOLD), and arterial spin labeling sequences in hip positions 0° and >90° before and after intravenous administration of 20 mg furosemide. Results: Unexpectedly, graft perfusion values were significantly higher in flexed compared to neutral hip position. Main diffusion-derived parameters were not affected by hip position. BOLD-derived cortico-medullary R2* ratio was significantly modified during hip flexion suggesting an intrarenal redistribution of the oxygenation in favor of the medulla and to the detriment of the cortex. Furthermore, the increase in medullary oxygenation induced by furosemide was significantly blunted during hip flexion (p < 0.001). Conclusion: Hip flexion has an acute impact on perfusion and tissue oxygenation in kidney grafts. Whether these position-dependent changes affect the long-term function and outcome of kidney transplants needs further investigation.
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Affiliation(s)
- Laila-Yasmin Mani
- Department of Nephrology and Hypertension, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
| | - Maryam Seif
- Departments of Biomedical Research and Radiology, University of Bern, Bern, Switzerland.,Spinal Cord Injury Center, Balgrist University Hospital, University of Zurich, Zurich, Switzerland
| | - Florence Nikles
- Departments of Biomedical Research and Radiology, University of Bern, Bern, Switzerland
| | - Dechen W Tshering Vogel
- Department of Diagnostic, Interventional and Pediatric Radiology, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
| | - Gaëlle Diserens
- Departments of Biomedical Research and Radiology, University of Bern, Bern, Switzerland
| | - Petros Martirosian
- Section on Experimental Radiology, University of Tübingen, Tübingen, Germany
| | - Michel Burnier
- Service of Nephrology and Hypertension, Department of Medicine, Lausanne University Hospital, Lausanne, Switzerland
| | - Bruno Vogt
- Department of Nephrology and Hypertension, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
| | - Peter Vermathen
- Departments of Biomedical Research and Radiology, University of Bern, Bern, Switzerland
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9
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Schutter R, Lantinga VA, Hamelink TL, Pool MBF, van Varsseveld OC, Potze JH, Hillebrands JL, van den Heuvel MC, Dierckx RAJO, Leuvenink HGD, Moers C, Borra RJH. Magnetic resonance imaging assessment of renal flow distribution patterns during ex vivo normothermic machine perfusion in porcine and human kidneys. Transpl Int 2021; 34:1643-1655. [PMID: 34448269 PMCID: PMC9290094 DOI: 10.1111/tri.13991] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2021] [Revised: 07/13/2021] [Accepted: 07/14/2021] [Indexed: 02/06/2023]
Abstract
Acceptance criteria of deceased donor organs have gradually been extended toward suboptimal quality, posing an urgent need for more objective pre‐transplant organ assessment. Ex vivo normothermic machine perfusion (NMP) combined with magnetic resonance imaging (MRI) could assist clinicians in deciding whether a donor kidney is suitable for transplantation. Aim of this study was to characterize the regional distribution of perfusate flow during NMP, to better understand how ex vivo kidney assessment protocols should eventually be designed. Nine porcine and 4 human discarded kidneys underwent 3 h of NMP in an MRI‐compatible perfusion setup. Arterial spin labeling scans were performed every 15 min, resulting in perfusion‐weighted images that visualize intrarenal flow distribution. At the start of NMP, all kidneys were mainly centrally perfused and it took time for the outer cortex to reach its physiological dominant perfusion state. Calculated corticomedullary ratios based on the perfusion maps reached a physiological range comparable to in vivo observations, but only after 1 to 2 h after the start of NMP. Before that, the functionally important renal cortex appeared severely underperfused. Our findings suggest that early functional NMP quality assessment markers may not reflect actual physiology and should therefore be interpreted with caution.
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Affiliation(s)
- Rianne Schutter
- Department of Surgery - Organ Donation and Transplantation, University of Groningen, University Medical Center, Groningen, The Netherlands
| | - Veerle A Lantinga
- Department of Surgery - Organ Donation and Transplantation, University of Groningen, University Medical Center, Groningen, The Netherlands
| | - Tim L Hamelink
- Department of Surgery - Organ Donation and Transplantation, University of Groningen, University Medical Center, Groningen, The Netherlands
| | - Merel B F Pool
- Department of Surgery - Organ Donation and Transplantation, University of Groningen, University Medical Center, Groningen, The Netherlands
| | - Otis C van Varsseveld
- Department of Surgery - Organ Donation and Transplantation, University of Groningen, University Medical Center, Groningen, The Netherlands
| | - Jan Hendrik Potze
- Department of Radiology, University of Groningen, University Medical Center, Groningen, The Netherlands
| | - Jan-Luuk Hillebrands
- Department of Pathology & Medical Biology, University of Groningen, University Medical Center, Groningen, The Netherlands
| | - Marius C van den Heuvel
- Department of Pathology & Medical Biology, University of Groningen, University Medical Center, Groningen, The Netherlands
| | - Rudi A J O Dierckx
- Department of Radiology, University of Groningen, University Medical Center, Groningen, The Netherlands.,Department of Nuclear Medicine, University of Groningen, University Medical Center, Groningen, The Netherlands
| | - Henri G D Leuvenink
- Department of Surgery - Organ Donation and Transplantation, University of Groningen, University Medical Center, Groningen, The Netherlands
| | - Cyril Moers
- Department of Surgery - Organ Donation and Transplantation, University of Groningen, University Medical Center, Groningen, The Netherlands
| | - Ronald J H Borra
- Department of Radiology, University of Groningen, University Medical Center, Groningen, The Netherlands.,Department of Nuclear Medicine, University of Groningen, University Medical Center, Groningen, The Netherlands
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10
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Wilcox CS, Testani JM, Pitt B. Pathophysiology of Diuretic Resistance and Its Implications for the Management of Chronic Heart Failure. Hypertension 2020; 76:1045-1054. [PMID: 32829662 PMCID: PMC10683075 DOI: 10.1161/hypertensionaha.120.15205] [Citation(s) in RCA: 54] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Diuretic resistance implies a failure to increase fluid and sodium (Na+) output sufficiently to relieve volume overload, edema, or congestion, despite escalating doses of a loop diuretic to a ceiling level (80 mg of furosemide once or twice daily or greater in those with reduced glomerular filtration rate or heart failure). It is a major cause of recurrent hospitalizations in patients with chronic heart failure and predicts death but is difficult to diagnose unequivocally. Pharmacokinetic mechanisms include the low and variable bioavailability of furosemide and the short duration of all loop diuretics that provides time for the kidneys to restore diuretic-induced Na+ losses between doses. Pathophysiological mechanisms of diuretic resistance include an inappropriately high daily salt intake that exceeds the acute diuretic-induced salt loss, hyponatremia or hypokalemic, hypochloremic metabolic alkalosis, and reflex activation of the renal nerves. Nephron mechanisms include tubular tolerance that can develop even during the time that the renal tubules are exposed to a single dose of diuretic, or enhanced reabsorption in the proximal tubule that limits delivery to the loop, or an adaptive increase in reabsorption in the downstream distal tubule and collecting ducts that offsets ongoing blockade of Na+ reabsorption in the loop of Henle. These provide rationales for novel strategies including the concurrent use of diuretics that block these nephron segments and even sequential nephron blockade with multiple diuretics and aquaretics combined in severely diuretic-resistant patients with heart failure.
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Affiliation(s)
- Christopher Stuart Wilcox
- From the Division of Nephrology and Hypertension and Hypertension Center, Georgetown University, Washington DC (C.S.W.)
| | | | - Bertram Pitt
- Division of Cardiology, University of Michigan, Ann Arbor, MI (B.P.)
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11
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Niendorf T, Seeliger E, Cantow K, Flemming B, Waiczies S, Pohlmann A. Probing renal blood volume with magnetic resonance imaging. Acta Physiol (Oxf) 2020; 228:e13435. [PMID: 31876349 DOI: 10.1111/apha.13435] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2019] [Revised: 12/18/2019] [Accepted: 12/19/2019] [Indexed: 02/06/2023]
Abstract
Damage to the kidney substantially reduces life expectancy. Renal tissue hypoperfusion and hypoxia are key elements in the pathophysiology of acute kidney injury and its progression to chronic kidney disease. In vivo assessment of renal haemodynamics and tissue oxygenation remains a challenge. Blood oxygenation level-dependent (BOLD) magnetic resonance imaging (MRI) is sensitive to changes in the effective transversal relaxation time (T2 *) in vivo, and is non-invasive and indicative of renal tissue oxygenation. However, the renal T2 * to tissue pO2 relationship is not governed exclusively by renal blood oxygenation, but is affected by physiological confounders with alterations in renal blood volume fraction (BVf) being of particular relevance. To decipher this interference probing renal BVf is essential for the pursuit of renal MR oximetry. Superparamagnetic iron oxide nanoparticle (USPIO) preparations can be used as MRI visible blood pool markers for detailing alterations in BVf. This review promotes the opportunities of MRI-based assessment of renal BVf. Following an outline on the specifics of renal oxygenation and perfusion, changes in renal BVf upon interventions and their potential impact on renal T2 * are discussed. We also describe the basic principles of renal BVf assessment using ferumoxytol-enhanced MRI in the equilibrium concentration regimen. We demonstrate that ferumoxytol does not alter control of renal haemodynamics and oxygenation. Preclinical applications of ferumoxytol enhanced renal MRI as well as considerations for its clinical implementation for examining renal BVf changes are provided alongside practical considerations. Finally, we explore the future directions of MRI-based assessment of renal BVf.
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Affiliation(s)
- Thoralf Niendorf
- Berlin Ultrahigh Field Facility (B.U.F.F.) Max Delbrück Center for Molecular Medicine in the Helmholtz Association Berlin Germany
| | - Erdmann Seeliger
- Institute of Physiology Charité – Universitätsmedizin Berlin Campus Mitte, and Center for Cardiovascular Research (CCR) Berlin Germany
| | - Kathleen Cantow
- Institute of Physiology Charité – Universitätsmedizin Berlin Campus Mitte, and Center for Cardiovascular Research (CCR) Berlin Germany
| | - Bert Flemming
- Institute of Physiology Charité – Universitätsmedizin Berlin Campus Mitte, and Center for Cardiovascular Research (CCR) Berlin Germany
| | - Sonia Waiczies
- Berlin Ultrahigh Field Facility (B.U.F.F.) Max Delbrück Center for Molecular Medicine in the Helmholtz Association Berlin Germany
| | - Andreas Pohlmann
- Berlin Ultrahigh Field Facility (B.U.F.F.) Max Delbrück Center for Molecular Medicine in the Helmholtz Association Berlin Germany
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12
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Nery F, Buchanan CE, Harteveld AA, Odudu A, Bane O, Cox EF, Derlin K, Gach HM, Golay X, Gutberlet M, Laustsen C, Ljimani A, Madhuranthakam AJ, Pedrosa I, Prasad PV, Robson PM, Sharma K, Sourbron S, Taso M, Thomas DL, Wang DJJ, Zhang JL, Alsop DC, Fain SB, Francis ST, Fernández-Seara MA. Consensus-based technical recommendations for clinical translation of renal ASL MRI. MAGMA (NEW YORK, N.Y.) 2019. [PMID: 31833014 DOI: 10.1007/s10334‐019‐00800‐z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
OBJECTIVES This study aimed at developing technical recommendations for the acquisition, processing and analysis of renal ASL data in the human kidney at 1.5 T and 3 T field strengths that can promote standardization of renal perfusion measurements and facilitate the comparability of results across scanners and in multi-centre clinical studies. METHODS An international panel of 23 renal ASL experts followed a modified Delphi process, including on-line surveys and two in-person meetings, to formulate a series of consensus statements regarding patient preparation, hardware, acquisition protocol, analysis steps and data reporting. RESULTS Fifty-nine statements achieved consensus, while agreement could not be reached on two statements related to patient preparation. As a default protocol, the panel recommends pseudo-continuous (PCASL) or flow-sensitive alternating inversion recovery (FAIR) labelling with a single-slice spin-echo EPI readout with background suppression and a simple but robust quantification model. DISCUSSION This approach is considered robust and reproducible and can provide renal perfusion images of adequate quality and SNR for most applications. If extended kidney coverage is desirable, a 2D multislice readout is recommended. These recommendations are based on current available evidence and expert opinion. Nonetheless they are expected to be updated as more data become available, since the renal ASL literature is rapidly expanding.
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Affiliation(s)
- Fabio Nery
- Developmental Imaging and Biophysics Section, UCL Great Ormond Street Institute of Child Health, London, UK
| | - Charlotte E Buchanan
- Sir Peter Mansfield Imaging Centre, School of Physics and Astronomy, University of Nottingham, Nottingham, UK
| | - Anita A Harteveld
- Department of Radiology, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands
| | - Aghogho Odudu
- Division of Cardiovascular Sciences, School of Medical Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK
| | - Octavia Bane
- Translational and Molecular Imaging Institute and Department of Radiology, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Eleanor F Cox
- Sir Peter Mansfield Imaging Centre, School of Physics and Astronomy, University of Nottingham, Nottingham, UK
| | - Katja Derlin
- Department of Radiology, Hannover Medical School, Hannover, Germany
| | - H Michael Gach
- Departments of Radiation Oncology, Radiology, and Biomedical Engineering, Washington University in St. Louis, St. Louis, MO, USA
| | - Xavier Golay
- Department of Brain Repair and Rehabilitation, UCL Queen Square Institute of Neurology, University College London, London, UK
| | - Marcel Gutberlet
- Department of Radiology, Hannover Medical School, Hannover, Germany
| | - Christoffer Laustsen
- MR Research Centre, Department of Clinical Medicine, Aarhus University, Aarhus, Denmark
| | - Alexandra Ljimani
- Department of Diagnostic and Interventional Radiology, Medical Faculty, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Ananth J Madhuranthakam
- Department of Radiology and Advanced Imaging Research Center, UT Southwestern Medical Center, Dallas, TX, USA
| | - Ivan Pedrosa
- Department of Radiology and Advanced Imaging Research Center, UT Southwestern Medical Center, Dallas, TX, USA
| | - Pottumarthi V Prasad
- Department of Radiology, Center for Advanced Imaging, NorthShore University Health System, Evanston, IL, USA
| | - Philip M Robson
- Translational and Molecular Imaging Institute and Department of Radiology, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Kanishka Sharma
- Imaging Biomarkers Group, Department of Biomedical Imaging Sciences, University of Leeds, Leeds, UK
| | - Steven Sourbron
- Imaging Biomarkers Group, Department of Biomedical Imaging Sciences, University of Leeds, Leeds, UK
| | - Manuel Taso
- Division of MRI Research, Department of Radiology, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA, USA
| | - David L Thomas
- Department of Brain Repair and Rehabilitation, UCL Queen Square Institute of Neurology, University College London, London, UK
| | - Danny J J Wang
- Stevens Neuroimaging and Informatics Institute, University of Southern California, Los Angeles, CA, USA
| | - Jeff L Zhang
- A.A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, Boston, USA
| | - David C Alsop
- Division of MRI Research, Department of Radiology, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA, USA
| | - Sean B Fain
- Departments of Medical Physics, Radiology, and Biomedical Engineering, University of Wisconsin, Madison, Madison, USA
| | - Susan T Francis
- Sir Peter Mansfield Imaging Centre, School of Physics and Astronomy, University of Nottingham, Nottingham, UK
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13
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Nery F, Buchanan CE, Harteveld AA, Odudu A, Bane O, Cox EF, Derlin K, Gach HM, Golay X, Gutberlet M, Laustsen C, Ljimani A, Madhuranthakam AJ, Pedrosa I, Prasad PV, Robson PM, Sharma K, Sourbron S, Taso M, Thomas DL, Wang DJJ, Zhang JL, Alsop DC, Fain SB, Francis ST, Fernández-Seara MA. Consensus-based technical recommendations for clinical translation of renal ASL MRI. MAGNETIC RESONANCE MATERIALS IN PHYSICS BIOLOGY AND MEDICINE 2019; 33:141-161. [PMID: 31833014 PMCID: PMC7021752 DOI: 10.1007/s10334-019-00800-z] [Citation(s) in RCA: 67] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/05/2019] [Revised: 11/08/2019] [Accepted: 11/11/2019] [Indexed: 12/14/2022]
Abstract
Objectives This study aimed at developing technical recommendations for the acquisition, processing and analysis of renal ASL data in the human kidney at 1.5 T and 3 T field strengths that can promote standardization of renal perfusion measurements and facilitate the comparability of results across scanners and in multi-centre clinical studies. Methods An international panel of 23 renal ASL experts followed a modified Delphi process, including on-line surveys and two in-person meetings, to formulate a series of consensus statements regarding patient preparation, hardware, acquisition protocol, analysis steps and data reporting. Results Fifty-nine statements achieved consensus, while agreement could not be reached on two statements related to patient preparation. As a default protocol, the panel recommends pseudo-continuous (PCASL) or flow-sensitive alternating inversion recovery (FAIR) labelling with a single-slice spin-echo EPI readout with background suppression and a simple but robust quantification model. Discussion This approach is considered robust and reproducible and can provide renal perfusion images of adequate quality and SNR for most applications. If extended kidney coverage is desirable, a 2D multislice readout is recommended. These recommendations are based on current available evidence and expert opinion. Nonetheless they are expected to be updated as more data become available, since the renal ASL literature is rapidly expanding. Electronic supplementary material The online version of this article (10.1007/s10334-019-00800-z) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Fabio Nery
- Developmental Imaging and Biophysics Section, UCL Great Ormond Street Institute of Child Health, London, UK
| | - Charlotte E Buchanan
- Sir Peter Mansfield Imaging Centre, School of Physics and Astronomy, University of Nottingham, Nottingham, UK
| | - Anita A Harteveld
- Department of Radiology, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands
| | - Aghogho Odudu
- Division of Cardiovascular Sciences, School of Medical Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK
| | - Octavia Bane
- Translational and Molecular Imaging Institute and Department of Radiology, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Eleanor F Cox
- Sir Peter Mansfield Imaging Centre, School of Physics and Astronomy, University of Nottingham, Nottingham, UK
| | - Katja Derlin
- Department of Radiology, Hannover Medical School, Hannover, Germany
| | - H Michael Gach
- Departments of Radiation Oncology, Radiology, and Biomedical Engineering, Washington University in St. Louis, St. Louis, MO, USA
| | - Xavier Golay
- Department of Brain Repair and Rehabilitation, UCL Queen Square Institute of Neurology, University College London, London, UK
| | - Marcel Gutberlet
- Department of Radiology, Hannover Medical School, Hannover, Germany
| | - Christoffer Laustsen
- MR Research Centre, Department of Clinical Medicine, Aarhus University, Aarhus, Denmark
| | - Alexandra Ljimani
- Department of Diagnostic and Interventional Radiology, Medical Faculty, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Ananth J Madhuranthakam
- Department of Radiology and Advanced Imaging Research Center, UT Southwestern Medical Center, Dallas, TX, USA
| | - Ivan Pedrosa
- Department of Radiology and Advanced Imaging Research Center, UT Southwestern Medical Center, Dallas, TX, USA
| | - Pottumarthi V Prasad
- Department of Radiology, Center for Advanced Imaging, NorthShore University Health System, Evanston, IL, USA
| | - Philip M Robson
- Translational and Molecular Imaging Institute and Department of Radiology, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Kanishka Sharma
- Imaging Biomarkers Group, Department of Biomedical Imaging Sciences, University of Leeds, Leeds, UK
| | - Steven Sourbron
- Imaging Biomarkers Group, Department of Biomedical Imaging Sciences, University of Leeds, Leeds, UK
| | - Manuel Taso
- Division of MRI Research, Department of Radiology, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA, USA
| | - David L Thomas
- Department of Brain Repair and Rehabilitation, UCL Queen Square Institute of Neurology, University College London, London, UK
| | - Danny J J Wang
- Stevens Neuroimaging and Informatics Institute, University of Southern California, Los Angeles, CA, USA
| | - Jeff L Zhang
- A.A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, Boston, USA
| | - David C Alsop
- Division of MRI Research, Department of Radiology, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA, USA
| | - Sean B Fain
- Departments of Medical Physics, Radiology, and Biomedical Engineering, University of Wisconsin, Madison, Madison, USA
| | - Susan T Francis
- Sir Peter Mansfield Imaging Centre, School of Physics and Astronomy, University of Nottingham, Nottingham, UK
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14
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Zöllner FG, Šerifović-Trbalić A, Kabelitz G, Kociński M, Materka A, Rogelj P. Image registration in dynamic renal MRI-current status and prospects. MAGNETIC RESONANCE MATERIALS IN PHYSICS BIOLOGY AND MEDICINE 2019; 33:33-48. [PMID: 31598799 PMCID: PMC7210245 DOI: 10.1007/s10334-019-00782-y] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 06/30/2019] [Revised: 09/16/2019] [Accepted: 09/25/2019] [Indexed: 12/26/2022]
Abstract
Magnetic resonance imaging (MRI) modalities have achieved an increasingly important role in the clinical work-up of chronic kidney diseases (CKD). This comprises among others assessment of hemodynamic parameters by arterial spin labeling (ASL) or dynamic contrast-enhanced (DCE-) MRI. Especially in the latter, images or volumes of the kidney are acquired over time for up to several minutes. Therefore, they are hampered by motion, e.g., by pulsation, peristaltic, or breathing motion. This motion can hinder subsequent image analysis to estimate hemodynamic parameters like renal blood flow or glomerular filtration rate (GFR). To overcome motion artifacts in time-resolved renal MRI, a wide range of strategies have been proposed. Renal image registration approaches could be grouped into (1) image acquisition techniques, (2) post-processing methods, or (3) a combination of image acquisition and post-processing approaches. Despite decades of progress, the translation in clinical practice is still missing. The aim of the present article is to discuss the existing literature on renal image registration techniques and show today’s limitations of the proposed techniques that hinder clinical translation. This paper includes transformation, criterion function, and search types as traditional components and emerging registration technologies based on deep learning. The current trend points towards faster registrations and more accurate results. However, a standardized evaluation of image registration in renal MRI is still missing.
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Affiliation(s)
- Frank G Zöllner
- Computer Assisted Clinical Medicine, Medical Faculty Mannheim, Heidelberg University, Theodor-Kutzer-Ufer 1-3, 68167, Mannheim, Germany.
| | | | - Gordian Kabelitz
- Computer Assisted Clinical Medicine, Medical Faculty Mannheim, Heidelberg University, Theodor-Kutzer-Ufer 1-3, 68167, Mannheim, Germany
| | - Marek Kociński
- Institute of Electronics, Lodz University of Technology, Lodz, Poland
| | - Andrzej Materka
- Institute of Electronics, Lodz University of Technology, Lodz, Poland
| | - Peter Rogelj
- Faculty of Mathematics, Natural Sciences and Information Technologies, University of Primorska, Koper, Slovenia
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15
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Hellms S, Gueler F, Gutberlet M, Schebb NH, Rund K, Kielstein JT, VoChieu V, Rauhut S, Greite R, Martirosian P, Haller H, Wacker F, Derlin K. Single-dose diclofenac in healthy volunteers can cause decrease in renal perfusion measured by functional magnetic resonance imaging. ACTA ACUST UNITED AC 2019; 71:1262-1270. [PMID: 31131893 DOI: 10.1111/jphp.13105] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2019] [Accepted: 04/22/2019] [Indexed: 12/18/2022]
Abstract
OBJECTIVES We investigated changes of renal perfusion after topical and oral diclofenac administration in healthy volunteers using functional magnetic resonance imaging (MRI) with arterial spin labelling (ASL). METHODS Twenty-four healthy human participants (21-51 years) underwent 1.5T MRI before and 1 h after a single oral dose of diclofenac (50 mg). Twelve of 24 participants underwent an additional MRI examination following 3-day topical diclofenac administration. For renal perfusion imaging, a flow-sensitive alternating inversion-recovery TrueFISP ASL sequence was applied. Plasma concentrations of diclofenac and serum concentrations of thromboxane were determined. KEY FINDINGS After oral diclofenac application, large interindividual differences in plasma concentrations were observed (range <3-4604 nm). Topical diclofenac application did not result in relevant systemic diclofenac levels (range 5-75 nm). MRI showed a significant reduction of renal perfusion in individuals with diclofenac levels ≥225 nm (baseline: 347 ± 7 vs diclofenac: 323 ± 8 ml/min/100 g, P < 0.01); no significant differences were observed in participants with diclofenac levels <225 nm. Diclofenac levels correlated negatively with thromboxane B2 levels pointing towards target engagement. CONCLUSIONS Single-dose diclofenac caused a decrease in renal perfusion in participants with diclofenac levels ≥225 nm. We demonstrated that even a single dose of diclofenac can impair renal perfusion, which could be detrimental in patients with underlying chronic kidney disease or acute kidney injury.
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Affiliation(s)
- Susanne Hellms
- Institute for Diagnostic and Interventional Radiology, Hannover Medical School, Hannover, Germany
| | - Faikah Gueler
- Nephrology Hannover Medical School, Hannover, Germany
| | - Marcel Gutberlet
- Institute for Diagnostic and Interventional Radiology, Hannover Medical School, Hannover, Germany
| | - Nils Helge Schebb
- Institute for Food Toxicology and Analytical Chemistry, University of Veterinary Medicine Hannover, Hannover, Germany.,Food Chemistry, Faculty of Mathematics and Natural Sciences, University of Wuppertal, Wuppertal, Germany
| | - Katharina Rund
- Institute for Food Toxicology and Analytical Chemistry, University of Veterinary Medicine Hannover, Hannover, Germany
| | - Jan T Kielstein
- Medical Clinic V (Nephrology, Rheumatology, Blood Purification), Academic Teaching Hospital Braunschweig, Braunschweig, Germany
| | - VanDai VoChieu
- Institute for Diagnostic and Interventional Radiology, Hannover Medical School, Hannover, Germany
| | | | - Robert Greite
- Nephrology Hannover Medical School, Hannover, Germany
| | - Petros Martirosian
- Section on Experimental Radiology, University of Tuebingen, Tübingen, Germany
| | | | - Frank Wacker
- Institute for Diagnostic and Interventional Radiology, Hannover Medical School, Hannover, Germany
| | - Katja Derlin
- Institute for Diagnostic and Interventional Radiology, Hannover Medical School, Hannover, Germany
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Nery F, De Vita E, Clark CA, Gordon I, Thomas DL. Robust kidney perfusion mapping in pediatric chronic kidney disease using single-shot 3D-GRASE ASL with optimized retrospective motion correction. Magn Reson Med 2018; 81:2972-2984. [PMID: 30536817 DOI: 10.1002/mrm.27614] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2018] [Revised: 10/24/2018] [Accepted: 10/25/2018] [Indexed: 12/18/2022]
Abstract
PURPOSE To develop a robust renal arterial spin labeling (ASL) acquisition and processing strategy for mapping renal blood flow (RBF) in a pediatric cohort with severe kidney disease. METHODS A single-shot background-suppressed 3D gradient and spin-echo (GRASE) flow-sensitive alternating inversion recovery (FAIR) ASL acquisition method was used to perform 2 studies. First, an evaluation of the feasibility of single-shot 3D-GRASE and retrospective noise reduction methods was performed in healthy volunteers. Second, a pediatric cohort with severe chronic kidney disease underwent single-shot 3D-GRASE FAIR ASL and RBF was quantified following several retrospective motion correction pipelines, including image registration and threshold-free weighted averaging. The effect of motion correction on the fit errors of saturation recovery (SR) images (required for RBF quantification) and on the perfusion-weighted image (PWI) temporal signal-to-noise ratio (tSNR) was evaluated, as well as the intra- and inter-session repeatability of renal longitudinal relaxation time (T1 ) and RBF. RESULTS The mean cortical and/or functional renal parenchyma RBF in healthy volunteers and CKD patients was 295 ± 97 and 95 ± 47 mL/100 g/min, respectively. Motion-correction reduced image artefacts in both T1 and RBF maps, significantly reduced SR fit errors, significantly increased the PWI tSNR and improved the improved the repeatability of T1 and RBF in the pediatric patient cohort. CONCLUSION Single-shot 3D-GRASE ASL combined with retrospective motion correction enabled repeatable non-invasive RBF mapping in the first pediatric cohort with severe kidney disease undergoing ASL scans.
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Affiliation(s)
- Fabio Nery
- Developmental Imaging and Biophysics Section, University College London Great Ormond Street Institute of Child Health, London, United Kingdom
| | - Enrico De Vita
- Department of Biomedical Engineering, School of Biomedical Engineering & Imaging Sciences, King's College London, King's Health Partners, St Thomas' Hospital, London, United Kingdom
| | - Chris A Clark
- Developmental Imaging and Biophysics Section, University College London Great Ormond Street Institute of Child Health, London, United Kingdom
| | - Isky Gordon
- Developmental Imaging and Biophysics Section, University College London Great Ormond Street Institute of Child Health, London, United Kingdom
| | - David L Thomas
- Department of Brain Repair and Rehabilitation, University College London Queen Square Institute of Neurology, Queen Square, London, United Kingdom.,Leonard Wolfson Experimental Neurology Centre, University College London Queen Square Institute of Neurology, Queen Square, London, United Kingdom
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17
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Odudu A, Nery F, Harteveld AA, Evans RG, Pendse D, Buchanan CE, Francis ST, Fernández-Seara MA. Arterial spin labelling MRI to measure renal perfusion: a systematic review and statement paper. Nephrol Dial Transplant 2018; 33:ii15-ii21. [PMID: 30137581 PMCID: PMC6106644 DOI: 10.1093/ndt/gfy180] [Citation(s) in RCA: 73] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2018] [Accepted: 05/15/2018] [Indexed: 01/03/2023] Open
Abstract
Renal perfusion provides the driving pressure for glomerular filtration and delivers the oxygen and nutrients to fuel solute reabsorption. Renal ischaemia is a major mechanism in acute kidney injury and may promote the progression of chronic kidney disease. Thus, quantifying renal tissue perfusion is critically important for both clinicians and physiologists. Current reference techniques for assessing renal tissue perfusion have significant limitations. Arterial spin labelling (ASL) is a magnetic resonance imaging (MRI) technique that uses magnetic labelling of water in arterial blood as an endogenous tracer to generate maps of absolute regional perfusion without requiring exogenous contrast. The technique holds enormous potential for clinical use but remains restricted to research settings. This statement paper from the PARENCHIMA network briefly outlines the ASL technique and reviews renal perfusion data in 53 studies published in English through January 2018. Renal perfusion by ASL has been validated against reference methods and has good reproducibility. Renal perfusion by ASL reduces with age and excretory function. Technical advancements mean that a renal ASL study can acquire a whole kidney perfusion measurement in less than 5-10 min. The short acquisition time permits combination with other MRI techniques that might inform drug mechanisms and renal physiology. The flexibility of renal ASL has yielded several variants of the technique, but there are limited data comparing these approaches. We make recommendations for acquiring and reporting renal ASL data and outline the knowledge gaps that future research should address.
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Affiliation(s)
- Aghogho Odudu
- Division of Cardiovascular Sciences, School of Medical Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK
| | - Fabio Nery
- Developmental Imaging & Biophysics Section, University College London, Great Ormond Street Institute of Child Health, London, UK
| | - Anita A Harteveld
- Department of Radiology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Roger G Evans
- Department of Physiology, Cardiovascular Disease Program, Biomedicine Discovery Institute, Monash University, Melbourne, Victoria, Australia
| | - Douglas Pendse
- Centre for Medical Imaging, University College London, London, UK
| | - Charlotte E Buchanan
- Sir Peter Mansfield Imaging Centre, School of Physics and Astronomy, University of Nottingham, Nottingham, UK
| | - Susan T Francis
- Sir Peter Mansfield Imaging Centre, School of Physics and Astronomy, University of Nottingham, Nottingham, UK
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18
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Shirvani S, Tokarczuk P, Statton B, Quinlan M, Berry A, Tomlinson J, Weale P, Kühn B, O'Regan DP. Motion-corrected multiparametric renal arterial spin labelling at 3 T: reproducibility and effect of vasodilator challenge. Eur Radiol 2018; 29:232-240. [PMID: 29992384 PMCID: PMC6291439 DOI: 10.1007/s00330-018-5628-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2018] [Revised: 06/14/2018] [Accepted: 06/22/2018] [Indexed: 02/02/2023]
Abstract
OBJECTIVES We investigated the feasibility and reproducibility of free-breathing motion-corrected multiple inversion time (multi-TI) pulsed renal arterial spin labelling (PASL), with general kinetic model parametric mapping, to simultaneously quantify renal perfusion (RBF), bolus arrival time (BAT) and tissue T1. METHODS In a study approved by the Health Research Authority, 12 healthy volunteers (mean age, 27.6 ± 18.5 years; 5 male) gave informed consent for renal imaging at 3 T using multi-TI ASL and conventional single-TI ASL. Glyceryl trinitrate (GTN) was used as a vasodilator challenge in six subjects. Flow-sensitive alternating inversion recovery (FAIR) preparation was used with background suppression and 3D-GRASE (gradient and spin echo) read-out, and images were motion-corrected. Parametric maps of RBF, BAT and T1 were derived for both kidneys. Agreement was assessed using Pearson correlation and Bland-Altman plots. RESULTS Inter-study correlation of whole-kidney RBF was good for both single-TI (r2 = 0.90), and multi-TI ASL (r2 = 0.92). Single-TI ASL gave a higher estimate of whole-kidney RBF compared to multi-TI ASL (mean bias, 29.3 ml/min/100 g; p <0.001). Using multi-TI ASL, the median T1 of renal cortex was shorter than that of medulla (799.6 ms vs 807.1 ms, p = 0.01), and mean whole-kidney BAT was 269.7 ± 56.5 ms. GTN had an effect on systolic blood pressure (p < 0.05) but the change in RBF was not significant. CONCLUSIONS Free-breathing multi-TI renal ASL is feasible and reproducible at 3 T, providing simultaneous measurement of renal perfusion, haemodynamic parameters and tissue characteristics at baseline and during pharmacological challenge. KEY POINTS • Multiple inversion time arterial spin labelling (ASL) of the kidneys is feasible and reproducible at 3 T. • This approach allows simultaneous mapping of renal perfusion, bolus arrival time and tissue T 1 during free breathing. • This technique enables repeated measures of renal haemodynamic characteristics during pharmacological challenge.
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Affiliation(s)
- Saba Shirvani
- Medical Research Council (MRC), London Institute of Medical Sciences (LMS), Imperial College London, Hammersmith Hospital Campus, Du Cane Road, London, W12 0NN, UK
- Department of Chemistry, Imperial College London, South Kensington Campus, Exhibition Road, London, UK
| | - Paweł Tokarczuk
- Medical Research Council (MRC), London Institute of Medical Sciences (LMS), Imperial College London, Hammersmith Hospital Campus, Du Cane Road, London, W12 0NN, UK
| | - Ben Statton
- Medical Research Council (MRC), London Institute of Medical Sciences (LMS), Imperial College London, Hammersmith Hospital Campus, Du Cane Road, London, W12 0NN, UK
| | - Marina Quinlan
- Medical Research Council (MRC), London Institute of Medical Sciences (LMS), Imperial College London, Hammersmith Hospital Campus, Du Cane Road, London, W12 0NN, UK
| | - Alaine Berry
- Medical Research Council (MRC), London Institute of Medical Sciences (LMS), Imperial College London, Hammersmith Hospital Campus, Du Cane Road, London, W12 0NN, UK
| | - James Tomlinson
- Medical Research Council (MRC), London Institute of Medical Sciences (LMS), Imperial College London, Hammersmith Hospital Campus, Du Cane Road, London, W12 0NN, UK
| | | | - Bernd Kühn
- Siemens Healthcare GmbH, Erlangen, Germany
| | - Declan P O'Regan
- Medical Research Council (MRC), London Institute of Medical Sciences (LMS), Imperial College London, Hammersmith Hospital Campus, Du Cane Road, London, W12 0NN, UK.
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Hall ME, Jordan JH, Juncos LA, Hundley WG, Hall JE. BOLD magnetic resonance imaging in nephrology. Int J Nephrol Renovasc Dis 2018; 11:103-112. [PMID: 29559807 PMCID: PMC5856054 DOI: 10.2147/ijnrd.s112299] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Magnetic resonance (MR) imaging, a non-invasive modality that provides anatomic and physiologic information, is increasingly used for diagnosis of pathophysiologic conditions and for understanding renal physiology in humans. Although functional MR imaging methods were pioneered to investigate the brain, they also offer powerful techniques for investigation of other organ systems such as the kidneys. However, imaging the kidneys provides unique challenges due to potential complications from contrast agents. Therefore, development of non-contrast techniques to study kidney anatomy and physiology is important. Blood oxygen level-dependent (BOLD) MR is a non-contrast imaging technique that provides functional information related to renal tissue oxygenation in various pathophysiologic conditions. Here we discuss technical considerations, clinical uses and future directions for use of BOLD MR as well as complementary MR techniques to better understand renal pathophysiology. Our intent is to summarize kidney BOLD MR applications for the clinician rather than focusing on the complex physical challenges that functional MR imaging encompasses; however, we briefly discuss some of those issues.
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Affiliation(s)
- Michael E Hall
- Department of Medicine, University of Mississippi Medical Center, Jackson, MS, USA.,Department of Physiology and Biophysics, University of Mississippi Medical Center, Jackson, MS, USA
| | - Jennifer H Jordan
- Department of Internal Medicine, Section on Cardiovascular Medicine, Wake Forest University School of Medicine, Winston-Salem, NC, USA
| | - Luis A Juncos
- Department of Medicine, University of Mississippi Medical Center, Jackson, MS, USA.,Department of Physiology and Biophysics, University of Mississippi Medical Center, Jackson, MS, USA
| | - W Gregory Hundley
- Department of Internal Medicine, Section on Cardiovascular Medicine, Wake Forest University School of Medicine, Winston-Salem, NC, USA
| | - John E Hall
- Department of Physiology and Biophysics, University of Mississippi Medical Center, Jackson, MS, USA
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20
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Lubas A, Kade G, Saracyn M, Niemczyk S, Dyrla P. Dynamic tissue perfusion assessment reflects associations between antihypertensive treatment and renal cortical perfusion in patients with chronic kidney disease and hypertension. Int Urol Nephrol 2018; 50:509-516. [PMID: 29374813 PMCID: PMC5845077 DOI: 10.1007/s11255-018-1798-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2017] [Accepted: 01/15/2018] [Indexed: 02/07/2023]
Abstract
PURPOSE Renal cortical perfusion measured in noninvasive, dynamic ultrasonic method is connected with the hemodynamic cardiac properties and renal function. Antihypertensive drugs affect the functioning of the heart and kidneys. The aim of the study was to evaluate the effect of a chronic use of antihypertensive drugs on ultrasound parameters of renal cortical perfusion. METHODS The study included 56 consecutive patients (49 M + 7 F, age 54.0 ± 13.3) with stable chronic kidney disease and hypertension. Color Doppler dynamic tissue perfusion measurement was used to assess renal cortical perfusion. RESULTS Patients were treated with a mean of 2.7 ± 1.4 antihypertensive drugs, of which diuretics accounted for 25%, angiotensin-converting enzyme inhibitors (ACE-I) together with angiotensin receptor blockers (ARB) 24%, beta-blockers (BB) 23%, calcium channel blockers 16%, alpha-1 blockers (α1B) 9% and centrally acting drugs 3%. All investigated groups of drugs correlated significantly with parameters of renal perfusion. In multivariable regression analyses adjusted to age, diuretics were connected with the decrease (r = - 0.473) and ACE-I + ARB (r = 0.390) with the improvement of proximal and whole renal cortex perfusion (R2 = 0.28; p < 0.001), whereas BB (r = - 0.372) and α1B (r = - 0.280) independently correlated with worsened perfusion of renal distal cortex (R2 = 0.21, p < 0.01). CONCLUSIONS The type of antihypertensive therapy had a significant influence on the ultrasound parameters of renal cortical perfusion. Noninvasive, ultrasonic dynamic tissue perfusion measurement method appears to be an adequate tool to assess the impact of drugs on renal cortical perfusion.
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Affiliation(s)
- Arkadiusz Lubas
- Department of Internal Diseases, Nephrology and Dialysis, Military Institute of Medicine, Szaserów str. 128, 04-141, Warsaw, Poland.
| | - Grzegorz Kade
- Department of Internal Diseases, Nephrology and Dialysis, Military Institute of Medicine, Szaserów str. 128, 04-141, Warsaw, Poland
| | - Marek Saracyn
- Department of Endocrinology and Isotope Therapy, Military Institute of Medicine, Szaserów str. 128, 04-141, Warsaw, Poland
| | - Stanisław Niemczyk
- Department of Internal Diseases, Nephrology and Dialysis, Military Institute of Medicine, Szaserów str. 128, 04-141, Warsaw, Poland
| | - Przemysław Dyrla
- Department of Gastroenterology, Military Institute of Medicine, Szaserów str. 128, 04-141, Warsaw, Poland
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21
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Non-Invasive Renal Perfusion Imaging Using Arterial Spin Labeling MRI: Challenges and Opportunities. Diagnostics (Basel) 2018; 8:diagnostics8010002. [PMID: 29303965 PMCID: PMC5871985 DOI: 10.3390/diagnostics8010002] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2017] [Revised: 12/25/2017] [Accepted: 01/02/2018] [Indexed: 12/28/2022] Open
Abstract
Tissue perfusion allows for delivery of oxygen and nutrients to tissues, and in the kidneys is also a key determinant of glomerular filtration. Quantification of regional renal perfusion provides a potential window into renal (patho) physiology. However, non-invasive, practical, and robust methods to measure renal perfusion remain elusive, particularly in the clinic. Arterial spin labeling (ASL), a magnetic resonance imaging (MRI) technique, is arguably the only available method with potential to meet all these needs. Recent developments suggest its viability for clinical application. This review addresses several of these developments and discusses remaining challenges with the emphasis on renal imaging in human subjects.
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22
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Mikkelsen EFR, Mariager CØ, Nørlinger T, Qi H, Schulte RF, Jakobsen S, Frøkiær J, Pedersen M, Stødkilde-Jørgensen H, Laustsen C. Hyperpolarized [1- 13C]-acetate Renal Metabolic Clearance Rate Mapping. Sci Rep 2017; 7:16002. [PMID: 29167446 PMCID: PMC5700138 DOI: 10.1038/s41598-017-15929-x] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2017] [Accepted: 11/03/2017] [Indexed: 01/02/2023] Open
Abstract
11C-acetate is a positron emission tomography (PET) tracer of oxidative metabolism, whereas hyperpolarized 13C-acetate can be used in magnetic resonance imaging (MRI) for investigating specific metabolic processes. The aims of this study were to examine if the kinetic formalism of 11C-acetate PET in the kidneys is comparable to that of 13C-acetate MRI, and to compare the dynamic metabolic information of hyperpolarized 13C-acetate MRI with that obtained with 11C-acetate PET. Rats were examined with dynamic hyperpolarized 13C-acetate MRI or 11C-acetate PET before and after intravenous injection of furosemide, a loop diuretic known to alter both the hemodynamics and oxygen consumption in the kidney. The metabolic clearance rates (MCR) were estimated and compared between the two modalities experimentally in vivo and in simulations. There was a clear dependency on the mean transit time and MCR for both 13C-acetate and 11C-acetate following furosemide administration, while no dependencies on the apparent renal perfusion were observed. This study demonstrated that hyperpolarized 13C-acetate MRI is feasible for measurements of the intrarenal energetic demand via the MCR, and that the quantitative measures are correlated with those measured by 11C-acetate PET, even though the temporal window is more than 30 times longer with 11C-acetate.
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Affiliation(s)
- Emmeli F R Mikkelsen
- MR Research Centre, Aarhus University Hospital, Palle Juul-Jensens Boulevard 99, 8200, Aarhus N, Denmark.,Comparative Medicine Lab, Aarhus University Hospital, Palle Juul-Jensens Boulevard 99, 8200, Aarhus N, Denmark
| | | | - Thomas Nørlinger
- MR Research Centre, Aarhus University Hospital, Palle Juul-Jensens Boulevard 99, 8200, Aarhus N, Denmark.,Comparative Medicine Lab, Aarhus University Hospital, Palle Juul-Jensens Boulevard 99, 8200, Aarhus N, Denmark
| | - Haiyun Qi
- MR Research Centre, Aarhus University Hospital, Palle Juul-Jensens Boulevard 99, 8200, Aarhus N, Denmark
| | - Rolf F Schulte
- GE healthcare, Freisinger Landstraße 50, 85748, Munich, Germany
| | - Steen Jakobsen
- Department of Nuclear Medicine and PET Center, Aarhus University Hospital, Nørrebrogade, 8000, Aarhus C, Denmark
| | - Jørgen Frøkiær
- Department of Nuclear Medicine and PET Center, Aarhus University Hospital, Nørrebrogade, 8000, Aarhus C, Denmark
| | - Michael Pedersen
- Comparative Medicine Lab, Aarhus University Hospital, Palle Juul-Jensens Boulevard 99, 8200, Aarhus N, Denmark
| | - Hans Stødkilde-Jørgensen
- MR Research Centre, Aarhus University Hospital, Palle Juul-Jensens Boulevard 99, 8200, Aarhus N, Denmark
| | - Christoffer Laustsen
- MR Research Centre, Aarhus University Hospital, Palle Juul-Jensens Boulevard 99, 8200, Aarhus N, Denmark.
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23
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Kirpalani A, Hashim E, Leung G, Kim JK, Krizova A, Jothy S, Deeb M, Jiang NN, Glick L, Mnatzakanian G, Yuen DA. Magnetic Resonance Elastography to Assess Fibrosis in Kidney Allografts. Clin J Am Soc Nephrol 2017; 12:1671-1679. [PMID: 28855238 PMCID: PMC5628708 DOI: 10.2215/cjn.01830217] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2017] [Accepted: 06/26/2017] [Indexed: 01/06/2023]
Abstract
BACKGROUND AND OBJECTIVES Fibrosis is a major cause of kidney allograft injury. Currently, the only means of assessing allograft fibrosis is by biopsy, an invasive procedure that samples <1% of the kidney. We examined whether magnetic resonance elastography, an imaging-based measure of organ stiffness, could noninvasively estimate allograft fibrosis and predict progression of allograft dysfunction. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS Kidney allograft recipients >1 year post-transplant undergoing an allograft biopsy first underwent free-breathing, flow-compensated magnetic resonance elastography on a 3.0-T magnetic resonance imaging scanner. Each patient had serial eGFR measurements after the elastography scan for a follow-up period of up to 1 year. The mean stiffness value of the kidney allograft was compared with both the histopathologic Banff fibrosis score and the rate of eGFR change during the follow-up period. RESULTS Sixteen patients who underwent magnetic resonance elastography and biopsy were studied (mean age: 54±9 years old). Whole-kidney mean stiffness ranged between 3.5 and 7.3 kPa. Whole-kidney stiffness correlated with biopsy-derived Banff fibrosis score (Spearman rho =0.67; P<0.01). Stiffness was heterogeneously distributed within each kidney, providing a possible explanation for the lack of a stronger stiffness-fibrosis correlation. We also found negative correlations between whole-kidney stiffness and both baseline eGFR (Spearman rho =-0.65; P<0.01) and eGFR change over time (Spearman rho =-0.70; P<0.01). Irrespective of the baseline eGFR, increased kidney stiffness was associated with a greater eGFR decline (regression r2=0.48; P=0.03). CONCLUSIONS Given the limitations of allograft biopsy, our pilot study suggests the potential for magnetic resonance elastography as a novel noninvasive measure of whole-allograft fibrosis burden that may predict future changes in kidney function. Future studies exploring the utility and accuracy of magnetic resonance elastography are needed.
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Affiliation(s)
- Anish Kirpalani
- Departments of Medical Imaging and
- Li Ka Shing Knowledge Institute and
| | | | - General Leung
- Departments of Medical Imaging and
- Li Ka Shing Knowledge Institute and
| | | | | | | | - Maya Deeb
- Division of Nephrology, Department of Medicine, St. Michael’s Hospital and University of Toronto, Toronto, Ontario, Canada; and
| | | | - Lauren Glick
- Keenan Research Centre for Biomedical Science, St. Michael’s Hospital, Toronto, Ontario, Canada
| | | | - Darren A. Yuen
- Division of Nephrology, Department of Medicine, St. Michael’s Hospital and University of Toronto, Toronto, Ontario, Canada; and
- Keenan Research Centre for Biomedical Science, St. Michael’s Hospital, Toronto, Ontario, Canada
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24
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Romero CA, Cabral G, Knight RA, Ding G, Peterson EL, Carretero OA. Noninvasive measurement of renal blood flow by magnetic resonance imaging in rats. Am J Physiol Renal Physiol 2017; 314:F99-F106. [PMID: 28978533 DOI: 10.1152/ajprenal.00332.2017] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Renal blood flow (RBF) provides important information regarding renal physiology and nephropathies. Arterial spin labeling-magnetic resonance imaging (ASL-MRI) is a noninvasive method of measuring blood flow without exogenous contrast media. However, low signal-to-noise ratio and respiratory motion artifacts are challenges for RBF measurements in small animals. Our objective was to evaluate the feasibility and reproducibility of RBF measurements by ASL-MRI using respiratory-gating and navigator correction methods to reduce motion artifacts. ASL-MRI images were obtained from the kidneys of Sprague-Dawley (SD) rats on a 7-Tesla Varian MRI system with a spin-echo imaging sequence. After 4 days, the study was repeated to evaluate its reproducibility. RBF was also measured in animals under unilateral nephrectomy and in renal artery stenosis (RST) to evaluate the sensitivity in high and low RBF models, respectively. RBF was also evaluated in Dahl salt-sensitive (SS) rats and spontaneous hypertensive rats (SHR). In SD rats, the cortical RBFs (cRBF) were 305 ± 59 and 271.8 ± 39 ml·min-1·100 g tissue-1 in the right and left kidneys, respectively. Retest analysis revealed no differences ( P = 0.2). The test-retest reliability coefficient was 92 ± 5%. The cRBFs before and after the nephrectomy were 296.8 ± 30 and 428.2 ± 45 ml·min-1·100 g tissue-1 ( P = 0.02), respectively. The kidneys with RST exhibited a cRBF decrease compared with sham animals (86 ± 17.6 vs. 198 ± 33.7 ml·min-1·100 g tissue-1; P < 0.01). The cRBFs in SD, Dahl-SS, and SHR rats were not different ( P = 0.35). We conclude that ASL-MRI performed with navigator correction and respiratory gating is a feasible and reliable noninvasive method for measuring RBF in rats.
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Affiliation(s)
- Cesar A Romero
- Hypertension and Vascular Research Division, Department of Internal Medicine, Henry Ford Hospital , Detroit, Michigan
| | - Glauber Cabral
- Department of Neurology-NMR Research, Henry Ford Hospital , Detroit, Michigan
| | - Robert A Knight
- Department of Neurology-NMR Research, Henry Ford Hospital , Detroit, Michigan
| | - Guangliang Ding
- Department of Neurology-NMR Research, Henry Ford Hospital , Detroit, Michigan
| | - Edward L Peterson
- Department of Public Health Sciences, Henry Ford Hospital , Detroit, Michigan
| | - Oscar A Carretero
- Hypertension and Vascular Research Division, Department of Internal Medicine, Henry Ford Hospital , Detroit, Michigan
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25
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Cox EF, Buchanan CE, Bradley CR, Prestwich B, Mahmoud H, Taal M, Selby NM, Francis ST. Multiparametric Renal Magnetic Resonance Imaging: Validation, Interventions, and Alterations in Chronic Kidney Disease. Front Physiol 2017; 8:696. [PMID: 28959212 PMCID: PMC5603702 DOI: 10.3389/fphys.2017.00696] [Citation(s) in RCA: 84] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2017] [Accepted: 08/30/2017] [Indexed: 12/15/2022] Open
Abstract
Background: This paper outlines a multiparametric renal MRI acquisition and analysis protocol to allow non-invasive assessment of hemodynamics (renal artery blood flow and perfusion), oxygenation (BOLD T2*), and microstructure (diffusion, T1 mapping). Methods: We use our multiparametric renal MRI protocol to provide (1) a comprehensive set of MRI parameters [renal artery and vein blood flow, perfusion, T1, T2*, diffusion (ADC, D, D*, fp), and total kidney volume] in a large cohort of healthy participants (127 participants with mean age of 41 ± 19 years) and show the MR field strength (1.5 T vs. 3 T) dependence of T1 and T2* relaxation times; (2) the repeatability of multiparametric MRI measures in 11 healthy participants; (3) changes in MRI measures in response to hypercapnic and hyperoxic modulations in six healthy participants; and (4) pilot data showing the application of the multiparametric protocol in 11 patients with Chronic Kidney Disease (CKD). Results: Baseline measures were in-line with literature values, and as expected, T1-values were longer at 3 T compared with 1.5 T, with increased T1 corticomedullary differentiation at 3 T. Conversely, T2* was longer at 1.5 T. Inter-scan coefficients of variation (CoVs) of T1 mapping and ADC were very good at <2.9%. Intra class correlations (ICCs) were high for cortex perfusion (0.801), cortex and medulla T1 (0.848 and 0.997 using SE-EPI), and renal artery flow (0.844). In response to hypercapnia, a decrease in cortex T2* was observed, whilst no significant effect of hyperoxia on T2* was found. In CKD patients, renal artery and vein blood flow, and renal perfusion was lower than for healthy participants. Renal cortex and medulla T1 was significantly higher in CKD patients compared to healthy participants, with corticomedullary T1 differentiation reduced in CKD patients compared to healthy participants. No significant difference was found in renal T2*. Conclusions: Multiparametric MRI is a powerful technique for the assessment of changes in structure, hemodynamics, and oxygenation in a single scan session. This protocol provides the potential to assess the pathophysiological mechanisms in various etiologies of renal disease, and to assess the efficacy of drug treatments.
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Affiliation(s)
- Eleanor F Cox
- Sir Peter Mansfield Imaging Centre, University of NottinghamNottingham, United Kingdom
| | - Charlotte E Buchanan
- Sir Peter Mansfield Imaging Centre, University of NottinghamNottingham, United Kingdom
| | - Christopher R Bradley
- Sir Peter Mansfield Imaging Centre, University of NottinghamNottingham, United Kingdom
| | - Benjamin Prestwich
- Sir Peter Mansfield Imaging Centre, University of NottinghamNottingham, United Kingdom
| | - Huda Mahmoud
- Centre for Kidney Research and Innovation, Royal Derby Hospital, University of NottinghamDerby, United Kingdom
| | - Maarten Taal
- Centre for Kidney Research and Innovation, Royal Derby Hospital, University of NottinghamDerby, United Kingdom
| | - Nicholas M Selby
- Centre for Kidney Research and Innovation, Royal Derby Hospital, University of NottinghamDerby, United Kingdom
| | - Susan T Francis
- Sir Peter Mansfield Imaging Centre, University of NottinghamNottingham, United Kingdom
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26
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Do QN, Madhuranthakam AJ, Bendel P, Lenkinski RE. Quantification of Mouse Renal Perfusion Using Arterial Spin Labeled MRI at 1 T. Acad Radiol 2017; 24:1079-1085. [PMID: 28495212 DOI: 10.1016/j.acra.2017.04.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2017] [Revised: 04/03/2017] [Accepted: 04/03/2017] [Indexed: 10/19/2022]
Abstract
RATIONALE AND OBJECTIVES Quantitative measurement of renal perfusion in murine models provides important information on the organ physiology and disease states. The 1-T desktop magnetic resonance imaging has a small footprint and a self-contained fringe field. This resultant flexibility in siting makes the system ideal for preclinical imaging research. Our objective was to evaluate the capability of the 1-T desktop magnetic resonance imaging to measure mouse renal perfusion without the administration of exogenous contrast agents. MATERIALS AND METHODS We implemented a flow-sensitive alternating inversion recovery (FAIR)-based arterial spin labeling sequence with a mouse volume coil on a 1-T desktop magnetic resonance scanner. The validity of the implementation was tested by comparing obtained renal perfusion results with literature values for normal mice and challenging the technique with mice treated with furosemide, a blood vessel vasoconstrictor drug. RESULTS The measured cortical and medullary perfusions were quantified to be 402 ± 95 and 184 ± 52 mL/100 g/min, respectively, in agreement with literature values. The ratio of cortical to medullary renal blood flow was between 2 and 3 and was independent of the mouse weight. As expected, upon furosemide injection, a decrease (~50%) in cortical perfusion was observed in the mice population, at 1 hour post injection compared to baseline (P < 0.0001), which returned to baseline after 24 hours (P = 0.68). CONCLUSIONS We reported the successful application of FAIR-based arterial spin labeling for noncontrast perfusion measurement of mouse kidneys using a 1-T desktop scanner. The easy implementation of FAIR sequence on a 1-T desktop scanner offers the potential for longitudinal perfusion studies in limited access areas such as behind the barrier in mouse facilities and in multimodality preclinical imaging laboratories without the administration of exogenous contrast agents.
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27
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Araujo M, Welch WJ, Zhou X, Sullivan K, Walsh S, Pasternak A, Wilcox CS. Inhibition of ROMK blocks macula densa tubuloglomerular feedback yet causes renal vasoconstriction in anesthetized rats. Am J Physiol Renal Physiol 2017; 312:F1120-F1127. [PMID: 28228405 DOI: 10.1152/ajprenal.00662.2016] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2016] [Revised: 02/15/2017] [Accepted: 02/16/2017] [Indexed: 11/22/2022] Open
Abstract
The Na+-K+-2Cl- cotransporter (NKCC2) on the loop of Henle is the site of action of furosemide. Because outer medullary potassium channel (ROMK) inhibitors prevent reabsorption by NKCC2, we tested the hypothesis that ROMK inhibition with a novel selective ROMK inhibitor (compound C) blocks tubuloglomerular feedback (TGF) and reduces vascular resistance. Loop perfusion of either ROMK inhibitor or furosemide caused dose-dependent blunting of TGF, but the response to furosemide was 10-fold more sensitive (IC50 = 10-6 M for furosemide and IC50 = 10-5 M for compound C). During systemic infusion, both diuretics inhibited TGF, but ROMK inhibitor was 10-fold more sensitive (compound C: 63% inhibition; furosemide: 32% inhibition). Despite blockade of TGF, 1 h of constant systemic infusion of both diuretics reduced the glomerular filtration rate (GFR) and renal blood flow (RBF) by 40-60% and increased renal vascular resistance (RVR) by 100-200%. Neither diuretic altered blood pressure or hematocrit. Proximal tubule hydrostatic pressures (PPT) increased transiently with both diuretics (compound C: 56% increase; furosemide: 70% increase) but returned to baseline. ROMK inhibitor caused more natriuresis (3,400 vs. 1,600% increase) and calciuresis (1,200 vs. 800% increase) but less kaliuresis (33 vs. 167% increase) than furosemide. In conclusion, blockade of ROMK or Na+-K+-2Cl- transport inhibits TGF yet increases renal vascular resistance. The renal vasoconstriction was independent of volume depletion, blood pressure, TGF, or PPT.
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Affiliation(s)
- Magali Araujo
- Hypertension Research Center and Division of Nephrology and Hypertension, Georgetown University, Washington, District of Columbia; and
| | - William J Welch
- Hypertension Research Center and Division of Nephrology and Hypertension, Georgetown University, Washington, District of Columbia; and
| | - Xiaoyan Zhou
- Department of Cardiometabolic Diseases, Merck & Company, Incorporated, Kenilworth, New Jersey
| | - Kathleen Sullivan
- Department of Cardiometabolic Diseases, Merck & Company, Incorporated, Kenilworth, New Jersey
| | - Shawn Walsh
- Department of Cardiometabolic Diseases, Merck & Company, Incorporated, Kenilworth, New Jersey
| | - Alexander Pasternak
- Department of Cardiometabolic Diseases, Merck & Company, Incorporated, Kenilworth, New Jersey
| | - Christopher S Wilcox
- Hypertension Research Center and Division of Nephrology and Hypertension, Georgetown University, Washington, District of Columbia; and
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28
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Becker AS, Rossi C. Renal Arterial Spin Labeling Magnetic Resonance Imaging. Nephron Clin Pract 2016; 135:1-5. [PMID: 27760424 DOI: 10.1159/000450797] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2016] [Accepted: 09/06/2016] [Indexed: 12/13/2022] Open
Abstract
Arterial spin labeling (ASL) MRI allows the quantification of tissue perfusion without administration of exogenous contrast agents. Patients with reduced renal function or other contraindications to Gadolinium-based contrast media may benefit from the non-invasive monitoring of tissue microcirculation. So far, only few studies have investigated the sensitivity, the specificity and the reliability of the ASL techniques for the assessment of renal perfusion. Moreover, only little is known about the interplay between ASL markers of perfusion and functional renal filtration parameters. In this editorial, we discuss the main technical issues related to the quantification of renal perfusion by ASL and, in particular, the latest results in patients with kidney disorders.
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Affiliation(s)
- Anton S Becker
- Department of Diagnostic and Interventional Radiology, University Hospital Zurich, Zurich, Switzerland
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29
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Gillis KA, McComb C, Patel RK, Stevens KK, Schneider MP, Radjenovic A, Morris STW, Roditi GH, Delles C, Mark PB. Non-Contrast Renal Magnetic Resonance Imaging to Assess Perfusion and Corticomedullary Differentiation in Health and Chronic Kidney Disease. Nephron Clin Pract 2016; 133:183-92. [PMID: 27362585 DOI: 10.1159/000447601] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2016] [Accepted: 06/10/2016] [Indexed: 11/19/2022] Open
Abstract
AIMS Arterial spin labelling (ASL) MRI measures perfusion without administration of contrast agent. While ASL has been validated in animals and healthy volunteers (HVs), application to chronic kidney disease (CKD) has been limited. We investigated the utility of ASL MRI in patients with CKD. METHODS We studied renal perfusion in 24 HVs and 17 patients with CKD (age 22-77 years, 40% male) using ASL MRI at 3.0T. Kidney function was determined using estimated glomerular filtration rate (eGFR). T1 relaxation time was measured using modified look-locker inversion and xFB02;ow-sensitive alternating inversion recovery true-fast imaging and steady precession was performed to measure cortical and whole kidney perfusion. RESULTS T1 was higher in CKD within cortex and whole kidney, and there was association between T1 time and eGFR. No association was seen between kidney size and volume and either T1, or ASL perfusion. Perfusion was lower in CKD in cortex (136 ± 37 vs. 279 ± 69 ml/min/100 g; p < 0.001) and whole kidney (146 ± 24 vs. 221 ± 38 ml/min/100 g; p < 0.001). There was significant, negative, association between T1 longitudinal relaxation time and ASL perfusion in both the cortex (r = -0.75, p < 0.001) and whole kidney (r = -0.50, p < 0.001). There was correlation between eGFR and both cortical (r = 0.73, p < 0.01) and whole kidney (r = 0.69, p < 0.01) perfusion. CONCLUSIONS Significant differences in renal structure and function were demonstrated using ASL MRI. T1 may be representative of structural changes associated with CKD; however, further investigation is required into the pathological correlates of reduced ASL perfusion and increased T1 time in CKD.
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Affiliation(s)
- Keith A Gillis
- Institute of Cardiovascular and Medical Sciences, University of Glasgow, Glasgow, UK
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30
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Takakura K, Kido A, Fujimoto K, Kiguchi K, Fushimi Y, Sakashita N, Kimura T, Togashi K. [Evaluation of Appropriate Readout Sequence for Renal MRI Perfusion Using ASTAR (ASL) Technique]. Nihon Hoshasen Gijutsu Gakkai Zasshi 2016; 72:1105-1112. [PMID: 27867170 DOI: 10.6009/jjrt.2016_jsrt_72.11.1105] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
The aim of this study was to compare true-steady state free precession (True-SSFP) with fast field echo (FFE) as readout imaging sequences for renal arterial spin labeling (ASL), and to optimize the imaging condition. Renal ASL perfusion images were acquired using signal targeting with alternated radio frequency using asymmetric inversion slab (ASTAR) technique with respiratory triggering at 3T MRI system, using either 3D True-SSFP or FFE as the readout sequence. Inversion time (TI) varied from 800 to 2400 ms. Appropriate flip angles were estimated for each sequence by simulating signal intensity (SI). The SI of the renal cortex, vertebral body, and intestinal tract were measured, and the contrast ratio of the cortex (CRcortex) or intestine (CRintestine) related to vertebra was calculated. The image quality of the kidneys, background signal suppression, and misregistration were evaluated by four-point scales. As a result, in quantitative evaluation, the average of CRcortex of each TI (800, 1200, 1600, 2000, and 2400 msec) were 0.49, 0.57, 0.63, 0.63, and 0.56 in FFE, and 0.59, 0.71, 0.73, 0.73, and 0.68 in True-SSFP, respectively. IN qualitative evaluation, ASL images with True-SSFP readout were significantly better than those with FFE readout. In conclusion, True-SSFP sequences will be recommended as read out imaging sequence for obtaining ASL image compared with FFE image.
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Affiliation(s)
- Kyoko Takakura
- Department of Diagnostic Radiology and Nuclear Medicine, Graduate School of Medicine, Kyoto University
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Niendorf T, Pohlmann A, Arakelyan K, Flemming B, Cantow K, Hentschel J, Grosenick D, Ladwig M, Reimann H, Klix S, Waiczies S, Seeliger E. How bold is blood oxygenation level-dependent (BOLD) magnetic resonance imaging of the kidney? Opportunities, challenges and future directions. Acta Physiol (Oxf) 2015; 213:19-38. [PMID: 25204811 DOI: 10.1111/apha.12393] [Citation(s) in RCA: 87] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2014] [Revised: 07/04/2014] [Accepted: 09/04/2014] [Indexed: 12/11/2022]
Abstract
Renal tissue hypoperfusion and hypoxia are key elements in the pathophysiology of acute kidney injury and its progression to chronic kidney disease. Yet, in vivo assessment of renal haemodynamics and tissue oxygenation remains a challenge. Many of the established approaches are invasive, hence not applicable in humans. Blood oxygenation level-dependent (BOLD) magnetic resonance imaging (MRI) offers an alternative. BOLD-MRI is non-invasive and indicative of renal tissue oxygenation. Nonetheless, recent (pre-) clinical studies revived the question as to how bold renal BOLD-MRI really is. This review aimed to deliver some answers. It is designed to inspire the renal physiology, nephrology and imaging communities to foster explorations into the assessment of renal oxygenation and haemodynamics by exploiting the powers of MRI. For this purpose, the specifics of renal oxygenation and perfusion are outlined. The fundamentals of BOLD-MRI are summarized. The link between tissue oxygenation and the oxygenation-sensitive MR biomarker T2∗ is outlined. The merits and limitations of renal BOLD-MRI in animal and human studies are surveyed together with their clinical implications. Explorations into detailing the relation between renal T2∗ and renal tissue partial pressure of oxygen (pO2 ) are discussed with a focus on factors confounding the T2∗ vs. tissue pO2 relation. Multi-modality in vivo approaches suitable for detailing the role of the confounding factors that govern T2∗ are considered. A schematic approach describing the link between renal perfusion, oxygenation, tissue compartments and renal T2∗ is proposed. Future directions of MRI assessment of renal oxygenation and perfusion are explored.
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Affiliation(s)
- T. Niendorf
- Berlin Ultrahigh Field Facility (B.U.F.F.); Max Delbrück Center for Molecular Medicine; Berlin Germany
| | - A. Pohlmann
- Berlin Ultrahigh Field Facility (B.U.F.F.); Max Delbrück Center for Molecular Medicine; Berlin Germany
| | - K. Arakelyan
- Berlin Ultrahigh Field Facility (B.U.F.F.); Max Delbrück Center for Molecular Medicine; Berlin Germany
- Institute of Physiology and Center for Cardiovascular Research (CCR); Charité - Universitätsmedizin Berlin; Berlin Germany
| | - B. Flemming
- Institute of Physiology and Center for Cardiovascular Research (CCR); Charité - Universitätsmedizin Berlin; Berlin Germany
| | - K. Cantow
- Institute of Physiology and Center for Cardiovascular Research (CCR); Charité - Universitätsmedizin Berlin; Berlin Germany
| | - J. Hentschel
- Berlin Ultrahigh Field Facility (B.U.F.F.); Max Delbrück Center for Molecular Medicine; Berlin Germany
| | - D. Grosenick
- Physikalisch-Technische Bundesanstalt (PTB); Berlin Germany
| | - M. Ladwig
- Institute of Physiology and Center for Cardiovascular Research (CCR); Charité - Universitätsmedizin Berlin; Berlin Germany
| | - H. Reimann
- Berlin Ultrahigh Field Facility (B.U.F.F.); Max Delbrück Center for Molecular Medicine; Berlin Germany
| | - S. Klix
- Berlin Ultrahigh Field Facility (B.U.F.F.); Max Delbrück Center for Molecular Medicine; Berlin Germany
| | - S. Waiczies
- Berlin Ultrahigh Field Facility (B.U.F.F.); Max Delbrück Center for Molecular Medicine; Berlin Germany
| | - E. Seeliger
- Institute of Physiology and Center for Cardiovascular Research (CCR); Charité - Universitätsmedizin Berlin; Berlin Germany
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Cai W, Li F, Wang J, Du H, Wang X, Zhang J, Fang J, Jiang X. A comparison of arterial spin labeling perfusion MRI and DCE-MRI in human prostate cancer. NMR IN BIOMEDICINE 2014; 27:817-825. [PMID: 24809332 DOI: 10.1002/nbm.3124] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/25/2012] [Revised: 03/21/2014] [Accepted: 03/21/2014] [Indexed: 06/03/2023]
Abstract
Perfusion MRI has the potential to provide pathophysiological biomarkers for the evaluating, staging and therapy monitoring of prostate cancer. The objective of this study was to explore the feasibility of noninvasive arterial spin labeling (ASL) to detect prostate cancer in the peripheral zone and to investigate the correlation between the blood flow (BF) measured by ASL and the pharmacokinetic parameters K(trans) (forward volume transfer constant), kep (reverse reflux rate constant between extracellular space and plasma) and ve (the fractional volume of extracellular space per unit volume of tissue) measured by dynamic contrast-enhanced (DCE) MRI in patients with prostate cancer. Forty-three consecutive patients (ages ranging from 49 to 86 years, with a median age of 74 years) with pathologically confirmed prostate cancer were recruited. An ASL scan with four different inversion times (TI = 1000, 1200, 1400 and 1600 ms) and a DCE-MRI scan were performed on a clinical 3.0 T GE scanner. BF, K(trans), kep and ve maps were calculated. In order to determine whether the BF values in the cancerous area were statistically different from those in the noncancerous area, an independent t-test was performed. Spearman's bivariate correlation was used to assess the relationship between BF and the pharmacokinetic parameters K(trans), kep and ve. The mean BF values in the cancerous areas (97.1 ± 30.7, 114.7 ± 28.7, 102.3 ± 22.5, 91.2 ± 24.2 ml/100 g/min, respectively, for TI = 1000, 1200, 1400, 1600 ms) were significantly higher (p < 0.01 for all cases) than those in the noncancerous regions (35.8 ± 12.5, 42.2 ± 13.7, 53.5 ± 19.1, 48.5 ± 13.5 ml/100 g/min, respectively). Significant positive correlations (p < 0.01 for all cases) between BF and the pharmacokinetic parameters K(trans), kep and ve were also observed for all four TI values (r = 0.671, 0.407, 0.666 for TI = 1000 ms; 0.713, 0.424, 0.698 for TI = 1200 ms; 0.604, 0.402, 0.595 for TI = 1400 ms; 0.605, 0.422, 0.548 for TI = 1600 ms). It can be seen that the quantitative ASL measurements show significant differences between cancerous and benign tissues, and exhibit strong to moderate correlations with the parameters obtained using DCE-MRI. These results show the promise of ASL as a noninvasive alternative to DCE-MRI.
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Affiliation(s)
- Wenchao Cai
- Department of Radiology, Peking University First Hospital, Peking University, Beijing, China
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Evans RG, Smith JA, Wright C, Gardiner BS, Smith DW, Cochrane AD. Urinary oxygen tension: a clinical window on the health of the renal medulla? Am J Physiol Regul Integr Comp Physiol 2014; 306:R45-50. [DOI: 10.1152/ajpregu.00437.2013] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We describe the determinants of urinary oxygen tension (Po2) and the potential for use of urinary Po2 as a “physiological biomarker” of the risk of acute kidney injury (AKI) in hospital settings. We also identify knowledge gaps required for clinical translation of bedside monitoring of urinary Po2. Hypoxia in the renal medulla is a hallmark of AKI of diverse etiology. Urine in the collecting ducts would be expected to equilibrate with the tissue Po2 of the inner medulla. Accordingly, the Po2 of urine in the renal pelvis changes in response to stimuli that would be expected to alter oxygenation of the renal medulla. Oxygen exchange across the walls of the ureter and bladder will confound measurement of the Po2 of bladder urine. Nevertheless, the Po2 of bladder urine also changes in response to stimuli that would be expected to alter renal medullary oxygenation. If confounding influences can be understood, urinary bladder Po2 may provide prognostically useful information, including for prediction of AKI after cardiopulmonary bypass surgery. To translate bedside monitoring of urinary Po2 into the clinical setting, we require 1) a more detailed knowledge of the relationship between renal medullary oxygenation and the Po2 of pelvic urine under physiological and pathophysiological conditions; 2) a quantitative understanding of the impact of oxygen transport across the ureteric epithelium on urinary Po2 measured from the bladder; and 3) a simple, robust medical device that can be introduced into the bladder via a standard catheter to provide reliable and continuous measurement of urinary Po2.
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Affiliation(s)
| | | | - Christopher Wright
- Faculty of Medicine, Nursing and Health Sciences, Monash University, Melbourne, Australia
| | - Bruce S. Gardiner
- School of Computer Science and Software Engineering, The University of Western Australia, Perth, Australia
| | - David W. Smith
- School of Computer Science and Software Engineering, The University of Western Australia, Perth, Australia
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Pohlmann A, Cantow K, Hentschel J, Arakelyan K, Ladwig M, Flemming B, Hoff U, Persson PB, Seeliger E, Niendorf T. Linking non-invasive parametric MRI with invasive physiological measurements (MR-PHYSIOL): towards a hybrid and integrated approach for investigation of acute kidney injury in rats. Acta Physiol (Oxf) 2013; 207:673-89. [PMID: 23336404 DOI: 10.1111/apha.12065] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2012] [Revised: 12/17/2012] [Accepted: 01/16/2013] [Indexed: 01/11/2023]
Abstract
Acute kidney injury of various origins shares a common link in the pathophysiological chain of events: imbalance between renal medullary oxygen delivery and oxygen demand. For in vivo assessment of kidney haemodynamics and oxygenation in animals, quantitative but invasive physiological methods are established. A very limited number of studies attempted to link these invasive methods with parametric Magnetic Resonance Imaging (MRI) of the kidney. Moreover, the validity of parametric MRI (pMRI) as a surrogate marker for renal tissue perfusion and renal oxygenation has not been systematically examined yet. For this reason, we set out to combine invasive techniques and non-invasive MRI in an integrated hybrid setup (MR-PHYSIOL) with the ultimate goal to calibrate, monitor and interpret parametric MR and physiological parameters by means of standardized interventions. Here we present a first report on the current status of this multi-modality approach. For this purpose, we first highlight key characteristics of renal perfusion and oxygenation. Second, concepts for in vivo characterization of renal perfusion and oxygenation are surveyed together with the capabilities of MRI for probing blood oxygenation-dependent tissue stages. Practical concerns evoked by the use of strong magnetic fields in MRI and interferences between MRI and invasive physiological probes are discussed. Technical solutions that balance the needs of in vivo physiological measurements together with the constraints dictated by small bore MR scanners are presented. An early implementation of the integrated MR-PHYSIOL approach is demonstrated including brief interventions of hypoxia and hyperoxia.
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Affiliation(s)
- A. Pohlmann
- Berlin Ultrahigh Field Facility (B.U.F.F.); Max Delbrück Center for Molecular Medicine; Berlin; Germany
| | - K. Cantow
- Institute of Physiology; Charité - Universitätsmedizin Berlin; Campus Mitte, and Center for Cardiovascular Research; Berlin; Germany
| | - J. Hentschel
- Berlin Ultrahigh Field Facility (B.U.F.F.); Max Delbrück Center for Molecular Medicine; Berlin; Germany
| | | | - M. Ladwig
- Institute of Physiology; Charité - Universitätsmedizin Berlin; Campus Mitte, and Center for Cardiovascular Research; Berlin; Germany
| | - B. Flemming
- Institute of Physiology; Charité - Universitätsmedizin Berlin; Campus Mitte, and Center for Cardiovascular Research; Berlin; Germany
| | - U. Hoff
- Nephrology and Intensive Care Medicine; Charité - Universitätsmedizin Berlin; Campus Virchow-Klinikum, and Center for Cardiovascular Research; Berlin; Germany
| | - P. B. Persson
- Institute of Physiology; Charité - Universitätsmedizin Berlin; Campus Mitte, and Center for Cardiovascular Research; Berlin; Germany
| | - E. Seeliger
- Institute of Physiology; Charité - Universitätsmedizin Berlin; Campus Mitte, and Center for Cardiovascular Research; Berlin; Germany
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Influence of early (F+0) intravenous furosemide injection on the split renal function using 99mTc-DTPA renography. Nucl Med Commun 2013; 34:354-8. [PMID: 23376860 DOI: 10.1097/mnm.0b013e32835e7437] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
In busy nuclear medicine departments, the F+0 protocol for diuretic renography is routinely used to shorten the acquisition time. The aim of this study was to evaluate the influence of the F+0 protocol on the split renal function (SRF) during a dynamic renal scan using technetium-99m diethylene triamine pentaacetic acid (Tc-DTPA) compared with that using the standard technetium-99m dimercaptosuccinic acid (Tc-DMSA). A total of 102 patients referred for a dynamic renal scan for varied etiologies were divided into two groups: the F+0 group, comprising 53 patients who were injected with furosemide just before Tc-DTPA injection, and the F+10 group, comprising 49 patients who were injected with the diuretic at the 10th minute after radiotracer injection. All patients were also subjected to a static cortical Tc-DMSA scan with geometric quantification of SRF. A highly significant statistical difference (P<0.001) was obtained on comparing the mean value of the difference in SRF calculated using DTPA and DMSA between the F+0 and F+10 groups, being 5.0±2.6 and 1.5±0.6%, respectively. All 49 patients in the F+10 group had a difference in split function of 5% or less, whereas 17/53 patients representing 32.1% of the F+0 group had a difference in SRF of greater than 5%. Early (F+0) furosemide injection before administration of Tc-DTPA has a significant influence on the estimation of SRF of the diseased kidney (either obstructed or functionally impaired) when compared with furosemide injection after standard Tc-DMSA administration. Care should be taken during interpretation of the scan findings when accurate split function is required.
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