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Birchall JR, Horvat-Menih I, Kaggie JD, Riemer F, Benjamin AJV, Graves MJ, Wilkinson I, Gallagher FA, McLean MA. Quantitative 23Na magnetic resonance imaging in the abdomen at 3 T. MAGMA (NEW YORK, N.Y.) 2024:10.1007/s10334-024-01167-6. [PMID: 38822992 DOI: 10.1007/s10334-024-01167-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2023] [Revised: 05/01/2024] [Accepted: 05/14/2024] [Indexed: 06/03/2024]
Abstract
OBJECTIVES To assess the feasibility of sodium-23 MRI for performing quantitative and non-invasive measurements of total sodium concentration (TSC) and relaxation in a variety of abdominal organs. MATERIALS AND METHODS Proton and sodium imaging of the abdomen was performed in 19 healthy volunteers using a 3D cones sequence and a sodium-tuned 4-rung transmit/receive body coil on a clinical 3 T system. The effects of B1 non-uniformity on TSC measurements were corrected using the double-angle method. The long-component of 23Na T2* relaxation time was measured using a series of variable echo-times. RESULTS The mean and standard deviation of TSC and long-component 23Na T2* values were calculated across the healthy volunteer group in the kidneys, cerebrospinal fluid (CSF), liver, gallbladder, spleen, aorta, and inferior vena cava. DISCUSSION Mean TSC values in the kidneys, liver, and spleen were similar to those reported using 23Na-MRI previously in the literature. Measurements in the CSF and gallbladder were lower, potentially due to the reduced spatial resolution achievable in a clinically acceptable scan time. Mean long-component 23Na T2* values were consistent with previous reports from the kidneys and CSF. Intra-population standard error was larger in smaller, fluid-filled structures due to fluid motion and partial volume effects.
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Affiliation(s)
| | | | | | - Frank Riemer
- Department of Radiology, Mohn Medical Imaging and Visualization Centre, Haukeland University Hospital Helse Bergen, Bergen, Norway
| | | | | | - Ian Wilkinson
- Cambridge Cardiovascular, University of Cambridge, Cambridge, UK
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Gullaksen S, Vernstrøm L, Sørensen SS, Ringgaard S, Laustsen C, Birn H, Funck KL, Poulsen PL, Laugesen E. The effects of semaglutide, empagliflozin and their combination on the kidney sodium signal from magnetic resonance imaging: A prespecified, secondary analysis from a randomized, clinical trial. J Diabetes Complications 2024; 38:108673. [PMID: 38219335 DOI: 10.1016/j.jdiacomp.2023.108673] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/08/2023] [Revised: 12/17/2023] [Accepted: 12/24/2023] [Indexed: 01/16/2024]
Abstract
AIMS To evaluate the effect of treatment with semaglutide and empagliflozin on the cortico-medullary sodium gradient (MCR; medulla/cortex ratio), urine sodium/creatinine ratio (UNACR), and estimated plasma volume (ePV) and to compare the MCR between persons with and without type 2 diabetes. METHODS Using the 23Na magnetic resonance imaging (23Na-MRI) technique, we investigated the effects of 32 weeks of treatment with semaglutide, empagliflozin or their combination on MCR in 65 participants with type 2 diabetes and high risk of cardiovascular disease. The participants were recruited from a randomized, controlled interventional trial and further characterized by UNACR and ePV. In addition, in a cross-sectional design, we compared MCR by 23Na-MRI in 12 persons with type 2 diabetes and 17 matched controls. Data from the interventional trial were analyzed using a single, multivariate linear mixed model strategy for repeated measurements. Data from the cross-sectional study were analyzed by fitting a linear regression model adjusted for age and sex. RESULTS Compared to placebo, semaglutide, but not empagliflozin, significantly decreased the MCR (-9 %, 95%CI (-18, -0.06)%, p = 0.035 and -0.05 %, 95%CI(-0.15, 0.05)%, p = 0.319, respectively). The UNACR decreased in the semaglutide group(-35 %, 95 % CI(-52, -14) %, p = 0.003) but not in the empagliflozin group (7 %, 95 % CI(-21, 44)%, p = 0.657), whereas the ePV decreased in the combination group. The MCR was not different between persons with and without type 2 diabetes. CONCLUSION 23Na magnetic resonance imaging can identify drug induced changes in the MCR in persons with type 2 diabetes, and 32 weeks of semaglutide decreases the MCR in such persons. There is no difference in the MCR between persons with and without type 2 diabetes. TRIAL NUMBER AND REGISTRY EUDRACT 2019-000781-38, clinicaltrialsregister.eu.
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Affiliation(s)
- Søren Gullaksen
- Department of Clinical Medicine, Aarhus University, 8000 Aarhus C, Denmark; Department of Internal Medicine & Endocrinology, Aarhus University Hospital, 8200 Aarhus N, Denmark; Department of Medicine, Regional Hospital Horsens, 8700 Horsens, Denmark.
| | - Liv Vernstrøm
- Department of Clinical Medicine, Aarhus University, 8000 Aarhus C, Denmark; Department of Internal Medicine & Endocrinology, Aarhus University Hospital, 8200 Aarhus N, Denmark
| | - Steffen S Sørensen
- Department of Clinical Medicine, Aarhus University, 8000 Aarhus C, Denmark; Department of Internal Medicine & Endocrinology, Aarhus University Hospital, 8200 Aarhus N, Denmark
| | | | | | - Henrik Birn
- Department of Clinical Medicine, Aarhus University, 8000 Aarhus C, Denmark; Department of Renal Medicine, Aarhus University Hospital, 8200 Aarhus N, Denmark; Department of Biomedicine, Aarhus University, 8000 Aarhus C, Denmark
| | - Kristian L Funck
- Department of Internal Medicine & Endocrinology, Aarhus University Hospital, 8200 Aarhus N, Denmark; Steno Diabetes Center, Aarhus University Hospital, 8200 Aarhus N, Denmark
| | - Per L Poulsen
- Department of Clinical Medicine, Aarhus University, 8000 Aarhus C, Denmark; Steno Diabetes Center, Aarhus University Hospital, 8200 Aarhus N, Denmark
| | - Esben Laugesen
- Diagnostic Centre, Silkeborg Regional Hospital, 8600 Silkeborg, Denmark; Steno Diabetes Center, Aarhus University Hospital, 8200 Aarhus N, Denmark
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Gast LV, Platt T, Nagel AM, Gerhalter T. Recent technical developments and clinical research applications of sodium ( 23Na) MRI. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2023; 138-139:1-51. [PMID: 38065665 DOI: 10.1016/j.pnmrs.2023.04.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2023] [Revised: 04/11/2023] [Accepted: 04/13/2023] [Indexed: 12/18/2023]
Abstract
Sodium is an essential ion that plays a central role in many physiological processes including the transmembrane electrochemical gradient and the maintenance of the body's homeostasis. Due to the crucial role of sodium in the human body, the sodium nucleus is a promising candidate for non-invasively assessing (patho-)physiological changes. Almost 10 years ago, Madelin et al. provided a comprehensive review of methods and applications of sodium (23Na) MRI (Madelin et al., 2014) [1]. More recent review articles have focused mainly on specific applications of 23Na MRI. For example, several articles covered 23Na MRI applications for diseases such as osteoarthritis (Zbyn et al., 2016, Zaric et al., 2020) [2,3], multiple sclerosis (Petracca et al., 2016, Huhn et al., 2019) [4,5] and brain tumors (Schepkin, 2016) [6], or for imaging certain organs such as the kidneys (Zollner et al., 2016) [7], the brain (Shah et al., 2016, Thulborn et al., 2018) [8,9], and the heart (Bottomley, 2016) [10]. Other articles have reviewed technical developments such as radiofrequency (RF) coils for 23Na MRI (Wiggins et al., 2016, Bangerter et al., 2016) [11,12], pulse sequences (Konstandin et al., 2014) [13], image reconstruction methods (Chen et al., 2021) [14], and interleaved/simultaneous imaging techniques (Lopez Kolkovsky et al., 2022) [15]. In addition, 23Na MRI topics have been covered in review articles with broader topics such as multinuclear MRI or ultra-high-field MRI (Niesporek et al., 2019, Hu et al., 2019, Ladd et al., 2018) [16-18]. During the past decade, various research groups have continued working on technical improvements to sodium MRI and have investigated its potential to serve as a diagnostic and prognostic tool. Clinical research applications of 23Na MRI have covered a broad spectrum of diseases, mainly focusing on the brain, cartilage, and skeletal muscle (see Fig. 1). In this article, we aim to provide a comprehensive summary of methodological and hardware developments, as well as a review of various clinical research applications of sodium (23Na) MRI in the last decade (i.e., published from the beginning of 2013 to the end of 2022).
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Affiliation(s)
- Lena V Gast
- Institute of Radiology, University Hospital Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen, Germany.
| | - Tanja Platt
- Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany.
| | - Armin M Nagel
- Institute of Radiology, University Hospital Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen, Germany; Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany.
| | - Teresa Gerhalter
- Institute of Radiology, University Hospital Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen, Germany.
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Rasmussen CW, Bøgh N, Bech SK, Thorsen TH, Hansen ESS, Bertelsen LB, Laustsen C. Fibrosis imaging with multiparametric proton and sodium MRI in pig injury models. NMR IN BIOMEDICINE 2023; 36:e4838. [PMID: 36151711 PMCID: PMC10078455 DOI: 10.1002/nbm.4838] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Revised: 09/10/2022] [Accepted: 09/12/2022] [Indexed: 05/10/2023]
Abstract
Chronic kidney disease (CKD) is common and has huge implications for health and mortality. It is aggravated by intrarenal fibrosis, but the assessment of fibrosis is limited to kidney biopsies, which carry a risk of complications and sampling errors. This calls for a noninvasive modality for diagnosing and staging intrarenal fibrosis. The current, exploratory study evaluates a multiparametric MRI protocol including sodium imaging (23 Na-MRI) to determine the opportunities within this modality to assess kidney injury as a surrogate endpoint of fibrosis. The study includes 43 pigs exposed to ischemia-reperfusion injury (IRI) or unilateral ureteral obstruction (UUO), or serving as healthy controls. Fibrosis was determined using gene expression analysis of collagen. The medulla/cortex ratio of 23 Na-MRI decreased in the injured kidney in the IRI pigs, but not in the UUO pigs (p = 0.0180, p = 0.0754). To assess the combination of MRI parameters in estimating fibrosis, we created a linear regression model consisting of the cortical apparent diffusion coefficient, ΔR2*, ΔT1, the 23 Na medulla/cortex ratio, and plasma creatinine (R2 = 0.8009, p = 0.0117). The 23 Na medulla/cortex ratio only slightly improved the fibrosis prediction model, leaving 23 Na-MRI in an ambiguous place for evaluation of intrarenal fibrosis. Use of multiparametric MRI in combination with plasma creatinine shows potential for the estimation of fibrosis in human kidney disease, but more translational and clinical work is warranted before MRI can contribute to earlier diagnosis and evaluation of treatment for acute kidney injury and CKD.
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Affiliation(s)
- Camilla W. Rasmussen
- The MR Research Center, Department of Clinical MedicineAarhus UniversityAarhusDenmark
| | - Nikolaj Bøgh
- The MR Research Center, Department of Clinical MedicineAarhus UniversityAarhusDenmark
| | - Sabrina K. Bech
- The MR Research Center, Department of Clinical MedicineAarhus UniversityAarhusDenmark
| | - Thomas H. Thorsen
- The MR Research Center, Department of Clinical MedicineAarhus UniversityAarhusDenmark
| | - Esben S. S. Hansen
- The MR Research Center, Department of Clinical MedicineAarhus UniversityAarhusDenmark
| | - Lotte B. Bertelsen
- The MR Research Center, Department of Clinical MedicineAarhus UniversityAarhusDenmark
| | - Christoffer Laustsen
- The MR Research Center, Department of Clinical MedicineAarhus UniversityAarhusDenmark
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Vaeggemose M, Schulte RF, Laustsen C. Clinically feasible B 1 field correction for multi-organ sodium imaging at 3 T. NMR IN BIOMEDICINE 2023; 36:e4835. [PMID: 36115017 PMCID: PMC10078323 DOI: 10.1002/nbm.4835] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/02/2022] [Revised: 09/12/2022] [Accepted: 09/12/2022] [Indexed: 06/15/2023]
Abstract
Sodium MRI allows the non-invasive quantification of intra-organ sodium concentration. RF inhomogeneity introduces uncertainty in this estimated concentration. B1 field corrections can be used to overcome some of these limitations. However, the low signal-to-noise ratio in sodium MRI makes accurate B1 mapping in reasonable scan times challenging. The study aims to evaluate Bloch-Siegert off-resonance (BLOSI) B1 field correction for sodium MRI using a 3D Fermat looped, orthogonally encoded trajectories (FLORET) read-out trajectory. We propose a clinically feasible B1 field map correction method for sodium imaging at 3 T, evaluating five healthy subjects' brain, heart blood, kidneys, and thigh muscle. We scanned the subjects twice for repeatability measures and used sodium phantoms to determine organ total sodium concentration. Conventional proton scans were compared with sodium images for organ structural integrity. The BLOSI approach based on the 3D FLORET read-out trajectory was used in B1 field correction and 3D density-adapted radial acquisition for sodium imaging. Results indicate improvements in sodium imaging based on B1 field correction in a clinically feasible protocol. Improvements are determined in all organs by enhanced anatomical representation, organ homogeneity, and an increase in the total sodium concentration after applying a B1 field correction. The proposed BLOSI-based B1 field correction using a 3D FLORET read-out trajectory is clinically feasible for sodium imaging, which is shown in the brain, heart, kidney, and thigh muscle. This supports using fast B1 field mapping in the clinical setting.
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Affiliation(s)
- Michael Vaeggemose
- GE HealthcareBrondbyDenmark
- MR Research Centre, Department of Clinical MedicineAarhus UniversityAarhusDenmark
| | | | - Christoffer Laustsen
- MR Research Centre, Department of Clinical MedicineAarhus UniversityAarhusDenmark
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Kemėšienė J, Rühle A, Gomolka R, Wurnig MC, Rossi C, Boss A. Advanced diffusion imaging of abdominal organs in different hydration states of the human body: stability of biomarkers. Heliyon 2021; 7:e06072. [PMID: 33553749 PMCID: PMC7848648 DOI: 10.1016/j.heliyon.2021.e06072] [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: 03/01/2020] [Revised: 07/24/2020] [Accepted: 01/20/2021] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND MR diffusion weighted imaging (DWI) may provide important information regarding the pathophysiology of parenchymal abdominal organs. The purpose of our study was to investigate the stability of imaging biomarkers of diffusion weighted imaging (DWI), intravoxel incoherent motion (IVIM) and diffusion kurtosis imaging (DKI) in abdominal parenchymal organs regarding two body hydration states. METHODS Ten healthy volunteers twice underwent DWI of abdominal organs using a double-refocused spin-echo echo-planar imaging sequences with 11 different b-values (ranging from 0 to 1,500 s/mm2): after 4 h of fluid deprivation; 45 min following 1000 ml of water intake. Four different diffusion models were evaluated and compared: standard DWI, DKI with mono-exponential fitting, multistep algorithm with variable b-value threshold for IVIM, combined IVIM-Kurtosis; in four abdominal organs: kidneys, liver, spleen and psoas muscle. RESULTS Diffusion parameters from all four models remained similar for the renal parenchyma before and after the water challenge. Significant differences were found for the liver, spleen, and psoas muscle. The largest effects were seen for: the liver parenchyma after the water challenge by means of IVIM model's true diffusion (p < 0.02); the spleen, for IVIM's perfusion fraction (p < 0.03), the psoas muscle for the ADC value (p < 0.02). CONCLUSIONS Herein, we showed that diffusion parameters of the kidney remain remarkably stable regarding the hydration status. This may be attributed to the kidney-specific compensatory mechanisms. For the liver, spleen and psoas muscle the diffusion parameters were sensitive to changes of the hydration. This phenomenon needs to be considered when evaluating diffusion data of these organs.
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Affiliation(s)
- Jūratė Kemėšienė
- Department of Radiology, Hospital of Lithuanian University of Health Sciences, Kaunas Clinics, Lithuania
| | - Alexander Rühle
- Department of Molecular Radiation Oncology, German Cancer Research Center (dkfz), Heidelberg, Germany
| | - Ryszard Gomolka
- Institute of Diagnostic and Interventional Radiology, University Hospital Zurich, Switzerland
| | - Moritz C. Wurnig
- Institute of Diagnostic and Interventional Radiology, University Hospital Zurich, Switzerland
| | - Cristina Rossi
- Institute of Diagnostic and Interventional Radiology, University Hospital Zurich, Switzerland
| | - Andreas Boss
- Institute of Diagnostic and Interventional Radiology, University Hospital Zurich, Switzerland
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Abstract
In this article, an overview of the current developments and research applications for non-proton magnetic resonance imaging (MRI) at ultrahigh magnetic fields (UHFs) is given. Due to technical and methodical advances, efficient MRI of physiologically relevant nuclei, such as Na, Cl, Cl, K, O, or P has become feasible and is of interest to obtain spatially and temporally resolved information that can be used for biomedical and diagnostic applications. Sodium (Na) MRI is the most widespread multinuclear imaging method with applications ranging over all regions of the human body. Na MRI yields the second largest in vivo NMR signal after the clinically used proton signal (H). However, other nuclei such as O and P (energy metabolism) or Cl and K (cell viability) are used in an increasing number of MRI studies at UHF. One major advancement has been the increased availability of whole-body MR scanners with UHFs (B0 ≥7T) expanding the range of detectable nuclei. Nevertheless, efforts in terms of pulse sequence and post-processing developments as well as hardware designs must be made to obtain valuable information in clinically feasible measurement times. This review summarizes the available methods in the field of non-proton UHF MRI, especially for Na MRI, as well as introduces potential applications in clinical research.
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Affiliation(s)
- Sebastian C Niesporek
- Division of Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Armin M Nagel
- Division of Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany
- Institute of Radiology, University Hospital Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen, Germany
- Institute of Medical Physics, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen, Germany
| | - Tanja Platt
- Division of Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany
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Meyer MM, Haneder S, Konstandin S, Budjan J, Morelli JN, Schad LR, Kerl HU, Schoenberg SO, Kabbasch C. Repeatability and reproducibility of cerebral 23Na imaging in healthy subjects. BMC Med Imaging 2019; 19:26. [PMID: 30943911 PMCID: PMC6446283 DOI: 10.1186/s12880-019-0324-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2018] [Accepted: 03/11/2019] [Indexed: 02/04/2023] Open
Abstract
Background Initial reports of 23Na magnetic resonance imaging (MRI) date back to the 1970s. However, methodological challenges of the technique hampered its widespread adoption for many years. Recent technical developments have overcome some of these limitations and have led to more optimal conditions for 23Na-MR imaging. In order to serve as a reliable tool for the assessment of clinical stroke or brain tumor patients, we investigated the repeatability and reproducibility of cerebral sodium (23Na) imaging in healthy subjects. Methods In this prospective, IRB approved study 12 consecutive healthy volunteers (8 female, age 31 ± 8.3) underwent three cerebral 23Na-MRI examinations at 3.0 T (TimTrio, Siemens Healthineers) distributed between two separate visits with an 8 day interval. For each scan a T1w MP-RAGE sequence for anatomical referencing and a 3D-density-adapted, radial GRE-sequence for 23Na-imaging were acquired using a dual-tuned (23Na/1H) head-coil. On 1 day, these scans were repeated consecutively; on the other day, the scans were performed once. 23Na-sequences were reconstructed according to the MP-RAGE sequence, allowing direct cross-referencing of ROIs. Circular ROIs were placed in predetermined anatomic regions: gray and white matter (GM, WM), head of the caudate nucleus (HCN), pons, and cerebellum. External 23Na-reference phantoms were used to calculate the tissue sodium content. Results Excellent correlation was found between repeated measurements on the same day (r2 = 0.94), as well as on a different day (r2 = 0.86). No significant differences were found based on laterality other than in the HCN (63.1 vs. 58.7 mmol/kg WW on the right (p = 0.01)). Pronounced inter-individual differences were identified in all anatomic regions. Moderate to good correlation (0.310 to 0.701) was found between the readers. Conclusion Our study has shown that intra-individual 23Na-concentrations in healthy subjects do not significantly differ after repeated scans on the same day and a pre-set time interval. This confirms the repeatability and reproducibility of cerebral 23Na-imaging. However, with manual ROI placement in predetermined anatomic landmarks, fluctuations in 23Na-concentrations can be observed.
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Affiliation(s)
- Melissa M Meyer
- Institute of Clinical Radiology and Nuclear Medicine, Medical Faculty Mannheim, University of Heidelberg, Theodor-Kutzer-Ufer 1-3, 68167, Mannheim, Germany.
| | - Stefan Haneder
- Institute of Clinical Radiology and Nuclear Medicine, Medical Faculty Mannheim, University of Heidelberg, Theodor-Kutzer-Ufer 1-3, 68167, Mannheim, Germany.,Institute of Diagnostic and Interventional Radiology, University Hospital Cologne, University of Cologne, Cologne, Germany
| | | | - Johannes Budjan
- Institute of Clinical Radiology and Nuclear Medicine, Medical Faculty Mannheim, University of Heidelberg, Theodor-Kutzer-Ufer 1-3, 68167, Mannheim, Germany
| | - John N Morelli
- St. John's Medical Center, 1923 South Utica Ave, Tulsa, OK, 74104, USA
| | - Lothar R Schad
- Department of Computer Assisted Clinical Medicine, Heidelberg University, Mannheim, Germany
| | - Hans U Kerl
- Department of Neuroradiology, University Medical Center Mannheim, Heidelberg University, Mannheim, Germany
| | - Stefan O Schoenberg
- Institute of Clinical Radiology and Nuclear Medicine, Medical Faculty Mannheim, University of Heidelberg, Theodor-Kutzer-Ufer 1-3, 68167, Mannheim, Germany
| | - Christoph Kabbasch
- Institute of Diagnostic and Interventional Radiology, University Hospital Cologne, University of Cologne, Cologne, Germany
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Abstract
Kidney diseases can be caused by a wide range of genetic, hemodynamic, toxic, infectious, and autoimmune factors. The diagnosis of kidney disease usually involves the biochemical analysis of serum and blood, but these tests are often insufficiently sensitive or specific to make a definitive diagnosis. Although radiologic imaging currently has a limited role in the evaluation of most kidney diseases, several new imaging methods hold great promise for improving our ability to non-invasively detect structural, functional, and molecular changes within the kidney. New methods, such as dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) and blood oxygen level-dependent (BOLD) MRI, allow functional imaging of the kidney. The use of novel contrast agents, such as microbubbles and nanoparticles, allows the detection of specific molecules in the kidney. These methods could greatly advance our ability to diagnose disease and also to safely monitor patients over time. This could improve the care of individual patients, and it could also facilitate the evaluation of new treatment strategies.
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Affiliation(s)
- Joshua Thurman
- Department of Medicine, University of Colorado School of Medicine, Aurora, CO, USA
| | - Faikah Gueler
- Department of Nephrology, Hannover Medical School, Hannover, Germany
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Platt T, Umathum R, Fiedler TM, Nagel AM, Bitz AK, Maier F, Bachert P, Ladd ME, Wielpütz MO, Kauczor HU, Behl NG. In vivo self-gated 23
Na MRI at 7 T using an oval-shaped body resonator. Magn Reson Med 2018; 80:1005-1019. [DOI: 10.1002/mrm.27103] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2017] [Revised: 12/08/2017] [Accepted: 01/02/2018] [Indexed: 12/24/2022]
Affiliation(s)
- Tanja Platt
- Division of Medical Physics in Radiology, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280; 69120 Heidelberg Germany
| | - Reiner Umathum
- Division of Medical Physics in Radiology, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280; 69120 Heidelberg Germany
| | - Thomas M. Fiedler
- Division of Medical Physics in Radiology, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280; 69120 Heidelberg Germany
| | - Armin M. Nagel
- Division of Medical Physics in Radiology, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280; 69120 Heidelberg Germany
- Institute of Radiology; University Hospital Erlangen, Maximiliansplatz 3; 91054 Erlangen Germany
| | - Andreas K. Bitz
- Division of Medical Physics in Radiology, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280; 69120 Heidelberg Germany
- Faculty of Electrical Engineering and Information Technology; University of Applied Sciences Aachen, Eupener Str. 70; 52066 Aachen Germany
| | - Florian Maier
- Division of Medical Physics in Radiology, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280; 69120 Heidelberg Germany
| | - Peter Bachert
- Division of Medical Physics in Radiology, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280; 69120 Heidelberg Germany
- Faculty of Physics and Astronomy; University of Heidelberg, Im Neuenheimer Feld 226; 69120 Heidelberg Germany
| | - Mark E. Ladd
- Division of Medical Physics in Radiology, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280; 69120 Heidelberg Germany
- Faculty of Physics and Astronomy; University of Heidelberg, Im Neuenheimer Feld 226; 69120 Heidelberg Germany
- Faculty of Medicine; University of Heidelberg, Im Neuenheimer Feld 672; 69120 Heidelberg Germany
| | - Mark O. Wielpütz
- Translational Lung Research Center (TLRC); University of Heidelberg, German Center for Lung Research (DZL), Im Neuenheimer Feld 430; 69120 Heidelberg Germany
- Department of Diagnostic and Interventional Radiology; University Hospital of Heidelberg, Im Neuenheimer Feld 110; 69120 Heidelberg Germany
- Department of Diagnostic and Interventional Radiology with Nuclear Medicine; Thoraxklinik at University of Heidelberg, Röntgenstr. 1; 69126 Heidelberg Germany
| | - Hans-Ulrich Kauczor
- Translational Lung Research Center (TLRC); University of Heidelberg, German Center for Lung Research (DZL), Im Neuenheimer Feld 430; 69120 Heidelberg Germany
- Department of Diagnostic and Interventional Radiology; University Hospital of Heidelberg, Im Neuenheimer Feld 110; 69120 Heidelberg Germany
- Department of Diagnostic and Interventional Radiology with Nuclear Medicine; Thoraxklinik at University of Heidelberg, Röntgenstr. 1; 69126 Heidelberg Germany
| | - Nicolas G.R. Behl
- Division of Medical Physics in Radiology, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280; 69120 Heidelberg Germany
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Francis S, Buchanan CE, Prestwich B, Taal MW. Sodium MRI: a new frontier in imaging in nephrology. Curr Opin Nephrol Hypertens 2017; 26:435-441. [PMID: 28877041 DOI: 10.1097/mnh.0000000000000370] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
PURPOSE OF REVIEW This review focuses on the recent technological advances in quantitative sodium (Na) MRI to provide a noninvasive measure of tissue viability for use in clinical studies of patients with kidney disease. Na MRI is the only noninvasive imaging technique that allows for the absolute spatial quantification of tissue sodium concentration (TSC), providing assessment of the corticomedullary sodium gradient (CMSG) in the kidney, and allowing measures of TSC in the skin and muscle. RECENT FINDINGS Na MRI of the kidney has demonstrated the sensitivity to measure the CMSG, providing the normal range in healthy individuals and demonstrating a reduction in CMSG in kidney disease and transplanted kidneys. Studies using Na and H MRI have shown that in humans, skeletal muscle and skin can store sodium without water retention, and that sodium concentrations in muscle and skin increase with advancing age. Recent studies have shown that TSC can be mobilised during haemodialysis, and that skin sodium content links closely to left ventricular mass in patients with chronic kidney disease. SUMMARY Na MRI is currently a research technique, but with future advances, Na MRI has potential to become a noninvasive renal biomarker and a measure of tissue sodium storage for clinical studies.
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Affiliation(s)
- Susan Francis
- aSir Peter Mansfield Imaging Centre, School of Physics and Astronomy bCentre for Kidney Research and Innovation, Division of Medical Sciences and Graduate Entry Medicine, University of Nottingham, Nottingham, United Kingdom
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van Eijs MJM, van Zuilen AD, de Boer A, Froeling M, Nguyen TQ, Joles JA, Leiner T, Verhaar MC. Innovative Perspective: Gadolinium-Free Magnetic Resonance Imaging in Long-Term Follow-Up after Kidney Transplantation. Front Physiol 2017; 8:296. [PMID: 28559850 PMCID: PMC5432553 DOI: 10.3389/fphys.2017.00296] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2017] [Accepted: 04/24/2017] [Indexed: 12/23/2022] Open
Abstract
Since the mid-1980s magnetic resonance imaging (MRI) has been investigated as a non- or minimally invasive tool to probe kidney allograft function. Despite this long-standing interest, MRI still plays a subordinate role in daily practice of transplantation nephrology. With the introduction of new functional MRI techniques, administration of exogenous gadolinium-based contrast agents has often become unnecessary and true non-invasive assessment of allograft function has become possible. This raises the question why application of MRI in the follow-up of kidney transplantation remains restricted, despite promising results. Current literature on kidney allograft MRI is mainly focused on assessment of (sub) acute kidney injury after transplantation. The aim of this review is to survey whether MRI can provide valuable diagnostic information beyond 1 year after kidney transplantation from a mechanistic point of view. The driving force behind chronic allograft nephropathy is believed to be chronic hypoxia. Based on this, techniques that visualize kidney perfusion and oxygenation, scarring, and parenchymal inflammation deserve special interest. We propose that functional MRI mechanistically provides tools for diagnostic work-up in long-term follow-up of kidney allografts.
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Affiliation(s)
- Mick J M van Eijs
- Department of Nephrology and Hypertension, University Medical Center UtrechtUtrecht, Netherlands
| | - Arjan D van Zuilen
- Department of Nephrology and Hypertension, University Medical Center UtrechtUtrecht, Netherlands
| | - Anneloes de Boer
- Department of Radiology, University Medical Center UtrechtUtrecht, Netherlands
| | - Martijn Froeling
- Department of Radiology, University Medical Center UtrechtUtrecht, Netherlands
| | - Tri Q Nguyen
- Department of Pathology, University Medical Center UtrechtUtrecht, Netherlands
| | - Jaap A Joles
- Department of Nephrology and Hypertension, University Medical Center UtrechtUtrecht, Netherlands
| | - Tim Leiner
- Department of Radiology, University Medical Center UtrechtUtrecht, Netherlands
| | - Marianne C Verhaar
- Department of Nephrology and Hypertension, University Medical Center UtrechtUtrecht, Netherlands
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Zöllner FG, Konstandin S, Lommen J, Budjan J, Schoenberg SO, Schad LR, Haneder S. Quantitative sodium MRI of kidney. NMR IN BIOMEDICINE 2016; 29:197-205. [PMID: 25728879 DOI: 10.1002/nbm.3274] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/02/2014] [Revised: 01/13/2015] [Accepted: 01/25/2015] [Indexed: 05/25/2023]
Abstract
One of the main tasks of the human kidneys is to maintain the homeostasis of the body's fluid and electrolyte balance by filtration of the plasma and excretion of the end products. Herein, the regulation of extracellular sodium in the kidney is of particular importance. Sodium MRI ((23)Na MRI) allows for the absolute quantification of the tissue sodium concentration (TSC) and thereby provides a direct link between TSC and tissue viability. Renal (23)Na MRI can provide new insights into physiological tissue function and viability thought to differ from the information obtained by standard (1)H MRI. Sodium imaging has the potential to become an independent surrogate biomarker not only for renal imaging, but also for oncology indications. However, this technique is now on the threshold of clinical implementation. Numerous, initial pre-clinical and clinical studies have already outlined the potential of this technique; however, future studies need to be extended to larger patient groups to show the diagnostic outcome. In conclusion, (23)Na MRI is seen as a powerful technique with the option to establish a non-invasive renal biomarker for tissue viability, but is still a long way from real clinical implementation.
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Affiliation(s)
- Frank G Zöllner
- Computer Assisted Clinical Medicine, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
| | - Simon Konstandin
- Computer Assisted Clinical Medicine, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
- MR-Imaging and Spectroscopy, Faculty 01 (Physics/Electrical Engineering), University of Bremen, Bremen, Germany
| | - Jonathan Lommen
- Computer Assisted Clinical Medicine, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
| | - Johannes Budjan
- Institute of Clinical Radiology and Nuclear Medicine, University Medical Center Mannheim, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
| | - Stefan O Schoenberg
- Institute of Clinical Radiology and Nuclear Medicine, University Medical Center Mannheim, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
| | - Lothar R Schad
- Computer Assisted Clinical Medicine, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
| | - Stefan Haneder
- Institute of Clinical Radiology and Nuclear Medicine, University Medical Center Mannheim, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
- Department of Radiology, University Hospital of Cologne, Cologne, Germany
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Konstandin S, Krämer P, Günther M, Schad LR. Sodium magnetic resonance imaging using ultra-short echo time sequences with anisotropic resolution and uniform k-space sampling. Magn Reson Imaging 2014; 33:319-27. [PMID: 25527394 DOI: 10.1016/j.mri.2014.12.007] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2014] [Revised: 12/01/2014] [Accepted: 12/01/2014] [Indexed: 01/12/2023]
Abstract
A method for uniform k-space sampling of 3D ultra-short echo time (UTE) techniques with anisotropic resolution in one direction is introduced to increase signal-to-noise ratio (SNR). State-of-the-art acquisition schemes for sodium MRI with radial (projection reconstruction) and twisting (twisted projection imaging (TPI)) trajectories are investigated regarding SNR efficiency, blurring behavior under T2(⁎) decay, and measurement time in case of anisotropic field-of-view and resolution. 3D radial and twisting trajectories are redistributed in k-space for UTE sodium MRI with homogeneous noise distribution and optimal SNR efficiency, if T2(⁎) decay can be neglected. Simulations based on Voronoi tessellations and phantom simulations/measurements were performed to calculate SNR efficiency. Point-spread functions were simulated to demonstrate the influence of T2(⁎) decay on SNR and resolution. Phantom simulations/measurements and in vivo measurements confirm the SNR gain obtained by simulations based on Voronoi cells. An increase in SNR of up to 21% at an anisotropy factor of 10 could be theoretically achieved by TPI with projection adaption compared to the same sequence but without redistribution of projections in k-space. Sodium MRI with anisotropic resolution and uniform k-space sampling is demonstrated by in vivo measurements of human intervertebral disks and heart at 3 T. The SNR gain can be invested in a measurement time reduction of up to 32%, which is important especially for sodium MRI.
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Affiliation(s)
- Simon Konstandin
- Computer Assisted Clinical Medicine, Medical Faculty Mannheim, Heidelberg University, Theodor-Kutzer-Ufer 1-3, 68167 Mannheim, Germany; MR-Imaging and Spectroscopy, Faculty 01 (Physics/Electrical Engineering), University of Bremen, NW 1 Otto-Hahn-Allee 1, 28359 Bremen, Germany.
| | - Philipp Krämer
- Computer Assisted Clinical Medicine, Medical Faculty Mannheim, Heidelberg University, Theodor-Kutzer-Ufer 1-3, 68167 Mannheim, Germany
| | - Matthias Günther
- MR-Imaging and Spectroscopy, Faculty 01 (Physics/Electrical Engineering), University of Bremen, NW 1 Otto-Hahn-Allee 1, 28359 Bremen, Germany; Fraunhofer MEVIS, Universitätsallee 29, 28359 Bremen, Germany
| | - Lothar R Schad
- Computer Assisted Clinical Medicine, Medical Faculty Mannheim, Heidelberg University, Theodor-Kutzer-Ufer 1-3, 68167 Mannheim, Germany
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Dose-dependent changes in renal (1)H-/(23)Na MRI after adjuvant radiochemotherapy for gastric cancer. Strahlenther Onkol 2014; 191:356-64. [PMID: 25445156 DOI: 10.1007/s00066-014-0787-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2014] [Accepted: 10/31/2014] [Indexed: 10/24/2022]
Abstract
PURPOSE Combined radiochemotherapy (RCT) for gastric cancer with three-dimensional conformal radiotherapy (3D-CRT) results in ablative doses to the upper left kidney, while image-guided intensity-modulated radiotherapy (IG-IMRT) allows kidney sparing despite improved target coverage. Renal function in long-term gastric cancer survivors was evaluated with 3T functional magnetic resonance imaging (MRI) including diffusion-weighted imaging (DWI) and (23)Na imaging. PATIENTS AND METHODS Five healthy volunteers and 13 patients after radiotherapy were included: 11×IG-IMRT; 1×3D-CRT; 1× "positive control" with stereotactic body radiotherapy (SBRT) of a metastasis between the spleen/left kidney. Radiation doses were documented for the upper/middle/lower kidney subvolumes. Late toxicity was evaluated based on CTC criteria, questionnaire, and creatinine values. Morphological sequences, DWI images, and (23)Na images were acquired using a (1)H/(23)Na-tuned body-coil before/after intravenous water load (WL). Statistics for [(23)Na] (concentration) and apparent diffusion coefficient (ADC) values were calculated for upper/middle/lower renal subvolumes. Corticomedullary [(23)Na] gradients and [(23)Na] differences after WL were determined. RESULTS No major morphological alteration was detected in any patient. Minor scars were observed in the cranial subvolume of the left kidney of the 3D-CRT and the whole kidney of the control SBRT patient. All participants presented a corticomedullary [(23)Na] gradient. After WL, a significant physiological [(23)Na] gradient decrease (p < 0.001) was observed in all HV and IG-IMRT patients. In the cranial left kidney of the 3D-CRT patient and the positive control SBRT patient, the decrease was nonsignificant (p = 0.01, p = 0.02). ADC values were altered nonsignificantly in all renal subvolumes (all participants). Renal subvolumes with doses ≥ 35 Gy showed a reduced change of the [(23)Na] gradient after WL (p = 0.043). No participants showed clinical renal impairment. CONCLUSIONS Functional parameters of renal (23)Na MRI after gastric IG-IMRT are identical to those of healthy volunteers, in contrast to renal subvolumes after ablative doses in the control and 3D-CRT patient. While kidney doses to the cortex below 20-25 Gy in fractional doses of ~ 1 Gy in IG-IMRT (combined with intensified chemotherapy) do not seem to cause significant MRI morphological or functional alterations, doses of > 35 Gy in 1.5-2 Gy fractions clearly result in impairment.
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Haneder S, Ong MML, Budjan JM, Schmidt R, Konstandin S, Morelli JN, Schad LR, Schoenberg SO, Kerl UH. 23Na-magnetic resonance imaging of the human lumbar vertebral discs: in vivo measurements at 3.0 T in healthy volunteers and patients with low back pain. Spine J 2014; 14:1343-50. [PMID: 24472875 DOI: 10.1016/j.spinee.2014.01.031] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/31/2013] [Revised: 12/12/2013] [Accepted: 01/17/2014] [Indexed: 02/09/2023]
Abstract
BACKGROUND CONTEXT 1H magnetic resonance imaging (MRI) of the spine can rule out common causes of low back pain (LBP), such as disc protrusions or nerve root compression; however, no significant causal relation exists between morphology and the extent of symptoms. Functional MRI techniques, such as 23Na, may provide additional information, allowing indirect assessment of vertebral glycosaminoglycan concentrations, decreases in which are associated with early degenerative changes. PURPOSE To evaluate 23Na-MRI of asymptomatic healthy volunteers and symptomatic patients with LPB and correlate the results to the Pfirrmann classification of MRI disc morphology. STUDY DESIGN Retrospective cohort study at an academic medical center. PATIENT SAMPLE Two groups were studied: (1) 55 healthy volunteers (31 men, 24 women; mean age 28.8 years) and (2) 12 patients (6 men, 6 women; mean age: 35.3 years) with a recent history of LBP. METHODS Lumbar spines of the aforementioned groups were examined on a 3.0 T MRI scanner with morphological 1H and 23Na imaging. Intervertebral disc (IVD) 23Na at each level was normalized (23Nanorm). Distribution and differences between mean 23Nanorm corresponding to each Pfirrmann classification were evaluated in the two study groups (analysis of variance). Linear correlations between 23Nanorm, body mass index (BMI), and age were assessed (Pearson correlation coefficient). Gender-dependent differences were evaluated (paired t test). OUTCOME MEASURES Physiological measure: IVD 23Nanorm as determined by 23Na-MRI. RESULTS A normal distribution of 23Nanorm was confirmed for both groups (p=.072 and p=.073, respectively). The mean Pfirrmann score statistically significantly differed between them (p<.0001). 23Nanorm was statistically significantly reduced in degenerated IVDs (Pfirrmann scores 4+5) (p<.0001). No statistically significant differences were seen for the mean 23Nanorm of IVDs with the same Pfirrmann score in healthy volunteers and patients (.469<p<.967). Age (0.007<R2<0.202) and BMI (0.074<R2<0.288) showed either weak or no correlation to 23Nanorm. Mean 23Nanorm was significantly (p=.0002) greater in women relative to men. CONCLUSIONS The results underline the feasibility and robustness of 23Na-MRI of human IVDs and affirm, in a large cohort, decreases in 23Na IVD content seen with disc degeneration.
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Affiliation(s)
- Stefan Haneder
- Institute of Clinical Radiology and Nuclear Medicine, University Medical Center Mannheim, Heidelberg University, Theodor-Kutzer-Ufer 1-3, 68167 Mannheim, Germany.
| | - Melissa M L Ong
- Institute of Clinical Radiology and Nuclear Medicine, University Medical Center Mannheim, Heidelberg University, Theodor-Kutzer-Ufer 1-3, 68167 Mannheim, Germany
| | - Johannes M Budjan
- Institute of Clinical Radiology and Nuclear Medicine, University Medical Center Mannheim, Heidelberg University, Theodor-Kutzer-Ufer 1-3, 68167 Mannheim, Germany
| | - René Schmidt
- Department of Orthopedic and Traumatology, Alb-Fils Hospital Goeppingen, Eicherstr. 3, 73035 Goeppingen, Germany
| | - Simon Konstandin
- Computer Assisted Clinical Medicine, Heidelberg University, Theodor-Kutzer-Ufer 1-3, 68167 Mannheim, Germany
| | - John N Morelli
- The Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins Hospital, 601 North Caroline Street, Baltimore, MD 21287-0006, USA
| | - Lothar R Schad
- Computer Assisted Clinical Medicine, Heidelberg University, Theodor-Kutzer-Ufer 1-3, 68167 Mannheim, Germany
| | - Stefan O Schoenberg
- Institute of Clinical Radiology and Nuclear Medicine, University Medical Center Mannheim, Heidelberg University, Theodor-Kutzer-Ufer 1-3, 68167 Mannheim, Germany
| | - Ulrich H Kerl
- Department of Neuroradiology, University Medical Center Mannheim, Heidelberg University, Theodor-Kutzer-Ufer 1-3, 68167 Mannheim, Germany
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Moon CH, Furlan A, Kim JH, Zhao T, Shapiro R, Bae KT. Quantitative sodium MR imaging of native versus transplanted kidneys using a dual-tuned proton/sodium (1H/ 23Na) coil: initial experience. Eur Radiol 2014; 24:1320-6. [PMID: 24668008 DOI: 10.1007/s00330-014-3138-5] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2013] [Revised: 01/26/2014] [Accepted: 02/18/2014] [Indexed: 11/30/2022]
Abstract
OBJECTIVES To compare sodium ((23)Na) characteristics between native and transplanted kidneys using dual-tuned proton ((1)H)/sodium MRI. METHODS Six healthy volunteers and six renal transplant patients (3 normal function, 3 acute allograft rejection) were included. Proton/sodium MRI was obtained at 3 T using a dual-tuned coil. Signal to noise ratio (SNR), sodium concentration ([(23)Na]) and cortico-medullary sodium gradient (CMSG) were measured. Reproducibility of [(23)Na] measurement was also tested. SNR, [(23)Na] and CMSG of the native and transplanted kidneys were compared. RESULTS Proton and sodium images of kidneys were successfully acquired. SNR and [(23)Na] measurements of the native kidneys were reproducible at two different sessions. [(23)Na] and CMSG of the transplanted kidneys was significantly lower than those of the native kidneys: 153.5 ± 11.9 vs. 192.9 ± 9.6 mM (P = 0.002) and 8.9 ± 1.5 vs. 10.5 ± 0.9 mM/mm (P = 0.041), respectively. [(23)Na] and CMSG of the transplanted kidneys with normal function vs. acute rejection were not statistically different. CONCLUSIONS Sodium quantification of kidneys was reliably performed using proton/sodium MRI. [(23)Na] and CMSG of the transplanted kidneys were lower than those of the native kidneys, but without a statistically significant difference between patients with or without renal allograft rejection. KEY POINTS Dual-tuned proton/sodium RF coil enables co-registered proton and sodium MRI. Structural and sodium biochemical property can be acquired by dual-tuned proton/sodium MRI. Sodium and sodium gradient of kidneys can be measured by dual-tuned MRI. Sodium concentration was lower in transplanted kidneys than in native kidneys. Sodium gradient of transplanted kidneys was lower than for native kidneys.
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Affiliation(s)
- Chan Hong Moon
- Department of Radiology, University of Pittsburgh, 200 Lothrop Street, Presby South tower Suite 3950, Pittsburgh, PA, 15213, USA
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