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Tasbihi E, Gladytz T, Millward JM, Periquito JS, Starke L, Waiczies S, Cantow K, Seeliger E, Niendorf T. In vivo monitoring of renal tubule volume fraction using dynamic parametric MRI. Magn Reson Med 2024; 91:2532-2545. [PMID: 38321592 DOI: 10.1002/mrm.30023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2023] [Revised: 01/05/2024] [Accepted: 01/06/2024] [Indexed: 02/08/2024]
Abstract
PURPOSE The increasing incidence of kidney diseases is a global concern, and current biomarkers and treatments are inadequate. Changes in renal tubule luminal volume fraction (TVF) serve as a rapid biomarker for kidney disease and improve understanding of renal (patho)physiology. This study uses the amplitude of the long T2 component as a surrogate for TVF in rats, by applying multiexponential analysis of the T2-driven signal decay to examine micromorphological changes in renal tissue. METHODS Simulations were conducted to identify a low mean absolute error (MAE) protocol and an accelerated protocol customized for the in vivo study of T2 mapping of the rat kidney at 9.4 T. We then validated our bi-exponential approach in a phantom mimicking the relaxation properties of renal tissue. This was followed by a proof-of-principle demonstration using in vivo data obtained during a transient increase of renal pelvis and tubular pressure. RESULTS Using the low MAE protocol, our approach achieved an accuracy of MAE < 1% on the mechanical phantom. The T2 mapping protocol customized for in vivo study achieved an accuracy of MAE < 3%. Transiently increasing pressure in the renal pelvis and tubules led to significant changes in TVF in renal compartments: ΔTVFcortex = 4.9%, ΔTVFouter_medulla = 4.5%, and ΔTVFinner_medulla = -14.6%. CONCLUSION These results demonstrate that our approach is promising for research into quantitative assessment of renal TVF in in vivo applications. Ultimately, these investigations have the potential to help reveal mechanism in acute renal injury that may lead to chronic kidney disease, which will support research into renal disorders.
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Affiliation(s)
- Ehsan Tasbihi
- Berlin Ultrahigh Field Facility, Max Delbrueck Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany
- Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Thomas Gladytz
- Berlin Ultrahigh Field Facility, Max Delbrueck Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany
| | - Jason M Millward
- Berlin Ultrahigh Field Facility, Max Delbrueck Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany
- Hasso Plattner Institute for Digital Engineering, University of Potsdam, Potsdam, Germany
| | - Joāo S Periquito
- Berlin Ultrahigh Field Facility, Max Delbrueck Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany
| | - Ludger Starke
- Berlin Ultrahigh Field Facility, Max Delbrueck Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany
- Experimental and Clinical Research Center, a Joint Cooperation Between the Charité Medical Faculty and the Max Delbrück Center for Molecular Medicine, Berlin, Germany
| | - Sonia Waiczies
- Berlin Ultrahigh Field Facility, Max Delbrueck Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany
- Hasso Plattner Institute for Digital Engineering, University of Potsdam, Potsdam, Germany
| | - Kathleen Cantow
- Institute of Translational Physiology, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Erdmann Seeliger
- Institute of Translational Physiology, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Thoralf Niendorf
- Berlin Ultrahigh Field Facility, Max Delbrueck Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany
- Experimental and Clinical Research Center, a Joint Cooperation Between the Charité Medical Faculty and the Max Delbrück Center for Molecular Medicine, Berlin, Germany
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Liu X, Tang S, Cui D, Bok RA, Chen HY, Gordon JW, Wang ZJ, Larson PEZ. A metabolite specific 3D stack-of-spirals bSSFP sequence for improved bicarbonate imaging in hyperpolarized [1- 13C]Pyruvate MRI. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2023; 353:107518. [PMID: 37402333 PMCID: PMC10498937 DOI: 10.1016/j.jmr.2023.107518] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/20/2023] [Revised: 06/23/2023] [Accepted: 06/25/2023] [Indexed: 07/06/2023]
Abstract
13C-bicarbonate is a crucial measure of pyruvate oxidation and TCA cycle flux, but is challenging to measure due to its relatively low concentration and thus will greatly benefit from improved signal-to-noise ratio (SNR). To address this, we developed and investigated the feasibility of a 3D stack-of-spirals metabolite-specific balanced steady-state free precession (MS-bSSFP) sequence for improving the SNR and spatial resolution of dynamic 13C-bicarbonate imaging in hyperpolarized [1-13C]pyruvate studies. The bicarbonate MS-bSSFP sequence was evaluated by simulations, phantoms studies, preclinical studies on five rats, brain studies on two healthy volunteers and renal study on one renal cell carcinoma patient. The simulations and phantom results showed that the bicarbonate-specific pulse had minimal perturbation of other metabolites (<1%). In the animal studies, the MS-bSSFP sequence provided an approximately 2.6-3 × improvement in 13C-bicarbonate SNR compared to a metabolite-specific gradient echo (MS-GRE) sequence without altering the bicarbonate or pyruvate kinetics, and the shorter spiral readout in the MS-bSSFP approach reduced blurring. Using the SNR ratio between MS-bSSFP and MS-GRE, the T2 values of bicarbonate and lactate in the rat kidneys were estimated as 0.5 s and 1.1 s, respectively. The in-vivo feasibility of bicarbonate MS-bSSFP sequence was demonstrated in two human brain studies and one renal study. These studies demonstrate the potential of the sequence for in-vivo applications, laying the foundation for future studies to observe this relatively low concentration metabolite with high-quality images and improve measurements of pyruvate oxidation.
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Affiliation(s)
- Xiaoxi Liu
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, CA, USA
| | | | - Di Cui
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, CA, USA
| | - Robert A Bok
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, CA, USA
| | - Hsin-Yu Chen
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, CA, USA
| | - Jeremy W Gordon
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, CA, USA
| | - Zhen J Wang
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, CA, USA
| | - Peder E Z Larson
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, CA, USA; Graduate Program in Bioengineering, University of California, Berkeley and San Francisco, San Francisco, CA, USA.
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Liu X, Tang S, Mu C, Qin H, Cu D, Lai YC, Riselli AM, Delos Santos R, Carvajal L, Gebrezgiabhier D, Bok RA, Chen HY, Flavell RR, Gordon JW, Vigneron DB, Kurhanewicz J, Larson PE. Development of specialized magnetic resonance acquisition techniques for human hyperpolarized [ 13 C, 15 N 2 ]urea + [1- 13 C]pyruvate simultaneous perfusion and metabolic imaging. Magn Reson Med 2022; 88:1039-1054. [PMID: 35526263 PMCID: PMC9810116 DOI: 10.1002/mrm.29266] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2022] [Revised: 03/22/2022] [Accepted: 03/23/2022] [Indexed: 01/05/2023]
Abstract
PURPOSE This study aimed to develop and demonstrate the in vivo feasibility of a 3D stack-of-spiral balanced steady-state free precession(3D-bSSFP) urea sequence, interleaved with a metabolite-specific gradient echo (GRE) sequence for pyruvate and metabolic products, for improving the SNR and spatial resolution of the first hyperpolarized 13 C-MRI human study with injection of co-hyperpolarized [1-13 C]pyruvate and [13 C,15 N2 ]urea. METHODS A metabolite-specific bSSFP urea imaging sequence was designed using a urea-specific excitation pulse, optimized TR, and 3D stack-of-spiral readouts. Simulations and phantom studies were performed to validate the spectral response of the sequence. The image quality of urea data acquired by the 3D-bSSFP sequence and the 2D-GRE sequence was evaluated with 2 identical injections of co-hyperpolarized [1-13 C]pyruvate and [13 C,15 N2 ]urea formula in a rat. Subsequently, the feasibility of the acquisition strategy was validated in a prostate cancer patient. RESULTS Simulations and phantom studies demonstrated that 3D-bSSFP sequence achieved urea-only excitation, while minimally perturbing other metabolites (<1%). An animal study demonstrated that compared to GRE, bSSFP sequence provided an ∼2.5-fold improvement in SNR without perturbing urea or pyruvate kinetics, and bSSFP approach with a shorter spiral readout reduced blurring artifacts caused by J-coupling of [13 C,15 N2 ]urea. The human study demonstrated the in vivo feasibility and data quality of the acquisition strategy. CONCLUSION The 3D-bSSFP urea sequence with a stack-of-spiral acquisition demonstrated significantly increased SNR and image quality for [13 C,15 N2 ]urea in co-hyperpolarized [1-13 C]pyruvate and [13 C,15 N2 ]urea imaging studies. This work lays the foundation for future human studies to achieve high-quality and high-SNR metabolism and perfusion images.
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Affiliation(s)
- Xiaoxi Liu
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, California, USA
| | - Shuyu Tang
- HeartVista Inc., Los Altos, California, USA
| | - Changhua Mu
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, California, USA
| | - Hecong Qin
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, California, USA
| | - Di Cu
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, California, USA
| | - Ying-Chieh Lai
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, California, USA
- Department of Medical Imaging and Intervention, Chang Gung Memorial Hospital at Linkou, Taoyuan 333, Taiwan
| | - Andrew M. Riselli
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, California, USA
| | - Romelyn Delos Santos
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, California, USA
| | - Lucas Carvajal
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, California, USA
| | - Daniel Gebrezgiabhier
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, California, USA
| | - Robert A. Bok
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, California, USA
| | - Hsin-Yu Chen
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, California, USA
| | - Robert R. Flavell
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, California, USA
| | - Jeremy W. Gordon
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, California, USA
| | - Daniel B. Vigneron
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, California, USA
- Graduate Program in Bioengineering, University of California, Berkeley and San Francisco, San Francisco, California, USA
| | - John Kurhanewicz
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, California, USA
- Graduate Program in Bioengineering, University of California, Berkeley and San Francisco, San Francisco, California, USA
| | - Peder E.Z. Larson
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, California, USA
- Graduate Program in Bioengineering, University of California, Berkeley and San Francisco, San Francisco, California, USA
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Fok WYR, Grashei M, Skinner JG, Menze BH, Schilling F. Prediction of multiple pH compartments by deep learning in magnetic resonance spectroscopy with hyperpolarized 13C-labelled zymonic acid. EJNMMI Res 2022; 12:24. [PMID: 35460436 PMCID: PMC9035201 DOI: 10.1186/s13550-022-00894-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2022] [Accepted: 04/05/2022] [Indexed: 11/11/2022] Open
Abstract
Background Hyperpolarization enhances the sensitivity of nuclear magnetic resonance experiments by between four and five orders of magnitude. Several hyperpolarized sensor molecules have been introduced that enable high sensitivity detection of metabolism and physiological parameters. However, hyperpolarized magnetic resonance spectroscopy imaging (MRSI) often suffers from poor signal-to-noise ratio and spectral analysis is complicated by peak overlap. Here, we study measurements of extracellular pH (pHe) by hyperpolarized zymonic acid, where multiple pHe compartments, such as those observed in healthy kidney or other heterogeneous tissue, result in a cluster of spectrally overlapping peaks, which is hard to resolve with conventional spectroscopy analysis routines. Methods We investigate whether deep learning methods can yield improved pHe prediction in hyperpolarized zymonic acid spectra of multiple pHe compartments compared to conventional line fitting. As hyperpolarized 13C-MRSI data sets are often small, a convolutional neural network (CNN) and a multilayer perceptron (MLP) were trained with either a synthetic or a mixed (synthetic and augmented) data set of acquisitions from the kidneys of healthy mice. Results Comparing the networks’ performances compartment-wise on a synthetic test data set and eight real kidney data shows superior performance of CNN compared to MLP and equal or superior performance compared to conventional line fitting. For correct prediction of real kidney pHe values, training with a mixed data set containing only 0.5% real data shows a large improvement compared to training with synthetic data only. Using a manual segmentation approach, pH maps of kidney compartments can be improved by neural network predictions for voxels including three pH compartments. Conclusion The results of this study indicate that CNNs offer a reliable, accurate, fast and non-interactive method for analysis of hyperpolarized 13C MRS and MRSI data, where low amounts of acquired data can be complemented to achieve suitable network training.
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Affiliation(s)
- Wai-Yan Ryana Fok
- Department of Informatics, Technical University of Munich, 85748, Garching, Germany
| | - Martin Grashei
- Department of Nuclear Medicine, TUM School of Medicine, Klinikum Rechts der Isar, Technical University of Munich, 81675, Munich, Germany
| | - Jason G Skinner
- Department of Nuclear Medicine, TUM School of Medicine, Klinikum Rechts der Isar, Technical University of Munich, 81675, Munich, Germany
| | - Bjoern H Menze
- Department of Informatics, Technical University of Munich, 85748, Garching, Germany
| | - Franz Schilling
- Department of Nuclear Medicine, TUM School of Medicine, Klinikum Rechts der Isar, Technical University of Munich, 81675, Munich, Germany. .,Munich Institute of Biomedical Engineering, Technical University of Munich, 85748, Garching, Germany.
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pH Dependence of T2 for Hyperpolarizable 13C-Labelled Small Molecules Enables Spatially Resolved pH Measurement by Magnetic Resonance Imaging. Pharmaceuticals (Basel) 2021; 14:ph14040327. [PMID: 33918366 PMCID: PMC8067065 DOI: 10.3390/ph14040327] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2021] [Revised: 03/22/2021] [Accepted: 03/30/2021] [Indexed: 11/16/2022] Open
Abstract
Hyperpolarized 13C magnetic resonance imaging often uses spin-echo-based pulse sequences that are sensitive to the transverse relaxation time T2. In this context, local T2-changes might introduce a quantification bias to imaging biomarkers. Here, we investigated the pH dependence of the apparent transverse relaxation time constant (denoted here as T2) of six 13C-labelled molecules. We obtained minimum and maximum T2 values within pH 1–13 at 14.1 T: [1-13C]acetate (T2,min = 2.1 s; T2,max = 27.7 s), [1-13C]alanine (T2,min = 0.6 s; T2,max = 10.6 s), [1,4-13C2]fumarate (T2,min = 3.0 s; T2,max = 18.9 s), [1-13C]lactate (T2,min = 0.7 s; T2,max = 12.6 s), [1-13C]pyruvate (T2,min = 0.1 s; T2,max = 18.7 s) and 13C-urea (T2,min = 0.1 s; T2,max = 0.1 s). At 7 T, T2-variation in the physiological pH range (pH 6.8–7.8) was highest for [1-13C]pyruvate (ΔT2 = 0.95 s/0.1pH) and [1-13C]acetate (ΔT2 = 0.44 s/0.1pH). Concentration, salt concentration, and temperature alterations caused T2 variations of up to 45.4% for [1-13C]acetate and 23.6% for [1-13C]pyruvate. For [1-13C]acetate, spatially resolved pH measurements using T2-mapping were demonstrated with 1.6 pH units accuracy in vitro. A strong proton exchange-based pH dependence of T2 suggests that pH alterations potentially influence signal strength for hyperpolarized 13C-acquisitions.
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6
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Analysis Methods for Hyperpolarized Carbon ( 13C) MRI of the Kidney. Methods Mol Biol 2021. [PMID: 33476032 DOI: 10.1007/978-1-0716-0978-1_42] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
Abstract
Hyperpolarized 13C MR is a novel medical imaging modality with substantially different signal dynamics as compared to conventional 1H MR, thus requiring new methods for processing the data in order to access and quantify the embedded metabolic and functional information. Here we describe step-by-step analysis protocols for functional renal hyperpolarized 13C imaging. These methods are useful for investigating renal blood flow and function as well as metabolic status of rodents in vivo under various experimental physiological conditions.This chapter is based upon work from the COST Action PARENCHIMA, a community-driven network funded by the European Cooperation in Science and Technology (COST) program of the European Union, which aims to improve the reproducibility and standardization of renal MRI biomarkers. This analysis protocol chapter is complemented by two separate chapters describing the basic concept and experimental procedure.
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von Morze C, Engelbach JA, Reed GD, Chen AP, Quirk JD, Blazey T, Mahar R, Malloy CR, Garbow JR, Merritt ME. 15 N-carnitine, a novel endogenous hyperpolarized MRI probe with long signal lifetime. Magn Reson Med 2020; 85:1814-1820. [PMID: 33179825 DOI: 10.1002/mrm.28578] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2020] [Revised: 10/05/2020] [Accepted: 10/09/2020] [Indexed: 12/22/2022]
Abstract
PURPOSE The purpose of this study was to investigate hyperpolarization and in vivo imaging of [15 N]carnitine, a novel endogenous MRI probe with long signal lifetime. METHODS L-[15 N]carnitine-d9 was hyperpolarized by the method of dynamic nuclear polarization followed by rapid dissolution. The T1 signal lifetimes were estimated in aqueous solution and in vivo following intravenous injection in rats, using a custom-built dual-tuned 15 N/1 H RF coil at 4.7 T. 15 N chemical shift imaging and 15 N fast spin-echo images of rat abdomen were acquired 3 minutes after [15 N]carnitine injection. RESULTS Estimated T1 times of [15 N]carnitine at 4.7 T were 210 seconds (in H2 O) and 160 seconds (in vivo), with an estimated polarization level of 10%. Remarkably, the [15 N]carnitine coherence was detectable in rat abdomen for 5 minutes after injection for the nonlocalized acquisition. No downstream metabolites were detected on localized or nonlocalized 15 N spectra. Diffuse liver enhancement was detected on 15 N fast spin-echo imaging 3 minutes after injection, with mean hepatic SNR of 18 ± 5 at a spatial resolution of 4 × 4 mm. CONCLUSION This study showed the feasibility of hyperpolarizing and imaging the biodistribution of HP [15 N]carnitine.
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Affiliation(s)
- Cornelius von Morze
- Mallinckrodt Institute of Radiology, Washington University, St Louis, Missouri, USA
| | - John A Engelbach
- Mallinckrodt Institute of Radiology, Washington University, St Louis, Missouri, USA
| | | | | | - James D Quirk
- Mallinckrodt Institute of Radiology, Washington University, St Louis, Missouri, USA
| | - Tyler Blazey
- Mallinckrodt Institute of Radiology, Washington University, St Louis, Missouri, USA
| | - Rohit Mahar
- Department of Biochemistry, University of Florida, Gainesville, Florida, USA
| | - Craig R Malloy
- Advanced Imaging Research Center, University of Texas, Southwestern, Dallas, Texas, USA
| | - Joel R Garbow
- Mallinckrodt Institute of Radiology, Washington University, St Louis, Missouri, USA
| | - Matthew E Merritt
- Department of Biochemistry, University of Florida, Gainesville, Florida, USA
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Shin SH, Wendland MF, Vandsburger MH. Delayed urea differential enhancement CEST (dudeCEST)-MRI with T 1 correction for monitoring renal urea handling. Magn Reson Med 2020; 85:2791-2804. [PMID: 33180343 DOI: 10.1002/mrm.28583] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2020] [Revised: 10/12/2020] [Accepted: 10/13/2020] [Indexed: 12/12/2022]
Abstract
PURPOSE We demonstrate a method of delayed urea differential enhancement CEST for probing urea recycling action of the kidney using expanded multi-pool Lorentzian fitting and apparent exchange-dependent relaxation compensation. METHODS T1 correction of urea CEST contrast by apparent exchange-dependent relaxation was tested in phantoms. Nine mice were scanned at 7 Tesla following intraperitoneal injection of 2M 150 μL urea, and later saline. T1 maps and Z-spectra were acquired before and 20 and 40 min postinjection. Z-spectra were fit to a 7-pool Lorentzian model for CEST quantification and compared to urea assay of kidney homogenate. Renal injury was induced by aristolochic acid in 7 mice, and the same scan protocol was performed. RESULTS Apparent exchange-dependent relaxation corrected for variable T1 times in phantoms. Urea CEST contrast at +1 ppm increased significantly at both time points following urea injection in the inner medulla and papilla. When normalizing the postinjection urea CEST contrast to the corresponding baseline value, both urea and saline injection resulted in identical fold changes in urea CEST contrast. Urea assay of kidney homogenate showed a significant correlation to both apparent exchange-dependent relaxation (R2 = 0.4687, P = .0017) and non-T1 -corrected Lorentzian amplitudes (R2 = 0.4964, P = .0011). Renal injury resulted in increased T1 time in the cortex and reduced CEST contrast change upon urea and saline infusion. CONCLUSION Delayed urea enhancement following infusion can provide insight into renal urea handling. In addition, changes in CEST contrast at 1.0 ppm following saline infusion may provide insight into renal function.
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Affiliation(s)
- Soo Hyun Shin
- Department of Bioengineering, University of California, Berkeley, Berkeley, California, USA
| | - Michael F Wendland
- Berkeley Preclinical Imaging Core (BPIC), University of California, Berkeley, Berkeley, California, USA
| | - Moriel H Vandsburger
- Department of Bioengineering, University of California, Berkeley, Berkeley, California, USA
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Grist JT, Miller JJ, Zaccagna F, McLean MA, Riemer F, Matys T, Tyler DJ, Laustsen C, Coles AJ, Gallagher FA. Hyperpolarized 13C MRI: A novel approach for probing cerebral metabolism in health and neurological disease. J Cereb Blood Flow Metab 2020; 40:1137-1147. [PMID: 32153235 PMCID: PMC7238376 DOI: 10.1177/0271678x20909045] [Citation(s) in RCA: 42] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/24/2019] [Revised: 01/24/2020] [Accepted: 01/28/2020] [Indexed: 12/13/2022]
Abstract
Cerebral metabolism is tightly regulated and fundamental for healthy neurological function. There is increasing evidence that alterations in this metabolism may be a precursor and early biomarker of later stage disease processes. Proton magnetic resonance spectroscopy (1H-MRS) is a powerful tool to non-invasively assess tissue metabolites and has many applications for studying the normal and diseased brain. However, the technique has limitations including low spatial and temporal resolution, difficulties in discriminating overlapping peaks, and challenges in assessing metabolic flux rather than steady-state concentrations. Hyperpolarized carbon-13 magnetic resonance imaging is an emerging clinical technique that may overcome some of these spatial and temporal limitations, providing novel insights into neurometabolism in both health and in pathological processes such as glioma, stroke and multiple sclerosis. This review will explore the growing body of pre-clinical data that demonstrates a potential role for the technique in assessing metabolism in the central nervous system. There are now a number of clinical studies being undertaken in this area and this review will present the emerging clinical data as well as the potential future applications of hyperpolarized 13C magnetic resonance imaging in the brain, in both clinical and pre-clinical studies.
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Affiliation(s)
- James T Grist
- Institute of Cancer and Genomic Sciences, University of
Birmingham, Birmingham, UK
- Department of Radiology, University of Cambridge, Cambridge,
UK
| | - Jack J Miller
- Department of Physiology, Anatomy, and Genetics, University of
Oxford, Oxford, UK
- Department of Physics, Clarendon Laboratory, University of
Oxford, Oxford, UK
- Oxford Centre for Clinical Magnetic Resonance Research, John
Radcliffe Hospital, Oxford, UK
| | - Fulvio Zaccagna
- Department of Radiology, University of Cambridge, Cambridge,
UK
| | - Mary A McLean
- Department of Radiology, University of Cambridge, Cambridge,
UK
- CRUK Cambridge Institute, Cambridge, UK
| | - Frank Riemer
- Department of Radiology, University of Cambridge, Cambridge,
UK
| | - Tomasz Matys
- Department of Radiology, University of Cambridge, Cambridge,
UK
| | - Damian J Tyler
- Department of Physiology, Anatomy, and Genetics, University of
Oxford, Oxford, UK
- Oxford Centre for Clinical Magnetic Resonance Research, John
Radcliffe Hospital, Oxford, UK
| | | | - Alasdair J Coles
- Department of Clinical Neurosciences, University of Cambridge,
Cambridge, UK
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10
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Milshteyn E, Reed GD, Gordon JW, von Morze C, Cao P, Tang S, Leynes AP, Larson PEZ, Vigneron DB. Simultaneous T 1 and T 2 mapping of hyperpolarized 13C compounds using the bSSFP sequence. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2020; 312:106691. [PMID: 32058912 PMCID: PMC7227792 DOI: 10.1016/j.jmr.2020.106691] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/09/2019] [Revised: 01/29/2020] [Accepted: 01/30/2020] [Indexed: 06/10/2023]
Abstract
As in conventional 1H MRI, T1 and T2 relaxation times of hyperpolarized (HP) 13C nuclei can provide important biomedical information. Two new approaches were developed for simultaneous T1 and T2 mapping of HP 13C probes based on balanced steady state free precession (bSSFP) acquisitions: a method based on sequential T1 and T2 mapping modules, and a model-based joint T1/T2 approach analogous to MR fingerprinting. These new methods were tested in simulations, HP 13C phantoms, and in vivo in normal Sprague-Dawley rats. Non-localized T1 values, low flip angle EPI T1 maps, bSSFP T2 maps, and Bloch-Siegert B1 maps were also acquired for comparison. T1 and T2 maps acquired using both approaches were in good agreement with both literature values and data from comparative acquisitions. Multiple HP 13C compounds were successfully mapped, with their relaxation time parameters measured within heart, liver, kidneys, and vasculature in one acquisition for the first time.
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Affiliation(s)
- Eugene Milshteyn
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, CA, USA.
| | | | - Jeremy W Gordon
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, CA, USA
| | - Cornelius von Morze
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, CA, USA
| | - Peng Cao
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, CA, USA
| | - Shuyu Tang
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, CA, USA
| | - Andrew P Leynes
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, CA, USA
| | - Peder E Z Larson
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, CA, USA
| | - Daniel B Vigneron
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, CA, USA
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Pedersen M, Ursprung S, Jensen JD, Jespersen B, Gallagher F, Laustsen C. Hyperpolarised 13C-MRI metabolic and functional imaging: an emerging renal MR diagnostic modality. MAGMA (NEW YORK, N.Y.) 2020; 33:23-32. [PMID: 31782036 DOI: 10.1007/s10334-019-00801-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2019] [Revised: 10/21/2019] [Accepted: 11/12/2019] [Indexed: 12/11/2022]
Abstract
Magnetic resonance imaging (MRI) is a well-established modality for assessing renal morphology and function, as well as changes that occur during disease. However, the significant metabolic changes associated with renal disease are more challenging to assess with MRI. Hyperpolarized carbon-13 MRI is an emerging technique which provides an opportunity to probe metabolic alterations at high sensitivity by providing an increase in the signal-to-noise ratio of 20,000-fold or more. This review will highlight the current status of hyperpolarised 13C-MRI and its translation into the clinic and how it compares to metabolic measurements provided by competing technologies such as positron emission tomography (PET).
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Affiliation(s)
| | - Stephan Ursprung
- Department of Radiology, University of Cambridge, Addenbrooke's Hospital, Cambridge, UK
| | - Jens Dam Jensen
- Department of Renal Medicine, Aarhus University Hospital, Aarhus, Denmark
| | - Bente Jespersen
- Department of Renal Medicine, Aarhus University Hospital, Aarhus, Denmark
| | - Ferdia Gallagher
- Department of Radiology, University of Cambridge, Addenbrooke's Hospital, Cambridge, UK
| | - Christoffer Laustsen
- MR Research Centre, Department of Clinical Medicine, Aarhus University Hospital, Palle Juul Jensens Boulevard, 8200, Aarhus N, Denmark.
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12
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Grist JT, Mariager CØ, Qi H, Nielsen PM, Laustsen C. Detection of acute kidney injury with hyperpolarized [ 13 C, 15 N]Urea and multiexponential relaxation modeling. Magn Reson Med 2019; 84:943-949. [PMID: 31840294 DOI: 10.1002/mrm.28134] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2019] [Revised: 11/26/2019] [Accepted: 11/26/2019] [Indexed: 01/06/2023]
Abstract
PURPOSE To assess the utility of Laplacian fitting to describe the differences in hyperpolarized [13 C, 15 N]urea T2 relaxation in ischemic and healthy rodent kidneys. METHODS Six rats with unilateral renal ischemia were investigated. [13 C, 15 N]Urea T2 mapping was undertaken with a radial fast spin echo method, with subsequent postprocessing performed with regularized Laplacian fitting. RESULTS Simulations showed that Laplacian fitting was stable down to a signal-to-noise ratio of 20. In vivo results showed a significant increase in the mono- and decrease in biexponential pools in ischemia reperfusion injury kidneys, in comparison to healthy (14 ± 10% versus 4 ± 2%, 85 ± 10% versus 95 ± 3%; P < .05). CONCLUSION We demonstrate, for the first time, the differences in multiexponential behavior of [13 C, 15 N]urea between the healthy and ischemic rodent kidney. The distribution of relaxation pools were found to be both visually and numerically significantly different. The ability to improve the information level in hyperpolarized MR, by using the relaxation contrast mechanisms is an appealing option, that can easily be adopted in large animals and even in clinical studies in the near future.
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Affiliation(s)
- James T Grist
- The Institute of Child Health, Institute of Cancer and Genomic Sciences, School of Medical and Dental Sciences, The University of Birmingham, Birmingham, United Kingdom
| | | | - Haiyun Qi
- MR Research Centre, Department of Clinical Medicine, Aarhus University, Aarhus, Denmark
| | - Per Mose Nielsen
- MR Research Centre, Department of Clinical Medicine, Aarhus University, Aarhus, Denmark
| | - Christoffer Laustsen
- MR Research Centre, Department of Clinical Medicine, Aarhus University, Aarhus, Denmark
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13
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von Morze C, Merritt ME. Cancer in the crosshairs: targeting cancer metabolism with hyperpolarized carbon-13 MRI technology. NMR IN BIOMEDICINE 2019; 32:e3937. [PMID: 29870085 PMCID: PMC6281789 DOI: 10.1002/nbm.3937] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/21/2017] [Revised: 04/03/2018] [Accepted: 04/07/2018] [Indexed: 05/07/2023]
Abstract
Magnetic resonance (MR)-based hyperpolarized (HP) 13 C metabolic imaging is under active pursuit as a new clinical diagnostic method for cancer detection, grading, and monitoring of therapeutic response. Following the tremendous success of metabolic imaging by positron emission tomography, which already plays major roles in clinical oncology, the added value of HP 13 C MRI is emerging. Aberrant glycolysis and central carbon metabolism is a hallmark of many forms of cancer. The chemical transformations associated with these pathways produce metabolites ranging in general from three to six carbons, and are dependent on the redox state and energy charge of the tissue. The significant changes in chemistry associated with flux through these pathways imply that HP imaging can take advantage of the underlying chemical shift information encoded into an MR experiment to produce images of the injected substrate as well as its metabolites. However, imaging of HP metabolites poses unique constraints on pulse sequence design related to detection of X-nuclei, decay of the HP magnetization due to T1 , and the consumption of HP signal by the inspection pulses. Advancements in the field continue to depend critically on customization of MRI systems and pulse sequences for optimized detection of HP 13 C signals, focused largely on extracting the maximum amount of information during the short lifetime of the HP magnetization. From a clinical perspective, the success of HP 13 C MRI of cancer will largely depend upon the utility of HP pyruvate for the detection of lactate pools associated with the Warburg effect, though several other agents are also under investigation, with novel agents continually being formulated. In this review, the salient aspects of HP 13 C imaging will be highlighted, with an emphasis on both technological challenges and the biochemical aspects of HP experimental design.
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Affiliation(s)
- Cornelius von Morze
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, CA, USA
| | - Matthew E Merritt
- Department of Biochemistry and Molecular Biology, University of Florida, Gainesville, FL, USA
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14
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Shin SH, Wendland MF, Zhang B, Tran A, Tang A, Vandsburger MH. Noninvasive imaging of renal urea handling by CEST-MRI. Magn Reson Med 2019; 83:1034-1044. [PMID: 31483529 DOI: 10.1002/mrm.27968] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2019] [Revised: 08/01/2019] [Accepted: 08/04/2019] [Indexed: 12/13/2022]
Abstract
PURPOSE Renal function is characterized by concentration of urea for removal in urine. We tested urea as a CEST-MRI contrast agent for measurement of the concentrating capacity of distinct renal anatomical regions. METHODS The CEST contrast of urea was examined using phantoms with different concentrations and pH levels. Ten C57BL/6J mice were scanned twice at 7 T, once following intraperitoneal injection of 2M 150 µL urea and separately following an identical volume of saline. Kidneys were segmented into regions encompassing the cortex, outer medulla, and inner medulla and papilla to monitor spatially varying urea concentration. Z-spectra were acquired before and 20 minutes after injection, with dynamic scanning of urea handling performed in between via serial acquisition of CEST images acquired following saturation at +1 ppm. RESULTS Phantom experiments revealed concentration and pH-dependent CEST contrast of urea that was both acid- and base-catalyzed. Z-spectra acquired before injection showed significantly higher CEST contrast in the inner medulla and papilla (2.3% ± 1.9%) compared with the cortex (0.15% ± 0.75%, P = .011) and outer medulla (0.12% ± 0.58%, P = .008). Urea infusion increased CEST contrast in the inner medulla and papilla by 2.1% ± 1.9% (absolute), whereas saline infusion decreased CEST contrast by -0.5% ± 2.0% (absolute, P = .028 versus urea). Dynamic scanning revealed that thermal drift and diuretic status are confounding factors. CONCLUSION Urea CEST has a potential of monitoring renal function by capturing the spatially varying urea concentrating ability of the kidneys.
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Affiliation(s)
- Soo Hyun Shin
- Department of Bioengineering, University of California, Berkeley, Berkeley, California
| | - Michael F Wendland
- Berkeley Preclinical Imaging Core, University of California, Berkeley, Berkeley, California
| | - Brandon Zhang
- Department of Bioengineering, University of California, Berkeley, Berkeley, California
| | - An Tran
- Department of Bioengineering, University of California, Berkeley, Berkeley, California
| | - Albert Tang
- Department of Bioengineering, University of California, Berkeley, Berkeley, California
| | - Moriel H Vandsburger
- Department of Bioengineering, University of California, Berkeley, Berkeley, California
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15
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Qi H, Mariager CØ, Nielsen PM, Schroeder M, Lindhardt J, Nørregaard R, Klein JD, Sands JM, Laustsen C. Glucagon infusion alters the hyperpolarized 13 C-urea renal hemodynamic signature. NMR IN BIOMEDICINE 2019; 32:e4028. [PMID: 30426590 DOI: 10.1002/nbm.4028] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/22/2018] [Revised: 08/13/2018] [Accepted: 09/19/2018] [Indexed: 06/09/2023]
Abstract
Renal urea handling is central to the urine concentrating mechanism, and as such the ability to image urea transport in the kidney is an important potential imaging biomarker for renal functional assessment. Glucagon levels associated with changes in dietary protein intake have been shown to influence renal urea handling; however, the exact mechanism has still to be fully understood. Here we investigate renal function and osmolite distribution using [13 C,15 N] urea dynamics and 23 Na distribution before and 60 min after glucagon infusion in six female rats. Glucagon infusion increased the renal [13 C,15 N] urea mean transit time by 14%, while no change was seen in the sodium distribution, glomerular filtration rate or oxygen consumption. This change is related to the well-known effect of increased urea excretion associated with glucagon infusion, independent of renal functional effects. This study demonstrates for the first time that hyperpolarized 13 C-urea enables monitoring of renal urinary excretion effects in vivo.
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Affiliation(s)
- Haiyun Qi
- MR Research Centre, Department of Clinical Medicine, Aarhus University, Aarhus, Denmark
| | | | - Per Mose Nielsen
- MR Research Centre, Department of Clinical Medicine, Aarhus University, Aarhus, Denmark
| | - Marie Schroeder
- MR Research Centre, Department of Clinical Medicine, Aarhus University, Aarhus, Denmark
| | - Jakob Lindhardt
- MR Research Centre, Department of Clinical Medicine, Aarhus University, Aarhus, Denmark
| | - Rikke Nørregaard
- Water Salt Centre, Department of Clinical Medicine, Aarhus University, Aarhus, Denmark
| | - Janet D Klein
- Renal Division, Department of Medicine, Emory University, Giorgia, USA
| | - Jeff M Sands
- Renal Division, Department of Medicine, Emory University, Giorgia, USA
| | - Christoffer Laustsen
- MR Research Centre, Department of Clinical Medicine, Aarhus University, Aarhus, Denmark
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16
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Milshteyn E, von Morze C, Gordon JW, Zhu Z, Larson PEZ, Vigneron DB. High spatiotemporal resolution bSSFP imaging of hyperpolarized [1- 13 C]pyruvate and [1- 13 C]lactate with spectral suppression of alanine and pyruvate-hydrate. Magn Reson Med 2018; 80:1048-1060. [PMID: 29451329 PMCID: PMC5980670 DOI: 10.1002/mrm.27104] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2017] [Revised: 12/02/2017] [Accepted: 01/03/2018] [Indexed: 12/23/2022]
Abstract
Purpose The bSSFP acquisition enables high spatiotemporal resolution for hyperpolarized 13C MRI at 3T, but is limited by spectral contamination from adjacent resonances. The purpose of this study was to develop a framework for in vivo dynamic high resolution imaging of hyperpolarized [1-13C]pyruvate and [1-13C]lactate generated in vivo at 3T by simplifying the spectrum through the use of selective suppression pulses. Methods Spectral suppression pulses were incorporated into the bSSFP sequence for suppression of [1-13C]alanine and [1-13C]pyruvate-hydrate signals, leaving only the pyruvate and lactate resonances. Subsequently, the bSSFP pulse width, time-bandwidth, and repetition time were optimized for imaging these dual resonances. Results The spectral suppression reduced both the alanine and pyruvate-hydrate signals by 85.5 ± 4.9% and had no significant effect on quantitation of pyruvate to lactate conversion (liver: P = 0.400, kidney: P = 0.499). High resolution (2 × 2 mm2 and 3 × 3 mm2) sub-second 2D coronal projections and 3D 2.5 mm isotropic images were obtained in rats and tumor-bearing mice with 1.8-5 s temporal resolution, allowing for calculation of lactate-to-pyruvate ratios and k PL. Conclusion The developed framework presented here shows the capability for dynamic high resolution volumetric hyperpolarized bSSFP imaging of pyruvate-to-lactate conversion on a clinical 3T MR scanner.
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Affiliation(s)
- Eugene Milshteyn
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, California, USA
- UC Berkeley-UCSF Graduate Program in Bioengineering, University of California, San Francisco and University of California, Berkeley, California, USA
| | - Cornelius von Morze
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, California, USA
| | - Jeremy W. Gordon
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, California, USA
| | - Zihan Zhu
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, California, USA
- UC Berkeley-UCSF Graduate Program in Bioengineering, University of California, San Francisco and University of California, Berkeley, California, USA
| | - Peder E. Z. Larson
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, California, USA
- UC Berkeley-UCSF Graduate Program in Bioengineering, University of California, San Francisco and University of California, Berkeley, California, USA
| | - Daniel B. Vigneron
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, California, USA
- UC Berkeley-UCSF Graduate Program in Bioengineering, University of California, San Francisco and University of California, Berkeley, California, USA
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17
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Milshteyn E, von Morze C, Reed GD, Shang H, Shin PJ, Larson PEZ, Vigneron DB. Using a local low rank plus sparse reconstruction to accelerate dynamic hyperpolarized 13C imaging using the bSSFP sequence. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2018; 290:46-59. [PMID: 29567434 PMCID: PMC6054792 DOI: 10.1016/j.jmr.2018.03.006] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2017] [Revised: 03/03/2018] [Accepted: 03/09/2018] [Indexed: 05/27/2023]
Abstract
Acceleration of dynamic 2D (T2 Mapping) and 3D hyperpolarized 13C MRI acquisitions using the balanced steady-state free precession sequence was achieved with a specialized reconstruction method, based on the combination of low rank plus sparse and local low rank reconstructions. Methods were validated using both retrospectively and prospectively undersampled in vivo data from normal rats and tumor-bearing mice. Four-fold acceleration of 1-2 mm isotropic 3D dynamic acquisitions with 2-5 s temporal resolution and two-fold acceleration of 0.25-1 mm2 2D dynamic acquisitions was achieved. This enabled visualization of the biodistribution of [2-13C]pyruvate, [1-13C]lactate, [13C, 15N2]urea, and HP001 within heart, kidneys, vasculature, and tumor, as well as calculation of high resolution T2 maps.
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Affiliation(s)
- Eugene Milshteyn
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, CA, USA; UC Berkeley-UCSF Graduate Program in Bioengineering, University of California, San Francisco, Berkeley, CA, USA
| | - Cornelius von Morze
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, CA, USA
| | | | | | - Peter J Shin
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, CA, USA
| | - Peder E Z Larson
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, CA, USA; UC Berkeley-UCSF Graduate Program in Bioengineering, University of California, San Francisco, Berkeley, CA, USA
| | - Daniel B Vigneron
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, CA, USA; UC Berkeley-UCSF Graduate Program in Bioengineering, University of California, San Francisco, Berkeley, CA, USA.
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18
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Mariager CØ, Nielsen PM, Qi H, Ringgaard S, Laustsen C. Hyperpolarized 13
C,15
N2
-urea T2
relaxation changes in acute kidney injury. Magn Reson Med 2017; 80:696-702. [DOI: 10.1002/mrm.27050] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2017] [Revised: 11/29/2017] [Accepted: 11/29/2017] [Indexed: 01/18/2023]
Affiliation(s)
| | - Per Mose Nielsen
- MR Research Centre, Department of Clinical Medicine; Aarhus University; Aarhus Denmark
| | - Haiyun Qi
- MR Research Centre, Department of Clinical Medicine; Aarhus University; Aarhus Denmark
| | - Steffen Ringgaard
- MR Research Centre, Department of Clinical Medicine; Aarhus University; Aarhus Denmark
| | - Christoffer Laustsen
- MR Research Centre, Department of Clinical Medicine; Aarhus University; Aarhus Denmark
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19
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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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20
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Østergaard Mariager C, Nielsen PM, Qi H, Schroeder M, Bertelsen LB, Laustsen C. Can Hyperpolarized 13C-Urea be Used to Assess Glomerular Filtration Rate? A Retrospective Study. ACTA ACUST UNITED AC 2017; 3:146-152. [PMID: 30042978 PMCID: PMC6024438 DOI: 10.18383/j.tom.2017.00010] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
This study investigated a simple method for calculating the single-kidney glomerular filtration rate (GFR) using dynamic hyperpolarized 13C-urea magnetic resonance (MR) renography. A retrospective data analysis was applied to renal hyperpolarized 13C-urea MR data acquired from control rats, prediabetic nephropathy rats, and rats in which 1 kidney was subjected to ischemia-reperfusion. Renal blood flow was determined by the model-free bolus differentiation method, GFR was determined using the Baumann–Rudin model method. Reference single-kidney and total GFRs were measured by plasma creatinine content and compared to 1H dynamic contrast-enhanced estimated GFR and fluorescein isothiocyanate-inulin clearance GFR estimation. In healthy and prediabetic nephropathy rats, single-kidney hyperpolarized 13C-urea GFR was estimated to be 2.5 ± 0.7 mL/min in good agreement with both gold-standard inulin clearance GFR (2.7 ± 1.2 ml/min) and 1H dynamic contrast-enhanced estimated GFR (1.8 ± 0.8 mL/min), as well as plasma creatinine measurements and literature findings. Following ischemia-reperfusion, hyperpolarized 13C-urea revealed a significant reduction in single-kidney GFR of 57% compared with the contralateral kidney. Hyperpolarized 13C MR could be a promising tool for accurate determination of GFR. The model-free renal blood flow and arterial input function-insensitive GFR estimations are simple to implement and warrant further translational adaptation.
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Affiliation(s)
| | - Per Mose Nielsen
- Department of Clinical Medicine, MR Research Centre, Aarhus University, Aarhus, Denmark
| | - Haiyun Qi
- Department of Clinical Medicine, MR Research Centre, Aarhus University, Aarhus, Denmark
| | - Marie Schroeder
- Department of Clinical Medicine, MR Research Centre, Aarhus University, Aarhus, Denmark
| | - Lotte Bonde Bertelsen
- Department of Clinical Medicine, MR Research Centre, Aarhus University, Aarhus, Denmark
| | - Christoffer Laustsen
- Department of Clinical Medicine, MR Research Centre, Aarhus University, Aarhus, Denmark
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21
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Ohliger MA, von Morze C, Marco-Rius I, Gordon J, Larson PEZ, Bok R, Chen HY, Kurhanewicz J, Vigneron D. Combining hyperpolarized 13 C MRI with a liver-specific gadolinium contrast agent for selective assessment of hepatocyte metabolism. Magn Reson Med 2017; 77:2356-2363. [PMID: 27298073 PMCID: PMC5156580 DOI: 10.1002/mrm.26296] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2016] [Revised: 04/23/2016] [Accepted: 05/16/2016] [Indexed: 12/13/2022]
Abstract
PURPOSE Hyperpolarized 13 C MRI is a powerful tool for studying metabolism, but can lack tissue specificity. Gadoxetate is a gadolinium-based MRI contrast agent that is selectively taken into hepatocytes. The goal of this project was to investigate whether gadoxetate can be used to selectively suppress the hyperpolarized signal arising from hepatocytes, which could in future studies be applied to generate specificity for signal from abnormal cell types. METHODS Baseline gadoxetate uptake kinetics were measured using T1 -weighted contrast enhanced imaging. Relaxivity of gadoxetate was measured for [1-13 C]pyruvate, [1-13 C]lactate, and [1-13 C]alanine. Four healthy rats were imaged with hyperpolarized [1-13 C]pyruvate using a three-dimensional (3D) MRSI sequence prior to and 15 min following administration of gadoxetate. The lactate:pyruvate ratio and alanine:pyruvate ratios were measured in liver and kidney. RESULTS Overall, the hyperpolarized signal decreased approximately 60% as a result of pre-injection of gadoxetate. In liver, the lactate:pyruvate and alanine:pyruvate ratios decreased 42% and 78%, respectively (P < 0.05) following gadoxetate administration. In kidneys, these ratios did not change significantly. Relaxivity of gadoxetate for [1-13 C]alanine was 12.6 times higher than relaxivity of gadoxetate for [1-13 C]pyruvate, explaining the greater selective relaxation effect on alanine. CONCLUSIONS The liver-specific gadolinium contrast-agent gadoxetate can selectively suppress normal hepatocyte contributions to hyperpolarized 13 C MRI signals. Magn Reson Med 77:2356-2363, 2017. © 2016 International Society for Magnetic Resonance in Medicine.
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Affiliation(s)
- Michael A. Ohliger
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, CA
| | - Cornelius von Morze
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, CA
| | - Irene Marco-Rius
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, CA
| | - Jeremy Gordon
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, CA
| | - Peder E. Z. Larson
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, CA
| | - Robert Bok
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, CA
| | - Hsin-yu Chen
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, CA
| | - John Kurhanewicz
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, CA
| | - Daniel Vigneron
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, CA
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22
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Milshteyn E, von Morze C, Reed GD, Shang H, Shin PJ, Zhu Z, Chen HY, Bok R, Goga A, Kurhanewicz J, Larson PEZ, Vigneron DB. Development of high resolution 3D hyperpolarized carbon-13 MR molecular imaging techniques. Magn Reson Imaging 2017; 38:152-162. [PMID: 28077268 PMCID: PMC5360530 DOI: 10.1016/j.mri.2017.01.003] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2016] [Revised: 01/05/2017] [Accepted: 01/06/2017] [Indexed: 01/08/2023]
Abstract
The goal of this project was to develop and apply techniques for T2 mapping and 3D high resolution (1.5mm isotropic; 0.003cm3) 13C imaging of hyperpolarized (HP) probes [1-13C]lactate, [1-13C]pyruvate, [2-13C]pyruvate, and [13C,15N2]urea in vivo. A specialized 2D bSSFP sequence was implemented on a clinical 3T scanner and used to obtain the first high resolution T2 maps of these different hyperpolarized compounds in both rats and tumor-bearing mice. These maps were first used to optimize timings for highest SNR for single time-point 3D bSSFP acquisitions with a 1.5mm isotropic spatial resolution of normal rats. This 3D acquisition approach was extended to serial dynamic imaging with 2-fold compressed sensing acceleration without changing spatial resolution. The T2 mapping experiments yielded measurements of T2 values of >1s for all compounds within rat kidneys/vasculature and TRAMP tumors, except for [2-13C]pyruvate which was ~730ms and ~320ms, respectively. The high resolution 3D imaging enabled visualization the biodistribution of [1-13C]lactate, [1-13C]pyruvate, and [2-13C]pyruvate within different kidney compartments as well as in the vasculature. While the mouse anatomy is smaller, the resolution was also sufficient to image the distribution of all compounds within kidney, vasculature, and tumor. The development of the specialized 3D sequence with compressed sensing provided improved structural and functional assessments at a high (0.003cm3) spatial and 2s temporal resolution in vivo utilizing HP 13C substrates by exploiting their long T2 values. This 1.5mm isotropic resolution is comparable to 1H imaging and application of this approach could be extended to future studies of uptake, metabolism, and perfusion in cancer and other disease models and may ultimately be of value for clinical imaging.
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Affiliation(s)
- Eugene Milshteyn
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, CA, USA; UC Berkeley-UCSF Graduate Program in Bioengineering, University of California, San Francisco and University of California, Berkeley, CA, USA
| | - Cornelius von Morze
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, CA, USA
| | | | - Hong Shang
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, CA, USA; UC Berkeley-UCSF Graduate Program in Bioengineering, University of California, San Francisco and University of California, Berkeley, CA, USA
| | - Peter J Shin
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, CA, USA
| | - Zihan Zhu
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, CA, USA; UC Berkeley-UCSF Graduate Program in Bioengineering, University of California, San Francisco and University of California, Berkeley, CA, USA
| | - Hsin-Yu Chen
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, CA, USA; UC Berkeley-UCSF Graduate Program in Bioengineering, University of California, San Francisco and University of California, Berkeley, CA, USA
| | - Robert Bok
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, CA, USA
| | - Andrei Goga
- Department of Cell and Tissue Biology, University of California, San Francisco, CA, USA
| | - John Kurhanewicz
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, CA, USA; UC Berkeley-UCSF Graduate Program in Bioengineering, University of California, San Francisco and University of California, Berkeley, CA, USA
| | - Peder E Z Larson
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, CA, USA; UC Berkeley-UCSF Graduate Program in Bioengineering, University of California, San Francisco and University of California, Berkeley, CA, USA
| | - Daniel B Vigneron
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, CA, USA; UC Berkeley-UCSF Graduate Program in Bioengineering, University of California, San Francisco and University of California, Berkeley, CA, USA.
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23
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Shang H, Sukumar S, von Morze C, Bok RA, Marco-Rius I, Kerr A, Reed GD, Milshteyn E, Ohliger MA, Kurhanewicz J, Larson PEZ, Pauly JM, Vigneron DB. Spectrally selective three-dimensional dynamic balanced steady-state free precession for hyperpolarized C-13 metabolic imaging with spectrally selective radiofrequency pulses. Magn Reson Med 2016; 78:963-975. [PMID: 27770458 DOI: 10.1002/mrm.26480] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2016] [Revised: 08/30/2016] [Accepted: 09/02/2016] [Indexed: 12/12/2022]
Abstract
PURPOSE Balanced steady-state free precession (bSSFP) sequences can provide superior signal-to-noise ratio efficiency for hyperpolarized (HP) carbon-13 (13 C) magnetic resonance imaging by efficiently utilizing the nonrecoverable magnetization, but managing their spectral response is challenging in the context of metabolic imaging. A new spectrally selective bSSFP sequence was developed for fast imaging of multiple HP 13 C metabolites with high spatiotemporal resolution. THEORY AND METHODS This novel approach for bSSFP spectral selectivity incorporates optimized short-duration spectrally selective radiofrequency pulses within a bSSFP pulse train and a carefully chosen repetition time to avoid banding artifacts. RESULTS The sequence enabled subsecond 3D dynamic spectrally selective imaging of 13 C metabolites of copolarized [1-13 C]pyruvate and [13 C]urea at 2-mm isotropic resolution, with excellent spectral selectivity (∼100:1). The sequence was successfully tested in phantom studies and in vivo studies with normal mice. CONCLUSION This sequence is expected to benefit applications requiring dynamic volumetric imaging of metabolically active 13 C compounds at high spatiotemporal resolution, including preclinical studies at high field and, potentially, clinical studies. Magn Reson Med 78:963-975, 2017. © 2016 International Society for Magnetic Resonance in Medicine.
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Affiliation(s)
- Hong Shang
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, California, USA.,UC Berkeley-UCSF Graduate Program in Bioengineering, University of California, San Francisco and University of California, Berkeley, California, USA
| | - Subramaniam Sukumar
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, California, USA
| | - Cornelius von Morze
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, California, USA
| | - Robert A Bok
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, California, USA
| | - Irene Marco-Rius
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, California, USA
| | - Adam Kerr
- Electrical Engineering, Stanford University, Stanford, California, USA
| | | | - Eugene Milshteyn
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, California, USA.,UC Berkeley-UCSF Graduate Program in Bioengineering, University of California, San Francisco and University of California, Berkeley, California, USA
| | - Michael A Ohliger
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, California, USA
| | - John Kurhanewicz
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, California, USA.,UC Berkeley-UCSF Graduate Program in Bioengineering, University of California, San Francisco and University of California, Berkeley, California, USA
| | - Peder E Z Larson
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, California, USA.,UC Berkeley-UCSF Graduate Program in Bioengineering, University of California, San Francisco and University of California, Berkeley, California, USA
| | - John M Pauly
- Electrical Engineering, Stanford University, Stanford, California, USA
| | - Daniel B Vigneron
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, California, USA.,UC Berkeley-UCSF Graduate Program in Bioengineering, University of California, San Francisco and University of California, Berkeley, California, USA
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24
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Hansen ESS, Stewart NJ, Wild JM, Stødkilde-Jørgensen H, Laustsen C. Hyperpolarized 13 C, 15 N 2 -Urea MRI for assessment of the urea gradient in the porcine kidney. Magn Reson Med 2016; 76:1895-1899. [PMID: 27670826 DOI: 10.1002/mrm.26483] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2016] [Revised: 08/10/2016] [Accepted: 09/07/2016] [Indexed: 12/24/2022]
Abstract
PURPOSE A decline in cortico-medullary osmolality gradient of the kidney may serve as an early indicator of pathological disruption of the tubular reabsorption process. The purpose of this study was to investigate the feasibility of hyperpolarized 13 C,15 N2 -urea MRI as a biomarker of renal function in healthy porcine kidneys resembling the human physiology. METHODS Five healthy female Danish domestic pigs (weight 30 kg) were scanned at 3 Tesla (T) using a 13 C 3D balanced steady-state MR pulse sequence following injection of hyperpolarized 13 C,15 N2 -urea via a femoral vein catheter. Images were acquired at different time points after urea injection, and following treatment with furosemide. RESULTS A gradient in cortico-medullary urea was observed with an intramedullary accumulation 75 s after injection of hyperpolarized 13 C,15 N2 -urea, whereas images acquired at earlier time points postinjection were dominated by cortical perfusion. Furosemide treatment resulted in an increased urea accumulation in the cortical space, leading to a reduction of the medullary-to-cortical signal ratio of 49%. CONCLUSION This study demonstrates that hyperpolarized 13 C,15 N2 -urea MRI is capable of identifying the intrarenal accumulation of urea and can differentiate acute renal functional states in multipapillary kidneys, highlighting the potential for human translation. Magn Reson Med 76:1895-1899, 2016. © 2016 International Society for Magnetic Resonance in Medicine.
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Affiliation(s)
- Esben S S Hansen
- MR Research Centre, Department of Clinical Medicine, Aarhus University, Aarhus, Denmark.,Danish Diabetes Academy, Odense, Denmark
| | - Neil J Stewart
- Academic Unit of Radiology, University of Sheffield, Sheffield, UK
| | - Jim M Wild
- Academic Unit of Radiology, University of Sheffield, Sheffield, UK
| | | | - Christoffer Laustsen
- MR Research Centre, Department of Clinical Medicine, Aarhus University, Aarhus, Denmark
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25
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Nielsen PM, Szocska Hansen ES, Nørlinger TS, Nørregaard R, Bonde Bertelsen L, Stødkilde Jørgensen H, Laustsen C. Renal ischemia and reperfusion assessment with three-dimensional hyperpolarized 13 C, 15 N2-urea. Magn Reson Med 2016; 76:1524-1530. [PMID: 27548739 DOI: 10.1002/mrm.26377] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2016] [Revised: 06/25/2016] [Accepted: 07/19/2016] [Indexed: 01/01/2023]
Abstract
PURPOSE The aim of this work was to investigate whether hyperpolarized 13 C,15 N2 -urea can be used as an imaging marker of renal injury in renal unilateral ischemic reperfusion injury (IRI), given that urea is correlated with the renal osmotic gradient, which describes the renal function. METHODS Hyperpolarized three-dimensional balanced steady-state 13 C magnetic resonance imaging (MRI) experiments alongside kidney function parameters and quantitative polymerase chain reaction measurements were performed in rats subjected to unilateral renal ischemia for 60-minute and 24-hour reperfusion. RESULTS We revealed a significant reduction in the intrarenal gradient in the ischemic kidney in agreement with cortical injury markers neutrophil gelatinase-associated lipocalin and kidney injury molecule 1, as well as functional kidney parameters. CONCLUSION Hyperpolarized functional 13 C,15 N2 urea MRI can be used to successfully detect changes in the intrarenal urea gradient post-IRI, thereby enabling in vivo monitoring of the intrarenal functional status in the rat kidney. Magn Reson Med 76:1524-1530, 2016. © 2016 International Society for Magnetic Resonance in Medicine.
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Affiliation(s)
- Per Mose Nielsen
- MR Research Centre, Department of Clinical Medicine, Aarhus University, Aarhus, Denmark
| | - Esben Søvsø Szocska Hansen
- MR Research Centre, Department of Clinical Medicine, Aarhus University, Aarhus, Denmark.,Danish Diabetes Academy, Odense, Denmark
| | | | - Rikke Nørregaard
- Department of Clinical Medicine, Aarhus University, Aarhus, Denmark
| | - Lotte Bonde Bertelsen
- MR Research Centre, Department of Clinical Medicine, Aarhus University, Aarhus, Denmark
| | | | - Christoffer Laustsen
- MR Research Centre, Department of Clinical Medicine, Aarhus University, Aarhus, Denmark.
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26
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Laustsen C. Hyperpolarized Renal Magnetic Resonance Imaging: Potential and Pitfalls. Front Physiol 2016; 7:72. [PMID: 26973539 PMCID: PMC4771722 DOI: 10.3389/fphys.2016.00072] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2015] [Accepted: 02/15/2016] [Indexed: 01/02/2023] Open
Abstract
The introduction of dissolution dynamic nuclear polarization (d-DNP) technology has enabled a new paradigm for renal imaging investigations. It allows standard magnetic resonance imaging complementary renal metabolic and functional fingerprints within seconds without the use of ionizing radiation. Increasing evidence supports its utility in preclinical research in which the real-time interrogation of metabolic turnover can aid the physiological and pathophysiological metabolic and functional effects in ex vivo and in vivo models. The method has already been translated to humans, although the clinical value of this technology is unknown. In this paper, I review the potential benefits and pitfalls associated with dissolution dynamic nuclear polarization in preclinical research and its translation to renal patients.
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Affiliation(s)
- Christoffer Laustsen
- Department of Clinical Medicine, MR Research Centre, Aarhus University Aarhus, Denmark
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