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van den Wildenberg L, Runderkamp BA, Seelen LWF, van Laarhoven HWM, Gosselink MWJM, van der Kemp WJM, Haj Mohammad N, Klomp DWJ, Prompers JJ. Measurement of metabolite levels and treatment-induced changes in hepatic metastases of gastro-esophageal cancer using 7-T phosphorus magnetic resonance spectroscopic imaging. NMR IN BIOMEDICINE 2024:e5155. [PMID: 38616046 DOI: 10.1002/nbm.5155] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/19/2023] [Revised: 03/05/2024] [Accepted: 03/06/2024] [Indexed: 04/16/2024]
Abstract
Methods for early treatment response evaluation to systemic therapy of liver metastases are lacking. Tumor tissue often exhibits an increased ratio of phosphomonoesters to phosphodiesters (PME/PDE), which can be noninvasively measured by phosphorus magnetic resonance spectroscopy (31P MRS), and may be a marker for early therapy response assessment in liver metastases. However, with commonly used 31P surface coils for liver 31P MRS, the liver is not fully covered, and metastases may be missed. The objective of this study was to demonstrate the feasibility of 31P MRS imaging (31P MRSI) with full liver coverage to assess 31P metabolite levels and chemotherapy-induced changes in liver metastases of gastro-esophageal cancer, using a 31P whole-body birdcage transmit coil in combination with a 31P body receive array at 7 T. 3D 31P MRSI data were acquired in two patients with hepatic metastases of esophageal cancer, before the start of chemotherapy and after 2 (and 9 in patient 2) weeks of chemotherapy. 3D 31P MRSI acquisitions were performed using an integrated 31P whole-body transmit coil in combination with a 16-channel body receive array at 7 T, with a field of view covering the full abdomen and a nominal voxel size of 20-mm isotropic. From the 31P MRSI data, 12 31P metabolite signals were quantified. Prior to chemotherapy initiation, both PMEs, that is, phosphocholine (PC) and phosphoethanolamine (PE), were significantly higher in all metastases compared with the levels previously determined in the liver of healthy volunteers. After 2 weeks of chemotherapy, PC and PE levels remained high or even increased further, resulting in increased PME/PDE ratios compared with healthy liver tissue, in correspondence with the clinical assessment of progressive disease after 2 months of chemotherapy. The suggested approach may present a viable tool for early therapy (non)response assessment of tumor metabolism in patients with liver metastases.
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Affiliation(s)
| | - Bobby A Runderkamp
- Department of Radiology and Nuclear Medicine, Amsterdam University Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Leonard W F Seelen
- Center for Image Sciences, University Medical Center Utrecht, Utrecht, The Netherlands
- Department of Surgery, UMC Utrecht Cancer Center, Utrecht, The Netherlands
- Sint Antonius Hospital Nieuwegein, Regional Academic Cancer Center Utrecht, Utrecht, The Netherlands
| | - Hanneke W M van Laarhoven
- Cancer Center Amsterdam, Imaging and Biomarkers, Amsterdam, The Netherlands
- Department of Medical Oncology, Amsterdam University Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Mark W J M Gosselink
- Center for Image Sciences, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Wybe J M van der Kemp
- Center for Image Sciences, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Nadia Haj Mohammad
- Department of Medical Oncology, Utrecht Medical Center Utrecht, Utrecht, The Netherlands
| | - Dennis W J Klomp
- Center for Image Sciences, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Jeanine J Prompers
- Center for Image Sciences, University Medical Center Utrecht, Utrecht, The Netherlands
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2
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van den Wildenberg L, Gursan A, Seelen LWF, van der Velden TA, Gosselink MWJM, Froeling M, van der Kemp WJM, Klomp DWJ, Prompers JJ. In vivo phosphorus magnetic resonance spectroscopic imaging of the whole human liver at 7 T using a phosphorus whole-body transmit coil and 16-channel receive array: Repeatability and effects of principal component analysis-based denoising. NMR IN BIOMEDICINE 2023; 36:e4877. [PMID: 36400716 DOI: 10.1002/nbm.4877] [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: 04/26/2022] [Revised: 11/14/2022] [Accepted: 11/16/2022] [Indexed: 06/16/2023]
Abstract
Quantitative three-dimensional (3D) imaging of phosphorus (31 P) metabolites is potentially a promising technique with which to assess the progression of liver disease and monitor therapy response. However, 31 P magnetic resonance spectroscopy has a low sensitivity and commonly used 31 P surface coils do not provide full coverage of the liver. This study aimed to overcome these limitations by using a 31 P whole-body transmit coil in combination with a 16-channel 31 P receive array at 7 T. Using this setup, we determined the repeatability of whole-liver 31 P magnetic resonance spectroscopic imaging (31 P MRSI) in healthy subjects and assessed the effects of principal component analysis (PCA)-based denoising on the repeatability parameters. In addition, spatial variations of 31 P metabolites within the liver were analyzed. 3D 31 P MRSI data of the liver were acquired with a nominal voxel size of 20 mm isotropic in 10 healthy volunteers twice on the same day. Data were reconstructed without denoising, and with PCA-based denoising before or after channel combination. From the test-retest data, repeatability parameters for metabolite level quantification were determined for 12 31 P metabolite signals. On average, 31 P MR spectra from 100 ± 25 voxels in the liver were analyzed. Only voxels with contamination from skeletal muscle or the gall bladder were excluded and no voxels were discarded based on (low) signal-to-noise ratio (SNR). Repeatability for most quantified 31 P metabolite levels in the liver was good to excellent, with an intrasubject variability below 10%. PCA-based denoising increased the SNR ~ 3-fold, but did not improve the repeatability for mean liver 31 P metabolite quantification with the fitting constraints used. Significant spatial heterogeneity of various 31 P metabolite levels within the liver was observed, with marked differences for the phosphomonoester and phosphodiester metabolites between the left and right lobe. In conclusion, using a 31 P whole-body transmit coil in combination with a 16-channel 31 P receive array at 7 T allowed 31 P MRSI acquisitions with full liver coverage and good to excellent repeatability.
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Affiliation(s)
| | - Ayhan Gursan
- Center for Image Sciences, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Leonard W F Seelen
- Center for Image Sciences, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Tijl A van der Velden
- Center for Image Sciences, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Mark W J M Gosselink
- Center for Image Sciences, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Martijn Froeling
- Center for Image Sciences, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Wybe J M van der Kemp
- Center for Image Sciences, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Dennis W J Klomp
- Center for Image Sciences, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Jeanine J Prompers
- Center for Image Sciences, University Medical Center Utrecht, Utrecht, The Netherlands
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3
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Seelen LWF, van den Wildenberg L, van der Kemp WJM, Mohamed Hoesein FAA, Mohammad NH, Molenaar IQ, van Santvoort HC, Prompers JJ, Klomp DWJ. Prospective of 31 P MR Spectroscopy in Hepatopancreatobiliary Cancer: A Systematic Review of the Literature. J Magn Reson Imaging 2023; 57:1144-1155. [PMID: 35916278 DOI: 10.1002/jmri.28372] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2022] [Revised: 07/13/2022] [Accepted: 07/14/2022] [Indexed: 12/16/2022] Open
Abstract
BACKGROUND The incidence of liver and pancreatic cancer is rising. Patients benefit from current treatments, but there are limitations in the evaluation of (early) response to treatment. Tumor metabolic alterations can be measured noninvasively with phosphorus (31 P) magnetic resonance spectroscopy (MRS). PURPOSE To conduct a quantitative analysis of the available literature on 31 P MRS performed in hepatopancreatobiliary cancer and to provide insight into its current and potential for therapy (non-) response assessment. POPULATION Patients with hepatopancreatobiliary cancer. FIELD STRENGTH/SEQUENCE: 31 P MRS. ASSESSMENT The PubMed, EMBASE, and Cochrane library databases were systematically searched for studies published to 17 March 17, 2022. All 31 P MRS studies in hepatopancreatobiliary cancer reporting 31 P metabolite levels were included. STATISTICAL TESTS Relative differences in 31 P metabolite levels/ratios between patients before therapy and healthy controls, and the relative changes in 31 P metabolite levels/ratios in patients before and after therapy were determined. RESULTS The search yielded 10 studies, comprising 301 subjects, of whom 132 (44%) healthy volunteers and 169 (56%) patients with liver cancer of various etiology. To date, 31 P MRS has not been applied in pancreatic cancer. In liver cancer, alterations in levels of 31 P metabolites involved in cell proliferation (phosphomonoesters [PMEs] and phosphodiesters [PDEs]) and energy metabolism (ATP and inorganic phosphate [Pi]) were observed. In particular, liver tumors were associated with elevations of PME/PDE and PME/Pi compared to healthy liver tissue, although there was a broad variety among studies (elevations of 2%-267% and 21%-233%, respectively). Changes in PME/PDE in liver tumors upon therapy were substantial, yet very heterogeneous and both decreases and increases were observed, whereas PME/Pi was consistently decreased after therapy in all studies (-13% to -76%). DATA CONCLUSION 31 P MRS has great potential for treatment monitoring in oncology. Future studies are needed to correlate the changes in 31 P metabolite levels in hepatopancreatobiliary tumors with treatment response. EVIDENCE LEVEL 3 TECHNICAL EFFICACY: Stage 2.
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Affiliation(s)
- Leonard W F Seelen
- Department of Radiology, University Medical Center Utrecht, Utrecht, The Netherlands.,Department of Surgery, UMC Utrecht Cancer Center and St Antonius Hospital Nieuwegein: Regional Academic Cancer Center Utrecht, Utrecht, The Netherlands
| | | | - Wybe J M van der Kemp
- Department of Radiology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Firdaus A A Mohamed Hoesein
- Department of Surgery, UMC Utrecht Cancer Center and St Antonius Hospital Nieuwegein: Regional Academic Cancer Center Utrecht, Utrecht, The Netherlands
| | - Nadia Haj Mohammad
- Department of Medical Oncology, UMC Utrecht Cancer Center, Regional Academic Cancer Center Utrecht, Utrecht, The Netherlands
| | - I Quintus Molenaar
- Department of Surgery, UMC Utrecht Cancer Center and St Antonius Hospital Nieuwegein: Regional Academic Cancer Center Utrecht, Utrecht, The Netherlands
| | - Hjalmar C van Santvoort
- Department of Surgery, UMC Utrecht Cancer Center and St Antonius Hospital Nieuwegein: Regional Academic Cancer Center Utrecht, Utrecht, The Netherlands
| | - Jeanine J Prompers
- Department of Radiology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Dennis W J Klomp
- Department of Radiology, University Medical Center Utrecht, Utrecht, The Netherlands
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Wishart DS, Cheng LL, Copié V, Edison AS, Eghbalnia HR, Hoch JC, Gouveia GJ, Pathmasiri W, Powers R, Schock TB, Sumner LW, Uchimiya M. NMR and Metabolomics-A Roadmap for the Future. Metabolites 2022; 12:678. [PMID: 35893244 PMCID: PMC9394421 DOI: 10.3390/metabo12080678] [Citation(s) in RCA: 37] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2022] [Revised: 07/21/2022] [Accepted: 07/21/2022] [Indexed: 12/03/2022] Open
Abstract
Metabolomics investigates global metabolic alterations associated with chemical, biological, physiological, or pathological processes. These metabolic changes are measured with various analytical platforms including liquid chromatography-mass spectrometry (LC-MS), gas chromatography-mass spectrometry (GC-MS) and nuclear magnetic resonance spectroscopy (NMR). While LC-MS methods are becoming increasingly popular in the field of metabolomics (accounting for more than 70% of published metabolomics studies to date), there are considerable benefits and advantages to NMR-based methods for metabolomic studies. In fact, according to PubMed, more than 926 papers on NMR-based metabolomics were published in 2021-the most ever published in a given year. This suggests that NMR-based metabolomics continues to grow and has plenty to offer to the scientific community. This perspective outlines the growing applications of NMR in metabolomics, highlights several recent advances in NMR technologies for metabolomics, and provides a roadmap for future advancements.
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Affiliation(s)
- David S. Wishart
- Departments of Biological Sciences and Computing Science, University of Alberta, Edmonton, AB T6G 2E9, Canada
| | - Leo L. Cheng
- Department of Pathology, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA;
| | - Valérie Copié
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, MT 59715, USA;
| | - Arthur S. Edison
- Complex Carbohydrate Research Center, University of Georgia, Athens, GA 30602, USA; (A.S.E.); (G.J.G.); (M.U.)
- Department of Biochemistry & Molecular Biology, University of Georgia, Athens, GA 30602-0001, USA
| | - Hamid R. Eghbalnia
- Department of Molecular Biology and Biophysics, UConn Health, Farmington, CT 06030-3305, USA; (H.R.E.); (J.C.H.)
| | - Jeffrey C. Hoch
- Department of Molecular Biology and Biophysics, UConn Health, Farmington, CT 06030-3305, USA; (H.R.E.); (J.C.H.)
| | - Goncalo J. Gouveia
- Complex Carbohydrate Research Center, University of Georgia, Athens, GA 30602, USA; (A.S.E.); (G.J.G.); (M.U.)
- Department of Biochemistry & Molecular Biology, University of Georgia, Athens, GA 30602-0001, USA
| | - Wimal Pathmasiri
- Nutrition Research Institute, Department of Nutrition, School of Public Health, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA;
| | - Robert Powers
- Department of Chemistry, University of Nebraska-Lincoln, Lincoln, NE 68588-0304, USA
- Nebraska Center for Integrated Biomolecular Communication, University of Nebraska-Lincoln, Lincoln, NE 68588-0304, USA
| | - Tracey B. Schock
- National Institute of Standards and Technology (NIST), Chemical Sciences Division, Charleston, SC 29412, USA;
| | - Lloyd W. Sumner
- Interdisciplinary Plant Group, MU Metabolomics Center, Bond Life Sciences Center, Department of Biochemistry, University of Missouri, Columbia, MO 65211, USA
| | - Mario Uchimiya
- Complex Carbohydrate Research Center, University of Georgia, Athens, GA 30602, USA; (A.S.E.); (G.J.G.); (M.U.)
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Seo JH, Chung JY. A Preliminary Study for Reference RF Coil at 11.7 T MRI: Based on Electromagnetic Field Simulation of Hybrid-BC RF Coil According to Diameter and Length at 3.0, 7.0 and 11.7 T. SENSORS 2022; 22:s22041512. [PMID: 35214409 PMCID: PMC8875900 DOI: 10.3390/s22041512] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/12/2022] [Revised: 02/13/2022] [Accepted: 02/14/2022] [Indexed: 02/05/2023]
Abstract
Magnetic resonance imaging (MRI) systems must undergo quantitative evaluation through daily and periodic performance assessments. In general, the reference or standard radiofrequency (RF) coils for these performance assessments of 1.5 to 7.0 T MRI systems have been low-pass-type birdcage (LP-BC) RF coils. However, LP-BC RF coils are inappropriate for use as reference RF coils because of their relatively lower magnetic field (B1-field) sensitivity than other types of BC RF coils, especially in ultrahigh-field (UHF) MRI systems above 3.0 T. Herein, we propose a hybrid-type BC (Hybrid-BC) RF coil as a reference RF coil with improved B1-field sensitivity in UHF MRI system and applied it to an 11.7 T MRI system. An electromagnetic field (EM-field) analysis on the Hybrid-BC RF coil was performed to provide the proper dimensions for its use as a reference RF coil. Commercial finite difference time-domain program was used in EM-field simulation, and home-made analysis programs were used in analysis. The optimal specifications of the proposed Hybrid-BC RF coils for them to qualify as reference RF coils are proposed based on their B1+-field sensitivity under unnormalized conditions, as well as by considering their B1+-field uniformity and RF safety under normalized conditions.
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Affiliation(s)
- Jeung-Hoon Seo
- Neuroscience Research Institute, Gachon University, Incheon 21988, Korea;
| | - Jun-Young Chung
- Department of Neuroscience, College of Medicine, Gachon University, Incheon 21565, Korea
- Correspondence: ; Tel.: +82-32-822-5361; Fax: +82-32-822-8251
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6
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Forner R, Nam K, de Koning KJ, van der Velden T, van der Kemp W, Raaijmakers A, Klomp DWJ. RF Coil Setup for 31P MRSI in Tongue Cancer in vivo at 7 T. Front Neurol 2021; 12:695202. [PMID: 34795625 PMCID: PMC8593189 DOI: 10.3389/fneur.2021.695202] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2021] [Accepted: 09/10/2021] [Indexed: 11/20/2022] Open
Abstract
Surgery for tongue cancer often results in a major loss in quality of life. While MRI may be used to minimise the volume of excised tissue, often the full tumour extent is missed. This tumour extent may be detected with metabolic imaging. One of the main reasons for the lack of metabolic information on tongue cancer would be the absence of an x-nuclear coil with the tongue as a focus target. Metabolic MRI through 31P MRSI is known as a powerful tool to non-invasively study elevated cell proliferation and disturbed energy metabolism in tumours. Severe magnetic field non-uniformities are inherently caused by the substantial difference in magnetic susceptibilities of tissue and air in the mouth and its environs. Despite this, the wide chemical shift dispersion of 31P could still facilitate precise detection of the cell proliferation biomarkers, phospomonoesters and diesters, as well as energy metabolites ATP, inorganic phosphate, and phosphocreatine potentially mapped over the tongue or tumour in vivo. In this study, we present the first 31P MRSI data of the human tongue in vivo from healthy volunteers and a patient with a tongue tumour at 7 T MRI using a 1H 8-channel transceiver setup placed inside a body 31P transmitter, which is able to get a uniform excitation from the tongue while providing comfortable access to the patient. In addition, a user-friendly external 31P receiver array is used to provide high sensitivity (80%) comparable to an uncomfortable inner mouth loop coil positioned on the tongue. The primary aim is the demonstration of 31P metabolite profiles in the tongue and the differences between healthy and malignant tissue. Indeed, clear elevated cell proliferation expressed as enhanced phosphomonoesters is observed in the tumour vs. the healthy part of the tongue. This can be performed within a total scan duration of 30 min, comparable to clinical scans, with a spatial resolution of 1.5 cm for the 10-min 31P MRSI scan.
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Affiliation(s)
- Ria Forner
- Division of Imaging and Oncology, University Medical Centre (UMC) Utrecht, Utrecht, Netherlands.,Ceresensa Inc., London, ON, Canada
| | - Kyungmin Nam
- Division of Imaging and Oncology, University Medical Centre (UMC) Utrecht, Utrecht, Netherlands
| | - Klijs J de Koning
- Surgery, University Medical Centre (UMC) Utrecht, Utrecht, Netherlands
| | - Tijl van der Velden
- Division of Imaging and Oncology, University Medical Centre (UMC) Utrecht, Utrecht, Netherlands
| | - Wybe van der Kemp
- Division of Imaging and Oncology, University Medical Centre (UMC) Utrecht, Utrecht, Netherlands
| | - Alexander Raaijmakers
- Division of Imaging and Oncology, University Medical Centre (UMC) Utrecht, Utrecht, Netherlands.,Division of Biomedical Image Analyses, Technical University Eindhoven (TU/e), Eindhoven, Netherlands
| | - Dennis W J Klomp
- Division of Imaging and Oncology, University Medical Centre (UMC) Utrecht, Utrecht, Netherlands
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Platt T, Ladd ME, Paech D. 7 Tesla and Beyond: Advanced Methods and Clinical Applications in Magnetic Resonance Imaging. Invest Radiol 2021; 56:705-725. [PMID: 34510098 PMCID: PMC8505159 DOI: 10.1097/rli.0000000000000820] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2021] [Revised: 08/07/2021] [Accepted: 08/07/2021] [Indexed: 12/15/2022]
Abstract
ABSTRACT Ultrahigh magnetic fields offer significantly higher signal-to-noise ratio, and several magnetic resonance applications additionally benefit from a higher contrast-to-noise ratio, with static magnetic field strengths of B0 ≥ 7 T currently being referred to as ultrahigh fields (UHFs). The advantages of UHF can be used to resolve structures more precisely or to visualize physiological/pathophysiological effects that would be difficult or even impossible to detect at lower field strengths. However, with these advantages also come challenges, such as inhomogeneities applying standard radiofrequency excitation techniques, higher energy deposition in the human body, and enhanced B0 field inhomogeneities. The advantages but also the challenges of UHF as well as promising advanced methodological developments and clinical applications that particularly benefit from UHF are discussed in this review article.
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Affiliation(s)
- Tanja Platt
- From the Medical Physics in Radiology, German Cancer Research Center (DKFZ)
| | - Mark E. Ladd
- From the Medical Physics in Radiology, German Cancer Research Center (DKFZ)
- Faculty of Physics and Astronomy
- Faculty of Medicine, University of Heidelberg, Heidelberg
- Erwin L. Hahn Institute for MRI, University of Duisburg-Essen, Essen
| | - Daniel Paech
- Division of Radiology, German Cancer Research Center (DKFZ), Heidelberg
- Clinic for Neuroradiology, University of Bonn, Bonn, Germany
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Froeling M, Prompers JJ, Klomp DWJ, van der Velden TA. PCA denoising and Wiener deconvolution of 31 P 3D CSI data to enhance effective SNR and improve point spread function. Magn Reson Med 2021; 85:2992-3009. [PMID: 33522635 PMCID: PMC7986807 DOI: 10.1002/mrm.28654] [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: 07/08/2020] [Revised: 11/10/2020] [Accepted: 12/01/2020] [Indexed: 12/19/2022]
Abstract
Purpose This study evaluates the performance of 2 processing methods, that is, principal component analysis‐based denoising and Wiener deconvolution, to enhance the quality of phosphorus 3D chemical shift imaging data. Methods Principal component analysis‐based denoising increases the SNR while maintaining spectral information. Wiener deconvolution reduces the FWHM of the voxel point spread function, which is increased by Hamming filtering or Hamming‐weighted acquisition. The proposed methods are evaluated using simulated and in vivo 3D phosphorus chemical shift imaging data by 1) visual inspection of the spatial signal distribution; 2) SNR calculation of the PCr peak; and 3) fitting of metabolite basis functions. Results With the optimal order of processing steps, we show that the effective SNR of in vivo phosphorus 3D chemical shift imaging data can be increased. In simulations, we show we can preserve phosphorus‐containing metabolite peaks that had an SNR < 1 before denoising. Furthermore, using Wiener deconvolution, we were able to reduce the FWHM of the voxel point spread function with only partially reintroducing Gibb‐ringing artifacts while maintaining the SNR. After data processing, fitting of the phosphorus‐containing metabolite signals improved. Conclusion In this study, we have shown that principal component analysis‐based denoising in combination with regularized Wiener deconvolution allows increasing the effective spectral SNR of in vivo phosphorus 3D chemical shift imaging data, with reduction of the FWHM of the voxel point spread function. Processing increased the effective SNR by at least threefold compared to Hamming weighted acquired data and minimized voxel bleeding. With these methods, fitting of metabolite amplitudes became more robust with decreased fitting residuals.
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Affiliation(s)
- Martijn Froeling
- Department of Radiology, Imaging Division, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Jeanine J Prompers
- Department of Radiology, Imaging Division, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Dennis W J Klomp
- Department of Radiology, Imaging Division, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Tijl A van der Velden
- Department of Radiology, Imaging Division, University Medical Center Utrecht, Utrecht, The Netherlands
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