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Seginer A, Keith GA, Porter DA, Schmidt R. Artifact suppression in readout-segmented consistent K-t space EPSI (RS-COKE) for fast 1 H spectroscopic imaging at 7 T. Magn Reson Med 2022; 88:2339-2357. [PMID: 35975965 PMCID: PMC9804880 DOI: 10.1002/mrm.29373] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2022] [Revised: 06/08/2022] [Accepted: 06/09/2022] [Indexed: 01/09/2023]
Abstract
PURPOSE Fast proton (1 H) MRSI is an important diagnostic tool for clinical investigations, providing metabolic and spatial information. MRSI at 7 T benefits from increased SNR and improved separation of peaks but requires larger spectral widths. RS-COKE (Readout-Segmented Consistent K-t space Epsi) is an echo planar spectroscopic imaging (Epsi) variant capable to support the spectral width required for human brain metabolites spectra at 7 T. However, mismatches between readout segments lead to artifacts, particularly when subcutaneous lipid signals are not suppressed. In this study, these mismatches and their effects are analyzed and reduced. METHODS The following corrections to the data were performed: i) frequency-dependent phase corrections; ii) k-space trajectory corrections, derived from short reference scans; and iii) smoothing of data at segment transitions to mitigate the effect of residual mismatches. The improvement was evaluated by performing single-slice RS-COKE on a head-shaped phantom with a "lipid" layer and healthy subjects, using varying resolutions and durations ranging from 4.1 × 4.7 × 15 mm3 in 5:46 min to 3.1 × 3.3 × 15 mm3 in 13:07 min. RESULTS Artifacts arising from the readout-segmented acquisition were substantially reduced, thus providing high-quality spectroscopic imaging in phantom and human scans. LCModel fitting of the human data resulted in a relative Cramer-Rao lower bounds within 6% for NAA, Cr, and Cho images in the majority of the voxels. CONCLUSION Using the new reference scans and reconstruction steps, RS-COKE was able to deliver fast 1 H MRSI at 7 T, overcoming the spectral width limitation of standard EPSI at this field strength.
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Affiliation(s)
| | - Graeme A. Keith
- Imaging Centre of ExcellenceUniversity of GlasgowGlasgowUnited Kingdom
| | - David A. Porter
- Imaging Centre of ExcellenceUniversity of GlasgowGlasgowUnited Kingdom
| | - Rita Schmidt
- Department of Brain SciencesWeizmann Institute of ScienceRehovotIsrael,The Azrieli National Institute for Human Brain Imaging and ResearchWeizmann Institute of ScienceRehovotIsrael
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Vaidya MV, Zhang B, Hong D, Brown R, Batsios G, Viswanath P, Paska J, Wulf G, Grant AK, Ronen SM, Larson PEZ. A 13C/ 31P surface coil to visualize metabolism and energetics in the rodent brain at 3 Tesla. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2022; 343:107286. [PMID: 36075133 PMCID: PMC9721620 DOI: 10.1016/j.jmr.2022.107286] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/20/2022] [Revised: 08/04/2022] [Accepted: 08/24/2022] [Indexed: 06/15/2023]
Abstract
PURPOSE We constructed a 13C/31P surface coil at 3 T for studying cancer metabolism and bioenergetics. In a single scan session, hyperpolarized 13C-pyruvate MRS and 31P MRS was carried out for a healthy rat brain. METHODS All experiments were carried out at 3 Tesla. The multinuclear surface coil was designed as two coplanar loops each tuned to either the 13C or 31P operating frequency with an LCC trap on the 13C loop. A commercial volume proton coil was used for anatomical localization and B0 shimming. Single tuned coils operating at either the 13C or 31P frequency were built to evaluate the relative performance of the multinuclear coil. Coil performance metrics consisted of measuring Q factor ratio, calculating system input power using a single-pulse acquisition, and acquiring SNR and flip angle maps using 2D CSI sequences. To observe in vivo spectra, a bolus of hyperpolarized [1-13C] pyruvate was administered via tail vein. In vivo13C and endogenous 31P spectra were obtained in a single scan session using 1D slice selective acquisitions. RESULTS When compared with single tuned surface coils, the multinuclear coil performance showed a decrease in Q factor ratio, SNR, and transmit efficiency. Flip angle maps showed adequate flip angles within the phantom when the transmit voltage was set using an external phantom. Results show good detection of 13C labeled lactate, alanine, and bicarbonate in addition to ATP from 31P MRS. CONCLUSIONS The coil enables obtaining complementary information within a scan session, thus reducing the number of trials and minimizing biological variability for studies of metabolism and bioenergetics.
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Affiliation(s)
- Manushka V Vaidya
- Department of Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, CA, USA.
| | - Bei Zhang
- Advanced Imaging Research Center, UT Southwestern Medical Center, Dallas, TX, USA
| | - DongHyun Hong
- Department of Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, CA, USA
| | - Ryan Brown
- Center for Advanced Imaging Innovation and Research, and Center for Biomedical Imaging, Department of Radiology, New York University School of Medicine, New York, NY, USA
| | - Georgios Batsios
- Department of Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, CA, USA
| | - Pavithra Viswanath
- Department of Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, CA, USA
| | - Jan Paska
- Center for Advanced Imaging Innovation and Research, and Center for Biomedical Imaging, Department of Radiology, New York University School of Medicine, New York, NY, USA
| | - Gerburg Wulf
- Department of Hematology-Oncology, Beth Israel Deaconess Medical Center, Boston, MA, USA
| | - Aaron K Grant
- Department of Radiology, Beth Israel Deaconess Medical Center, Boston, MA, USA
| | - Sabrina M Ronen
- 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
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Plank JR, Glover SC, Moloney BD, Hoeh NR, Sundram F, Sumner RL, Muthukumaraswamy S, Lin JC. A randomized, double-blind, placebo-controlled, hybrid parallel-arm study of low-dose naltrexone as an adjunctive anti-inflammatory treatment for major depressive disorder. Trials 2022; 23:822. [PMID: 36175917 PMCID: PMC9524133 DOI: 10.1186/s13063-022-06738-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2022] [Accepted: 09/13/2022] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Major depressive disorder (MDD) is a leading cause of disability worldwide. The current treatments are ineffective in approximately one-third of patients, resulting in a large economic burden and reduced quality of life for a significant proportion of the global population. There is considerable evidence that increased inflammation may distinguish a sub-type of MDD, and there are no validated diagnostic tools or treatments for neuroinflammation in MDD patients. The current study aims to explore the potential role of low-dose naltrexone (LDN), a drug with purported anti-inflammatory properties in the central nervous system, as an adjunctive treatment in patients with MDD. METHODS/DESIGN This double-blind placebo-controlled hybrid parallel arm study enables the exploration of peripheral and central inflammatory markers with LDN as an approach to investigate inflammation as a pathophysiological contributor to MDD. Eligible participants with MDD (n = 48) will be stratified into the high and low inflammatory groups according to the levels of high-sensitivity C-reactive protein (hs-CRP) and then randomized to receive LDN or placebo for an initial 12 weeks, followed by a further 12 weeks during which all participants will receive LDN. The primary outcome measure will be the Montgomery-Åsberg Depression Rating Scale (MADRS) administered at baseline, 2 weeks, 4 weeks, 8 weeks, 12 weeks, 14 weeks, 16 weeks, 20 weeks, and 24 weeks, to assess the effectiveness of the anti-depressant response. The secondary outcomes include the use of MRI techniques including quantitative magnetization transfer (qMT), echo-planar spectroscopic imaging (EPSI), and diffusion-weighted imaging (DWI) to help to elucidate the neurobiological mechanism of LDN, and the inflammatory mechanisms in action in MDD. Electroencephalography, blood samples, cognitive tasks, and additional questionnaires will also be used to determine if there is a specific profile of symptoms in individuals with inflammatory MDD. Healthy participants (n = 24) will be recruited for baseline outcome measures only, to enable comparison with patients with MDD. DISCUSSION This trial contributes to the literature on inflammation in MDD, including the understanding of the pathophysiology and efficacy of anti-inflammatory treatments. The investigation of inflammatory mechanisms in MDD is an important first step in the development of biomarkers to classify patient sub-groups, increase the accuracy of diagnosis, and tailor the approach to patients in clinical practice. This study may provide evidence of the benefit of LDN for the groups in whom conventional anti-depressants are ineffective and lead the way for translation into clinical practice. TRIAL REGISTRATION Australian New Zealand Clinical Trials Registry ACTRN12622000881730 . Registered on 21 June 2022.
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Affiliation(s)
- Julia R Plank
- School of Pharmacy, Faculty of Medical and Health Sciences, University of Auckland, 85 Park Road, Grafton, Auckland, 1023, New Zealand
| | - Stephanie C Glover
- School of Pharmacy, Faculty of Medical and Health Sciences, University of Auckland, 85 Park Road, Grafton, Auckland, 1023, New Zealand
| | - Ben D Moloney
- School of Pharmacy, Faculty of Medical and Health Sciences, University of Auckland, 85 Park Road, Grafton, Auckland, 1023, New Zealand
| | - Nicholas R Hoeh
- Department of Psychological Medicine, School of Medicine, Faculty of Medical and Health Sciences, University of Auckland, 22-30 Park Avenue, Grafton, Auckland, 1023, New Zealand
| | - Frederick Sundram
- Department of Psychological Medicine, School of Medicine, Faculty of Medical and Health Sciences, University of Auckland, 22-30 Park Avenue, Grafton, Auckland, 1023, New Zealand
| | - Rachael L Sumner
- School of Pharmacy, Faculty of Medical and Health Sciences, University of Auckland, 85 Park Road, Grafton, Auckland, 1023, New Zealand
| | - Suresh Muthukumaraswamy
- School of Pharmacy, Faculty of Medical and Health Sciences, University of Auckland, 85 Park Road, Grafton, Auckland, 1023, New Zealand
| | - Joanne C Lin
- School of Pharmacy, Faculty of Medical and Health Sciences, University of Auckland, 85 Park Road, Grafton, Auckland, 1023, New Zealand.
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Rotkopf LT, Kampf T, Triphan SMF, Schlemmer HP, Ziener CH. Influence of flow and susceptibility effects on spin dephasing in lung tissue. Med Phys 2022; 49:5981-5992. [PMID: 35638106 DOI: 10.1002/mp.15784] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Revised: 05/17/2022] [Accepted: 05/21/2022] [Indexed: 11/10/2022] Open
Abstract
PURPOSE Magnetic resonance imaging (MRI) of the lung can be used for diagnosis and monitoring of interstitial lung disease. Biophysical models of alveolar lung tissue are needed to understand the complex interplay of susceptibility, diffusion, and flow effects, and their influence on magnetic resonance (MR) spin dephasing. METHODS In this work, we present a method for modeling the signal decay of lung tissue by utilizing a two-compartment model, which considers the different spin dephasing mechanisms in the alveolar vasculature and interstitial tissue. This allows calculating the magnetization dynamics and the MR lineshape, which can be measured noninvasively using clinical MR scanners. RESULTS The accuracy of the method was evaluated using finite element simulations and the experimentally measured lineshapes of a healthy volunteer. In this comparison, the model performs well, indicating that the relevant spin dephasing mechanisms are correctly taken into account. CONCLUSIONS The proposed method can be used to estimate the influence of blood flow and alveolar geometry on the MR lineshape of lung tissue.
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Affiliation(s)
- Lukas T Rotkopf
- Department of Radiology, German Cancer Research Center, Im Neuenheimer Feld, Heidelberg, Germany.,Medical Faculty, Ruprecht-Karls-University Heidelberg, Heidelberg, Germany
| | - Thomas Kampf
- Department of Neuroradiology, Würzburg University Hospital, Würzburg, Germany.,Department of Experimental Physics 5, University of Würzburg, Würzburg, Germany
| | - Simon M F Triphan
- Department of Diagnostic and Interventional Radiology, University Hospital Heidelberg, Heidelberg, Germany.,Translational Lung Research Center Heidelberg (TLRC), German Center for Lung Research (DZL), Heidelberg, Germany
| | - Heinz-Peter Schlemmer
- Department of Radiology, German Cancer Research Center, Im Neuenheimer Feld, Heidelberg, Germany
| | - Christian H Ziener
- Department of Radiology, German Cancer Research Center, Im Neuenheimer Feld, Heidelberg, Germany
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5
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Time- and site-resolved kinetic NMR for real-time monitoring of off-equilibrium reactions by 2D spectrotemporal correlations. Nat Commun 2022; 13:833. [PMID: 35149671 PMCID: PMC8837778 DOI: 10.1038/s41467-022-28304-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2021] [Accepted: 01/13/2022] [Indexed: 11/25/2022] Open
Abstract
Nuclear magnetic resonance (NMR) spectroscopy provides detailed information about dynamic processes through line-shape changes, which are traditionally limited to equilibrium conditions. However, a wealth of information is available by studying chemical reactions under off-equilibrium conditions—e.g., in states that arise upon mixing reactants that subsequently undergo chemical changes—and in monitoring the reactants and products in real time. Herein, we propose and demonstrate a time-resolved kinetic NMR experiment that combines rapid mixing techniques, continuous flow, and single-scan spectroscopic imaging methods, leading in unison to a 2D spectrotemporal NMR correlation that provides high-quality kinetic information of off-equilibrium chemical reactions. These kinetic 2D NMR spectra possess a high-resolution spectral dimension revealing the individual chemical sites, correlated with a time-independent, steady-state spatial axis that delivers information concerning temporal changes along the reaction coordinate. A comprehensive description of the kinetic, spectroscopic, and experimental features associated with these spectrotemporal NMR analyses is presented. Experimental demonstrations are carried out using an enzymatically catalyzed reaction leading to site- and time-resolved kinetic NMR data, that are in excellent agreement with control experiments and literature values. Time-resolved NMR spectra provide unique structural and dynamical information, but their measurement in systems undergoing chemical reactions is challenging. Here the authors, combining single-scan spectroscopic imaging, rapid mixing and continuous flow techniques, obtain chemically resolved snapshots of a reacting system throughout the reaction coordinate.
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Blazey T, Reed GD, Garbow JR, von Morze C. Metabolite-Specific Echo-Planar Imaging of Hyperpolarized [1- 13C]Pyruvate at 4.7 T. Tomography 2021; 7:466-476. [PMID: 34564302 PMCID: PMC8482109 DOI: 10.3390/tomography7030040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2021] [Revised: 08/14/2021] [Accepted: 09/06/2021] [Indexed: 11/16/2022] Open
Abstract
Although hyperpolarization (HP) greatly increases the sensitivity of 13C MR, the usefulness of HP in vivo is limited by the short lifetime of HP agents. To address this limitation, we developed an echo-planar (EPI) sequence with spectral-spatial radiofrequency (SSRF) pulses for fast and efficient metabolite-specific imaging of HP [1-13C]pyruvate and [1-13C]lactate at 4.7 T. The spatial and spectral selectivity of each SSRF pulse was verified using simulations and phantom testing. EPI and CSI imaging of the rat abdomen were compared in the same rat after injecting HP [1-13C]pyruvate. A procedure was also developed to automatically set the SSRF excitation pulse frequencies based on real-time scanner feedback. The most significant results of this study are the demonstration that a greater spatial and temporal resolution is attainable by metabolite-specific EPI as compared with CSI, and the enhanced lifetime of the HP signal in EPI, which is attributable to the independent flip angle control between metabolites. Real-time center frequency adjustment was also highly effective for minimizing off-resonance effects. To the best of our knowledge, this is the first demonstration of metabolite-specific HP 13C EPI at 4.7 T. In conclusion, metabolite-specific EPI using SSRF pulses is an effective way to image HP [1-13C]pyruvate and [1-13C]lactate at 4.7 T.
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Affiliation(s)
- Tyler Blazey
- Mallinckrodt Institute of Radiology, Washington University, St. Louis, MO 63110, USA; (T.B.); (J.R.G.)
| | | | - Joel R Garbow
- Mallinckrodt Institute of Radiology, Washington University, St. Louis, MO 63110, USA; (T.B.); (J.R.G.)
| | - Cornelius von Morze
- Mallinckrodt Institute of Radiology, Washington University, St. Louis, MO 63110, USA; (T.B.); (J.R.G.)
- Correspondence:
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7
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Müller CA, Hundshammer C, Braeuer M, Skinner JG, Berner S, Leupold J, Düwel S, Nekolla SG, Månsson S, Hansen AE, von Elverfeldt D, Ardenkjaer-Larsen JH, Schilling F, Schwaiger M, Hennig J, Hövener JB. Dynamic 2D and 3D mapping of hyperpolarized pyruvate to lactate conversion in vivo with efficient multi-echo balanced steady-state free precession at 3 T. NMR IN BIOMEDICINE 2020; 33:e4291. [PMID: 32154970 DOI: 10.1002/nbm.4291] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/18/2019] [Revised: 02/20/2020] [Accepted: 02/21/2020] [Indexed: 06/10/2023]
Abstract
The aim of this study was to acquire the transient MRI signal of hyperpolarized tracers and their metabolites efficiently, for which specialized imaging sequences are required. In this work, a multi-echo balanced steady-state free precession (me-bSSFP) sequence with Iterative Decomposition with Echo Asymmetry and Least squares estimation (IDEAL) reconstruction was implemented on a clinical 3 T positron-emission tomography/MRI system for fast 2D and 3D metabolic imaging. Simulations were conducted to obtain signal-efficient sequence protocols for the metabolic imaging of hyperpolarized biomolecules. The sequence was applied in vitro and in vivo for probing the enzymatic exchange of hyperpolarized [1-13 C]pyruvate and [1-13 C]lactate. Chemical shift resolution was achieved using a least-square, iterative chemical species separation algorithm in the reconstruction. In vitro, metabolic conversion rate measurements from me-bSSFP were compared with NMR spectroscopy and free induction decay-chemical shift imaging (FID-CSI). In vivo, a rat MAT-B-III tumor model was imaged with me-bSSFP and FID-CSI. 2D metabolite maps of [1-13 C]pyruvate and [1-13 C]lactate acquired with me-bSSFP showed the same spatial distributions as FID-CSI. The pyruvate-lactate conversion kinetics measured with me-bSSFP and NMR corresponded well. Dynamic 2D metabolite mapping with me-bSSFP enabled the acquisition of up to 420 time frames (scan time: 180-350 ms/frame) before the hyperpolarized [1-13 C]pyruvate was relaxed below noise level. 3D metabolite mapping with a large field of view (180 × 180 × 48 mm3 ) and high spatial resolution (5.6 × 5.6 × 2 mm3 ) was conducted with me-bSSFP in a scan time of 8.2 seconds. It was concluded that Me-bSSFP improves the spatial and temporal resolution for metabolic imaging of hyperpolarized [1-13 C]pyruvate and [1-13 C]lactate compared with either of the FID-CSI or EPSI methods reported at 3 T, providing new possibilities for clinical and preclinical applications.
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Affiliation(s)
- Christoph A Müller
- Department of Radiology, Medical Physics, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
- German Consortium for Translational Cancer Research (DKTK), Partnersite Freiburg, German Center for Cancer Research (DKFZ), Heidelberg, Germany
| | - Christian Hundshammer
- Department of Nuclear Medicine, University Hospital rechts der Isar, Munich, Germany
- Department of Chemistry, Technical University of Munich, Garching, Germany
- Munich School of Bioengineering, Technical University of Munich, Garching, Germany
| | - Miriam Braeuer
- Department of Nuclear Medicine, University Hospital rechts der Isar, Munich, Germany
| | - Jason G Skinner
- Department of Radiology, Medical Physics, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
- Department of Nuclear Medicine, University Hospital rechts der Isar, Munich, Germany
| | - Stephan Berner
- Department of Radiology, Medical Physics, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
- German Consortium for Translational Cancer Research (DKTK), Partnersite Freiburg, German Center for Cancer Research (DKFZ), Heidelberg, Germany
| | - Jochen Leupold
- Department of Radiology, Medical Physics, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Stephan Düwel
- Department of Nuclear Medicine, University Hospital rechts der Isar, Munich, Germany
| | - Stephan G Nekolla
- Department of Nuclear Medicine, University Hospital rechts der Isar, Munich, Germany
| | - Sven Månsson
- Medical Radiation Physics, Department of Translational Medicine, Lund University, Skåne University Hospital, Malmö, Sweden
| | - Adam E Hansen
- Department of Clinical Physiology, Nuclear Medicine & PET, Rigshospitalet, University of Copenhagen, Denmark
| | - Dominik von Elverfeldt
- Department of Radiology, Medical Physics, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | | | - Franz Schilling
- Department of Nuclear Medicine, University Hospital rechts der Isar, Munich, Germany
| | - Markus Schwaiger
- Department of Nuclear Medicine, University Hospital rechts der Isar, Munich, Germany
| | - Jürgen Hennig
- Department of Radiology, Medical Physics, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Jan-Bernd Hövener
- Department of Radiology, Medical Physics, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
- Section Biomedical Imaging, Molecular Imaging North Competence Center (MOIN CC), Department of Radiology and Neuroradiology, University Medical Center Schleswig Holstein (UKSH), Kiel University, Germany
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Topping GJ, Hundshammer C, Nagel L, Grashei M, Aigner M, Skinner JG, Schulte RF, Schilling F. Acquisition strategies for spatially resolved magnetic resonance detection of hyperpolarized nuclei. MAGMA (NEW YORK, N.Y.) 2020; 33:221-256. [PMID: 31811491 PMCID: PMC7109201 DOI: 10.1007/s10334-019-00807-6] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/09/2019] [Revised: 10/08/2019] [Accepted: 11/21/2019] [Indexed: 12/13/2022]
Abstract
Hyperpolarization is an emerging method in magnetic resonance imaging that allows nuclear spin polarization of gases or liquids to be temporarily enhanced by up to five or six orders of magnitude at clinically relevant field strengths and administered at high concentration to a subject at the time of measurement. This transient gain in signal has enabled the non-invasive detection and imaging of gas ventilation and diffusion in the lungs, perfusion in blood vessels and tissues, and metabolic conversion in cells, animals, and patients. The rapid development of this method is based on advances in polarizer technology, the availability of suitable probe isotopes and molecules, improved MRI hardware and pulse sequence development. Acquisition strategies for hyperpolarized nuclei are not yet standardized and are set up individually at most sites depending on the specific requirements of the probe, the object of interest, and the MRI hardware. This review provides a detailed introduction to spatially resolved detection of hyperpolarized nuclei and summarizes novel and previously established acquisition strategies for different key areas of application.
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Affiliation(s)
- Geoffrey J Topping
- Department of Nuclear Medicine, Klinikum rechts der Isar, Technical University of Munich, Munich, Germany
| | - Christian Hundshammer
- Department of Nuclear Medicine, Klinikum rechts der Isar, Technical University of Munich, Munich, Germany
| | - Luca Nagel
- Department of Nuclear Medicine, Klinikum rechts der Isar, Technical University of Munich, Munich, Germany
| | - Martin Grashei
- Department of Nuclear Medicine, Klinikum rechts der Isar, Technical University of Munich, Munich, Germany
| | - Maximilian Aigner
- Department of Nuclear Medicine, Klinikum rechts der Isar, Technical University of Munich, Munich, Germany
| | - Jason G Skinner
- Department of Nuclear Medicine, Klinikum rechts der Isar, Technical University of Munich, Munich, Germany
| | | | - Franz Schilling
- Department of Nuclear Medicine, Klinikum rechts der Isar, Technical University of Munich, Munich, Germany.
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Benders S, Blümich B. Applications of magnetic resonance imaging in chemical engineering. PHYSICAL SCIENCES REVIEWS 2019. [DOI: 10.1515/psr-2018-0177] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Abstract
While there are many techniques to study phenomena that occur in chemical engineering applications, magnetic resonance imaging (MRI) receives increasing scientific interest. Its non-invasive nature and wealth of parameters with the ability to generate functional images and contrast favors the use of MRI for many purposes, in particular investigations of dynamic phenomena, since it is very sensitive to motion. Recent progress in flow-MRI has led to shorter acquisition times and enabled studies of transient phenomena. Reactive systems can easily be imaged if NMR parameters such as relaxation change along the reaction coordinate. Moreover, materials and devices can be examined, such as batteries by mapping the magnetic field around them.
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10
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Schmidt R, Seginer A, Tal A. Combining multiband slice selection with consistent k-t-space EPSI for accelerated spectral imaging. Magn Reson Med 2019; 82:867-876. [PMID: 30990227 DOI: 10.1002/mrm.27767] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2019] [Revised: 03/19/2019] [Accepted: 03/20/2019] [Indexed: 01/20/2023]
Abstract
PURPOSE To design and implement a multislice MRSI method for fast spectroscopic imaging, using a modified version of echo planar spectroscopic imaging (EPSI) that offers higher spectral width and/or shorter scan time. METHODS Echo planar spectroscopic imaging suffers from inconsistencies between readout lines acquired with gradients of opposite signs, which has typically been addressed by reconstructing the "positive" and "negative" data sets separately and averaging the two. Nevertheless, consistency between the readout lines of each phase encode can be achieved by interposing the EPSI readouts with alternating "blipped" phase-encode gradients. This method exchanges inconsistencies along the temporal dimension with inconsistencies along the phase-encode dimension, which are straightforward to correct, as is conventionally done in various EPI reconstruction schemes. Such consistent k-t-space EPSI doubles the spectral width in comparison to EPSI, or, in an alternative realization, yields the same spectral width as EPSI, but at half the acquisition time. In this work, multiband CAIPIRINHA (controlled aliasing in parallel imaging results in higher acceleration) slice selection was integrated with consistent k-t-space EPSI to further accelerate the measurement 2-fold. RESULTS The feasibility of a consistent k-t-space EPSI was demonstrated in both phantoms and in vivo brain imaging at 3 T, and four pulse scheme variants were evaluated. It was demonstrated to be useful in optimizing the spectral width and scan acceleration, both of which are limiting factors in vivo. Dual-band implementation was shown to shorten the duration of the scan 4-fold. CONCLUSION The consistent k-t-space EPSI can be used to accelerate MRSI or, alternatively, double its spectral width. Adding dual-band CAIPIRINHA further accelerates the acquisition by a factor of 2.
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Affiliation(s)
- Rita Schmidt
- Department of Neurobiology, Weizmann Institute of Science, Rehovot, Israel
| | - Amir Seginer
- Department of Chemical and Biological Physics, Weizmann Institute of Science, Rehovot, Israel
| | - Assaf Tal
- Department of Chemical and Biological Physics, Weizmann Institute of Science, Rehovot, Israel
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11
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Vidya Shankar R, Chang JC, Hu HH, Kodibagkar VD. Fast data acquisition techniques in magnetic resonance spectroscopic imaging. NMR IN BIOMEDICINE 2019; 32:e4046. [PMID: 30637822 DOI: 10.1002/nbm.4046] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2015] [Revised: 10/30/2018] [Accepted: 10/31/2018] [Indexed: 06/09/2023]
Abstract
Magnetic resonance spectroscopic imaging (MRSI) is an important technique for assessing the spatial variation of metabolites in vivo. The long scan times in MRSI limit clinical applicability due to patient discomfort, increased costs, motion artifacts, and limited protocol flexibility. Faster acquisition strategies can address these limitations and could potentially facilitate increased adoption of MRSI into routine clinical protocols with minimal addition to the current anatomical and functional acquisition protocols in terms of imaging time. Not surprisingly, a lot of effort has been devoted to the development of faster MRSI techniques that aim to capture the same underlying metabolic information (relative metabolite peak areas and spatial distribution) as obtained by conventional MRSI, in greatly reduced time. The gain in imaging time results, in some cases, in a loss of signal-to-noise ratio and/or in spatial and spectral blurring. This review examines the current techniques and advances in fast MRSI in two and three spatial dimensions and their applications. This review categorizes the acceleration techniques according to their strategy for acquisition of the k-space. Techniques such as fast/turbo-spin echo MRSI, echo-planar spectroscopic imaging, and non-Cartesian MRSI effectively cover the full k-space in a more efficient manner per TR . On the other hand, techniques such as parallel imaging and compressed sensing acquire fewer k-space points and employ advanced reconstruction algorithms to recreate the spatial-spectral information, which maintains statistical fidelity in test conditions (ie no statistically significant differences on voxel-wise comparisions) with the fully sampled data. The advantages and limitations of each state-of-the-art technique are reviewed in detail, concluding with a note on future directions and challenges in the field of fast spectroscopic imaging.
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Affiliation(s)
- Rohini Vidya Shankar
- School of Biological and Health Systems Engineering, Arizona State University, Tempe, AZ, USA
| | - John C Chang
- Banner M D Anderson Cancer Center, Gilbert, AZ, USA
- School for Engineering of Matter, Transport and Energy, Arizona State University, Tempe, AZ, USA
| | - Houchun H Hu
- Department of Radiology and Medical Imaging, Phoenix Children's Hospital, Phoenix, AZ, USA
| | - Vikram D Kodibagkar
- School of Biological and Health Systems Engineering, Arizona State University, Tempe, AZ, USA
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Zhang SH, Maier SE, Panych LP. Improved spatial localization in magnetic resonance spectroscopic imaging with two-dimensional PSF-Choice encoding. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2018; 290:18-28. [PMID: 29547794 PMCID: PMC5895504 DOI: 10.1016/j.jmr.2018.03.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/18/2017] [Revised: 02/20/2018] [Accepted: 03/02/2018] [Indexed: 05/09/2023]
Abstract
PURPOSE Magnetic resonance spectroscopic imaging (MRSI), under low-spatial resolution settings, often suffers signal contamination from neighboring voxels due to ringing artifacts. Spatial localization can be improved by constraining the point-spread-function (PSF). Here the effectiveness of the two-dimensional PSF-Choice technique in providing improved spatial localization for MRSI is demonstrated. THEORY AND METHODS The PSF-Choice technique constrains the PSF to a desired shape by manipulating the weighting of RF excitation pulse throughout phase-encode steps. Based on a Point REsolved SpectroScopy (PRESS)-type sequence, PSF-Choice encoding was implemented along two dimensions to excite a two-dimensional Gaussian profile, by replacing the usual RF excitation pulse with a train of pulses that is modified at each phase-encoding step. The method was proven mathematically, and demonstrated experimentally in phantoms containing prostate relevant metabolic compounds of choline, creatine and citrate. RESULTS Using a dedicated prostate-mimicking spectroscopy phantom surrounded by oil, it was found that there is significantly less signal contamination from oil for PSF-Choice encoding compared with standard phase encoding. In particular, with standard phase encoding, there was a significant difference (p = 0.014) between ratios of Choline + Creatine to Citrate for voxels well within the phantom compared to voxels within the phantom but near the boundary with oil. The ratios in boundary voxels were also significantly different (p = 0.035) from reference values obtained using the prostate phantom with no oil present. In contrast, no significant differences were found in comparisons of these ratios when encoding with PSF-Choice. CONCLUSION The PSF-Choice scheme applied along two dimensions produces MR spectroscopic images with substantially reduced truncation artifacts and spectral contamination.
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Affiliation(s)
- Shelley HuaLei Zhang
- Department of Radiology, Brigham and Women's Hospital, Boston, MA, United States; Harvard Medical School, Boston, MA, United States.
| | - Stephan E Maier
- Department of Radiology, Brigham and Women's Hospital, Boston, MA, United States; Harvard Medical School, Boston, MA, United States; Institute of Clinical Sciences, Sahlgrenska Academy, Gothenburg University, Gothenburg, Sweden.
| | - Lawrence P Panych
- Department of Radiology, Brigham and Women's Hospital, Boston, MA, United States; Harvard Medical School, Boston, MA, United States.
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Pedrosa de Barros N, Slotboom J. Quality management in in vivo proton MRS. Anal Biochem 2017; 529:98-116. [DOI: 10.1016/j.ab.2017.01.017] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2016] [Revised: 11/18/2016] [Accepted: 01/19/2017] [Indexed: 12/27/2022]
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Siddiqui S, Kadlecek S, Pourfathi M, Xin Y, Mannherz W, Hamedani H, Drachman N, Ruppert K, Clapp J, Rizi R. The use of hyperpolarized carbon-13 magnetic resonance for molecular imaging. Adv Drug Deliv Rev 2017; 113:3-23. [PMID: 27599979 PMCID: PMC5783573 DOI: 10.1016/j.addr.2016.08.011] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2016] [Revised: 08/25/2016] [Accepted: 08/27/2016] [Indexed: 02/06/2023]
Abstract
Until recently, molecular imaging using magnetic resonance (MR) has been limited by the modality's low sensitivity, especially with non-proton nuclei. The advent of hyperpolarized (HP) MR overcomes this limitation by substantially enhancing the signal of certain biologically important probes through a process known as external nuclear polarization, enabling real-time assessment of tissue function and metabolism. The metabolic information obtained by HP MR imaging holds significant promise in the clinic, where it could play a critical role in disease diagnosis and therapeutic monitoring. This review will provide a comprehensive overview of the developments made in the field of hyperpolarized MR, including advancements in polarization techniques and delivery, probe development, pulse sequence optimization, characterization of healthy and diseased tissues, and the steps made towards clinical translation.
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Affiliation(s)
- Sarmad Siddiqui
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA 19104, USA; Department of Radiology, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Stephen Kadlecek
- Department of Radiology, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Mehrdad Pourfathi
- Department of Radiology, University of Pennsylvania, Philadelphia, PA 19104, USA; Department of Electrical and Systems Engineering, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Yi Xin
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA 19104, USA; Department of Radiology, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - William Mannherz
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Hooman Hamedani
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA 19104, USA; Department of Radiology, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Nicholas Drachman
- Department of Radiology, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Kai Ruppert
- Department of Radiology, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Justin Clapp
- Department of Anesthesiology and Critical Care, Hospital of the University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Rahim Rizi
- Department of Radiology, University of Pennsylvania, Philadelphia, PA 19104, USA.
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Prostate magnetic resonance imaging for brachytherapists: Anatomy and technique. Brachytherapy 2017; 16:679-687. [PMID: 28237429 DOI: 10.1016/j.brachy.2016.12.013] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2016] [Revised: 11/23/2016] [Accepted: 12/30/2016] [Indexed: 12/31/2022]
Abstract
PURPOSE To present an overview of mp MRI techniques necessary for high-resolution imaging of prostate. METHODS We summarize examples from our clinical experience and concepts from the current literature that illustrate normal prostate anatomy on multiparametric MRI (mp MRI). RESULTS Our experience regarding optimal mp MRI image acquisition is provided, as well as a summary of prostate and periprostatic anatomy and anatomical variants that pose challenges for BT. CONCLUSIONS mp MRI provides unparalleled assessment of the prostate and periprostatic anatomy, making it the most appropriate imaging modality to facilitate prostate BT treatment planning, implantation, and followup. This work provides an introduction to prostate mp MR imaging, anatomy, and anatomical variants essential for successful integration mp MRI into prostate brachytherapy practice.
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Miloushev VZ, Di Gialleonardo V, Salamanca-Cardona L, Correa F, Granlund KL, Keshari KR. Hyperpolarized 13C pyruvate mouse brain metabolism with absorptive-mode EPSI at 1T. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2017; 275:120-126. [PMID: 28061381 PMCID: PMC5554620 DOI: 10.1016/j.jmr.2016.12.009] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/27/2016] [Revised: 12/15/2016] [Accepted: 12/19/2016] [Indexed: 06/06/2023]
Abstract
The expected signal in echo-planar spectroscopic imaging experiments was explicitly modeled jointly in spatial and spectral dimensions. Using this as a basis, absorptive-mode type detection can be achieved by appropriate choice of spectral delays and post-processing techniques. We discuss the effects of gradient imperfections and demonstrate the implementation of this sequence at low field (1.05T), with application to hyperpolarized [1-13C] pyruvate imaging of the mouse brain. The sequence achieves sufficient signal-to-noise to monitor the conversion of hyperpolarized [1-13C] pyruvate to lactate in the mouse brain. Hyperpolarized pyruvate imaging of mouse brain metabolism using an absorptive-mode EPSI sequence can be applied to more sophisticated murine disease and treatment models. The simple modifications presented in this work, which permit absorptive-mode detection, are directly translatable to human clinical imaging and generate improved absorptive-mode spectra without the need for refocusing pulses.
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Affiliation(s)
- Vesselin Z Miloushev
- Department of Radiology, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, New York, NY 10065, USA.
| | - Valentina Di Gialleonardo
- Department of Radiology, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, New York, NY 10065, USA; Molecular Pharmacology Program, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, New York, NY 10065, USA
| | - Lucia Salamanca-Cardona
- Department of Radiology, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, New York, NY 10065, USA; Molecular Pharmacology Program, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, New York, NY 10065, USA
| | - Fabian Correa
- Department of Radiology, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, New York, NY 10065, USA; Molecular Pharmacology Program, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, New York, NY 10065, USA
| | - Kristin L Granlund
- Department of Radiology, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, New York, NY 10065, USA; Molecular Pharmacology Program, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, New York, NY 10065, USA
| | - Kayvan R Keshari
- Department of Radiology, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, New York, NY 10065, USA; Molecular Pharmacology Program, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, New York, NY 10065, USA; Weill Cornell Medical College, New York, NY 10065, USA.
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Weiss WA, Medved M, Karczmar GS, Giger ML. Preliminary assessment of dispersion versus absorption analysis of high spectral and spatial resolution magnetic resonance images in the diagnosis of breast cancer. J Med Imaging (Bellingham) 2015; 2:024502. [PMID: 26158106 DOI: 10.1117/1.jmi.2.2.024502] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2014] [Accepted: 04/06/2015] [Indexed: 11/14/2022] Open
Abstract
Water resonance lineshapes observed in breast lesions imaged with high spectral and spatial resolution (HiSS) magnetic resonance imaging have been shown to contain diagnostically useful non-Lorentzian components. The purpose of this work is to update a previous method of breast lesion diagnosis by including phase-corrected absorption and dispersion spectra. This update includes information about the shape of the complex water resonance, which could improve the performance of a computer-aided diagnosis breast lesion classification scheme. The non-Lorentzian characteristics observed in complex breast lesion water resonance spectra are characterized by comparing a plot of the real versus imaginary components of the spectrum to that of a perfect complex Lorentzian spectrum, a "dispersion versus absorption" (DISPA) analysis technique. Distortion in the shape of the observed spectra indicates underlying physiologic changes, which have been shown to be correlated with malignancy. These spectral shape distortions in each lesion voxel are quantified by summing the deviations in DISPA radius from an ideal complex Lorentzian spectrum over all Fourier components, yielding a "total radial difference" (TRD). We limited our analysis to those voxels in each lesion with the largest TRD. The number of voxels considered was dependent on the lesion size. The TRD was used to classify voxels from 15 malignant and 8 benign lesions ([Formula: see text] voxels after voxel elimination). Lesion discrimination performance was evaluated for both the average and variance of the TRD within each lesion. Area under the receiver operating characteristic curve (ROC AUC) was used to assess both the voxel- and lesion-based discrimination methods in the task of distinguishing between malignant and benign. In the task of distinguishing voxels from malignant and benign lesions, TRD yielded an AUC of 0.89 (95% confidence interval [0.84, 0.91]). In the task of distinguishing malignant from benign lesions, the average radial difference yielded an AUC of 0.90 (95% confidence interval [0.71, 1.00]) and the variance in the radial difference yielded an AUC of 0.84 (95% confidence interval [0.61, 0.99]). We have applied the DISPA spectroscopic analysis method to HiSS data in order to identify and quantify voxels in breast lesions displaying non-Lorentzian characteristics. We have shown that a breast lesion classification scheme based on the absorption and dispersion spectral data obtained from HiSS acquisitions may outperform a similar classifier based on single off-peak component analysis, as it uses shape details of the entire spectrum instead of the magnitude at a single spectral location.
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Affiliation(s)
- William A Weiss
- University of Chicago , Department of Radiology, 5841 South Maryland Avenue, Chicago, Illinois 60637, United States
| | - Milica Medved
- University of Chicago , Department of Radiology, 5841 South Maryland Avenue, Chicago, Illinois 60637, United States
| | - Gregory S Karczmar
- University of Chicago , Department of Radiology, 5841 South Maryland Avenue, Chicago, Illinois 60637, United States
| | - Maryellen L Giger
- University of Chicago , Department of Radiology, 5841 South Maryland Avenue, Chicago, Illinois 60637, United States
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Furuyama JK, Nagarajan R, Roberts CK, Lee CC, Hahn T, Thomas MA. A pilot validation of multi-echo based echo-planar correlated spectroscopic imaging in human calf muscles. NMR IN BIOMEDICINE 2014; 27:1176-83. [PMID: 25132520 PMCID: PMC4160415 DOI: 10.1002/nbm.3171] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/03/2014] [Revised: 06/11/2014] [Accepted: 06/27/2014] [Indexed: 05/18/2023]
Abstract
A current limitation of MR spectroscopic imaging of multiple skeletal muscles is prolonged scan duration. A significant reduction in the total scan duration using the echo-planar correlated spectroscopic imaging (EP-COSI) sequence was accomplished using two bipolar readout trains with different phase-encoded echoes for one of two spatial dimensions within a single repetition time (TR). The second bipolar readout was used for spatially encoding the outer k-space, whereas the first readout was used for the central k-space only. The performance of this novel sequence, called multi-echo based echo-planar correlated spectroscopic imaging (ME-EPCOSI), was demonstrated by localizing specific key features in calf muscles and bone marrow of 11 healthy volunteers and five subjects with type 2 diabetes (T2D). A 3 T MRI-MRS scanner equipped with a transmit-receive extremity coil was used. Localization of the ME-EPCOSI sequence was in good agreement with the earlier single-readout based EP-COSI sequence and the required scan time was reduced by a factor of two. In agreement with an earlier report using single-voxel based 2D MRS, significantly increased unsaturated pools of intramyocellular lipid (IMCL) and extramyocellular lipid (EMCL) and decreased IMCL and EMCL unsaturation indices (UIs) were observed in the soleus and tibialis anterior muscle regions of subjects with T2D compared with healthy controls. In addition, significantly decreased choline content was observed in the soleus of T2D subjects compared with healthy controls. Multi-voxel characterization of IMCL and EMCL ratios and UI in the calf muscle may be useful for the non-invasive assessment of altered lipid metabolism in the pathophysiology of T2D.
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Affiliation(s)
- Jon K. Furuyama
- Department of Radiological Sciences, University of California, Los Angeles, CA 90095
| | - Rajakumar Nagarajan
- Department of Radiological Sciences, University of California, Los Angeles, CA 90095
| | - Christian K. Roberts
- Exercise and Metabolic Disease Research Laboratory, Translational Sciences Section, School of Nursing, University of California, Los Angeles, CA 90095
| | - Cathy C. Lee
- Geriatrics, Research, Education and Clinical Center (GRECC), VA Greater Los Angeles, Healthcare System, Los Angeles, CA, USA
| | - Theodore Hahn
- Geriatrics, Research, Education and Clinical Center (GRECC), VA Greater Los Angeles, Healthcare System, Los Angeles, CA, USA
| | - M. Albert Thomas
- Department of Radiological Sciences, University of California, Los Angeles, CA 90095
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Weiss WA, Medved M, Karczmar GS, Giger ML. Residual analysis of the water resonance signal in breast lesions imaged with high spectral and spatial resolution (HiSS) MRI: a pilot study. Med Phys 2014; 41:012303. [PMID: 24387524 DOI: 10.1118/1.4851615] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
PURPOSE High spectral and spatial resolution magnetic resonance imaging (HiSS MRI) yields information on the local environment of suspicious lesions. Previous work has demonstrated the advantages of HiSS (complete fat-suppression, improved image contrast, no required contrast agent, etc.), leading to initial investigations of water resonance lineshape for the purpose of breast lesion classification. The purpose of this study is to investigate a quantitative imaging biomarker, which characterizes non-Lorentzian components of the water resonance in HiSS MRI datasets, for computer-aided diagnosis (CADx). METHODS The inhomogeneous broadening and non-Lorentzian or "off-peak" components seen in the water resonance of proton spectra of breast HiSS images are analyzed by subtracting a Lorentzian fit from the water peak spectra and evaluating the difference spectrum or "residual." The maxima of these residuals (referred to hereafter as "off-peak components") tend to be larger in magnitude in malignant lesions, indicating increased broadening in malignant lesions. The authors considered only those voxels with the highest magnitude off-peak components in each lesion, with the number of selected voxels dependent on lesion size. Our voxel-based method compared the magnitudes and frequencies of off-peak components of all voxels from all lesions in a database that included 15 malignant and 8 benign lesions (yielding ≈ 3900 voxels) based on the lesions' biopsy-confirmed diagnosis. Lesion classification was accomplished by comparing the average off-peak component magnitudes and frequencies in malignant and benign lesions. The area under the ROC curve (AUC) was used as a figure of merit for both the voxel-based and lesion-based methods. RESULTS In the voxel-based task of distinguishing voxels from malignant and benign lesions, off-peak magnitude yielded an AUC of 0.88 (95% confidence interval [0.84, 0.91]). In the lesion-based task of distinguishing malignant and benign lesions, average off-peak magnitude yielded an AUC 0.83 (95% confidence interval [0.61, 0.98]). CONCLUSIONS These promising AUC values suggest that analysis of the water-resonance in each HiSS image voxel using "residual analysis" could have high diagnostic utility and could be used to enhance current CADx methods and allow detection of breast cancer without the need to inject contrast agents.
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Affiliation(s)
- William A Weiss
- Department of Radiology, The University of Chicago, 5841 South Maryland Avenue, Chicago, Illinois 60637
| | - Milica Medved
- Department of Radiology, The University of Chicago, 5841 South Maryland Avenue, Chicago, Illinois 60637
| | - Gregory S Karczmar
- Department of Radiology, The University of Chicago, 5841 South Maryland Avenue, Chicago, Illinois 60637
| | - Maryellen L Giger
- Department of Radiology, The University of Chicago, 5841 South Maryland Avenue, Chicago, Illinois 60637
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Lam F, Liang ZP. A subspace approach to high-resolution spectroscopic imaging. Magn Reson Med 2014; 71:1349-57. [PMID: 24496655 DOI: 10.1002/mrm.25168] [Citation(s) in RCA: 94] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2013] [Revised: 12/30/2013] [Accepted: 01/15/2014] [Indexed: 11/08/2022]
Abstract
PURPOSE To accelerate spectroscopic imaging using sparse sampling of (k,t)-space and subspace (or low-rank) modeling to enable high-resolution metabolic imaging with good signal-to-noise ratio. METHODS The proposed method, called SPectroscopic Imaging by exploiting spatiospectral CorrElation, exploits a unique property known as partial separability of spectroscopic signals. This property indicates that high-dimensional spectroscopic signals reside in a very low-dimensional subspace and enables special data acquisition and image reconstruction strategies to be used to obtain high-resolution spatiospectral distributions with good signal-to-noise ratio. More specifically, a hybrid chemical shift imaging/echo-planar spectroscopic imaging pulse sequence is proposed for sparse sampling of (k,t)-space, and a low-rank model-based algorithm is proposed for subspace estimation and image reconstruction from sparse data with the capability to incorporate prior information and field inhomogeneity correction. RESULTS The performance of the proposed method has been evaluated using both computer simulations and phantom studies, which produced very encouraging results. For two-dimensional spectroscopic imaging experiments on a metabolite phantom, a factor of 10 acceleration was achieved with a minimal loss in signal-to-noise ratio compared to the long chemical shift imaging experiments and with a significant gain in signal-to-noise ratio compared to the accelerated echo-planar spectroscopic imaging experiments. CONCLUSION The proposed method, SPectroscopic Imaging by exploiting spatiospectral CorrElation, is able to significantly accelerate spectroscopic imaging experiments, making high-resolution metabolic imaging possible.
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Affiliation(s)
- Fan Lam
- Department of Electrical and Computer Engineering, Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois, 61801, USA
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Burns B, Wilson NE, Furuyama JK, Thomas MA. Non-uniformly under-sampled multi-dimensional spectroscopic imaging in vivo: maximum entropy versus compressed sensing reconstruction. NMR IN BIOMEDICINE 2014; 27:191-201. [PMID: 24738142 DOI: 10.1002/nbm.3052] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
The four-dimensional (4D) echo-planar correlated spectroscopic imaging (EP-COSI) sequence allows for the simultaneous acquisition of two spatial (ky, kx) and two spectral (t2, t1) dimensions in vivo in a single recording. However, its scan time is directly proportional to the number of increments in the ky and t1 dimensions, and a single scan can take 20–40 min using typical parameters, which is too long to be used for a routine clinical protocol. The present work describes efforts to accelerate EP-COSI data acquisition by application of non-uniform under-sampling (NUS) to the ky–t1 plane of simulated and in vivo EP-COSI datasets then reconstructing missing samples using maximum entropy (MaxEnt) and compressed sensing (CS). Both reconstruction problems were solved using the Cambridge algorithm, which offers many workflow improvements over other l1-norm solvers. Reconstructions of retrospectively under-sampled simulated data demonstrate that the MaxEnt and CS reconstructions successfully restore data fidelity at signal-to-noise ratios (SNRs) from 4 to 20 and 5× to 1.25× NUS. Retrospectively and prospectively 4× under-sampled 4D EP-COSI in vivo datasets show that both reconstruction methods successfully remove NUS artifacts; however, MaxEnt provides reconstructions equal to or better than CS. Our results show that NUS combined with iterative reconstruction can reduce 4D EP-COSI scan times by 75% to a clinically viable 5 min in vivo, with MaxEnt being the preferred method.
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Weis J, Bruvold M, Ortiz-Nieto F, Ahlström H. High-resolution echo-planar spectroscopic imaging of the human calf. PLoS One 2014; 9:e87533. [PMID: 24498129 PMCID: PMC3907517 DOI: 10.1371/journal.pone.0087533] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2013] [Accepted: 12/27/2013] [Indexed: 11/21/2022] Open
Abstract
Background This study exploits the speed benefits of echo-planar spectroscopic imaging (EPSI) to acquire lipid spectra of skeletal muscle. The main purpose was to develop a high-resolution EPSI technique for clinical MR scanner, to visualise the bulk magnetic susceptibility (BMS) shifts of extra-myocellular lipid (EMCL) spectral lines, and to investigate the feasibility of this method for the assessment of intra-myocellular (IMCL) lipids. Methods The study group consisted of six healthy volunteers. A two dimensional EPSI sequence with point-resolved spectroscopy (PRESS) spatial localization was implemented on a 3T clinical MR scanner. Measurements were performed by means of 64×64 spatial matrix and nominal voxel size 3×3×15 mm3. The total net measurement time was 3 min 12 sec for non-water-suppressed (1 acquisition) and 12 min 48 sec for water-suppressed scans (4 acquisitions). Results Spectra of the human calf had a very good signal-to-noise ratio and linewidths sufficient to differentiate IMCL resonances from EMCL. The use of a large spatial matrix reduces inter-voxel signal contamination of the strong EMCL signals. Small voxels enabled visualisation of the methylene EMCL spectral line splitting and their BMS shifts up to 0.5 ppm relative to the correspondent IMCL line. The mean soleus muscle IMCL content of our six volunteers was 0.30±0.10 vol% (range 0.18–0.46) or 3.6±1.2 mmol/kg wet weight (range: 2.1–5.4). Conclusion This study demonstrates that high-spatial resolution PRESS EPSI of the muscle lipids is feasible on standard clinical scanners.
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Affiliation(s)
- Jan Weis
- Department of Radiology, Uppsala University Hospital, Uppsala, Sweden
- * E-mail:
| | | | | | - Håkan Ahlström
- Department of Radiology, Uppsala University Hospital, Uppsala, Sweden
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Thomas MA, Nagarajan R, Huda A, Margolis D, Sarma MK, Sheng K, Reiter RE, Raman SS. Multidimensional MR spectroscopic imaging of prostate cancer in vivo. NMR IN BIOMEDICINE 2014; 27:53-66. [PMID: 23904127 DOI: 10.1002/nbm.2991] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/28/2013] [Revised: 04/12/2013] [Accepted: 05/21/2013] [Indexed: 06/02/2023]
Abstract
Prostate cancer (PCa) is the second most common type of cancer among men in the United States. A major limitation in the management of PCa is an inability to distinguish, early on, cancers that will progress and become life threatening. One-dimensional (1D) proton ((1)H) MRS of the prostate provides metabolic information such as levels of choline (Ch), creatine (Cr), citrate (Cit), and spermine (Spm) that can be used to detect and diagnose PCa. Ex vivo high-resolution magic angle spinning (HR-MAS) of PCa specimens has revealed detection of more metabolites such as myo-inositol (mI), glutamate (Glu), and glutamine (Gln). Due to the J-modulation and signal overlap, it is difficult to quantitate Spm and other resonances in the prostate clearly by single- and multivoxel-based 1D MR spectroscopy. This limitation can be minimized by adding at least one more spectral dimension by which resonances can be spread apart, thereby increasing the spectral dispersion. However, recording of multivoxel-based two-dimensional (2D) MRS such as J-resolved spectroscopy (JPRESS) and correlated spectroscopy (L-COSY) combined with 2D or three-dimensional (3D) magnetic resonance spectroscopic imaging (MRSI) using conventional phase-encoding can be prohibitively long to be included in a clinical protocol. To reduce the long acquisition time required for spatial encoding, the echo-planar spectroscopic imaging (EPSI) technique has been combined with correlated spectroscopy to give four-dimensional (4D) echo-planar correlated spectroscopic imaging (EP-COSI) as well as J-resolved spectroscopic imaging (EP-JRESI) and the multi-echo (ME) variants. Further acceleration can be achieved using non-uniform undersampling (NUS) and reconstruction using compressed sensing (CS). Earlier versions of 2D MRS, theory of 2D MRS, spectral apodization filters, newer developments and the potential role of multidimensional MRS in PCa detection and management will be reviewed here.
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Affiliation(s)
- M Albert Thomas
- Department of Radiological Sciences, David Geffen School of Medicine, University of California, Los Angeles, CA, 90095, USA
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Hegde JV, Mulkern RV, Panych LP, Fennessy FM, Fedorov A, Maier SE, Tempany CMC. Multiparametric MRI of prostate cancer: an update on state-of-the-art techniques and their performance in detecting and localizing prostate cancer. J Magn Reson Imaging 2013; 37:1035-54. [PMID: 23606141 DOI: 10.1002/jmri.23860] [Citation(s) in RCA: 170] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2011] [Accepted: 09/04/2012] [Indexed: 12/15/2022] Open
Abstract
Magnetic resonance (MR) examinations of men with prostate cancer are most commonly performed for detecting, characterizing, and staging the extent of disease to best determine diagnostic or treatment strategies, which range from biopsy guidance to active surveillance to radical prostatectomy. Given both the exam's importance to individual treatment plans and the time constraints present for its operation at most institutions, it is essential to perform the study effectively and efficiently. This article reviews the most commonly employed modern techniques for prostate cancer MR examinations, exploring the relevant signal characteristics from the different methods discussed and relating them to intrinsic prostate tissue properties. Also, a review of recent articles using these methods to enhance clinical interpretation and assess clinical performance is provided. J. Magn. Reson. Imaging 2013;37:1035-1054. © 2013 Wiley Periodicals, Inc.
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Affiliation(s)
- John V Hegde
- Department of Radiology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA
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25
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Geethanath S, Baek HM, Ganji SK, Ding Y, Maher EA, Sims RD, Choi C, Lewis MA, Kodibagkar VD. Compressive sensing could accelerate 1H MR metabolic imaging in the clinic. Radiology 2012; 262:985-94. [PMID: 22357898 DOI: 10.1148/radiol.11111098] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
PURPOSE To retrospectively evaluate the fidelity of magnetic resonance (MR) spectroscopic imaging data preservation at a range of accelerations by using compressed sensing. MATERIALS AND METHODS The protocols were approved by the institutional review board of the university, and written informed consent to acquire and analyze MR spectroscopic imaging data was obtained from the subjects prior to the acquisitions. This study was HIPAA compliant. Retrospective application of compressed sensing was performed on 10 clinical MR spectroscopic imaging data sets, yielding 600 voxels from six normal brain data sets, 163 voxels from two brain tumor data sets, and 36 voxels from two prostate cancer data sets for analysis. The reconstructions were performed at acceleration factors of two, three, four, five, and 10 and were evaluated by using the root mean square error (RMSE) metric, metabolite maps (choline, creatine, N-acetylaspartate [NAA], and/or citrate), and statistical analysis involving a voxelwise paired t test and one-way analysis of variance for metabolite maps and ratios for comparison of the accelerated reconstruction with the original case. RESULTS The reconstructions showed high fidelity for accelerations up to 10 as determined by the low RMSE (< 0.05). Similar means of the metabolite intensities and hot-spot localization on metabolite maps were observed up to a factor of five, with lack of statistically significant differences compared with the original data. The metabolite ratios of choline to NAA and choline plus creatine to citrate did not show significant differences from the original data for up to an acceleration factor of five in all cases and up to that of 10 for some cases. CONCLUSION A reduction of acquisition time by up to 80%, with negligible loss of information as evaluated with clinically relevant metrics, has been successfully demonstrated for hydrogen 1 MR spectroscopic imaging.
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Affiliation(s)
- Sairam Geethanath
- Joint Graduate Program in Biomedical Engineering, UT Arlington and UT Southwestern Medical Center, Dallas, Tex, USA
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Furuyama JK, Wilson NE, Burns BL, Nagarajan R, Margolis DJ, Thomas MA. Application of compressed sensing to multidimensional spectroscopic imaging in human prostate. Magn Reson Med 2012; 67:1499-505. [PMID: 22505247 DOI: 10.1002/mrm.24265] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2011] [Revised: 02/27/2012] [Accepted: 02/28/2012] [Indexed: 11/07/2022]
Abstract
The application of compressed sensing is demonstrated in a recently implemented four-dimensional echo-planar based J-resolved spectroscopic imaging sequence combining two spatial and two spectral dimensions. The echo-planar readout simultaneously acquires one spectral and one spatial dimension. Therefore, the compressed sensing undersampling is performed along the indirectly acquired spatial and spectral dimensions, and the reconstruction is performed using the split Bregman algorithm, an efficient TV-minimization solver. The four-dimensional echo-planar-based J-resolved spectroscopic imaging data acquired in a prostate phantom containing metabolites at physiological concentrations are accurately reconstructed with as little as 20% of the original data. Experimental data acquired in six healthy prostates using the external body matrix "receive" coil on a 3T magnetic resonance imaging scanner are reconstructed with acquisitions using only 25% of the Nyquist-Shannon required amount of data, indicating the potential for a 4-fold acceleration factor in vivo, bringing the required scan time for multidimensional magnetic resonance spectroscopic imaging within clinical feasibility.
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Affiliation(s)
- Jon K Furuyama
- Department of Radiological Sciences, University of California, Los Angeles, California 90095, USA
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Furuyama JK, Burns BL, Wilson NE, Thomas MA. Multi-Echo-Based Echo-Planar Spectroscopic Imaging Using a 3T MRI Scanner. MATERIALS (BASEL, SWITZERLAND) 2011; 4:1818-1834. [PMID: 28824110 PMCID: PMC5448876 DOI: 10.3390/ma4101818] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/02/2011] [Revised: 10/06/2011] [Accepted: 10/07/2011] [Indexed: 11/16/2022]
Abstract
The use of spin-echoes has been employed in an Echo-Planar Spectroscopic Imaging (EPSI) sequence to collect multiple phase encoded lines within a single TR in a Multi-Echo-based Echo-Planar Spectroscopic Imaging technique (MEEPSI). Despite the T₂ dependence on the amplitude of the spin-echoes, the Full Width at Half Maximum (FWHM) of the derived multi-echo Point Spread Function (PSF) is shown to decrease, indicating an improved overall spatial resolution without requiring any additional scan time. The improved spatial resolution is demonstrated in the one-dimensional (1D) spatial profiles of the N-Acetyl Aspartate (NAA) singlet along the phase encode dimension in a gray matter phantom. Although the improved spatial resolution comes at the expense of spectral resolution, it is shown in vivo that peak broadening due to T₂* decay is more significant than the loss of resolution from using spin-echoes and therefore does not affect the ability to quantify metabolites using the LCModel fitting algorithm.
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Affiliation(s)
- Jon K Furuyama
- Department of Radiological Sciences, University of California, Los Angeles, CA 90095, USA
| | - Brian L Burns
- Department of Radiological Sciences, University of California, Los Angeles, CA 90095, USA
- Medical Imaging Informatics (MII) Lab, University of California, Los Angeles, CA 90095, USA
| | - Neil E Wilson
- Department of Radiological Sciences, University of California, Los Angeles, CA 90095, USA
| | - M Albert Thomas
- Department of Radiological Sciences, University of California, Los Angeles, CA 90095, USA.
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Furuyama JK, Wilson NE, Thomas MA. Spectroscopic imaging using concentrically circular echo-planar trajectories in vivo. Magn Reson Med 2011; 67:1515-22. [DOI: 10.1002/mrm.23184] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2011] [Revised: 07/05/2011] [Accepted: 08/01/2011] [Indexed: 11/07/2022]
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29
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Haney CR, Pelizzari CA, Foxley S, Zamora MA, Mustafi D, Tretiakova M, Li S, Fan X, Karczmar GS. HiSStology: high spectral and spatial resolution magnetic resonance imaging detection of vasculature validated by histology and micro-computed tomography. Mol Imaging 2011; 10:187-96. [PMID: 21443840 DOI: 10.2310/7290.2010.00033] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2010] [Accepted: 03/31/2010] [Indexed: 11/18/2022] Open
Abstract
High spectral and spatial resolution (HiSS) data, acquired with echo-planar spectroscopic imaging (EPSI), can be used to acquire water spectra from each small image voxel. These images are sensitive to changes in local susceptibility caused by superparamagnetic iron oxide particles (SPIO); therefore, we hypothesized that images derived from HiSS data are very sensitive to tumor neovasculature following injection of SPIO. Accurate image registration was used to validate HiSS detection of neovasculature with histology and micro-computed tomographic (microCT) angiography. Athymic nude mice and Copenhagen rats were inoculated with Dunning AT6.1 prostate tumor cells in the right hind limb. The tumor region was imaged pre- and post-intravenous injection of SPIO. Three-dimensional assemblies of the CD31-stained histologic slices of the mouse legs and the microCT images of the rat vascular casts were registered with EPSI. The average distance between HiSS-predicted regions of high vascular density on magnetic resonance imaging and CD31-stained regions on histology was 200 μm. Similarly, vessels identified by HiSS in the rat images coincided with vasculature in the registered microCT image. The data demonstrate a strong correlation between tumor vasculature identified using HiSS and two gold standards: histology and microCT angiography.
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Affiliation(s)
- Chad R Haney
- Department of Radiology, University of Chicago, Chicago, IL 60637, USA.
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30
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Lipnick S, Verma G, Ramadan S, Furuyama J, Thomas MA. Echo planar correlated spectroscopic imaging: implementation and pilot evaluation in human calf in vivo. Magn Reson Med 2011; 64:947-56. [PMID: 20574964 DOI: 10.1002/mrm.22499] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Exploiting the speed benefits of echo-planar imaging (EPI), the echo-planar spectroscopic imaging (EPSI) sequence facilitates recording of one spectral and two to three spatial dimensions faster than the conventional magnetic resonance spectroscopic imaging (MRSI). A novel four dimensional (4D) echo-planar correlated spectroscopic imaging (EP-COSI) was implemented on a whole body 3 T MRI scanner combining two spectral with two spatial encodings. Similar to EPSI, the EP-COSI sequence used a bipolar spatial read-out train facilitating simultaneous spatial and spectral encoding, and the conventional phase and spectral encodings for the other spatial and indirect spectral dimensions, respectively. Multiple 2D correlated spectroscopy (COSY) spectra were recorded over the spatially resolved volume of interest (VOI) localized by a train of three slice-selective radiofrequency (RF) pulses (90°-180°-90°). After the initial optimization using phantom solutions, the EP-COSI data were recorded from the lower leg of eight healthy volunteers including one endurance trained volunteer. Pilot results showed acceptable spatial and spectral quality achievable using the EP-COSI sequence. There was a detectable separation of cross peaks arising from the skeletal muscle intramyocellular lipids (IMCLs) and extramyocellular lipids (EMCLs) saturated and unsaturated pools. Residual dipolar interaction between the N-methylene and N-methyl protons of creatine/phosphocreatine (Cr/PCr) was also observed in the tibialis anterior region.
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Affiliation(s)
- Scott Lipnick
- Department of Radiological Sciences, UCLA Geffen School of Medicine, Los Angeles, California 90095-1721, USA
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31
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Kuo AYC, Chiew M, Tam F, Cunningham C, Graham SJ. Multiecho coarse voxel acquisition for neurofeedback fMRI. Magn Reson Med 2010; 65:715-24. [DOI: 10.1002/mrm.22674] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2010] [Revised: 08/23/2010] [Accepted: 09/14/2010] [Indexed: 11/08/2022]
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32
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McDannold N, Barnes AS, Rybicki FJ, Oshio K, Chen NK, Hynynen K, Mulkern RV. Temperature mapping considerations in the breast with line scan echo planar spectroscopic imaging. Magn Reson Med 2008; 58:1117-23. [PMID: 18046702 DOI: 10.1002/mrm.21322] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
A line-scan echo planar spectroscopic imaging (LSEPSI) sequence was used to serially acquire spectra from 4,096 voxels every 6.4 s throughout the breasts of nine female subjects in vivo. Data from the serial acquisitions were analyzed to determine the potential of the technique to characterize temperature changes using either the water frequency alone or the water-methylene frequency difference. Fluctuations of the apparent temperature change under these conditions of no heating were smallest using the water-methylene frequency difference, most probably due to a substantial reduction of motion effects both within and without the imaged plane. The approach offers considerable advantages over other methods for temperature change monitoring in the breast with magnetic resonance but suffers from some limitations, including the unavailability of lipid and water resonances in some voxels as well as a surprisingly large distribution of water-methylene frequency differences, which may preclude absolute temperature measurement.
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Affiliation(s)
- Nathan McDannold
- Department of Radiology, Brigham and Women's Hospital, Boston, Massachusetts, USA
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33
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Tal A, Frydman L. Spectroscopic imaging from spatially-encoded single-scan multidimensional MRI data. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2007; 189:46-58. [PMID: 17869559 DOI: 10.1016/j.jmr.2007.08.003] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2007] [Accepted: 07/31/2007] [Indexed: 05/17/2023]
Abstract
We have recently proposed a protocol for retrieving multidimensional magnetic resonance images within a single scan, based on a spatial encoding of the spin interactions. This methodology relies on progressively dephasing spin coherences throughout a sample; for instance, by sweeping a radiofrequency pulse in the presence of a magnetic field gradient. When spins are suitably refocused by a second (acquisition) field gradient, this yields a time-domain signal reflecting in its magnitude the spatial distribution of spins throughout the sample. It is hereby shown that whereas the absolute value of the resulting signals conveys such imaging information, the hitherto unutilized phase modulation of the signal encodes the chemical shift offsets of the present speciae. Spectroscopically-resolved multidimensional images can thereby be retrieved in this fashion at no additional expense in either experimental complexity, sensitivity or acquisition time--simply by performing an additional analysis of the collected data. The resulting approach to single-scan spectroscopic imaging can also incorporate "RF shimming" compensating abilities, capable of providing high-resolution spectral and high-definition imaging data even under the presence of substantial magnetic field inhomogeneities. The principles of these methodologies as applied to spectroscopic imaging are briefly reviewed and compared against the background of traditional Fourier-based single-scan spectroscopic imaging protocols. Demonstrations of these new multidimensional spectroscopic MRI experiments on simple phantoms are also given.
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Affiliation(s)
- Assaf Tal
- Department of Chemical Physics, Weizmann Institute of Science, 76100 Rehovot, Israel
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34
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Ulrich M, Wokrina T, Ende G, Lang M, Bachert P. 31P-{1H} echo-planar spectroscopic imaging of the human brain in vivo. Magn Reson Med 2007; 57:784-90. [PMID: 17390361 DOI: 10.1002/mrm.21192] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Echo-planar spectroscopic imaging (EPSI) is one of the fastest spectroscopic imaging (SI) methods. It has been applied to (1)H MR spectroscopy (MRS) studies of the human brain in vivo. However, to our knowledge, EPSI with detection of the (31)P nucleus to monitor phosphorus-containing neurometabolites has not yet been considered. In this work, eight different (31)P-{(1)H} EPSI sequence versions with spectral widths ranging from 313 Hz to 2.27 kHz were implemented on a clinical 1.5T whole-body MR tomograph. The sequence versions utilized the heteronuclear nuclear Overhauser effect (NOE) for (31)P signal enhancement. The sensitivity observed in experiments with model solutions was in good agreement with theoretical predictions. In vivo measurements performed on healthy volunteers (N = 16) demonstrated the feasibility of performing two-dimensional (2D) (31)P-{(1)H} EPSI in the human brain, and the technique enabled fast acquisition of well-resolved localized spectra.
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Affiliation(s)
- M Ulrich
- Department of Neuroimaging, Central Institute of Mental Health, Mannheim, Germany.
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35
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Salvati A, Lynch I, Malmborg C, Topgaard D. Chemical shift imaging of molecular transport in colloidal systems: Visualization and quantification of diffusion processes. J Colloid Interface Sci 2007; 308:542-50. [PMID: 17182051 DOI: 10.1016/j.jcis.2006.11.035] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2006] [Revised: 11/06/2006] [Indexed: 11/29/2022]
Abstract
Magnetic resonance imaging with chemical shift resolution is demonstrated to provide detailed information about molecular transport on the macroscopic scale in complex colloidal systems. The concentrations of species with distinct 1H resonance lines can be quantified from spatially resolved, high-resolution, 1H nuclear magnetic resonance spectra. The method is demonstrated by experiments on three systems with multiple simultaneous transport processes where the diffusion coefficients depend on position and/or on the concentration of other species: (1) release of poly(ethylene glycol) and imidazole from a hydrogel into an external reservoir of water, (2) migration of acetic acid and tetramethylammonium ions in a highly concentrated water-in-oil emulsion with initially non-uniform concentration of solutes, and (3) release of tetramethylammonium ions loaded into a hydrogel triggered by the diffusion of methyl green into the gel matrix.
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Affiliation(s)
- Anna Salvati
- Physical Chemistry 1, Lund University, P.O.B. 124, SE-221 00 Lund, Sweden.
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36
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Lafitte G, Thuresson K, Söderman O. Diffusion of Nutrients Molecules and Model Drug Carriers Through Mucin Layer Investigated by Magnetic Resonance Imaging with Chemical Shift Resolution. J Pharm Sci 2007; 96:258-63. [PMID: 17039490 DOI: 10.1002/jps.20749] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Magnetic resonance imaging (MRI) with chemical shift resolution is a recent extension of MRI and it provides information about species resolved molecular transport on the macroscopic scale in complex systems. In this contribution, we show that by using this novel method, one can predict the behavior of drug and food molecules when they are in contact with the mucosal layer in the gastrointestinal tract. For the first time, the transport properties of a mixture of nutrients (i.e., a solution of ethanol and glucose) and of a model drug carrier (i.e., an equimolar solution of cationic and nonionic surfactants) through a mucin gel have been investigated. This study shows that transport properties of the diffusing molecules through a mucin gel are dependent on their size and physicochemical properties. In addition, we show that mucin gel acts as an efficient selective barrier. It favors the disintegration of mixed micelles of nonionic and cationic surfactants by stopping the diffusion of cationic surfactants with slightly affecting the diffusion of the nonionic surfactants.
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Affiliation(s)
- Géraldine Lafitte
- Physical Chemistry 1, Center for Chemistry and Chemical Engineering, Lund University, PO Box 124, SE-221 00 Lund, Sweden.
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37
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Leupold J, Wieben O, Månsson S, Speck O, Scheffler K, Petersson JS, Hennig J. Fast chemical shift mapping with multiecho balanced SSFP. MAGNETIC RESONANCE MATERIALS IN PHYSICS BIOLOGY AND MEDICINE 2006; 19:267-73. [PMID: 17119904 DOI: 10.1007/s10334-006-0056-9] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/11/2006] [Revised: 09/30/2006] [Accepted: 10/17/2006] [Indexed: 11/28/2022]
Abstract
OBJECT A method is proposed that provides spectroscopic images with high spatial resolution and moderate spectral resolution at very short total data acquisition times. MATERIALS AND METHODS Balanced steady-state free precession (bSSFP, TrueFISP, FIESTA, b-FFE) is combined with a multiecho readout gradient and frequency-sensitive reconstruction such as Fourier reconstruction known from echo-planar spectroscopic imaging (EPSI) or matrix inversion. Balanced SSFP imaging requires short repetition times to minimize banding artefacts, thereby restricting the achievable frequency resolution. RESULTS Two-dimensional (2D) high-resolution spectroscopic images were produced of three 1H resonances (water, acetone and fat) on phantoms and water/fat separation in vivo within 1-2 s. Additionally, fast 31P spectroscopic images were acquired from a phantom consisting of two resonances within 195 ms. CONCLUSION Frequency-sensitive reconstruction of multiecho bSSFP data can provide spectroscopic images with high spatial and temporal resolution while the frequency resolution is moderate at around 100 Hz. The method can also separate more than three resonances, allowing for hetero-nuclei metabolite mapping, for example 13C and 31P.
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Affiliation(s)
- Jochen Leupold
- Department of Diagnostic Radiology, Medical Physics, University Hospital Freiburg, Hugstetter Strasse 55, 79106, Freiburg, Germany.
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38
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Chen AP, Cunningham CH, Kurhanewicz J, Xu D, Hurd RE, Pauly JM, Carvajal L, Karpodinis K, Vigneron DB. High-resolution 3D MR spectroscopic imaging of the prostate at 3 T with the MLEV-PRESS sequence. Magn Reson Imaging 2006; 24:825-32. [PMID: 16916699 DOI: 10.1016/j.mri.2006.03.002] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2005] [Accepted: 03/02/2006] [Indexed: 11/15/2022]
Abstract
A 3 T MLEV-point-resolved spectroscopy (PRESS) sequence employing optimized spectral-spatial and very selective outer-voxel suppression pulses was tested in 25 prostate cancer patients. At an echo time of 85 ms, the MLEV-PRESS sequence resulted in maximally upright inner resonances and minimal outer resonances of the citrate doublet of doublets. Magnetic resonance spectroscopic imaging (MRSI) exams performed at both 3 and 1.5 T for 10 patients demonstrated a 2.08+/-0.36-fold increase in signal-to-noise ratio (SNR) at 3 T as compared with 1.5 T for the center citrate resonances. This permitted the acquisition of MRSI data with a nominal spatial resolution of 0.16 cm3 at 3 T with similar SNR as the 0.34-cm3 data acquired at 1.5 T. Due to the twofold increase in spectral resolution at 3 T and the improved magnetic field homogeneity provided by susceptibility-matched endorectal coils, the choline resonance was better resolved from polyamine and creatine resonances as compared with 1.5 T spectra. In prostate cancer patients, the elevation of choline and the reduction of polyamines were more clearly observed at 3 T, as compared with 1.5 T MRSI. The increased SNR and corresponding spatial resolution obtainable at 3 T reduced partial volume effects and allowed improved detection of the presence and extent of abnormal metabolite levels in prostate cancer patients, as compared with 1.5 T MRSI.
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Affiliation(s)
- Albert P Chen
- Department of Radiology, University of California at San Francisco, San Francisco, CA 94143-2512, USA
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39
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Srinivasan R, Cunningham C, Chen A, Vigneron D, Hurd R, Nelson S, Pelletier D. TE-Averaged two-dimensional proton spectroscopic imaging of glutamate at 3 T. Neuroimage 2006; 30:1171-8. [PMID: 16431138 DOI: 10.1016/j.neuroimage.2005.10.048] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2005] [Revised: 10/26/2005] [Accepted: 10/31/2005] [Indexed: 12/01/2022] Open
Abstract
Glutamate and glutamine are important neurochemicals in the central nervous system and the neurotoxic properties of excess glutamate have been associated with several neurodegenerative diseases. The TE-Averaged PRESS technique has been shown by our group to detect an unobstructed glutamate signal at 3 T that is resolved from glutamine and NAA at 2.35 ppm. TE-Averaged PRESS therefore provides an unambiguous measurement of glutamate as well as other metabolites such as NAA, choline, creatine, and myo-inositol. In this study, we extend the single voxel TE-Averaged PRESS technique for two-dimensional (2D) spectroscopic imaging (TE-Averaged MRSI) to generate 2D glutamate maps. To facilitate TE-Averaged MRSI within a reasonable time, a fast encoding trajectory was used. This enabled rapid acquisition of TE-Averaged spectral arrays with good spectral bandwidth (977 Hz) and resolution (approximately 2 Hz). MRSI data arrays of 10 x 16 were acquired with 1.8 cm3 spatial resolution over a approximately 110 cm3 volume in a scan time of approximately 21 min. Two-dimensional metabolite maps were obtained with good SNR and clear differentiation in glutamate levels was observed between gray and white matter with significantly higher glutamate in gray matter relative to white matter as anticipated.
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Affiliation(s)
- Radhika Srinivasan
- Center for Molecular and Functional Imaging, University of California San Francisco, 185 Berry Street, Suite #350, San Francisco, CA 94107-1739, USA.
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40
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Cunningham CH, Vigneron DB, Chen AP, Xu D, Nelson SJ, Hurd RE, Kelley DA, Pauly JM. Design of flyback echo-planar readout gradients for magnetic resonance spectroscopic imaging. Magn Reson Med 2006; 54:1286-9. [PMID: 16187273 DOI: 10.1002/mrm.20663] [Citation(s) in RCA: 85] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The spatial resolution of conventional magnetic resonance spectroscopic imaging-(MRSI) is typically coarse, mainly due to SNR limitations. The increased signal available with higher field scanners and new array coils now permits higher spatial resolution, but conventional chemical shift imaging (phase encoding) limits the spatial coverage possible in a patient-acceptable acquisition time. The "flyback" echo-planar trajectory is particularly insensitive to errors and provides data that are simple to process. In this study, high-efficiency gradient waveforms for flyback echo-planar MRSI were designed and implemented. Normal volunteer studies at 3 T showed the feasibility of acquiring high spatial resolution with large coverage in a short scan time (2048 voxels in 2.3 min and 4096 voxels in 8.5 min). The trajectories were insensitive to errors in timing and require only a modest (10 to 30%) penalty in SNR relative to conventional phase encoding using the same acquisition time.
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Affiliation(s)
- Charles H Cunningham
- Department of Electrical Engineering, Stanford University, Stanford, California, USA.
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41
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Mulkern RV, Chen NK, Oshio K, Panych LP, Rybicki FJ, Gambarota G. Fast spectroscopic imaging strategies for potential applications in fMRI. Magn Reson Imaging 2005; 22:1395-405. [PMID: 15707789 DOI: 10.1016/j.mri.2004.10.011] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2004] [Accepted: 10/08/2004] [Indexed: 01/28/2023]
Abstract
Technical aspects of two general fast spectroscopic imaging (SI) strategies, one based on gradient echo trains and the other on spin echo trains, are reviewed within the context of potential applications in the field of functional magnetic resonance imaging (fMRI). Fast spectroscopic imaging of water may prove useful for identifying mechanisms underlying the blood oxygenation level dependence (BOLD) of the water signal during brain activation studies. Reasonably rapid mapping of changes in proton signals from brain metabolites, like lactate, creatine or even neurotransmitter associated metabolites like GABA, is substantially more challenging but technically feasible particularly as higher field strengths become available. Fast spectroscopic methods directed towards the 31P signals from phosphocreatine (PCr) and adenosine tri-phosphates (ATP) are also technically feasible and may prove useful for studying cerebral energetics within fMRI contexts.
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Affiliation(s)
- Robert V Mulkern
- Department of Radiology, Children's Hospital, Harvard Medical School, Boston, MA 02115, USA.
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42
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Shrot Y, Frydman L. Spatially resolved multidimensional NMR spectroscopy within a single scan. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2004; 167:42-48. [PMID: 14987597 DOI: 10.1016/j.jmr.2003.10.008] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2003] [Indexed: 05/24/2023]
Abstract
We have recently demonstrated that the spatial encoding of internal nuclear magnetic resonance (NMR) spin interactions can be exploited to collect multidimensional NMR spectra within a single scan. Such experiments rely on an inhomogeneous spatial excitation of the spins throughout the sample, and lead to indirect-domain peaks via a constructive interference among the spatially resolved spin-packets that are thus created. The shape of the resulting indirect-domain echo peaks approaches a Sinc function when the chemical's distribution is uniform, but will depart from this function otherwise. It is hereby shown that a Fourier analysis of either the diagonal- or the cross-peaks resolved in these single-scan two-dimensional (2D) NMR experiments can in fact provide a weighted spatial distribution of the analyte originating such peak, thus opening up the possibility of completing spatially resolved multidimensional NMR measurements within a fraction of a second. Principles of this new mode of analysis are discussed, and examples where the potential of spatially resolved ultrafast 2D NMR spectroscopy is brought to bear are presented. Potential extensions of this approach to higher dimensions are also briefly addressed.
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Affiliation(s)
- Yoav Shrot
- Department of Chemical Physics, Weizmann Institute of Science, Rehovot 76100, Israel
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