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Albertova P, Gram M, Blaimer M, Bauer WR, Jakob PM, Nordbeck P. Rotary excitation of non-sinusoidal pulsed magnetic fields: Towards non-invasive direct detection of cardiac conduction. Magn Reson Med 2024; 92:1965-1979. [PMID: 38934418 DOI: 10.1002/mrm.30190] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2023] [Revised: 04/09/2024] [Accepted: 05/21/2024] [Indexed: 06/28/2024]
Abstract
PURPOSE There is a need for high resolution non-invasive imaging methods of physiologic magnetic fields. The purpose of this work is to develop a MRI detection approach for non-sinusoidal magnetic fields based on the rotary excitation (REX) mechanism which was previously successfully applied for the detection of oscillating magnetic fields in the sub-nT range. METHODS The new detection concept was examined by means of Bloch simulations, evaluating the interaction effect of spin-locked magnetization and low-frequency pulsed magnetic fields. The REX detection approach was validated under controlled conditions in phantom experiments at 3 T. Gaussian and sinc-shaped stimuli were investigated. In addition, the detection of artificial fields resembling a cardiac QRS complex, which is the most prominent peak visible on a magnetocardiogram, was tested. RESULTS Bloch simulations demonstrated that the REX method has a high sensitivity to pulsed fields in the resonance case, which is met when the spin-lock frequency coincides with a non-zero Fourier component of the stimulus field. In the experiments, we found that magnetic stimuli of different durations and waveforms can be distinguished by their characteristic REX response spectrum. The detected REX amplitude was proportional to the stimulus peak amplitude (R2 > 0.98) and the lowest field detection was 1 nT. Furthermore, the detection of QRS-like fields with varying QRS durations yielded significant results in a phantom setup (p < 0.001). CONCLUSION REX detection can be transferred to non-sinusoidal pulsed magnetic fields and could provide a non-invasive, quantitative tool for spatially resolved assessment of cardiac biomagnetism. Potential applications include the direct detection and characterization of cardiac conduction.
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Affiliation(s)
- Petra Albertova
- Department of Internal Medicine I, University Hospital Würzburg, Würzburg, Germany
- Experimental Physics 5, University of Würzburg, Würzburg, Germany
| | - Maximilian Gram
- Department of Internal Medicine I, University Hospital Würzburg, Würzburg, Germany
- Experimental Physics 5, University of Würzburg, Würzburg, Germany
| | - Martin Blaimer
- Fraunhofer Institute for Integrated Circuits IIS, Würzburg, Germany
| | | | | | - Peter Nordbeck
- Department of Internal Medicine I, University Hospital Würzburg, Würzburg, Germany
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Li X, Kim J, Yang M, Ok AH, Zbýň Š, Link TM, Majumdar S, Ma CB, Spindler KP, Winalski CS. Cartilage compositional MRI-a narrative review of technical development and clinical applications over the past three decades. Skeletal Radiol 2024; 53:1761-1781. [PMID: 38980364 PMCID: PMC11303573 DOI: 10.1007/s00256-024-04734-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/19/2023] [Revised: 06/11/2024] [Accepted: 06/13/2024] [Indexed: 07/10/2024]
Abstract
Articular cartilage damage and degeneration are among hallmark manifestations of joint injuries and arthritis, classically osteoarthritis. Cartilage compositional MRI (Cart-C MRI), a quantitative technique, which aims to detect early-stage cartilage matrix changes that precede macroscopic alterations, began development in the 1990s. However, despite the significant advancements over the past three decades, Cart-C MRI remains predominantly a research tool, hindered by various technical and clinical hurdles. This paper will review the technical evolution of Cart-C MRI, delve into its clinical applications, and conclude by identifying the existing gaps and challenges that need to be addressed to enable even broader clinical application of Cart-C MRI.
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Affiliation(s)
- Xiaojuan Li
- Program of Advanced Musculoskeletal Imaging (PAMI), Cleveland Clinic, 9500 Euclid Avenue, ND20, Cleveland, OH, 44195, USA.
- Department of Biomedical Engineering, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, USA.
- Department of Diagnostic Radiology, Cleveland Clinic, Cleveland, OH, USA.
| | - Jeehun Kim
- Program of Advanced Musculoskeletal Imaging (PAMI), Cleveland Clinic, 9500 Euclid Avenue, ND20, Cleveland, OH, 44195, USA
- Department of Biomedical Engineering, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, USA
| | - Mingrui Yang
- Program of Advanced Musculoskeletal Imaging (PAMI), Cleveland Clinic, 9500 Euclid Avenue, ND20, Cleveland, OH, 44195, USA
- Department of Biomedical Engineering, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, USA
| | - Ahmet H Ok
- Program of Advanced Musculoskeletal Imaging (PAMI), Cleveland Clinic, 9500 Euclid Avenue, ND20, Cleveland, OH, 44195, USA
- Department of Biomedical Engineering, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, USA
- Department of Diagnostic Radiology, Cleveland Clinic, Cleveland, OH, USA
| | - Štefan Zbýň
- Program of Advanced Musculoskeletal Imaging (PAMI), Cleveland Clinic, 9500 Euclid Avenue, ND20, Cleveland, OH, 44195, USA
- Department of Biomedical Engineering, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, USA
- Department of Diagnostic Radiology, Cleveland Clinic, Cleveland, OH, USA
| | - Thomas M Link
- Department of Radiology and Biomedical Imaging, University of California San Francisco (UCSF), San Francisco, CA, USA
| | - Sharmilar Majumdar
- Department of Radiology and Biomedical Imaging, University of California San Francisco (UCSF), San Francisco, CA, USA
| | - C Benjamin Ma
- Department of Orthopaedic Surgery, UCSF, San Francisco, CA, USA
| | - Kurt P Spindler
- Program of Advanced Musculoskeletal Imaging (PAMI), Cleveland Clinic, 9500 Euclid Avenue, ND20, Cleveland, OH, 44195, USA
- Department of Orthopaedic Surgery, Cleveland Clinic, Cleveland, OH, USA
| | - Carl S Winalski
- Program of Advanced Musculoskeletal Imaging (PAMI), Cleveland Clinic, 9500 Euclid Avenue, ND20, Cleveland, OH, 44195, USA
- Department of Biomedical Engineering, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, USA
- Department of Diagnostic Radiology, Cleveland Clinic, Cleveland, OH, USA
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Jin BZ, Capiglioni M, Federspiel A, Ahmadli U, Schindler K, Kiefer C, Wiest R. Neuronal current imaging of epileptic activity: An MRI study in patients with a first unprovoked epileptic seizure. Epilepsia Open 2024. [PMID: 38970780 DOI: 10.1002/epi4.13001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2023] [Revised: 06/07/2024] [Accepted: 06/11/2024] [Indexed: 07/08/2024] Open
Abstract
OBJECTIVE This study evaluates the performance of the novel MRI sequence stimulus-induced rotary saturation (SIRS) to map responses to interictal epileptic activity in the human cortex. Spin-lock pulses have been applied to indirectly detect neuronal activity through magnetic field perturbations. Following initial reports about the feasibility of the method in humans and animals with epilepsy, we aimed to investigate the diagnostic yield of spin-lock MR pulses in comparison with scalp-EEG in first seizure patients. METHODS We employed a novel method for measurements of neuronal activity through the detection of a resonant oscillating field, stimulus-induced rotary saturation contrast (SIRS) at spin-lock frequencies of 120 and 240 Hz acquired at a single 3T MRI system. Within a prospective observational study, we conducted SIRS experiments in 55 patients within 7 days after a suspected first unprovoked epileptic seizure and 61 healthy control subjects. In this study, we report on the analysis of data from a single 3T MRI system, encompassing 35 first seizure patients and 31 controls. RESULTS The SIRS method was applicable in all patients and healthy controls at frequencies of 120 and 240 Hz. We did not observe any significant age- or sex-related differences. Specificity of SIRS at 120 Hz was 90.3% and 93.5% at 240 Hz. Sensitivity was 17.1% at 120 Hz and 40.0% at 240 Hz. SIGNIFICANCE SIRS targets neuronal oscillating magnetic fields in patients with epilepsy. The coupling of presaturated spins to epilepsy-related magnetic field perturbations may serve as a-at this stage experimental-diagnostic test in first seizure patients to complement EEG findings as a standard screening test. PLAIN LANGUAGE SUMMARY Routine diagnostic tests carry several limitations when applied after a suspected first seizure. SIRS is a noninvasive MRI method to enable time-sensitive diagnosis of image correlates of epileptic activity with increased sensitivity compared to routine EEG.
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Affiliation(s)
- Baudouin Zongxin Jin
- Support Center of Advanced Neuroimaging, Institute of Diagnostic and Interventional Neuroradiology, Inselspital, Bern, Switzerland
- Sleep-Wake-Epilepsy-Center, Department of Neurology, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
- Graduate School of Health Sciences, Medical Faculty, University of Bern, Bern, Switzerland
| | - Milena Capiglioni
- Support Center of Advanced Neuroimaging, Institute of Diagnostic and Interventional Neuroradiology, Inselspital, Bern, Switzerland
| | - Andrea Federspiel
- Support Center of Advanced Neuroimaging, Institute of Diagnostic and Interventional Neuroradiology, Inselspital, Bern, Switzerland
| | - Uzeyir Ahmadli
- Support Center of Advanced Neuroimaging, Institute of Diagnostic and Interventional Neuroradiology, Inselspital, Bern, Switzerland
| | - Kaspar Schindler
- Sleep-Wake-Epilepsy-Center, Department of Neurology, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
| | - Claus Kiefer
- Support Center of Advanced Neuroimaging, Institute of Diagnostic and Interventional Neuroradiology, Inselspital, Bern, Switzerland
| | - Roland Wiest
- Support Center of Advanced Neuroimaging, Institute of Diagnostic and Interventional Neuroradiology, Inselspital, Bern, Switzerland
- Swiss Institute for Translational and Entrepreneurial Medicine, Sitem-Insel, Bern, Switzerland
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Wu L, Carchi C, Michaeli S, Mangia S, Idiyatullin D. Alternating Look-Locker for quantitative T 1 , T 1ρ and B 1 3D MRI mapping. Magn Reson Med 2024; 91:149-161. [PMID: 37582198 PMCID: PMC10651079 DOI: 10.1002/mrm.29839] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2023] [Revised: 08/01/2023] [Accepted: 08/02/2023] [Indexed: 08/17/2023]
Abstract
PURPOSE To develop a new MRI method, entitled alternating Look-Locker (aLL), for quantitativeT 1 $$ {T}_1 $$ ,T 1 ρ $$ {T}_{1\uprho} $$ , andB 1 $$ {B}_1 $$ 3D mapping. METHODS A Look-Locker scheme that alternates magnetization from +Z and -Z axes of the laboratory frame is utilized in combination with a 3D Multi-Band Sweep Imaging with Fourier Transformation (MB-SWIFT) readout. The analytical solution describing the spin evolution during aLL, as well as the correction required for segmented acquisition were derived. The simultaneousB 1 $$ {B}_1 $$ andT 1 $$ {T}_1 $$ mapping are demonstrated on an agar/saline phantom and on an in-vivo rat head.T 1 ρ $$ {T}_{1\uprho} $$ relaxation was achieved by cyclically applying magnetization preparation (MP) modules consisting of two adiabatic pulses.T 1 ρ $$ {T}_{1\uprho} $$ values in the rat brain in-vivo and in a gadobenate dimeglumine (Gd-DTPA) phantom were compared to those obtained with a previously introduced steady-state (SS) method. RESULTS The accuracy and precision of the analytical solution was tested by Bloch simulations. With the application of MP modules, the aLL method provides simultaneousT 1 $$ {T}_1 $$ andT 1 ρ $$ {T}_{1\uprho} $$ maps. Conversely, without it, the method can be used for simultaneousT 1 $$ {T}_1 $$ andB 1 $$ {B}_1 $$ mapping.T 1 ρ $$ {T}_{1\uprho} $$ values were similar with both aLL and SS techniques. However, the aLL method resulted in more robust quantitative mapping compared to the SS method. Unlike the SS method, the aLL method does not require additional scans for generatingT 1 $$ {T}_1 $$ maps. CONCLUSION The proposed method offers a new flexible tool for quantitative mapping ofT 1 $$ {T}_1 $$ ,T 1 ρ $$ {T}_{1\uprho} $$ , andB 1 $$ {B}_1 $$ . The aLL method can also be used with readout schemes different from MB-SWIFT.
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Affiliation(s)
- Lin Wu
- Center for Magnetic Resonance Research and Department of Radiology, University of Minnesota Medical School, Minneapolis, Minnesota, USA
| | - Chris Carchi
- Center for Magnetic Resonance Research and Department of Radiology, University of Minnesota Medical School, Minneapolis, Minnesota, USA
| | - Shalom Michaeli
- Center for Magnetic Resonance Research and Department of Radiology, University of Minnesota Medical School, Minneapolis, Minnesota, USA
| | - Silvia Mangia
- Center for Magnetic Resonance Research and Department of Radiology, University of Minnesota Medical School, Minneapolis, Minnesota, USA
| | - Djaudat Idiyatullin
- Center for Magnetic Resonance Research and Department of Radiology, University of Minnesota Medical School, Minneapolis, Minnesota, USA
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Coletti C, Fotaki A, Tourais J, Zhao Y, van de Steeg-Henzen C, Akçakaya M, Tao Q, Prieto C, Weingärtner S. Robust cardiac T 1 ρ $$ {\mathrm{T}}_{1_{\boldsymbol{\rho}}} $$ mapping at 3T using adiabatic spin-lock preparations. Magn Reson Med 2023; 90:1363-1379. [PMID: 37246420 PMCID: PMC10984724 DOI: 10.1002/mrm.29713] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2022] [Revised: 04/26/2023] [Accepted: 05/04/2023] [Indexed: 05/30/2023]
Abstract
PURPOSE The aim of this study is to develop and optimize an adiabaticT 1 ρ $$ {\mathrm{T}}_{1\uprho} $$ (T 1 ρ , adiab $$ {\mathrm{T}}_{1\uprho, \mathrm{adiab}} $$ ) mapping method for robust quantification of spin-lock (SL) relaxation in the myocardium at 3T. METHODS Adiabatic SL (aSL) preparations were optimized for resilience againstB 0 $$ {\mathrm{B}}_0 $$ andB 1 + $$ {\mathrm{B}}_1^{+} $$ inhomogeneities using Bloch simulations. OptimizedB 0 $$ {\mathrm{B}}_0 $$ -aSL, Bal-aSL andB 1 $$ {\mathrm{B}}_1 $$ -aSL modules, each compensating for different inhomogeneities, were first validated in phantom and human calf. MyocardialT 1 ρ $$ {\mathrm{T}}_{1\uprho} $$ mapping was performed using a single breath-hold cardiac-triggered bSSFP-based sequence. Then, optimizedT 1 ρ , adiab $$ {\mathrm{T}}_{1\uprho, \mathrm{adiab}} $$ preparations were compared to each other and to conventional SL-preparedT 1 ρ $$ {\mathrm{T}}_{1\uprho} $$ maps (RefSL) in phantoms to assess repeatability, and in 13 healthy subjects to investigate image quality, precision, reproducibility and intersubject variability. Finally, aSL and RefSL sequences were tested on six patients with known or suspected cardiovascular disease and compared with LGE,T 1 $$ {\mathrm{T}}_1 $$ , and ECV mapping. RESULTS The highestT 1 ρ , adiab $$ {\mathrm{T}}_{1\uprho, \mathrm{adiab}} $$ preparation efficiency was obtained in simulations for modules comprising 2 HS pulses of 30 ms each. In vivoT 1 ρ , adiab $$ {\mathrm{T}}_{1\uprho, \mathrm{adiab}} $$ maps yielded significantly higher quality than RefSL maps. Average myocardialT 1 ρ , adiab $$ {\mathrm{T}}_{1\uprho, \mathrm{adiab}} $$ values were 183.28± $$ \pm $$ 25.53 ms, compared with 38.21± $$ \pm $$ 14.37 ms RefSL-preparedT 1 ρ $$ {\mathrm{T}}_{1\uprho} $$ .T 1 ρ , adiab $$ {\mathrm{T}}_{1\uprho, \mathrm{adiab}} $$ maps showed a significant improvement in precision (avg. 14.47± $$ \pm $$ 3.71% aSL, 37.61± $$ \pm $$ 19.42% RefSL, p < 0.01) and reproducibility (avg. 4.64± $$ \pm $$ 2.18% aSL, 47.39± $$ \pm $$ 12.06% RefSL, p < 0.0001), with decreased inter-subject variability (avg. 8.76± $$ \pm $$ 3.65% aSL, 51.90± $$ \pm $$ 15.27% RefSL, p < 0.0001). Among aSL preparations,B 0 $$ {\mathrm{B}}_0 $$ -aSL achieved the better inter-subject variability. In patients,B 1 $$ {\mathrm{B}}_1 $$ -aSL preparations showed the best artifact resilience among the adiabatic preparations.T 1 ρ , adiab $$ {\mathrm{T}}_{1\uprho, \mathrm{adiab}} $$ times show focal alteration colocalized with areas of hyper-enhancement in the LGE images. CONCLUSION Adiabatic preparations enable robust in vivo quantification of myocardial SL relaxation times at 3T.
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Affiliation(s)
- Chiara Coletti
- Department of Imaging Physics, Delft University of Technology, Delft, The Netherlands
| | - Anastasia Fotaki
- Department of Biomedical Engineering, King’s College London, London, United Kingdom
| | - Joao Tourais
- Department of Imaging Physics, Delft University of Technology, Delft, The Netherlands
| | - Yidong Zhao
- Department of Imaging Physics, Delft University of Technology, Delft, The Netherlands
| | | | - Mehmet Akçakaya
- Department of Electrical and Computer Engineering and Center for Magnetic Resonance Research, University of Minnesota, Minnesota, USA
| | - Qian Tao
- Department of Imaging Physics, Delft University of Technology, Delft, The Netherlands
| | - Claudia Prieto
- Department of Biomedical Engineering, King’s College London, London, United Kingdom
- School of Engineering, Pontificia Universidad Católica de Chile, Santiago, Chile
- Milleniun Institute for Intelligent Healthcare Engineering, Santiago, Chile
| | - Sebastian Weingärtner
- Department of Imaging Physics, Delft University of Technology, Delft, The Netherlands
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Bustin A, Witschey WRT, van Heeswijk RB, Cochet H, Stuber M. Magnetic resonance myocardial T1ρ mapping : Technical overview, challenges, emerging developments, and clinical applications. J Cardiovasc Magn Reson 2023; 25:34. [PMID: 37331930 DOI: 10.1186/s12968-023-00940-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2022] [Accepted: 05/15/2023] [Indexed: 06/20/2023] Open
Abstract
The potential of cardiac magnetic resonance to improve cardiovascular care and patient management is considerable. Myocardial T1-rho (T1ρ) mapping, in particular, has emerged as a promising biomarker for quantifying myocardial injuries without exogenous contrast agents. Its potential as a contrast-agent-free ("needle-free") and cost-effective diagnostic marker promises high impact both in terms of clinical outcomes and patient comfort. However, myocardial T1ρ mapping is still at a nascent stage of development and the evidence supporting its diagnostic performance and clinical effectiveness is scant, though likely to change with technological improvements. The present review aims at providing a primer on the essentials of myocardial T1ρ mapping, and to describe the current range of clinical applications of the technique to detect and quantify myocardial injuries. We also delineate the important limitations and challenges for clinical deployment, including the urgent need for standardization, the evaluation of bias, and the critical importance of clinical testing. We conclude by outlining technical developments to be expected in the future. If needle-free myocardial T1ρ mapping is shown to improve patient diagnosis and prognosis, and can be effectively integrated in cardiovascular practice, it will fulfill its potential as an essential component of a cardiac magnetic resonance examination.
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Affiliation(s)
- Aurelien Bustin
- IHU LIRYC, Electrophysiology and Heart Modeling Institute, Université de Bordeaux, INSERM, Centre de Recherche Cardio-Thoracique de Bordeaux, U1045, Avenue du Haut Lévêque, 33604, Pessac, France.
- Department of Cardiovascular Imaging, Hôpital Cardiologique du Haut-Lévêque, CHU de Bordeaux, Avenue de Magellan, 33604, Pessac, France.
- Department of Diagnostic and Interventional Radiology, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland.
| | | | - Ruud B van Heeswijk
- Department of Diagnostic and Interventional Radiology, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland
| | - Hubert Cochet
- IHU LIRYC, Electrophysiology and Heart Modeling Institute, Université de Bordeaux, INSERM, Centre de Recherche Cardio-Thoracique de Bordeaux, U1045, Avenue du Haut Lévêque, 33604, Pessac, France
- Department of Cardiovascular Imaging, Hôpital Cardiologique du Haut-Lévêque, CHU de Bordeaux, Avenue de Magellan, 33604, Pessac, France
| | - Matthias Stuber
- IHU LIRYC, Electrophysiology and Heart Modeling Institute, Université de Bordeaux, INSERM, Centre de Recherche Cardio-Thoracique de Bordeaux, U1045, Avenue du Haut Lévêque, 33604, Pessac, France
- Department of Diagnostic and Interventional Radiology, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland
- Center for Biomedical Imaging (CIBM), Lausanne, Switzerland
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Capiglioni M, Turco F, Wiest R, Kiefer C. Analysis of the robustness and dynamics of spin-locking preparations for the detection of oscillatory magnetic fields. Sci Rep 2022; 12:16965. [PMID: 36216858 PMCID: PMC9550815 DOI: 10.1038/s41598-022-21232-1] [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: 02/17/2022] [Accepted: 09/23/2022] [Indexed: 12/29/2022] Open
Abstract
Extracting quantitative information of neuronal signals by non-invasive imaging is an outstanding challenge for understanding brain function and pathology. However, state-of-the-art techniques offer low sensitivity to deep electrical sources. Stimulus induced rotary saturation is a recently proposed magnetic resonance imaging sequence that detects oscillatory magnetic fields using a spin-lock preparation. Phantom experiments and simulations proved its efficiency and sensitivity, but the susceptibility of the method to field inhomogeneities is still not well understood. In this study, we simulated and analyzed the dynamic of three spin-lock preparations and their response to field inhomogeneities in the presence of a resonant oscillating field. We show that the composite spin-lock preparation is more robust against field variations within the double resonance effect. In addition, we tested the capability of the chosen composite spin-lock preparation to recover information about the spectral components of a composite signal. This study sets the bases to move one step further towards the clinical application of MR-based neuronal current imaging.
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Affiliation(s)
- Milena Capiglioni
- grid.5734.50000 0001 0726 5157Institute for Diagnostic and Interventional Neuroradiology, Support Center for Advanced Neuroimaging (SCAN), University of Bern, Freiburgstrasse 16, 3010 Bern, Switzerland
| | - Federico Turco
- grid.5734.50000 0001 0726 5157Institute for Diagnostic and Interventional Neuroradiology, Support Center for Advanced Neuroimaging (SCAN), University of Bern, Freiburgstrasse 16, 3010 Bern, Switzerland
| | - Roland Wiest
- grid.5734.50000 0001 0726 5157Institute for Diagnostic and Interventional Neuroradiology, Support Center for Advanced Neuroimaging (SCAN), University of Bern, Freiburgstrasse 16, 3010 Bern, Switzerland
| | - Claus Kiefer
- grid.5734.50000 0001 0726 5157Institute for Diagnostic and Interventional Neuroradiology, Support Center for Advanced Neuroimaging (SCAN), University of Bern, Freiburgstrasse 16, 3010 Bern, Switzerland
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8
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Pang Y. A self-compensated spin-locking scheme for quantitative R 1ρ dispersion MR imaging in ordered tissues. Magn Reson Imaging 2022; 94:112-118. [PMID: 36181969 DOI: 10.1016/j.mri.2022.09.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2022] [Revised: 09/01/2022] [Accepted: 09/25/2022] [Indexed: 11/24/2022]
Abstract
PURPOSE To propose a self-compensated spin-locking (SL) method for quantitative R1ρ dispersion imaging in ordered tissues. METHODS Two pairs of antiphase rotary-echo SL pulses were proposed in a new scheme with each pairs sandwiching one refocusing RF pulse. This proposed SL method was evaluated by Bloch simulations and experimental studies relative to three prior schemes. Quantitative R1ρR dispersion imaging studies with constant SL duration (TSL = 40 ms) were carried out on an agarose (1-4% w/v) phantom and one in vivo human knee at 3 T, using six SL RF strengths ranging from 50 to 1000 Hz. The performances of these SL schemes were characterized with an average coefficient of variation (CV) of the signal intensities in agarose gels and the sum of squared errors (SSE) for quantifying in vivo R1ρ dispersion of the femoral and tibial cartilage. RESULTS The simulations demonstrate that the proposed SL scheme was less prone to B0 and B1 field inhomogeneities. This theoretical prediction was supported by fewer image banding artifacts and less signal fluctuation signified by a reduced CV (%) on the phantom without R1ρ dispersion (i.e., 4.04 ± 1.36 vs. 18.87 ± 4.46 or 6.66 ± 2.92 or 5.71 ± 2.05 for others), and further by mostly decreased SSE (*10-3) for characterizing R1ρ dispersion of the femoral (i.e., 0.3 vs. 1.2 or 0.4 or 0.1) and tibial (i.e., 0.4 vs. 7.2 or 3.2 or 2.8) cartilage. CONCLUSION The proposed SL scheme is less sensitive to B0 and B1 field artifacts for a wide range of SL RF strengths and thus more suitable for quantitative R1ρ dispersion imaging in ordered tissues.
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Affiliation(s)
- Yuxi Pang
- Department of Radiology, University of Michigan, Ann Arbor, MI, USA.
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9
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Towards robust in vivo quantification of oscillating biomagnetic fields using Rotary Excitation based MRI. Sci Rep 2022; 12:15375. [PMID: 36100634 PMCID: PMC9469076 DOI: 10.1038/s41598-022-19275-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2022] [Accepted: 08/26/2022] [Indexed: 11/28/2022] Open
Abstract
Spin-lock based functional magnetic resonance imaging (fMRI) has the potential for direct spatially-resolved detection of neuronal activity and thus may represent an important step for basic research in neuroscience. In this work, the corresponding fundamental effect of Rotary EXcitation (REX) is investigated both in simulations as well as in phantom and in vivo experiments. An empirical law for predicting optimal spin-lock pulse durations for maximum magnetic field sensitivity was found. Experimental conditions were established that allow robust detection of ultra-weak magnetic field oscillations with simultaneous compensation of static field inhomogeneities. Furthermore, this work presents a novel concept for the emulation of brain activity utilizing the built-in MRI gradient system, which allows REX sequences to be validated in vivo under controlled and reproducible conditions. Via transmission of Rotary EXcitation (tREX), we successfully detected magnetic field oscillations in the lower nano-Tesla range in brain tissue. Moreover, tREX paves the way for the quantification of biomagnetic fields.
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Takayama Y, Nishie A, Ishimatsu K, Ushijima Y, Fujita N, Kubo Y, Yoshizumi T, Kouhashi KI, Maehara J, Akamine Y, Ishigami K. Diagnostic potential of T1ρ and T2 relaxations in assessing the severity of liver fibrosis and necro-inflammation. Magn Reson Imaging 2022; 87:104-112. [PMID: 34999164 DOI: 10.1016/j.mri.2022.01.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Revised: 12/20/2021] [Accepted: 01/04/2022] [Indexed: 12/11/2022]
Abstract
PURPOSE To investigate the utility of T1ρ and T2 relaxations for assessing the severity of liver fibrosis (F stage) and necro-inflammation (A stage) in patients with chronic liver disease (CLD). MATERIALS AND METHODS We calculated T1ρ and T2 relaxations of the liver parenchyma in 82 patients who underwent liver surgery. F and A stages of enrolled patients were assessed by referring to surgically resected specimens. The relationships between T1ρ or T2 relaxation and F or A stage were assessed using one-way analysis of variance followed by Tukey's multiple comparison test, Spearman's rank correlation test and a receiver operating characteristic analysis. RESULTS The T1ρ and T2 values of the liver parenchyma were significantly increased as the F and A stages progressed. The T1ρ and T2 values showed significant differences between F0 and F4, between F1 and F4, and between F2 and F4. In addition, T1ρ values showed a significant difference between F0 and F3 as well. The highest diagnostic ability for fibrosis was obtained when differentiating ≥F3 from ≤F2 using T1ρ: the sensitivity was 82.8%, the specificity 79.2% and the area under the curve (AUC) 0.87. The sensitivity and AUC of T1ρ relaxation (46.9% and 0.67) were significantly higher than those of T2 relaxation (29.7% and 0.60) for differentiating ≥A1 from A0. CONCLUSION T1ρ and T2 relaxations have potential as a biochemical marker for assessing the severity of liver fibrosis and necro-inflammation. T1ρ relaxation may be slightly superior to T2 relaxation in terms of diagnostic ability for liver fibrosis and necro-inflammation.
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Affiliation(s)
- Yukihisa Takayama
- Department of Clinical Radiology, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan; Department of Radiology, Faculty of Medicine, Fukuoka University, 7-45-1 Nanakuma, Jonan-ku, Fukuoka 814-0180, Japan
| | - Akihiro Nishie
- Department of Clinical Radiology, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan.
| | - Keisuke Ishimatsu
- Department of Clinical Radiology, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan
| | - Yasuhiro Ushijima
- Department of Clinical Radiology, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan
| | - Nobuhiro Fujita
- Department of Clinical Radiology, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan
| | - Yuichiro Kubo
- Department of Molecular Imaging and Diagnostic Radiology, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan
| | - Tomoharu Yoshizumi
- Department of Surgery and Science, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan
| | - Ken-Ichi Kouhashi
- Department of Anatomic Pathology, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan
| | - Junki Maehara
- Department of Anatomic Pathology, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan
| | - Yuta Akamine
- Philips Japan. Ltd., Konan 2-13-37, Minato-ku, Tokyo 108-8507, Japan
| | - Kousei Ishigami
- Department of Clinical Radiology, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan
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11
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Kim SY, Kim H, Lee J, Jung SI, Moon MH, Joo KW, Cho JY. Quantitative magnetic resonance imaging of chronic kidney disease: an experimental in vivo study using rat chronic kidney disease models. Acta Radiol 2021; 64:404-414. [PMID: 34928730 DOI: 10.1177/02841851211065143] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND Recent advances in magnetic resonance imaging (MRI) may allow it to be an alternative emerging tool for the non-invasive evaluation of renal parenchymal disease. PURPOSE To validate the usefulness of quantitative multiparametric MRI protocols and suggest the suitable quantitative MR sequence protocol to evaluate parenchymal fibrosis using an animal model of chronic kidney disease (CKD) by long-term adenine intake. MATERIAL AND METHODS In this prospective animal study, 16 male Wistar rats were analyzed and categorized into three groups. Rats in the CKD groups underwent 0.25% adenine administration for three or six weeks. Quantitative MRI protocols, including diffusion-weighted imaging (DWI), T1ρ (T1 rho), and T2* mapping were performed using a 9.4-T animal MR scanner. A semi-quantitative histopathologic analysis for renal fibrosis was conducted. Quantitative MR values measured from anatomic regions of kidneys underwent intergroup comparative analyses. RESULTS The apparent diffusion coefficient (ADC) and T1 (T1 rho) values were significantly increased in all CKD groups. Values measured from the cortex and outer medulla showed significant intergroup differences. Total ADC values tended to increase according to periods, and T1ρ values increased in three weeks and decreased in six weeks. CONCLUSION Quantitative MRI protocols could be a non-invasive assessment modality in the diagnosis and evaluation of CKD. Particularly, T1ρ may be a suitable MR sequence to quantitatively assess renal parenchymal fibrosis.
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Affiliation(s)
- Sang Youn Kim
- Department of Radiology, Seoul National University Hospital, Seoul National University College of Medicine, Seoul, Republic of Korea
- Institute of Radiation Medicine and Kidney Research Institute, Seoul National University, Seoul, Republic of Korea
| | - Hyeonjin Kim
- Department of Radiology, Seoul National University Hospital, Seoul National University College of Medicine, Seoul, Republic of Korea
- Institute of Radiation Medicine and Kidney Research Institute, Seoul National University, Seoul, Republic of Korea
- Department of Biomedical Sciences, Seoul National University, Seoul, Republic of Korea
| | - Joongyub Lee
- Medical Research Collaborating Center, Seoul National University Hospital, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Sung Il Jung
- Department of Radiology, Konkuk University Medical Center, Konkuk University School of Medicine, Seoul, Republic of Korea
| | - Min Hoan Moon
- Department of Radiology, SMG-SNU Boramae Medical Center, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Kwon Wook Joo
- Department of Internal Medicine, Seoul National University Hospital, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Jeong Yeon Cho
- Department of Radiology, Seoul National University Hospital, Seoul National University College of Medicine, Seoul, Republic of Korea
- Institute of Radiation Medicine and Kidney Research Institute, Seoul National University, Seoul, Republic of Korea
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12
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Velasco C, Cruz G, Lavin B, Hua A, Fotaki A, Botnar RM, Prieto C. Simultaneous T 1 , T 2 , and T 1ρ cardiac magnetic resonance fingerprinting for contrast agent-free myocardial tissue characterization. Magn Reson Med 2021; 87:1992-2002. [PMID: 34799854 DOI: 10.1002/mrm.29091] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2021] [Revised: 10/28/2021] [Accepted: 11/01/2021] [Indexed: 12/15/2022]
Abstract
PURPOSE To develop a simultaneous T1 , T2 , and T1ρ cardiac magnetic resonance fingerprinting (MRF) approach to enable comprehensive contrast agent-free myocardial tissue characterization in a single breath-hold scan. METHODS A 2D gradient-echo electrocardiogram-triggered cardiac MRF sequence with low flip angles, varying magnetization preparation, and spiral trajectory was acquired at 1.5 T to encode T1 , T2 , and T1⍴ simultaneously. The MRF images were reconstructed using low-rank inversion, regularized with a multicontrast patch-based higher-order reconstruction. Parametric maps were generated and matched in the singular value domain to extended phase graph-based dictionaries. The proposed approach was tested in phantoms and 10 healthy subjects and compared against conventional methods in terms of coefficients of determination and best fits for the phantom study, and in terms of Bland-Altman agreement, average values and coefficient of variation of T1 , T2 , and T1⍴ for the healthy subjects study. RESULTS The T1 , T2 , and T1⍴ MRF values showed excellent correlation with conventional spin-echo and clinical mapping methods in phantom studies (r2 > 0.97). Measured MRF values in myocardial tissue (mean ± SD) were 1133 ± 33 ms, 38.8 ± 3.5 ms, and 52.0 ± 4.0 ms for T1 , T2 and T1⍴ , respectively, against 1053 ± 47 ms, 50.4 ± 3.9 ms, and 55.9 ± 3.3 ms for T1 modified Look-Locker inversion imaging, T2 gradient and spin echo, and T1⍴ turbo field echo, respectively. CONCLUSION A cardiac MRF approach for simultaneous quantification of myocardial T1 , T2 , and T1ρ in a single breath-hold MR scan of about 16 seconds has been proposed. The approach has been investigated in phantoms and healthy subjects showing good agreement with reference spin echo measurements and conventional clinical maps.
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Affiliation(s)
- Carlos Velasco
- School of Biomedical Engineering and Imaging Sciences, King's College London, London, United Kingdom
| | - Gastão Cruz
- School of Biomedical Engineering and Imaging Sciences, King's College London, London, United Kingdom
| | - Begoña Lavin
- School of Biomedical Engineering and Imaging Sciences, King's College London, London, United Kingdom.,Department of Biochemistry and Molecular Biology, School of Chemistry, Complutense University of Madrid, Madrid, Spain
| | - Alina Hua
- School of Biomedical Engineering and Imaging Sciences, King's College London, London, United Kingdom
| | - Anastasia Fotaki
- School of Biomedical Engineering and Imaging Sciences, King's College London, London, United Kingdom
| | - René M Botnar
- School of Biomedical Engineering and Imaging Sciences, King's College London, London, United Kingdom.,School of Engineering, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Claudia Prieto
- School of Biomedical Engineering and Imaging Sciences, King's College London, London, United Kingdom.,School of Engineering, Pontificia Universidad Católica de Chile, Santiago, Chile
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13
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Pang Y, Palmieri-Smith RM, Maerz T. An efficient R 1ρ dispersion imaging method for human knee cartilage using constant magnetization prepared turbo-FLASH. NMR IN BIOMEDICINE 2021; 34:e4500. [PMID: 33675138 PMCID: PMC8122047 DOI: 10.1002/nbm.4500] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/06/2020] [Revised: 02/12/2021] [Accepted: 02/14/2021] [Indexed: 05/10/2023]
Abstract
This work aimed to develop an efficient R1ρ dispersion imaging method for clinical studies of human knee cartilage at 3 T. Eight constant magnetizations (Mprep ) were prepared by tailoring both the duration and amplitude (ω1 ) of a fully refocused spin-lock preparation pulse. The limited Mprep dynamic range was expanded by the measure, equivalent to that with ω1 = ∞, from the magic angle location in the deep femoral cartilage. The developed protocol with Mprep = 60% was demonstrated on one subject's bilateral and two subjects' unilateral asymptomatic knees. The repeatability of the proposed protocol was estimated by two repeated scans with a three-month gap for the last two subjects. The synthetic R1ρ and R2 derived from R1ρ dispersions were compared with the published references using state-of-the-art R1ρ and R2 mapping (MAPSS). The proposed protocol demonstrated good (<5%) repeatability quantified by the intra- and intersubject coefficients of variation in the femoral and tibial cartilage. The synthetic R1ρ (1/s) and the references were comparable in the femoral (23.0 ± 5.3 versus 24.1 ± 3.8, P = 0.67) and the tibial (29.1 ± 8.8 versus 27.1 ± 5.1, P = 0.62), but not the patellar (16.5 ± 4.9 versus 22.7 ± 1.6, P < 0.01) cartilage. The same trends were also observed for the current and the previous R2 . In conclusion, the developed R1ρ dispersion imaging scheme has been revealed to be not only efficient but also robust for clinical studies of human knee cartilage at 3 T.
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Affiliation(s)
- Yuxi Pang
- Department of Radiology, University of Michigan, Ann Arbor, Michigan, USA
| | - Riann M. Palmieri-Smith
- School of Kinesiology, University of Michigan, Ann Arbor, Michigan, USA
- Department of Orthopaedic Surgery, University of Michigan, Ann Arbor, Michigan, USA
| | - Tristan Maerz
- Department of Orthopaedic Surgery, University of Michigan, Ann Arbor, Michigan, USA
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14
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Sharafi A, Medina K, Zibetti MWV, Rao S, Cloos MA, Brown R, Regatte RR. Simultaneous T 1 , T 2 , and T 1ρ relaxation mapping of the lower leg muscle with MR fingerprinting. Magn Reson Med 2021; 86:372-381. [PMID: 33554369 DOI: 10.1002/mrm.28704] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2020] [Revised: 12/31/2020] [Accepted: 01/09/2021] [Indexed: 12/12/2022]
Abstract
PURPOSE To develop a novel MR-fingerprinting (MRF) pulse sequence that is insensitive to B 1 + and B0 imperfections for simultaneous T1 , T2 , and T1ρ relaxation mapping. METHODS We implemented a totally balanced spin-lock (TB-SL) module to encode T1ρ relaxation into an existing MRF framework that encoded T1 and T2 . The spin-lock module used two 180° pulses with compensatory phases to reduce T1ρ sensitivity to B1 and B0 inhomogeneities. We compared T1ρ measured using TB-SL MRF in Bloch simulations, model agar phantoms, and in vivo experiments to those with a self-compensated spin-lock preparation module (SC-SL). The TB-SL MRF repeatability was evaluated in maps acquired in the lower leg skeletal muscle of 12 diabetic peripheral neuropathy patients, scanned two times each during visits separated by about 30 days. RESULTS The phantom relaxation times measured with TB-SL and SC-SL MRF were in good agreement with reference values in regions with low B1 inhomogeneities. Compared with SC-SL, TB-SL MRF showed in experiments greater robustness against severe B1 inhomogeneities and in Bloch simulations greater robustness against B1 and B0 . We measured with TB-SL MRF an average T1 = 950.1 ± 28.7 ms, T2 = 26.0 ± 1.2 ms, and T1ρ = 31.7 ± 3.2 ms in skeletal muscle across patients. Bland-Altman analysis demonstrated low bias between TB-SL and SC-SL MRF and between TB-SL MRF maps acquired in two visits. The coefficient of variation was less than 3% for all measurements. CONCLUSION The proposed TB-SL MRF sequence is fast and insensitive to B 1 + and B0 imperfections. It can simultaneously map T1 , T2 , T1ρ , and B 1 + in a single scan and can potentially be used to study muscle composition.
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Affiliation(s)
- Azadeh Sharafi
- Bernard and Irene Schwartz Center for Biomedical Imaging, Department of Radiology, New York University Grossman School of Medicine, New York, New York, USA
| | - Katherine Medina
- Bernard and Irene Schwartz Center for Biomedical Imaging, Department of Radiology, New York University Grossman School of Medicine, New York, New York, USA
| | - Marcelo W V Zibetti
- Bernard and Irene Schwartz Center for Biomedical Imaging, Department of Radiology, New York University Grossman School of Medicine, New York, New York, USA
| | - Smita Rao
- Department of Physical Therapy, New York University, New York, New York, USA
| | - Martijn A Cloos
- Center of Advanced Imaging, University of Queensland, Brisbane, Australia
| | - Ryan Brown
- Bernard and Irene Schwartz Center for Biomedical Imaging, Department of Radiology, New York University Grossman School of Medicine, New York, New York, USA.,Center for Advanced Imaging Innovation and Research, Department of Radiology, New York University Grossman School of Medicine, New York, New York, USA.,Vilcek Institute of Graduate Biomedical Sciences, New York University Grossman School of Medicine, New York, New York, USA
| | - Ravinder R Regatte
- Bernard and Irene Schwartz Center for Biomedical Imaging, Department of Radiology, New York University Grossman School of Medicine, New York, New York, USA.,Center for Advanced Imaging Innovation and Research, Department of Radiology, New York University Grossman School of Medicine, New York, New York, USA.,Vilcek Institute of Graduate Biomedical Sciences, New York University Grossman School of Medicine, New York, New York, USA
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15
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Sogabe T, Ueda H, Ito Y, Taniguchi Y, Kobayashi T. Dependence of stimulus-induced rotary saturation on the direction of target oscillating magnetic fields: A phantom and simulation study. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2020; 321:106849. [PMID: 33128915 DOI: 10.1016/j.jmr.2020.106849] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/15/2020] [Revised: 09/23/2020] [Accepted: 10/09/2020] [Indexed: 06/11/2023]
Abstract
Several noninvasive techniques for the direct measurement of the neuronal activity using magnetic resonance imaging (MRI) have recently been reported. As a promising candidate, we focus on a spin-lock MRI sequence (i.e., stimulus-induced rotary saturation (SIRS)) directly measuring a tiny oscillating magnetic field. Previous phantom studies on SIRS have applied the target oscillating magnetic field parallel to the direction of the static magnetic field B0. However, in practice, the neuromagnetic fields are not always aligned in the same direction as in such a condition. This study investigates the MR signal changes during SIRS when the target magnetic field direction is not the same as that of the B0 field through both phantom experiments and Bloch simulations. The experimental results indicate that only the target magnetic field component along the B0 field affects the signal change, indicating that SIRS has partial sensitivity, even if the target magnetic fields are tilted from the B0 field. Furthermore, the simulation results show good agreements with the experimental results. These results clarify the sensitivity direction of SIRS-based fMRI and lead to the possibility that the direction of the generated neuromagnetic fields can be estimated, such that we can separate directional information from the other information contained in neuromagnetic fields (e.g., phase information).
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Affiliation(s)
- Tomoyuki Sogabe
- Department of Electrical Engineering, Graduate School of Engineering, Kyoto University, Kyoto-daigaku Katsura, Nishikyo-ku, Kyoto 615-8510, Japan
| | - Hiroyuki Ueda
- Department of Electrical Engineering, Graduate School of Engineering, Kyoto University, Kyoto-daigaku Katsura, Nishikyo-ku, Kyoto 615-8510, Japan
| | - Yosuke Ito
- Department of Electrical Engineering, Graduate School of Engineering, Kyoto University, Kyoto-daigaku Katsura, Nishikyo-ku, Kyoto 615-8510, Japan
| | - Yo Taniguchi
- Research & Development Group, Hitachi, Ltd., Japan
| | - Tetsuo Kobayashi
- Department of Electrical Engineering, Graduate School of Engineering, Kyoto University, Kyoto-daigaku Katsura, Nishikyo-ku, Kyoto 615-8510, Japan.
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16
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Multi-vendor multi-site T 1ρ and T 2 quantification of knee cartilage. Osteoarthritis Cartilage 2020; 28:1539-1550. [PMID: 32739341 PMCID: PMC8094841 DOI: 10.1016/j.joca.2020.07.005] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Revised: 07/03/2020] [Accepted: 07/22/2020] [Indexed: 02/02/2023]
Abstract
OBJECTIVE To develop 3D T1ρ and T2 imaging based on the same sequence structure on MR systems from multiple vendors, and to evaluate intra-site repeatability and inter-site inter-vendor reproducibility of T1ρ and T2 measurements of knee cartilage. METHODS 3D magnetization-prepared angle-modulated partitioned k-space spoiled gradient echo snapshots (3D MAPSS) were implemented on MR systems from Siemens, GE and Philips. Phantom and human subject data were collected at four sites using 3T MR systems from the three vendors with harmonized protocols. Phantom data were collected by means of different positioning of the coil. Volunteers were scanned and rescanned after repositioning. Two traveling volunteers were scanned at all sites. Data were transferred to one site for centralized processing. RESULTS Intra-site average coefficient of variations (CVs) ranged from 1.09% to 3.05% for T1ρ and 1.78-3.30% for T2 in phantoms, and 1.60-3.93% for T1ρ and 1.44-4.08% for T2 in volunteers. Inter-site average CVs were 5.23% and 6.45% for MAPSS T1ρ and T2, respectively in phantoms, and 8.14% and 10.06% for MAPSS T1ρ and T2, respectively, In volunteers. CONCLUSION This study showed promising results of multi-site, multi-vendor reproducibility of T1ρ and T2 values in knee cartilage. These quantitative measures may be applied in large-scale multi-site, multi-vendor trials with controlled sequence structure and scan parameters and centralized data processing.
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17
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Gram M, Seethaler M, Gensler D, Oberberger J, Jakob PM, Nordbeck P. Balanced spin-lock preparation for B 1 -insensitive and B 0 -insensitive quantification of the rotating frame relaxation time T 1ρ. Magn Reson Med 2020; 85:2771-2780. [PMID: 33166009 DOI: 10.1002/mrm.28585] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2020] [Revised: 09/04/2020] [Accepted: 10/13/2020] [Indexed: 01/04/2023]
Abstract
PURPOSE Accurate and artifact-free T1ρ quantification is still a major challenge due to a susceptibility of the spin-locking module to B0 and/or B1 field inhomogeneities. In this study, we present a novel spin-lock preparation module (B-SL) that enables an almost full compensation of both types of inhomogeneities. METHODS The new B-SL module contains a second 180° refocusing pulse to compensate each pulse in the preparation block by a corresponding pulse with opposite phase. For evaluation and validation of B-SL, extensive simulations as well as phantom measurements were performed. Furthermore, the new module was compared to three common established compensation methods. RESULTS Both simulations and measurements demonstrate a much lower susceptibility to artifacts for the B-SL module, therefore providing an improved accuracy in T1ρ quantification. In the presence of field inhomogeneities, measurements revealed an increased banding compensation by 79% compared with the frequently used composite module. The goodness of the mono-exponential T1ρ fitting procedure was improved by 58%. CONCLUSION The B-SL preparation enables the generation of accurate relaxation maps with significantly reduced artifacts, even in the case of large field imperfections. Therefore, the B-SL module is suggested to be highly beneficial for in vivo T1ρ quantification.
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Affiliation(s)
- Maximilian Gram
- Department of Internal Medicine I, University Hospital Würzburg, Würzburg, Germany.,Experimental Physics 5, University of Würzburg, Würzburg, Germany
| | - Michael Seethaler
- Experimental Physics 5, University of Würzburg, Würzburg, Germany.,Comprehensive Heart Failure Center, University Hospital Würzburg, Würzburg, Germany
| | - Daniel Gensler
- Department of Internal Medicine I, University Hospital Würzburg, Würzburg, Germany.,Comprehensive Heart Failure Center, University Hospital Würzburg, Würzburg, Germany
| | - Johannes Oberberger
- Department of Internal Medicine I, University Hospital Würzburg, Würzburg, Germany
| | - Peter M Jakob
- Experimental Physics 5, University of Würzburg, Würzburg, Germany
| | - Peter Nordbeck
- Department of Internal Medicine I, University Hospital Würzburg, Würzburg, Germany.,Comprehensive Heart Failure Center, University Hospital Würzburg, Würzburg, Germany
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18
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Watkins LE, Rubin EB, Mazzoli V, Uhlrich SD, Desai AD, Black M, Ho GK, Delp SL, Levenston ME, Beaupré GS, Gold GE, Kogan F. Rapid volumetric gagCEST imaging of knee articular cartilage at 3 T: evaluation of improved dynamic range and an osteoarthritic population. NMR IN BIOMEDICINE 2020; 33:e4310. [PMID: 32445515 PMCID: PMC7347437 DOI: 10.1002/nbm.4310] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/16/2020] [Revised: 03/03/2020] [Accepted: 03/20/2020] [Indexed: 05/22/2023]
Abstract
Chemical exchange saturation transfer of glycosaminoglycans, gagCEST, is a quantitative MR technique that has potential for assessing cartilage proteoglycan content at field strengths of 7 T and higher. However, its utility at 3 T remains unclear. The objective of this work was to implement a rapid volumetric gagCEST sequence with higher gagCEST asymmetry at 3 T to evaluate its sensitivity to osteoarthritic changes in knee articular cartilage and in comparison with T2 and T1ρ measures. We hypothesize that gagCEST asymmetry at 3 T decreases with increasing severity of osteoarthritis (OA). Forty-two human volunteers, including 10 healthy subjects and 32 subjects with medial OA, were included in the study. Knee Injury and Osteoarthritis Outcome Scores (KOOS) were assessed for all subjects, and Kellgren-Lawrence grading was performed for OA volunteers. Healthy subjects were scanned consecutively at 3 T to assess the repeatability of the volumetric gagCEST sequence at 3 T. For healthy and OA subjects, gagCEST asymmetry and T2 and T1ρ relaxation times were calculated for the femoral articular cartilage to assess sensitivity to OA severity. Volumetric gagCEST imaging had higher gagCEST asymmetry than single-slice acquisitions (p = 0.015). The average scan-rescan coefficient of variation was 6.8%. There were no significant differences in average gagCEST asymmetry between younger and older healthy controls (p = 0.655) or between healthy controls and OA subjects (p = 0.310). T2 and T1ρ relaxation times were elevated in OA subjects (p < 0.001 for both) compared with healthy controls and both were moderately correlated with total KOOS scores (rho = -0.181 and rho = -0.332 respectively). The gagCEST technique developed here, with volumetric scan times under 10 min and high gagCEST asymmetry at 3 T, did not vary significantly between healthy subjects and those with mild-moderate OA. This further supports a limited utility for gagCEST imaging at 3 T for assessment of early changes in cartilage composition in OA.
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Affiliation(s)
| | - Elka B Rubin
- Radiology, Stanford University, Stanford, California, USA
| | | | - Scott D Uhlrich
- Mechanical Engineering, Stanford University, Stanford, California, USA
| | - Arjun D Desai
- Electrical Engineering, Stanford University, Stanford, California, USA
| | - Marianne Black
- Radiology, Stanford University, Stanford, California, USA
- Mechanical Engineering, Stanford University, Stanford, California, USA
| | - Gabe K Ho
- Bioengineering, Stanford University, Stanford, California, USA
| | - Scott L Delp
- Bioengineering, Stanford University, Stanford, California, USA
- Mechanical Engineering, Stanford University, Stanford, California, USA
- Orthopaedic Surgery, Stanford University, Stanford, California, USA
| | - Marc E Levenston
- Bioengineering, Stanford University, Stanford, California, USA
- Mechanical Engineering, Stanford University, Stanford, California, USA
| | - Gary S Beaupré
- Bioengineering, Stanford University, Stanford, California, USA
- Veteran Affairs Palo Alto Health Care System, Palo Alto, California, USA
| | - Garry E Gold
- Bioengineering, Stanford University, Stanford, California, USA
- Radiology, Stanford University, Stanford, California, USA
- Orthopaedic Surgery, Stanford University, Stanford, California, USA
| | - Feliks Kogan
- Radiology, Stanford University, Stanford, California, USA
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19
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Kessler DA, MacKay JW, McDonald S, McDonnell S, Grainger AJ, Roberts AR, Janiczek RL, Graves MJ, Kaggie JD, Gilbert FJ. Effectively Measuring Exercise-Related Variations in T1ρ and T2 Relaxation Times of Healthy Articular Cartilage. J Magn Reson Imaging 2020; 52:1753-1764. [PMID: 32677070 DOI: 10.1002/jmri.27278] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Revised: 06/16/2020] [Accepted: 06/16/2020] [Indexed: 12/25/2022] Open
Abstract
BACKGROUND Determining the compositional response of articular cartilage to dynamic joint-loading using MRI may be a more sensitive assessment of cartilage status than conventional static imaging. However, distinguishing the effects of joint-loading vs. inherent measurement variability remains difficult, as the repeatability of these quantitative methods is often not assessed or reported. PURPOSE To assess exercise-induced changes in femoral, tibial, and patellar articular cartilage composition and compare these against measurement repeatability. STUDY TYPE Prospective observational study. POPULATION Phantom and 19 healthy participants. FIELD STRENGTH/SEQUENCE 3T; 3D fat-saturated spoiled gradient recalled-echo; T1ρ - and T2 -prepared pseudosteady-state 3D fast spin echo. ASSESSMENT The intrasessional repeatability of T1ρ and T2 relaxation mapping, with and without knee repositioning between two successive measurements, was determined in 10 knees. T1ρ and T2 relaxation mapping of nine knees was performed before and at multiple timepoints after a 5-minute repeated, joint-loading stepping activity. 3D surface models were created from patellar, femoral, and tibial articular cartilage. STATISTICAL TESTS Repeatability was assessed using root-mean-squared-CV (RMS-CV). Using Bland-Altman analysis, thresholds defined as the smallest detectable difference (SDD) were determined from the repeatability data with knee repositioning. RESULTS Without knee repositioning, both surface-averaged T1ρ and T2 were very repeatable on all cartilage surfaces, with RMS-CV <1.1%. Repositioning of the knee had the greatest effect on T1ρ of patellar cartilage with the surface-averaged RMS-CV = 4.8%. While T1ρ showed the greatest response to exercise at the patellofemoral cartilage region, the largest changes in T2 were determined in the lateral femorotibial region. Following thresholding, significant (>SDD) average exercise-induced in T1ρ and T2 of femoral (-8.0% and -5.3%), lateral tibial (-6.9% and -5.9%), medial tibial (+5.8% and +2.9%), and patellar (-7.9% and +2.8%) cartilage were observed. DATA CONCLUSION Joint-loading with a stepping activity resulted in T1ρ and T2 changes above background measurement error. EVIDENCE LEVEL 2 TECHNICAL EFFICACY STAGE: 1 J. MAGN. RESON. IMAGING 2020;52:1753-1764.
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Affiliation(s)
| | - James W MacKay
- Department of Radiology, University of Cambridge, UK.,Norwich Medical School, University of East Anglia, Norwich, UK
| | - Scott McDonald
- Cambridge University Hospitals NHS Foundation Trust, Addenbrooke's Hospital, Cambridge, UK
| | - Stephen McDonnell
- Division of Trauma and Orthopaedics, Department of Surgery, University of Cambridge, Cambridge, UK
| | - Andrew J Grainger
- Cambridge University Hospitals NHS Foundation Trust, Addenbrooke's Hospital, Cambridge, UK
| | | | | | - Martin J Graves
- Cambridge University Hospitals NHS Foundation Trust, Addenbrooke's Hospital, Cambridge, UK
| | | | - Fiona J Gilbert
- Department of Radiology, University of Cambridge, UK.,Cambridge University Hospitals NHS Foundation Trust, Addenbrooke's Hospital, Cambridge, UK
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20
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Johnson CP, Thedens DR, Kruger SJ, Magnotta VA. Three-Dimensional GRE T 1ρ mapping of the brain using tailored variable flip-angle scheduling. Magn Reson Med 2020; 84:1235-1249. [PMID: 32052489 DOI: 10.1002/mrm.28198] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2019] [Revised: 01/07/2020] [Accepted: 01/13/2020] [Indexed: 12/26/2022]
Abstract
PURPOSE To introduce a new approach called tailored variable flip-angle (VFA) scheduling for SNR-efficient 3D T1ρ mapping of the brain using a magnetization-prepared gradient-echo sequence. METHODS Simulations were used to assess the relative SNR efficiency, quantitative accuracy, and spatial blurring of tailored VFA scheduling for T1ρ mapping of brain tissue compared with magnetization-prepared angle-modulated partitioned k-space spoiled gradient-echo snapshots (MAPSS), a state-of-the-art technique for accurate 3D gradient-echo T1ρ mapping. Simulations were also used to calculate optimal imaging parameters for tailored VFA scheduling versus MAPSS, without and with nulling of CSF. Four participants were imaged at 3T MRI to demonstrate the feasibility of tailored VFA scheduling for T1ρ mapping of the brain. Using MAPSS as a reference standard, in vivo data were used to validate the relative SNR efficiency and quantitative accuracy of the new approach. RESULTS Tailored VFA scheduling can provide a 2-fold to 4-fold gain in the SNR of the resulting T1ρ map as compared with MAPSS when using identical sequence parameters while limiting T1ρ quantification errors to 2% or less. In vivo whole-brain 3D T1ρ maps acquired with tailored VFA scheduling had superior SNR efficiency than is achievable with MAPSS, and the SNR efficiency improved with a greater number of views per segment. CONCLUSIONS Tailored VFA scheduling is an SNR-efficient GRE technique for 3D T1ρ mapping of the brain that provides increased flexibility in choice of imaging parameters compared with MAPSS, which may benefit a variety of applications.
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Affiliation(s)
- Casey P Johnson
- Veterinary Clinical Sciences Department, University of Minnesota, Saint Paul, MN, USA.,Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, MN, USA
| | | | | | - Vincent A Magnotta
- Department of Radiology, University of Iowa, Iowa City, IA, USA.,Department of Psychiatry, University of Iowa, Iowa City, IA, USA.,Department of Biomedical Engineering, University of Iowa, Iowa City, IA, USA
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21
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Qi H, Bustin A, Kuestner T, Hajhosseiny R, Cruz G, Kunze K, Neji R, Botnar RM, Prieto C. Respiratory motion-compensated high-resolution 3D whole-heart T1ρ mapping. J Cardiovasc Magn Reson 2020; 22:12. [PMID: 32014001 PMCID: PMC6998259 DOI: 10.1186/s12968-020-0597-5] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2019] [Accepted: 01/03/2020] [Indexed: 12/11/2022] Open
Abstract
BACKGROUND Cardiovascular magnetic resonance (CMR) T1ρ mapping can be used to detect ischemic or non-ischemic cardiomyopathy without the need of exogenous contrast agents. Current 2D myocardial T1ρ mapping requires multiple breath-holds and provides limited coverage. Respiratory gating by diaphragmatic navigation has recently been exploited to enable free-breathing 3D T1ρ mapping, which, however, has low acquisition efficiency and may result in unpredictable and long scan times. This study aims to develop a fast respiratory motion-compensated 3D whole-heart myocardial T1ρ mapping technique with high spatial resolution and predictable scan time. METHODS The proposed electrocardiogram (ECG)-triggered T1ρ mapping sequence is performed under free-breathing using an undersampled variable-density 3D Cartesian sampling with spiral-like order. Preparation pulses with different T1ρ spin-lock times are employed to acquire multiple T1ρ-weighted images. A saturation prepulse is played at the start of each heartbeat to reset the magnetization before T1ρ preparation. Image navigators are employed to enable beat-to-beat 2D translational respiratory motion correction of the heart for each T1ρ-weighted dataset, after which, 3D translational registration is performed to align all T1ρ-weighted volumes. Undersampled reconstruction is performed using a multi-contrast 3D patch-based low-rank algorithm. The accuracy of the proposed technique was tested in phantoms and in vivo in 11 healthy subjects in comparison with 2D T1ρ mapping. The feasibility of the proposed technique was further investigated in 3 patients with suspected cardiovascular disease. Breath-hold late-gadolinium enhanced (LGE) images were acquired in patients as reference for scar detection. RESULTS Phantoms results revealed that the proposed technique provided accurate T1ρ values over a wide range of simulated heart rates in comparison to a 2D T1ρ mapping reference. Homogeneous 3D T1ρ maps were obtained for healthy subjects, with septal T1ρ of 58.0 ± 4.1 ms which was comparable to 2D breath-hold measurements (57.6 ± 4.7 ms, P = 0.83). Myocardial scar was detected in 1 of the 3 patients, and increased T1ρ values (87.4 ± 5.7 ms) were observed in the infarcted region. CONCLUSIONS An accelerated free-breathing 3D whole-heart T1ρ mapping technique was developed with high respiratory scan efficiency and near-isotropic spatial resolution (1.7 × 1.7 × 2 mm3) in a clinically feasible scan time of ~ 6 mins. Preliminary patient results suggest that the proposed technique may find applications in non-contrast myocardial tissue characterization.
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Affiliation(s)
- Haikun Qi
- School of Biomedical Engineering and Imaging Sciences, King's College London, 3rd Floor, Lambeth Wing, St Thomas' Hospital, Lambeth Palace Rd, London, SE1 7EH, UK.
| | - Aurelien Bustin
- School of Biomedical Engineering and Imaging Sciences, King's College London, 3rd Floor, Lambeth Wing, St Thomas' Hospital, Lambeth Palace Rd, London, SE1 7EH, UK
| | - Thomas Kuestner
- School of Biomedical Engineering and Imaging Sciences, King's College London, 3rd Floor, Lambeth Wing, St Thomas' Hospital, Lambeth Palace Rd, London, SE1 7EH, UK
| | - Reza Hajhosseiny
- School of Biomedical Engineering and Imaging Sciences, King's College London, 3rd Floor, Lambeth Wing, St Thomas' Hospital, Lambeth Palace Rd, London, SE1 7EH, UK
| | - Gastao Cruz
- School of Biomedical Engineering and Imaging Sciences, King's College London, 3rd Floor, Lambeth Wing, St Thomas' Hospital, Lambeth Palace Rd, London, SE1 7EH, UK
| | - Karl Kunze
- School of Biomedical Engineering and Imaging Sciences, King's College London, 3rd Floor, Lambeth Wing, St Thomas' Hospital, Lambeth Palace Rd, London, SE1 7EH, UK
- Siemens Healthcare, MR Research Collaborations, Frimley, UK
| | - Radhouene Neji
- School of Biomedical Engineering and Imaging Sciences, King's College London, 3rd Floor, Lambeth Wing, St Thomas' Hospital, Lambeth Palace Rd, London, SE1 7EH, UK
- Siemens Healthcare, MR Research Collaborations, Frimley, UK
| | - René M Botnar
- School of Biomedical Engineering and Imaging Sciences, King's College London, 3rd Floor, Lambeth Wing, St Thomas' Hospital, Lambeth Palace Rd, London, SE1 7EH, UK
- Escuela de Ingeniería, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Claudia Prieto
- School of Biomedical Engineering and Imaging Sciences, King's College London, 3rd Floor, Lambeth Wing, St Thomas' Hospital, Lambeth Palace Rd, London, SE1 7EH, UK
- Escuela de Ingeniería, Pontificia Universidad Católica de Chile, Santiago, Chile
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22
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Ponto LLB, Magnotta VA, Menda Y, Moser DJ, Oleson JJ, Harlynn EL, DeVries SD, Wemmie JA, Schultz SK. Comparison of T 1Rho MRI, Glucose Metabolism, and Amyloid Burden Across the Cognitive Spectrum: A Pilot Study. J Neuropsychiatry Clin Neurosci 2020; 32:352-361. [PMID: 32283991 PMCID: PMC8717916 DOI: 10.1176/appi.neuropsych.19100221] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
OBJECTIVE The pathological cascades associated with the development of Alzheimer's disease (AD) have a common element: acidosis. T1rho MRI is a pH-sensitive measure, with higher values associated with greater neuropathological burden. The authors investigated the relationship between T1rho imaging and AD-associated pathologies as determined by available diagnostic imaging techniques. METHODS Twenty-seven participants (men, N=13, women, N=14; ages 55-90) across the cognitive spectrum (healthy control subjects [HCs] with normal cognition, N=17; participants with mild cognitive impairment [MCI], N=7; participants with mild AD, N=3) underwent neuropsychological testing, MRI (T1-weighted and T1rho [spin-lattice relaxation time in the rotating frame]), and positron emission tomography imaging ([11C]Pittsburg compound B for amyloid burden [N=26] and [18F]fluorodeoxyglucose for cerebral glucose metabolism [N=12]). The relationships between global T1rho values and neuropsychological, demographic, and imaging measures were explored. RESULTS Global mean and median T1rho were positively associated with age. After controlling for age, higher global T1rho was associated with poorer cognitive function, poorer memory function (immediate and delayed memory scores), higher amyloid burden, and more abnormal cerebral glucose metabolism. Regional T1rho values, when controlling for age, significantly differed between HCs and participants with MCI or AD in select frontal, cingulate, and parietal regions. CONCLUSIONS Higher T1rho values were associated with greater cognitive impairment and pathological burden. T1rho, a biomarker that varies according to a feature common to each cascade rather than one that is unique to a particular pathology, has the potential to serve as a metric of neuropathology, theoretically providing a measure for assessing pathological status and for monitoring the neurodegeneration trajectory.
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Affiliation(s)
| | - Vincent A. Magnotta
- Department of Radiology, Carver College of Medicine, University of Iowa,Department of Psychiatry, Carver College of Medicine, University of Iowa
| | - Yusuf Menda
- Department of Radiology, Carver College of Medicine, University of Iowa
| | - David J. Moser
- Department of Psychiatry, Carver College of Medicine, University of Iowa
| | - Jacob J. Oleson
- Department of Biostatistics, College of Public Health, University of Iowa
| | - Emily L. Harlynn
- Department of Radiology, Carver College of Medicine, University of Iowa
| | - Sean D. DeVries
- Department of Biostatistics, College of Public Health, University of Iowa
| | - John A. Wemmie
- Department of Psychiatry, Carver College of Medicine, University of Iowa
| | - Susan K. Schultz
- Department of Psychiatry, Carver College of Medicine, University of Iowa
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23
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Nathani A, Gold GE, Monu U, Hargreaves B, Finlay AK, Rubin EB, Safran MR. Does Injection of Hyaluronic Acid Protect Against Early Cartilage Injury Seen After Marathon Running? A Randomized Controlled Trial Utilizing High-Field Magnetic Resonance Imaging. Am J Sports Med 2019; 47:3414-3422. [PMID: 31634003 DOI: 10.1177/0363546519879138] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
BACKGROUND Previous studies have shown that runners demonstrate elevated T2 and T1ρ values on magnetic resonance imaging (MRI) after running a marathon, with the greatest changes in the patellofemoral and medial compartment, which can persist after 3 months of reduced activity. Additionally, marathon running has been shown to increase serum inflammatory markers. Hyaluronic acid (HA) purportedly improves viscoelasticity of synovial fluid, serving as a lubricant while also having chondroprotective and anti-inflammatory effects. PURPOSE/HYPOTHESIS The purpose was to investigate whether intra-articular HA injection can protect articular cartilage from injury attributed to marathon running. The hypothesis was that the addition of intra-articular HA 1 week before running a marathon would reduce the magnitude of early cartilage breakdown measured by MRI. STUDY DESIGN Randomized controlled trial; Level of evidence, 2. METHODS After institutional review board approval, 20 runners were randomized into receiving an intra-articular injection of HA or normal saline (NS) 1 week before running a marathon. Exclusionary criteria included any prior knee injury or surgery and having run >3 prior marathons. Baseline 3-T knee MRI was obtained within 48 hours before the marathon (approximately 5 days after injection). Follow-up 3-T MRI scans of the same knee were obtained 48 to 72 hours and 3 months after the marathon. The T2 and T1ρ relaxation times of articular cartilage were measured in 8 locations-the medial and lateral compartments (including 2 areas of each femoral condyle) and the patellofemoral joint. The statistical analysis compared changes in T2 and T1ρ relaxation times (ms) from baseline to immediate and 3-month postmarathon scans between the HA and NS groups with repeated measures analysis of variance. RESULTS Fifteen runners completed the study: 6 women and 2 men in the HA group (mean age, 31 years; range, 23-50 years) and 6 women and 1 man in the NS group (mean age, 27 years; range, 20-49 years). There were no gross morphologic MRI changes after running the marathon. Postmarathon studies revealed no statistically significant changes between the HA and NS groups in all articular cartilage areas of the knee on both T2 and T1ρ relaxation times. CONCLUSION Increased T2 and T1ρ relaxation times have been observed in marathon runners, suggesting early cartilage injury. The addition of intra-articular HA did not significantly affect relaxation times in all areas of the knee when compared with an NS control.
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Affiliation(s)
- Amit Nathani
- Department of Orthopaedic Surgery, Sports Medicine and Shoulder Surgery, Stanford University, Redwood City, California, USA
| | - Garry E Gold
- Department of Orthopaedic Surgery, Sports Medicine and Shoulder Surgery, Stanford University, Redwood City, California, USA.,Department of Radiology, Stanford University, Stanford, California, USA.,Department of Bioengineering, Stanford University, Stanford, California, USA
| | - Uchechukwuka Monu
- Department of Bioengineering, Stanford University, Stanford, California, USA
| | - Brian Hargreaves
- Department of Radiology, Stanford University, Stanford, California, USA.,Department of Bioengineering, Stanford University, Stanford, California, USA
| | - Andrea K Finlay
- Department of Orthopaedic Surgery, Sports Medicine and Shoulder Surgery, Stanford University, Redwood City, California, USA
| | - Elka B Rubin
- Department of Radiology, Stanford University, Stanford, California, USA
| | - Marc R Safran
- Department of Orthopaedic Surgery, Sports Medicine and Shoulder Surgery, Stanford University, Redwood City, California, USA
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24
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Zhu Y, Liu Y, Ying L, Liu X, Zheng H, Liang D. Bio-SCOPE: fast biexponential T 1ρ mapping of the brain using signal-compensated low-rank plus sparse matrix decomposition. Magn Reson Med 2019; 83:2092-2106. [PMID: 31762102 DOI: 10.1002/mrm.28067] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2019] [Revised: 09/28/2019] [Accepted: 10/14/2019] [Indexed: 12/15/2022]
Abstract
PURPOSE To develop and evaluate a fast imaging method based on signal-compensated low-rank plus sparse matrix decomposition to accelerate data acquisition for biexponential brain T1ρ mapping (Bio-SCOPE). METHODS Two novel strategies were proposed to improve reconstruction performance. A variable-rate undersampling scheme was used with a varied acceleration factor for each k-space along the spin-lock time direction, and a modified nonlinear thresholding scheme combined with a feature descriptor was used for Bio-SCOPE reconstruction. In vivo brain T1ρ mappings were acquired from 4 volunteers. The fully sampled k-space data acquired from 3 volunteers were retrospectively undersampled by net acceleration rates (R) of 4.6 and 6.1. Reference values were obtained from the fully sampled data. The agreement between the accelerated T1ρ measurements and reference values was assessed with Bland-Altman analyses. Prospectively undersampled data with R = 4.6 and R = 6.1 were acquired from 1 volunteer. RESULTS T1ρ -weighted images were successfully reconstructed using Bio-SCOPE for R = 4.6 and 6.1 with signal-to-noise ratio variations <1 dB and normalized root mean square errors <4%. Accelerated and reference T1ρ measurements were in good agreement for R = 4.6 (T1ρ s : 18.6651 ± 1.7786 ms; T1ρ l : 88.9603 ± 1.7331 ms) and R = 6.1 (T1ρ s : 17.8403 ± 3.3302 ms; T1ρ l : 88.0275 ± 4.9606 ms) in the Bland-Altman analyses. T1ρ parameter maps from prospectively undersampled data also show reasonable image quality using the Bio-SCOPE method. CONCLUSION Bio-SCOPE achieves a high net acceleration rate for biexponential T1ρ mapping and improves reconstruction quality by using a variable-rate undersampling data acquisition scheme and a modified soft-thresholding algorithm in image reconstruction.
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Affiliation(s)
- Yanjie Zhu
- Paul C. Lauterbur Research Centre for Biomedical Imaging, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
| | - Yuanyuan Liu
- Paul C. Lauterbur Research Centre for Biomedical Imaging, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China.,University of Chinese Academy of Sciences, Beijing, China.,Shenzhen College of Advanced Technology, University of Chinese Academy of Sciences, Shenzhen, China
| | - Leslie Ying
- Department of Biomedical Engineering and Department of Electrical Engineering, University at Buffalo, The State University of New York, Buffalo, New York
| | - Xin Liu
- Paul C. Lauterbur Research Centre for Biomedical Imaging, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
| | - Hairong Zheng
- Paul C. Lauterbur Research Centre for Biomedical Imaging, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
| | - Dong Liang
- Paul C. Lauterbur Research Centre for Biomedical Imaging, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
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25
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Sharafi A, Baboli R, Zibetti M, Shanbhogue K, Olsen S, Block T, Chandarana H, Regatte R. Volumetric multicomponent T 1ρ relaxation mapping of the human liver under free breathing at 3T. Magn Reson Med 2019; 83:2042-2050. [PMID: 31724246 DOI: 10.1002/mrm.28061] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2019] [Revised: 10/10/2019] [Accepted: 10/11/2019] [Indexed: 12/16/2022]
Abstract
PURPOSE To develop a 3D sequence for T1ρ relaxation mapping using radial volumetric encoding (3D-T1ρ -RAVE) and to evaluate the multi relaxation components in the liver of healthy controls and chronic liver disease (CLD) patients. METHODS Fat saturation and T1ρ preparation modules were followed by a train of gradient-echo acquisitions and T1 restoration delay. The series of T1ρ -weighted images were fitted using mono-exponential, bi-exponential, and stretched-exponential models. The repeatability and reproducibility of the proposed technique were evaluated on National Institute of Standards and Technology phantom by calculating the coefficient of variation between test-retest scans on the same scanner and between two different 3T scanners, respectively. Mann-Whitney U-test was performed to assess differences in T1ρ components among patients (n = 3) and a control group (n = 10). RESULTS The phantom study showed an error of 8.9% and 11.5% in mono T2 relaxation time measurement relative to the reference on 2 different scanners. The coefficient of variation for test-retest scans performed on the same scanner was 5.7% and 2.4% for scans performed on 2 scanners. The comparison between healthy controls and CLD patients showed a significant difference (P < .05) in mono relaxation time (P = .002), stretched-exponential relaxation parameter (P = .04). The Akaike information criteria C criterion showed 2.53 ± 0.9% (2.3 ± 0.3% for CLD) of the voxels are bi-exponential while in 65.3 ± 5.8% (81.2 ± 0.06% for CLD) of the liver voxels, the stretched-exponential model was preferred. CONCLUSION The 3D-T1ρ -RAVE sequence allows volumetric, multicomponent T1ρ assessment of the liver during free breathing and can distinguish between healthy volunteers and CLD patients.
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Affiliation(s)
- Azadeh Sharafi
- Department of Radiology, New York University School of Medicine, New York, New York
| | - Rahman Baboli
- Department of Radiology, New York University School of Medicine, New York, New York
| | - Marcelo Zibetti
- Department of Radiology, New York University School of Medicine, New York, New York
| | - Krishna Shanbhogue
- Department of Radiology, New York University School of Medicine, New York, New York
| | - Sonja Olsen
- Department of Medicine, New York University School of Medicine, New York, New York
| | - Tobias Block
- Department of Radiology, New York University School of Medicine, New York, New York.,Department of Radiology, University Hospital Basel, Basel, Switzerland
| | - Hersh Chandarana
- Department of Radiology, New York University School of Medicine, New York, New York
| | - Ravinder Regatte
- Department of Radiology, New York University School of Medicine, New York, New York
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26
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Pang Y. An order parameter without magic angle effect (OPTIMA) derived from R 1 ρ dispersion in ordered tissue. Magn Reson Med 2019; 83:1783-1795. [PMID: 31691348 DOI: 10.1002/mrm.28045] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2019] [Revised: 09/26/2019] [Accepted: 09/27/2019] [Indexed: 12/25/2022]
Abstract
PURPOSE MR R2 imaging of ordered tissue exhibits the magic angle effect, potentially masking subtle pathological changes in cartilage. This work aimed to develop an orientation-independent order parameter (S) exclusively sensitive to collagen degeneration. METHODS A theory was developed based on R 1 ρ dispersion coupled with a simplified molecular motion model in which anisotropic R 2 a ( θ ) became directly proportional to correlation time τ b θ and S could be derived. This new parameter was validated with ex vivo R 1 ρ dispersion reported on orientated (n = 4), enzymatically depleted bovine cartilage (n = 6), and osteoarthritic human knee specimens (n = 14) at 9.4 Tesla, which was further demonstrated on 1 healthy human knee in vivo at 3 Tesla. RESULTS τ b θ from orientation-dependent R 1 ρ dispersion revealed a significantly high average correlation (r = 0.89 ± 0.05, P < 0.05) with R 2 a (θ) on cartilage samples and a moderate correlation (r = 0.48, P < 0.001) for the human knee in vivo. The derived S (10-3 ) significantly decreased in advanced osteoarthritis (1.64 ± 0.03 vs. 2.30 ± 0.11, P < 0.001) and collagen-depleted samples (1.30 ± 0.11 vs. 2.12 ± 0.12, P < 0.001) when compared with early osteoarthritis and the control, respectively. CONCLUSION The proposed order parameter could be a potentially useful orientation-independent MR biomarker for collagen alterations in cartilage and other highly structured tissues.
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Affiliation(s)
- Yuxi Pang
- Department of Radiology, University of Michigan, Ann Arbor, Michigan
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27
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Chen W, Karampinos DC. Chemical-shift encoding-based water-fat separation with multifrequency fat spectrum modeling in spin-lock MRI. Magn Reson Med 2019; 83:1608-1624. [PMID: 31592557 DOI: 10.1002/mrm.28026] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2019] [Revised: 08/18/2019] [Accepted: 09/09/2019] [Indexed: 01/19/2023]
Abstract
PURPOSE Chemical exchange saturation transfer is used commonly to generate MRI contrast based on the chemical exchange effect. The spin-lock techniques can also be used to probe the chemical exchange and other molecular motion processes in tissues. The presence of fat can cause errors in spin-lock MRI. Signals from fat are typically suppressed based on spectral selectivity or T1 nulling approaches in spin-lock imaging. However, these methods cannot be used to suppress fat signals from multiple fat peaks. To address this problem, we report chemical-shift encoding-based water-fat separation approaches with multifrequency fat spectrum modeling. METHODS Both the conventional spin-lock and the adiabatic continuous-wave constant-amplitude spin lock (ACCSL) with multi-echo acquisitions are investigated for chemical-shift encoding-based water-fat separation in spin-lock imaging. A comparison is made of reconstructions based on 3 models: a single-peak fat spectrum model, a standard precalibrated proton density 6-peak fat spectrum model, and the self-calibrated relaxation-dependent 3-peak fat spectrum model. Comparisons were performed using Bloch simulations, phantom, and in vivo experiments at 3 T. RESULTS Conventional spin-lock acquisitions cannot be used for reliable water-fat separation with a multipeak fat spectrum model. Water-fat separation based on ACCSL acquisitions achieves superior performance compared with the use of conventional spin-lock acquisitions. The best result is achieved from ACCSL acquisition with self-calibrated relaxation-dependent multipeak fat spectrum modeling. CONCLUSION The ACCSL acquisition can be used for chemical-shift encoding-based water-fat separation with multipeak fat spectrum modeling. This approach has the potential to improve quantitative analysis using spin-lock MRI for assessing the biochemical properties of tissues.
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Affiliation(s)
- Weitian Chen
- Department of Imaging and Interventional Radiology, the Chinese University of Hong Kong, Shatin, Hong Kong SAR, China
| | - Dimitrios C Karampinos
- Department of Diagnostic and Interventional Radiology, Technical University of Munich, Munich, Germany
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28
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Keeler EG, Fritzsching KJ, McDermott AE. Refocusing CSA during magic angle spinning rotating-frame relaxation experiments. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2018; 296:130-137. [PMID: 30253322 PMCID: PMC6512962 DOI: 10.1016/j.jmr.2018.09.004] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/06/2018] [Revised: 09/10/2018] [Accepted: 09/12/2018] [Indexed: 05/27/2023]
Abstract
We examine coherent evolution of spin-locked magnetization during magic-angle spinning (MAS), in the context of relaxation experiments designed to probe chemical exchange (rotating-frame relaxation (R1ρ)). Coherent evolution is expected in MAS based rotating-frame relaxation decay experiments if matching conditions are met (such as, ω1 = nωr) and if the chemical shielding anisotropy (CSA) is substantial. We show here using numerical simulations and experiments that even when such matching requirements are avoided (e.g., ω1 < 0.5ωr, ∼1.5ωr, >2.5ωr), coherent evolution of spin-locked magnetization with large CSA is still considerable. The coherent evolution has important consequences on the analysis of relaxation decay and the ability to extract accurate information of interest about dynamics. We present a pulse sequence that employs rotary echoes and refocuses CSA contributions, allowing for more sensitive measurement of rotating-frame relaxation with less interference from coherent evolution. In practice, the proposed pulse sequence, REfocused CSA Rotating-frame Relaxation (RECRR) is robust to carrier frequency offset, B1-field inhomogeneity, and slight miscalibrations of the refocusing pulses.
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Affiliation(s)
- Eric G Keeler
- Department of Chemistry, Columbia University, New York, NY 10027, United States
| | - Keith J Fritzsching
- Department of Chemistry, Columbia University, New York, NY 10027, United States
| | - Ann E McDermott
- Department of Chemistry, Columbia University, New York, NY 10027, United States.
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29
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Herz K, Gandhi C, Schuppert M, Deshmane A, Scheffler K, Zaiss M. CEST imaging at 9.4 T using adjusted adiabatic spin-lock pulses for on- and off-resonant T1⍴-dominated Z-spectrum acquisition. Magn Reson Med 2018; 81:275-290. [DOI: 10.1002/mrm.27380] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2018] [Revised: 04/08/2018] [Accepted: 05/08/2018] [Indexed: 12/18/2022]
Affiliation(s)
- Kai Herz
- Magnetic Resonance Center, Max Planck Institute for Biological Cybernetics; Tuebingen Germany
- IMPRS for Cognitive and Systems Neuroscience; University of Tuebingen; Tuebingen Germany
| | - Chirayu Gandhi
- Magnetic Resonance Center, Max Planck Institute for Biological Cybernetics; Tuebingen Germany
| | - Mark Schuppert
- Magnetic Resonance Center, Max Planck Institute for Biological Cybernetics; Tuebingen Germany
| | - Anagha Deshmane
- Magnetic Resonance Center, Max Planck Institute for Biological Cybernetics; Tuebingen Germany
| | - Klaus Scheffler
- Magnetic Resonance Center, Max Planck Institute for Biological Cybernetics; Tuebingen Germany
- Department of Biomedical Magnetic Resonance; University of Tuebingen; Tuebingen Germany
| | - Moritz Zaiss
- Magnetic Resonance Center, Max Planck Institute for Biological Cybernetics; Tuebingen Germany
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30
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Jiang B, Chen W. On-resonance and off-resonance continuous wave constant amplitude spin-lock and T 1ρ quantification in the presence of B 1 and B 0 inhomogeneities. NMR IN BIOMEDICINE 2018; 31:e3928. [PMID: 29693744 DOI: 10.1002/nbm.3928] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/22/2017] [Revised: 02/06/2018] [Accepted: 03/06/2018] [Indexed: 06/08/2023]
Abstract
Spin-lock MRI is a valuable diagnostic imaging technology, as it can be used to probe the macromolecule environment of tissues. Quantitative T1ρ imaging is one application of spin-lock MRI that is reported to be promising for a number of clinical applications. Spin-lock is often performed with a continuous RF wave at a constant RF amplitude either on resonance or off resonance. However, both on- and off-resonance spin-lock approaches are susceptible to B1 and B0 inhomogeneities, which results in image artifacts and quantification errors. In this work, we report a continuous wave constant amplitude spin-lock approach that can achieve negligible image artifacts in the presence of B1 and B0 inhomogeneities for both on- and off-resonance spin-lock. Under the adiabatic condition, by setting the maximum B1 amplitude of the adiabatic pulses equal to the B1 amplitude of spin-lock RF pulse, the spins are ensured to align along the effective field throughout the spin-lock process. We show that this results in simultaneous compensation of B1 and B0 inhomogeneities for both on- and off-resonance spin-lock. The relaxation effect during the entire adiabatic half passage (AHP) and reverse AHP, and the stationary solution of the Bloch-McConnell equation present at off-resonance frequency offset, are considered in the revised relaxation model. We demonstrate that these factors create a direct current component to the conventional relaxation model. In contrast to the previously reported dual-acquisition method, the revised relaxation model just requires one acquisition to perform quantification. The simulation, phantom, and in vivo experiments demonstrate that the proposed approach achieves superior image quality compared with the existing methods, and the revised relaxation model can perform T1ρ quantification with one acquisition instead of two.
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Affiliation(s)
- Baiyan Jiang
- Department of Imaging and Interventional Radiology, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, Hong Kong SAR, China
| | - Weitian Chen
- Department of Imaging and Interventional Radiology, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, Hong Kong SAR, China
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Sharafi A, Xia D, Chang G, Regatte RR. Biexponential T 1ρ relaxation mapping of human knee cartilage in vivo at 3 T. NMR IN BIOMEDICINE 2017; 30:10.1002/nbm.3760. [PMID: 28632901 PMCID: PMC5597480 DOI: 10.1002/nbm.3760] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
The purpose of this study was to demonstrate the feasibility of biexponential T1ρ relaxation mapping of human knee cartilage in vivo. A three-dimensional, customized, turbo-flash sequence was used to acquire T1ρ -weighted images from healthy volunteers employing a standard 3-T MRI clinical scanner. A series of T1ρ -weighted images was fitted using monoexponential and biexponential models with two- and four-parametric non-linear approaches, respectively. Non-parametric Kruskal-Wallis and Mann-Whitney U-statistical tests were used to evaluate the regional relaxation and gender differences, respectively, with a level of significance of P = 0.05. Biexponential relaxations were detected in the cartilage of all volunteers. The short and long relaxation components of T1ρ were estimated to be 6.9 and 51.0 ms, respectively. Similarly, the fractions of short and long T1ρ were 37.6% and 62.4%, respectively. The monoexponential relaxation of T1ρ was 32.6 ms. The experiments showed good repeatability with a coefficient of variation (CV) of less than 20%. A biexponential relaxation model showed a better fit than a monoexponential model to the T1ρ relaxation decay in knee cartilage. Biexponential T1ρ components could potentially be used to increase the specificity to detect early osteoarthritis by the measurement of different water compartments and their fractions.
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Affiliation(s)
- Azadeh Sharafi
- Bernard and Irene Schwartz Center for Biomedical Imaging, Department of Radiology, New York University School of Medicine, New York, New York, USA
| | - Ding Xia
- Bernard and Irene Schwartz Center for Biomedical Imaging, Department of Radiology, New York University School of Medicine, New York, New York, USA
| | - Gregory Chang
- Bernard and Irene Schwartz Center for Biomedical Imaging, Department of Radiology, New York University School of Medicine, New York, New York, USA
| | - Ravinder R Regatte
- Bernard and Irene Schwartz Center for Biomedical Imaging, Department of Radiology, New York University School of Medicine, New York, New York, USA
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Mastikhin IV, Bade KM, Ahmadi S. A rapid magnetization preparation for MRI measurements of sprays. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2017; 283:52-60. [PMID: 28881233 DOI: 10.1016/j.jmr.2017.08.011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2017] [Revised: 08/25/2017] [Accepted: 08/26/2017] [Indexed: 06/07/2023]
Abstract
The process of spray atomization, i.e., the transformation of a continuous liquid jet into μm-sub-mm sized droplets, is ubiquitous in industry yet quite complex to analyze theoretically and study experimentally. One of the main strengths of MRI is its ability to sensitize spatially-resolved NMR signal to a wide variety of physical and chemical parameters. However, standard preparation schemes are difficult to employ for studies of sprays due to sprays' fast speeds (>10-20m/s). In addition, sprays are usually low-density systems, leading to a poor SNR and a need for massive signal averaging and long acquisition time. In this paper, we reduced the interval between the preparation and the readout stages by performing SPI encoding on the rising gradients. This also enabled the use of 90-degree flip angles to maximize the spray signal and saturate the stationary water signal while avoiding unwanted slice-selection. The use of gradients during preparation stage was eliminated due to their time-consuming rise and stabilization times limiting possible preparation schemes to a combination of RF pulses and delays. The two preparation schemes presented here are Time-of-Flight (TOF) and T1ρ-weighting schemes. The total duration of the sequence (without TR) was 240-1100μs for the TOF and 410μs for T1ρ. The T1ρ prepared images of the near-atomization region (11 spin-locking frequencies, 0-15kHz) showed a strong signal attenuation at higher frequencies. In series of TOF images the clearly noticeable displacement of the liquid parcel can be utilized to measure spray speeds.
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Affiliation(s)
- I V Mastikhin
- Department of Physics, University of New Brunswick, Fredericton E3B 5A3, NB, Canada.
| | - K M Bade
- Spraying Systems Co., Spray Analysis and Research Services, Wheaton, IL, USA
| | - S Ahmadi
- Department of Physics, University of New Brunswick, Fredericton E3B 5A3, NB, Canada
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Li YT, Huang H, Zhuo Z, Lu PX, Chen W, Wáng YXJ. Bi-phase age-related brain gray matter magnetic resonance T1ρ relaxation time change in adults. Magn Reson Imaging 2017; 39:200-205. [DOI: 10.1016/j.mri.2017.03.005] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2016] [Revised: 02/02/2017] [Accepted: 03/15/2017] [Indexed: 12/18/2022]
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Chen W. Artifacts correction for T1rho imaging with constant amplitude spin-lock. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2017; 274:13-23. [PMID: 27842257 DOI: 10.1016/j.jmr.2016.11.002] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2016] [Revised: 10/16/2016] [Accepted: 11/04/2016] [Indexed: 06/06/2023]
Abstract
T1rho imaging with constant amplitude spin-lock is prone to artifacts in the presence of B1 RF and B0 field inhomogeneity. Despite significant technological progress, improvements on the robustness of constant amplitude spin-lock are necessary in order to use it for routine clinical practice. This work proposes methods to simultaneously correct for B1 RF and B0 field inhomogeneity in constant amplitude spin-lock. By setting the maximum B1 amplitude of the excitation adiabatic pulses equal to the expected constant amplitude spin-lock frequency, the spins become aligned along the effective field throughout the spin-lock process. This results in T1rho-weighted images free of artifacts, despite the spatial variation of the effective field caused by B1 RF and B0 field inhomogeneity. When the pulse is long, the relaxation effect during the adiabatic half passage may result in a non-negligible error in the mono-exponential relaxation model. A two-acquisition approach is presented to solve this issue. Simulation, phantom, and in-vivo scans demonstrate the proposed methods achieve superior image quality compared to existing methods, and that the two-acquisition method is effective in resolving the relaxation effect during the adiabatic half passage.
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Affiliation(s)
- Weitian Chen
- Department of Imaging and Interventional Radiology, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, Hong Kong Special Administrative Region.
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Schuenke P, Koehler C, Korzowski A, Windschuh J, Bachert P, Ladd ME, Mundiyanapurath S, Paech D, Bickelhaupt S, Bonekamp D, Schlemmer HP, Radbruch A, Zaiss M. Adiabatically prepared spin-lock approach for T1ρ-based dynamic glucose enhanced MRI at ultrahigh fields. Magn Reson Med 2016; 78:215-225. [DOI: 10.1002/mrm.26370] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2016] [Revised: 07/12/2016] [Accepted: 07/14/2016] [Indexed: 12/23/2022]
Affiliation(s)
- Patrick Schuenke
- German Cancer Research Center (DKFZ); Division of Medical Physics in Radiology; Heidelberg Germany
| | - Christina Koehler
- German Cancer Research Center (DKFZ); Division of Radiology; Heidelberg Germany
| | - Andreas Korzowski
- German Cancer Research Center (DKFZ); Division of Medical Physics in Radiology; Heidelberg Germany
| | - Johannes Windschuh
- German Cancer Research Center (DKFZ); Division of Medical Physics in Radiology; Heidelberg Germany
| | - Peter Bachert
- German Cancer Research Center (DKFZ); Division of Medical Physics in Radiology; Heidelberg Germany
| | - Mark E. Ladd
- German Cancer Research Center (DKFZ); Division of Medical Physics in Radiology; Heidelberg Germany
| | | | - Daniel Paech
- German Cancer Research Center (DKFZ); Division of Radiology; Heidelberg Germany
| | | | - David Bonekamp
- German Cancer Research Center (DKFZ); Division of Radiology; Heidelberg Germany
| | | | - Alexander Radbruch
- German Cancer Research Center (DKFZ); Division of Radiology; Heidelberg Germany
| | - Moritz Zaiss
- German Cancer Research Center (DKFZ); Division of Medical Physics in Radiology; Heidelberg Germany
- Max-Planck-Institute for Biological Cybernetics; Tübingen Baden-Württemberg Germany
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Yuan J, Lo G, King AD. Functional magnetic resonance imaging techniques and their development for radiation therapy planning and monitoring in the head and neck cancers. Quant Imaging Med Surg 2016; 6:430-448. [PMID: 27709079 PMCID: PMC5009093 DOI: 10.21037/qims.2016.06.11] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2016] [Accepted: 05/27/2016] [Indexed: 01/05/2023]
Abstract
Radiation therapy (RT), in particular intensity-modulated radiation therapy (IMRT), is becoming a more important nonsurgical treatment strategy in head and neck cancer (HNC). The further development of IMRT imposes more critical requirements on clinical imaging, and these requirements cannot be fully fulfilled by the existing radiotherapeutic imaging workhorse of X-ray based imaging methods. Magnetic resonance imaging (MRI) has increasingly gained more interests from radiation oncology community and holds great potential for RT applications, mainly due to its non-ionizing radiation nature and superior soft tissue image contrast. Beyond anatomical imaging, MRI provides a variety of functional imaging techniques to investigate the functionality and metabolism of living tissue. The major purpose of this paper is to give a concise and timely review of some advanced functional MRI techniques that may potentially benefit conformal, tailored and adaptive RT in the HNC. The basic principle of each functional MRI technique is briefly introduced and their use in RT of HNC is described. Limitation and future development of these functional MRI techniques for HNC radiotherapeutic applications are discussed. More rigorous studies are warranted to translate the hypotheses into credible evidences in order to establish the role of functional MRI in the clinical practice of head and neck radiation oncology.
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Affiliation(s)
- Jing Yuan
- Department of Medical Physics and Research, Hong Kong Sanatorium & Hospital, Happy Valley, Hong Kong SAR, China
| | - Gladys Lo
- Department of Diagnostic & Interventional Radiology, Hong Kong Sanatorium & Hospital, Happy Valley, Hong Kong SAR, China
| | - Ann D. King
- Department of Imaging and Interventional Radiology, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong SAR, China
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Mitrea BG, Krafft AJ, Song R, Loeffler RB, Hillenbrand CM. Paired self-compensated spin-lock preparation for improved T1ρ quantification. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2016; 268:49-57. [PMID: 27161095 DOI: 10.1016/j.jmr.2016.04.017] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/11/2015] [Revised: 04/28/2016] [Accepted: 04/29/2016] [Indexed: 06/05/2023]
Abstract
PURPOSE Spin-lock (SL) imaging allows quantification of the spin-lattice relaxation time in the rotating frame (T1ρ). B0 and B1 inhomogeneities impact T1ρ quantification because the preparatory block in SL imaging is sensitive to the field heterogeneities. Here, a modified preparatory block (PSC-SL) is proposed that attempts to alleviate SL sensitivity to field inhomogeneities in scenarios where existing approaches fail, i.e. high SL frequencies. METHODS Computer simulations, phantom and in vivo experiments were used to determine the effect of field inhomogeneities on T1ρ quantification. Existing SL preparations were compared with PSC-SL in different conditions to assess the advantages and disadvantages of each method. RESULTS Phantom experiments and computer modeling demonstrate that PSC-SL provides superior T1ρ quantification at high SL frequencies in situations where the existing SL preparation methods fail. This result has been confirmed in pre-clinical neuro and body imaging at 7T. CONCLUSION PSC-SL complements existing methods by increasing the accuracy of T1ρ quantification at high spin-lock frequencies when large field inhomogeneities are present. A-priory information about the experimental conditions such, as field distribution and spinlock frequency are useful for selecting an appropriate spin-lock preparation for specific applications.
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Affiliation(s)
- Bogdan G Mitrea
- Department of Diagnostic Imaging, St. Jude Children's Research Hospital, Memphis, TN, USA
| | - Axel J Krafft
- Department of Diagnostic Imaging, St. Jude Children's Research Hospital, Memphis, TN, USA
| | - Ruitian Song
- Department of Diagnostic Imaging, St. Jude Children's Research Hospital, Memphis, TN, USA
| | - Ralf B Loeffler
- Department of Diagnostic Imaging, St. Jude Children's Research Hospital, Memphis, TN, USA
| | - Claudia M Hillenbrand
- Department of Diagnostic Imaging, St. Jude Children's Research Hospital, Memphis, TN, USA.
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Yang Q, Yu T, Yun S, Zhang H, Chen X, Cheng Z, Zhong J, Huang J, Okuaki T, Chan Q, Liang B, Guo H. Comparison of multislice breath-hold and 3D respiratory triggeredT1ρ imaging of liver in healthy volunteers and liver cirrhosis patients in 3.0 T MRI. J Magn Reson Imaging 2016; 44:906-13. [PMID: 27149283 DOI: 10.1002/jmri.25253] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2015] [Accepted: 03/06/2016] [Indexed: 01/09/2023] Open
Affiliation(s)
- Qihua Yang
- Sun Yat-Sen Memorial Hospital; Guang Zhou Guang Dong China
| | - Taihui Yu
- Sun Yat-Sen Memorial Hospital; Guang Zhou Guang Dong China
| | - Su Yun
- Sun Yat-Sen Memorial Hospital; Guang Zhou Guang Dong China
| | - Hui Zhang
- Center for Biomedical Imaging Research; Department of Biomedical Engineering; Tsinghua University; Beijing China
| | - Xiaodong Chen
- Sun Yat-Sen Memorial Hospital; Guang Zhou Guang Dong China
| | - Ziliang Cheng
- Sun Yat-Sen Memorial Hospital; Guang Zhou Guang Dong China
| | - Jinglian Zhong
- Sun Yat-Sen Memorial Hospital; Guang Zhou Guang Dong China
| | - Jingwen Huang
- Sun Yat-Sen Memorial Hospital; Guang Zhou Guang Dong China
| | | | | | - Biling Liang
- Sun Yat-Sen Memorial Hospital; Guang Zhou Guang Dong China
| | - Hua Guo
- Center for Biomedical Imaging Research; Department of Biomedical Engineering; Tsinghua University; Beijing China
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Mok GSP, Zhang D, Chen SZ, Yuan J, Griffith JF, Wang YXJ. Comparison of three approaches for defining nucleus pulposus and annulus fibrosus on sagittal magnetic resonance images of the lumbar spine. J Orthop Translat 2016; 6:34-41. [PMID: 30035081 PMCID: PMC5987025 DOI: 10.1016/j.jot.2016.02.003] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/19/2015] [Revised: 02/08/2016] [Accepted: 02/22/2016] [Indexed: 12/14/2022] Open
Abstract
Objective To compare three methods commonly used in the literature to define intervertebral disc nucleus pulposus (NP) and annulus fibrosus (AF) on magnetic resonance (MR) images. Methods Fifty-two patients (26 males and 26 females; age range, 23-76 years) were recruited for this study; they underwent standard T1/T2-weighted MR imaging, and T2 and T1rho mapping acquisitions. The corresponding midsagittal images were analysed and a total of 256 discs were evaluated, using three different region-of-interest (ROI) drawing methods: (1) radiologist-guided manual ROI (M-ROI); (2) five square ROIs where each measured 20% of the midline disc diameter (5-ROI); and (3) seven square ROIs placed horizontally from anterior to posterior (7-ROI) to define NP and AF. The agreement between the three ROI methods was assessed using intraclass correlation coefficient values and Bland-Altman plots. Results Inner AF and NP could not be differentiated on T1/T2-weighted MR imaging, T2 maps, or T1rho maps. The intraclass correlation coefficient values were all > 0.75 when comparing the 5-/7-ROI methods with the M-ROI methods for NP, and 0.167-0.488 for AF when comparing the 7-ROI method with the M-ROI method. The intraclass correlation coefficient values for AF increased to 0.378-0.582 for the M-ROI method compared with the 5-ROI method. Comparable results were obtained with Bland-Altman plots. Conclusion The 5-/7-ROI methods agreed with the M-ROI approach for NP selection, while the agreement with AF was moderate to poor, with the 5-ROI method showing slight advantage over the 7-ROI method. Cautions should be taken to interpret the MR relaxometry findings when 5-/7-ROI methods are used to select AF.
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Affiliation(s)
- Greta S P Mok
- Biomedical Imaging Laboratory, Department of Electrical and Computer Engineering, University of Macau, Macau Special Administrative Region
| | - Duo Zhang
- Biomedical Imaging Laboratory, Department of Electrical and Computer Engineering, University of Macau, Macau Special Administrative Region
| | - Shu-Zhong Chen
- Department of Imaging and Interventional Radiology, Prince of Wales Hospital, The Chinese University of Hong Kong, Shatin, Hong Kong Special Administrative Region
| | - Jing Yuan
- Medical Physics and Research Department, Hong Kong Sanatorium and Hospital, Happy Valley, Hong Kong Special Administrative Region
| | - James F Griffith
- Department of Imaging and Interventional Radiology, Prince of Wales Hospital, The Chinese University of Hong Kong, Shatin, Hong Kong Special Administrative Region
| | - Yi Xiang J Wang
- Department of Imaging and Interventional Radiology, Prince of Wales Hospital, The Chinese University of Hong Kong, Shatin, Hong Kong Special Administrative Region
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Wáng YXJ, Zhang Q, Li X, Chen W, Ahuja A, Yuan J. T1ρ magnetic resonance: basic physics principles and applications in knee and intervertebral disc imaging. Quant Imaging Med Surg 2015; 5:858-85. [PMID: 26807369 PMCID: PMC4700236 DOI: 10.3978/j.issn.2223-4292.2015.12.06] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2015] [Accepted: 12/06/2015] [Indexed: 12/15/2022]
Abstract
T1ρ relaxation time provides a new contrast mechanism that differs from T1- and T2-weighted contrast, and is useful to study low-frequency motional processes and chemical exchange in biological tissues. T1ρ imaging can be performed in the forms of T1ρ-weighted image, T1ρ mapping and T1ρ dispersion. T1ρ imaging, particularly at low spin-lock frequency, is sensitive to B0 and B1 inhomogeneity. Various composite spin-lock pulses have been proposed to alleviate the influence of field inhomogeneity so as to reduce the banding-like spin-lock artifacts. T1ρ imaging could be specific absorption rate (SAR) intensive and time consuming. Efforts to address these issues and speed-up data acquisition are being explored to facilitate wider clinical applications. This paper reviews the T1ρ imaging's basic physic principles, as well as its application for cartilage imaging and intervertebral disc imaging. Compared to more established T2 relaxation time, it has been shown that T1ρ provides more sensitive detection of proteoglycan (PG) loss at early stages of cartilage degeneration. T1ρ has also been shown to provide more sensitive evaluation of annulus fibrosis (AF) degeneration of the discs.
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Zhao F, Yuan J, Lu G, Zhang LH, Chen ZY, Wáng YXJ. T1ρ relaxation time in brain regions increases with ageing: an experimental MRI observation in rats. Br J Radiol 2015; 89:20140704. [PMID: 26529226 DOI: 10.1259/bjr.20140704] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
OBJECTIVE T1ρ variation is associated with neurodegenerative diseases. This study aims to observe T1ρ relaxation time changes in rat brains associated with normal ageing in Sprague-Dawley (SD) rats, Wistar Kyoto (WKY) rats and spontaneously hypertension rats (SHRs). METHODS 18 male SD rats, 11 male WKY rats and 11 male SHRs were used. T1ρ measurement was performed at 3-T MR with a spin-lock frequency of 500 Hz. SD rats were scanned at the ages of 5, 8, 10 and 15 months. SHRs and WKY rats were scanned at the ages of 6, 9 and 12 months. RESULTS For SD rats, T1ρ at the thalamus, hippocampus and frontal cortices increased significantly from 5 to 15 months (p < 0.05). For the WKY rats and SHRs, the T1ρ values in the thalamus, hippocampus and frontal cortices also increased significantly from 6 to 12 months (p < 0.05). Furthermore, T1ρ in the thalamus, hippocampus and frontal cortices of SHRs were consistently higher than those of WKY rats at the ages of 6, 9 and 12 months (p < 0.05). The percentage regional T1ρ differences between WKY rats and SHRs did not change during ageing. CONCLUSION An increase in T1ρ was associated with age-related changes of the rat brain. ADVANCES IN KNOWLEDGE An age-related and hypertension-related T1ρ increase in rat brain regions was observed in the thalamus, hippocampus and frontal cortical regions of the rat brain.
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Affiliation(s)
- Feng Zhao
- 1 Department of Imaging and Interventional Radiology, Faculty of Medicine, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, Hong Kong
| | - Jing Yuan
- 1 Department of Imaging and Interventional Radiology, Faculty of Medicine, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, Hong Kong.,2 Medical Physics and Research Department, Hong Kong Sanatorium & Hospital, Happy Valley, Hong Kong
| | - Gang Lu
- 3 Division of Neurosurgery, Faculty of Medicine, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, Hong Kong
| | - Li H Zhang
- 4 School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, Hong Kong
| | - Zhi Y Chen
- 5 Laboratory of Ultrasound Molecular Imaging, The Third Affiliated Hospital of Guangzhou Medical University, Guangzhou, China
| | - Yì-Xiáng J Wáng
- 1 Department of Imaging and Interventional Radiology, Faculty of Medicine, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, Hong Kong
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Abstract
The spin-lattice relaxation time constant in rotating frame (T1rho) is useful for assessment of the properties of macromolecular environment inside tissue. Quantification of T1rho is found promising in various clinical applications. However, T1rho imaging is prone to image artifacts and quantification errors, which remains one of the greatest challenges to adopt this technique in routine clinical practice. The conventional continuous wave spin-lock is susceptible to B1 radiofrequency (RF) and B0 field inhomogeneity, which appears as banding artifacts in acquired images. A number of methods have been reported to modify T1rho prep RF pulse cluster to mitigate this effect. Adiabatic RF pulse can also be used for spin-lock with insensitivity to both B1 RF and B0 field inhomogeneity. Another source of quantification error in T1rho imaging is signal evolution during imaging data acquisition. Care is needed to affirm such error does not take place when specific pulse sequence is used for imaging data acquisition. Another source of T1rho quantification error is insufficient signal-to-noise ratio (SNR), which is common among various quantitative imaging approaches. Measurement of T1rho within an ROI can mitigate this issue, but at the cost of reduced resolution. Noise-corrected methods are reported to address this issue in pixel-wise quantification. For certain tissue type, T1rho quantification can be confounded by magic angle effect and the presence of multiple tissue components. Review of these confounding factors from inherent tissue properties is not included in this article.
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Affiliation(s)
- Weitian Chen
- Department of Imaging and Interventional Radiology, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, Hong Kong, China
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Singh A, Reddy D, Haris M, Cai K, Rajender Reddy K, Hariharan H, Reddy R. T1ρ MRI of healthy and fibrotic human livers at 1.5 T. J Transl Med 2015; 13:292. [PMID: 26350896 PMCID: PMC4562204 DOI: 10.1186/s12967-015-0648-0] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2015] [Accepted: 08/21/2015] [Indexed: 01/06/2023] Open
Abstract
Background Liver fibrosis is a public health problem worldwide. There is a need of noninvasive imaging based methods for better diagnosis of this disease. In the current study, we aim to evaluate the potential of T1ρ MRI technique in detecting and characterizing different grades of liver fibrosis in vivo in humans. Methods Healthy subjects and patients with liver fibrosis were prospectively recruited for T1ρ MRI of liver on a 1.5 T MR scanner. Single slice T1ρ weighted images were acquired at different spin lock duration (0, 10, 20 and 30 ms) with spin lock amplitude of 500 Hz in a single breath-hold. Additionally, liver’s T1ρ images were acquired from five healthy subjects on the same day (n = 2) and different day (n = 2) sessions for test–retest study. Liver biopsy samples from patients were obtained and used to calculate the METAVIR score to define the stage of fibrosis and inflammation grade. T1ρ maps were generated followed by computation of mean and standard deviation (SD) values. Coefficient of variation (COV) of T1ρ values between two MRI scans was computed to determine reproducibility in liver. T test was used to compare T1ρ values between healthy and fibrotic liver. Pearson correlation was performed between stages of liver fibrosis and T1ρ values. Results The mean (SD) T1ρ value among subject with healthy liver was 51.04 (3.06) ms. The COV of T1ρ values between two repetitions in the same day session was 0.83 ± 0.8 % and in different day session was 5.4 ± 2.7 %. T1ρ values in fibrotic liver were significantly higher compared to those of healthy liver (p < 0.05). A statically significant correlation between stages of fibrosis and T1ρ values was observed (r = 0.99, p < 0.05). Inflammation score for one patient was 2 and for remaining patients it was 1. Conclusions Proposed T1ρ pulse sequence design and protocol enabled acquisition of a single slice T1ρ weighted images in a single breath-hold and hence mitigated breathing motion related artifacts. Preliminary results have shown the sensitivity of T1ρ values to changes induced by liver fibrosis, and may potentially be used as a clinical biomarker to delineate the stages of liver fibrosis. Further, studies on a large number of subjects are required to validate the observations of the current study. Nevertheless, T1ρ imaging can be easily setup on a clinical scanner to monitor the progression of liver fibrosis and to the evaluate efficacy of anti-fibrotic drugs.
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Affiliation(s)
- Anup Singh
- Department of Radiology, CMROI, University of Pennsylvania, Philadelphia, PA, USA. .,Center for Biomedical Engineering, Indian Institute of Technology Delhi, Block-II, Room No. 389, Hauz Khas, Delhi, 110016, India.
| | - Damodar Reddy
- Department of Radiology, CMROI, University of Pennsylvania, Philadelphia, PA, USA
| | - Mohammad Haris
- Department of Radiology, CMROI, University of Pennsylvania, Philadelphia, PA, USA.,Research Branch, Sidra Medical and Research Center, Doha, Qatar
| | - Kejia Cai
- Department of Radiology, CMROI, University of Pennsylvania, Philadelphia, PA, USA.,Department of Radiology, University of Illinois at Chicago, Chicago, IL, USA
| | - K Rajender Reddy
- Division of Gastroenterology, Department of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Hari Hariharan
- Department of Radiology, CMROI, University of Pennsylvania, Philadelphia, PA, USA
| | - Ravinder Reddy
- Department of Radiology, CMROI, University of Pennsylvania, Philadelphia, PA, USA
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44
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Bhave S, Lingala SG, Johnson CP, Magnotta VA, Jacob M. Accelerated whole-brain multi-parameter mapping using blind compressed sensing. Magn Reson Med 2015; 75:1175-86. [PMID: 25850952 DOI: 10.1002/mrm.25722] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2014] [Revised: 02/22/2015] [Accepted: 03/12/2015] [Indexed: 01/16/2023]
Abstract
PURPOSE To introduce a blind compressed sensing (BCS) framework to accelerate multi-parameter MR mapping, and demonstrate its feasibility in high-resolution, whole-brain T1ρ and T2 mapping. METHODS BCS models the evolution of magnetization at every pixel as a sparse linear combination of bases in a dictionary. Unlike compressed sensing, the dictionary and the sparse coefficients are jointly estimated from undersampled data. Large number of non-orthogonal bases in BCS accounts for more complex signals than low rank representations. The low degree of freedom of BCS, attributed to sparse coefficients, translates to fewer artifacts at high acceleration factors (R). RESULTS From 2D retrospective undersampling experiments, the mean square errors in T1ρ and T2 maps were observed to be within 0.1% up to R = 10. BCS was observed to be more robust to patient-specific motion as compared to other compressed sensing schemes and resulted in minimal degradation of parameter maps in the presence of motion. Our results suggested that BCS can provide an acceleration factor of 8 in prospective 3D imaging with reasonable reconstructions. CONCLUSION BCS considerably reduces scan time for multiparameter mapping of the whole brain with minimal artifacts, and is more robust to motion-induced signal changes compared to current compressed sensing and principal component analysis-based techniques.
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Affiliation(s)
- Sampada Bhave
- Department of Electrical and Computer Engineering, The University of Iowa, Iowa, USA
| | - Sajan Goud Lingala
- Department of Electrical Engineering, University of Southern California, California, USA
| | | | | | - Mathews Jacob
- Department of Electrical and Computer Engineering, The University of Iowa, Iowa, USA
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45
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Brain abnormalities in bipolar disorder detected by quantitative T1ρ mapping. Mol Psychiatry 2015; 20:201-6. [PMID: 25560762 PMCID: PMC4346383 DOI: 10.1038/mp.2014.157] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/05/2014] [Revised: 09/19/2014] [Accepted: 10/09/2014] [Indexed: 12/21/2022]
Abstract
Abnormal metabolism has been reported in bipolar disorder, however, these studies have been limited to specific regions of the brain. To investigate whole-brain changes potentially associated with these processes, we applied a magnetic resonance imaging technique novel to psychiatric research, quantitative mapping of T1 relaxation in the rotating frame (T1ρ). This method is sensitive to proton chemical exchange, which is affected by pH, metabolite concentrations and cellular density with high spatial resolution relative to alternative techniques such as magnetic resonance spectroscopy and positron emission tomography. Study participants included 15 patients with bipolar I disorder in the euthymic state and 25 normal controls balanced for age and gender. T1ρ maps were generated and compared between the bipolar and control groups using voxel-wise and regional analyses. T1ρ values were found to be elevated in the cerebral white matter and cerebellum in the bipolar group. However, volumes of these areas were normal as measured by high-resolution T1- and T2-weighted magnetic resonance imaging. Interestingly, the cerebellar T1ρ abnormalities were normalized in participants receiving lithium treatment. These findings are consistent with metabolic or microstructural abnormalities in bipolar disorder and draw attention to roles of the cerebral white matter and cerebellum. This study highlights the potential utility of high-resolution T1ρ mapping in psychiatric research.
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46
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Bhave S, Lingala SG, Jacob M. A variable splitting based algorithm for fast multi-coil blind compressed sensing MRI reconstruction. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2015; 2014:2400-3. [PMID: 25570473 DOI: 10.1109/embc.2014.6944105] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Recent work on blind compressed sensing (BCS) has shown that exploiting sparsity in dictionaries that are learnt directly from the data at hand can outperform compressed sensing (CS) that uses fixed dictionaries. A challenge with BCS however is the large computational complexity during its optimization, which limits its practical use in several MRI applications. In this paper, we propose a novel optimization algorithm that utilize variable splitting strategies to significantly improve the convergence speed of the BCS optimization. The splitting allows us to efficiently decouple the sparse coefficient, and dictionary update steps from the data fidelity term, resulting in subproblems that take closed form analytical solutions, which otherwise require slower iterative conjugate gradient algorithms. Through experiments on multi coil parametric MRI data, we demonstrate the superior performance of BCS over conventional CS schemes, while achieving convergence speed up factors of over 10 fold over the previously proposed implementation of the BCS algorithm.
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47
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Roeloffs V, Meyer C, Bachert P, Zaiss M. Towards quantification of pulsed spinlock and CEST at clinical MR scanners: an analytical interleaved saturation-relaxation (ISAR) approach. NMR IN BIOMEDICINE 2015; 28:40-53. [PMID: 25328046 DOI: 10.1002/nbm.3192] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/05/2014] [Revised: 07/17/2014] [Accepted: 07/25/2014] [Indexed: 05/24/2023]
Abstract
Off-resonant spinlock (SL) enables an NMR imaging technique that can detect dilute metabolites similar to chemical exchange saturation transfer. However, in clinical MR scanners, RF pulse widths are restricted due to recommended specific absorption rate limits. Therefore, trains of short RF pulses that provide effective saturation during the required irradiation period are commonly employed. Quantitative evaluation of spectra obtained by pulsed saturation schemes is harder to achieve, since the theory of continuous wave saturation cannot be applied directly. In this paper we demonstrate the general feasibility of quantifying proton exchange rates from data obtained in pulsed SL experiments on a clinical 3 T MR scanner. We also propose a theoretical treatment of pulsed SL in the presence of chemical exchange using an interleaved saturation-relaxation approach. We show that modeling magnetization transfer during the pauses between the RF pulses is crucial, especially in the case of exchange rates that are small with respect to the delay times. The dynamics is still governed by a monoexponential decay towards steady state, for which we give the effective rate constant. The derived analytical model agrees well with the full numerical simulation of the Bloch-McConnell equations for a broad range of values of the system parameters.
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Affiliation(s)
- Volkert Roeloffs
- Deutsches Krebsforschungszentrum (DKFZ), German Cancer Research Center, Division of Medical Physics in Radiology, Heidelberg, Germany; Biomedizinische NMR Forschungs GmbH, am Max-Planck-Institut für biophysikalische Chemie, Göttingen, Germany
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48
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Johnson CP, Heo HY, Thedens DR, Wemmie JA, Magnotta VA. Rapid acquisition strategy for functional T1ρ mapping of the brain. Magn Reson Imaging 2014; 32:1067-77. [PMID: 25093630 PMCID: PMC4171198 DOI: 10.1016/j.mri.2014.07.010] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2013] [Revised: 05/27/2014] [Accepted: 07/25/2014] [Indexed: 11/29/2022]
Abstract
Functional T1ρ mapping has been proposed as a method to assess pH and metabolism dynamics in the brain with high spatial and temporal resolution. The purpose of this work is to describe and evaluate a variant of the spin-locked echo-planar imaging sequence for functional T1ρ mapping at 3T. The proposed sequence rapidly acquires a time series of T1ρ maps with 4.0second temporal resolution and 10 slices of volumetric coverage. Simulation, phantom, and in vivo experiments are used to evaluate many aspects of the sequence and its implementation including fidelity of measured T1ρ dynamics, potential confounds to the T1ρ response, imaging parameter tradeoffs, time series analysis approaches, and differences compared to blood oxygen level dependent functional magnetic resonance imaging. It is shown that the high temporal resolution and volumetric coverage of the sequence are obtained with some expense including underestimation of the T1ρ response, sensitivity to T1 dynamics, and reduced signal-to-noise ratio. In vivo studies using a flashing checkerboard functional magnetic resonance imaging paradigm suggest differences between T1ρ and blood oxygen level dependent activation patterns. Possible sources of the functional T1ρ response and potential sequence improvements are discussed. The capability of T1ρ to map whole-brain pH and metabolism dynamics with high temporal and spatial resolution is potentially unique and warrants further investigation and development.
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Affiliation(s)
| | - Hye-Young Heo
- Department of Biomedical Engineering, University of Iowa, Iowa City, IA
| | | | - John A Wemmie
- Department of Psychiatry, University of Iowa, Iowa City, IA; Department of Veterans Affairs Medical Center, Iowa City, IA
| | - Vincent A Magnotta
- Department of Radiology, University of Iowa, Iowa City, IA; Department of Biomedical Engineering, University of Iowa, Iowa City, IA; Department of Psychiatry, University of Iowa, Iowa City, IA
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49
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Berkowitz BA, Gorgis J, Patel A, Baameur F, Gurevich VV, Craft CM, Kefalov VJ, Roberts R. Development of an MRI biomarker sensitive to tetrameric visual arrestin 1 and its reduction via light-evoked translocation in vivo. FASEB J 2014; 29:554-64. [PMID: 25351983 DOI: 10.1096/fj.14-254953] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Rod tetrameric arrestin 1 (tet-ARR1), stored in the outer nuclear layer/inner segments in the dark, modulates photoreceptor synaptic activity; light exposure stimulates a reduction via translocation to the outer segments for terminating G-protein coupled phototransduction signaling. Here, we test the hypothesis that intraretinal spin-lattice relaxation rate in the rotating frame (1/T1ρ), an endogenous MRI contrast mechanism, has high potential for evaluating rod tet-ARR1 and its reduction via translocation. Dark- and light-exposed mice (null for the ARR1 gene, overexpressing ARR1, diabetic, or wild type with or without treatment with Mn2+, a calcium channel probe) were studied using 1/T1ρ MRI. Immunohistochemistry and single-cell recordings of the retinas were also performed. In wild-type mice with or without treatment with Mn2+, 1/T1ρ of avascular outer retina (64% to 72% depth) was significantly (P < 0.05) greater in the dark than in the light; a significant (P < 0.05) but opposite pattern was noted in the inner retina (<50% depth). Light-evoked outer retina Δ1/T1ρ was absent in ARR1-null mice and supernormal in overexpressing mice. In diabetic mice, the outer retinal Δ1/T1ρ pattern suggested normal dark-to-light tet-ARR1 translocation and chromophore content, conclusions confirmed ex vivo. Light-stimulated Δ1/T1ρ in inner retina was linked to changes in blood volume. Our data support 1/T1ρ MRI for noninvasively assessing rod tet-ARR1 and its reduction via protein translocation, which can be combined with other metrics of retinal function in vivo.
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Affiliation(s)
- Bruce A Berkowitz
- Department of Anatomy and Cell Biology and Department of Ophthalmology, Wayne State University, Detroit, Michigan, USA;
| | | | | | - Faiza Baameur
- Department of Pharmacology, Vanderbilt University, Nashville, Tennessee, USA
| | - Vsevolod V Gurevich
- Department of Pharmacology, Vanderbilt University, Nashville, Tennessee, USA
| | - Cheryl M Craft
- Mary D. Allen Laboratory for Vision Research, USC Eye Institute, and Department of Ophthalmology and Department of Cell and Neurobiology, Keck School of Medicine of the University of Southern California, Los Angeles, California, USA; and
| | - Vladimir J Kefalov
- Department of Ophthalmology and Visual Sciences, Washington University in St. Louis, St. Louis, Missouri, USA
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Wang YXJ, Griffith JF, Leung JCS, Yuan J. Age related reduction of T1rho and T2 magnetic resonance relaxation times of lumbar intervertebral disc. Quant Imaging Med Surg 2014; 4:259-64. [PMID: 25202661 DOI: 10.3978/j.issn.2223-4292.2014.07.14] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2014] [Accepted: 07/22/2014] [Indexed: 11/14/2022]
Abstract
This report aims to study the age related T1rho and T2 relaxation time changes in lumbar intervertebral disc. Lumbar sagittal magnetic resonance imaging (MRI) was performed with a 3 Tesla scanner in 52 subjects. With a spin-lock frequency of 500 Hz, T1rho was measured using a rotary echo spin-lock pulse embedded in a 3D balanced fast field echo sequence. A multi-echo turbo spin echo sequence was used for T2 mapping. Regions-of-interest were drawn over the T1rho and T2 maps, including nucleus pulposus and annulus fibrosus. For L1/2-L4/5 discs, results showed the age associated reduction of T1rho of nucleus pulposus had a of slope of -1.06, the reduction of T2 of nucleus pulposus had a slope of -1.47, the reduction of T1rho of annulus fibrosus had a slope of -0.25, and the reduction of T2 of annulus fibrosus had a slope of -0.18, with all the slopes significantly non-zero. In nucleus pulposus the slope of T2 was slightly steeper than that of T1rho (P=0.085), while in annulus fibrosus the slope of T1rho was slightly steeper than that of T2 (P=0.31). We conclude that significant age related reduction of T1rho and T2 magnetic resonance relaxation times of lumbar intervertebral disc was observed, however, the relative performances of T1rho vs. T2 were broadly similar.
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Affiliation(s)
- Yi-Xiang J Wang
- 1 Department of Imaging and Interventional Radiology, Faculty of Medicine, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, Hong Kong SAR, China ; 2 School of Public Health and Primary Care, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, Hong Kong SAR, China
| | - James F Griffith
- 1 Department of Imaging and Interventional Radiology, Faculty of Medicine, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, Hong Kong SAR, China ; 2 School of Public Health and Primary Care, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, Hong Kong SAR, China
| | - Jason C S Leung
- 1 Department of Imaging and Interventional Radiology, Faculty of Medicine, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, Hong Kong SAR, China ; 2 School of Public Health and Primary Care, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, Hong Kong SAR, China
| | - Jing Yuan
- 1 Department of Imaging and Interventional Radiology, Faculty of Medicine, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, Hong Kong SAR, China ; 2 School of Public Health and Primary Care, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, Hong Kong SAR, China
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