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Liu YJ, Tsai TS, Li YH, Peng JH, Chang HC, Peng HH, Lee YC, Lee TY, Liou CH, Lin TF, Chew FY, Chou RH, Juan CJ. Understanding ADC variation by fat content effect using a dual-function MRI phantom. Eur Radiol Exp 2024; 8:19. [PMID: 38347188 PMCID: PMC10861416 DOI: 10.1186/s41747-023-00414-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2023] [Accepted: 11/14/2023] [Indexed: 02/15/2024] Open
Abstract
BACKGROUND A dual-function phantom designed to quantify the apparent diffusion coefficient (ADC) in different fat contents (FCs) and glass bead densities (GBDs) to simulate the human tissues has not been documented yet. We propose a dual-function phantom to quantify the FC and to measure the ADC at different FCs and different GBDs. METHODS A fat-containing diffusion phantom comprised by 30 glass-bead-containing fat-water emulsions consisting of six different FCs (0, 10, 20, 30, 40, and 50%) multiplied by five different GBDs (0, 0.1, 0.25, 0.5, and 1.0 g/50 mL). The FC and ADC were measured by the "iterative decomposition of water and fat with echo asymmetry and least squares estimation-IQ," IDEAL-IQ, and single-shot echo-planar diffusion-weighted imaging, SS-EP-DWI, sequences, respectively. Linear regression analysis was used to evaluate the relationship among the fat fraction (FF) measured by IDEAL-IQ, GBD, and ADC. RESULTS The ADC was significantly, negatively, and linearly associated with the FF (the linear slope ranged from -0.005 to -0.017, R2 = 0.925 to 0.986, all p < 0.001). The slope of the linear relationship between the ADC and the FF, however, varied among different GBDs (the higher the GBD, the lower the slope). ADCs among emulsions across different GBDs and FFs were overlapped. Emulsions with low GBDs plus high FFs shared a same lower ADC range with those with median or high GBDs plus median or lower FFs. CONCLUSIONS A novel dual-function phantom simulating the human tissues allowed to quantify the influence of FC and GBD on ADC. RELEVANCE STATEMENT The study developed an innovative dual-function MRI phantom to explore the impact of FC on ADC variation that can affect clinical results. The results revealed the superimposed effect on FF and GBD density on ADC measurements. KEY POINTS • A dual-function phantom made of glass bead density (GBD) and fat fraction (FF) emulsion has been developed. • Apparent diffusion coefficient (ADC) values are determined by GBD and FF. • The dual-function phantom showed the mutual ADC addition between FF and GBD.
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Affiliation(s)
- Yi-Jui Liu
- Department of Automatic Control Engineering, Feng Chia University, Taichung, Taiwan, Republic of China
| | - Tung-Sheng Tsai
- Ph.D. Program in Electrical and Communication Engineering, Feng Chia University, Taichung, Taiwan, Republic of China
| | - Ya-Hui Li
- Department of Medical Imaging, China Medical University Hsinchu Hospital, 199, Sec. 1, Xinglong Rd., Zhubei City, Hsinchu County, 302, Taiwan, Republic of China
| | - Jo-Hua Peng
- Department of Biomedical Engineering and Environmental Sciences, National Tsing Hua University, Hsinchu, Taiwan, Republic of China
| | - Hing-Chiu Chang
- Department of Biomedical Engineering, Chinese University of Hong Kong, Hong Kong, China
| | - Hsu-Hsia Peng
- Department of Biomedical Engineering and Environmental Sciences, National Tsing Hua University, Hsinchu, Taiwan, Republic of China
| | - Ying-Chieh Lee
- Department of Automatic Control Engineering, Feng Chia University, Taichung, Taiwan, Republic of China
| | - Tung-Yang Lee
- Master's Program of Biomedical Informatics and Biomedical Engineering, Feng Chia University, Taichung, Taiwan, Republic of China
- Cheng Ching Hospital, Taichung, Taiwan, Republic of China
| | - Chang-Hsien Liou
- Department of Medical Imaging, China Medical University Hsinchu Hospital, 199, Sec. 1, Xinglong Rd., Zhubei City, Hsinchu County, 302, Taiwan, Republic of China
- Institute of Nuclear Engineering and Science, National Tsing Hua University, Hsinchu, Taiwan, Republic of China
| | - Tz-Feng Lin
- Department of Fiber and Composite Materials, Feng Chia University, Taichung, Taiwan, Republic of China
| | - Fatt-Yang Chew
- Department of Medical Imaging, China Medical University Hospital, Taichung, Taiwan, Republic of China
- Department of Radiology, School of Medicine, China Medical University, Taichung, Taiwan, Republic of China
| | - Ruey-Hwang Chou
- Graduate Institute of Biomedical Sciences, China Medical University, Taichung, 406, Taiwan, Republic of China.
- Center for Molecular Medicine, China Medical University Hospital, Taichung, Taiwan, Republic of China.
- Department of Medical Laboratory and Biotechnology, Asia University, Taichung, Taiwan, Republic of China.
| | - Chun-Jung Juan
- Department of Medical Imaging, China Medical University Hsinchu Hospital, 199, Sec. 1, Xinglong Rd., Zhubei City, Hsinchu County, 302, Taiwan, Republic of China.
- Department of Biomedical Engineering and Environmental Sciences, National Tsing Hua University, Hsinchu, Taiwan, Republic of China.
- Department of Radiology, School of Medicine, China Medical University, Taichung, Taiwan, Republic of China.
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Bialobroda J, Bouazizi K, Ponnaiah M, Kachenoura N, Charpentier E, Zarai M, Clement K, Andreelli F, Aron-Wisnewsky J, Hatem SN, Redheuil A. The epicardial adipose tissue confined in the atrioventricular groove can be used to assess atrial adipose tissue and atrial dysfunction in cardiac magnetic resonance imaging. EUROPEAN HEART JOURNAL. IMAGING METHODS AND PRACTICE 2024; 2:qyae057. [PMID: 39224099 PMCID: PMC11367945 DOI: 10.1093/ehjimp/qyae057] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/05/2024] [Accepted: 05/17/2024] [Indexed: 09/04/2024]
Abstract
Aims The growing interest in epicardial adipose tissue (EAT) as a biomarker of atrial fibrillation is limited by the difficulties in isolating EAT from other paracardial adipose tissues. We tested the feasibility and value of measuring the pure EAT contained in the atrioventricular groove (GEAT) using cardiovascular magnetic resonance (CMR) imaging in patients with distinct metabolic disorders. Methods and results CMR was performed on 100 patients from the MetaCardis cohort: obese (n = 18), metabolic syndrome (MSD) (n = 25), type-2 diabetes (T2D) (n = 42), and age- and gender-matched healthy controls (n = 15). GEAT volume measured from long-axis views was obtained in all patients with a strong correlation between GEAT and atrial EAT (r = 0.95; P < 0.0001). GEAT volume was higher in the three groups of patients with metabolic disorders and highest in the MSD group compared with controls. GEAT volume, as well as body mass and body fat, allowed obese, T2D, and MSD patients to be distinguished from controls. GEAT T1 relaxation and peak longitudinal left atrial (LA) strain in CMR were decreased in T2D patients. Logistic regression and random forest machine learning methods were used to create an algorithm combining GEAT volume, GEAT T1, and peak LA strain to identify T2D patients from other groups with an area under curve (AUC) of 0.81 (Se: 77%, Spe: 80%; 95% confidence interval 0.72-0.91, P < 0.0001). Conclusion Atrioventricular groove adipose tissue characteristics measured during routine CMR can be used as a proxy of atrial EAT and integrated in a multi-parametric CMR biomarker for early identification of atrial cardiomyopathy.
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Affiliation(s)
- Jonathan Bialobroda
- Institute of Cardiology, Foundation for Innovation in Cardiometabolism and Nutrition—ICAN, INSERM UMRS 1166, Sorbonne Université, AP-HP Pitié-Salpêtrière University Hospital, 47-83, Boulevard de l’Hôpital, 75013 Paris, France
| | - Khaoula Bouazizi
- Laboratoire d’Imagerie Biomédicale, CNRS, INSERM UMR 1146, Sorbonne Université, Paris, France
- Foundation for Innovation in Cardiometabolism and Nutrition (IHU-ICAN, ANR-10-IAHU-05), 47-83, Boulevard de l’Hôpital, 75013 Paris, France
| | - Maharajah Ponnaiah
- Foundation for Innovation in Cardiometabolism and Nutrition (IHU-ICAN, ANR-10-IAHU-05), 47-83, Boulevard de l’Hôpital, 75013 Paris, France
| | - Nadjia Kachenoura
- Laboratoire d’Imagerie Biomédicale, CNRS, INSERM UMR 1146, Sorbonne Université, Paris, France
| | - Etienne Charpentier
- Institute of Cardiometabolism and Nutrition—ICAN, INSERM UMR 1146, Laboratoire d’Imagerie Biomédicale, Unité D’Imagerie Cardiovasculaire et Thoracique, Sorbonne Université, AP-HP Hôpital Pitié-Salpêtrière, Paris, France
| | - Mohamed Zarai
- Institute of Cardiometabolism and Nutrition—ICAN, INSERM UMR 1146, Laboratoire d’Imagerie Biomédicale, Unité D’Imagerie Cardiovasculaire et Thoracique, Sorbonne Université, AP-HP Hôpital Pitié-Salpêtrière, Paris, France
| | - Karine Clement
- Nutrition and Obesity: Systemic Approaches, NutriOmics, Sorbonne Université, INSERM, Paris, France
- Department of Nutrition, Sorbonne Université, Assistance Publique- Hôpitaux de Paris, AP-HP, Pitié-Salpêtrière University Hospital, 47-83 Boulevard de l'Hôpital, 75013 Paris, France
| | - Fabrizio Andreelli
- Nutrition and Obesity: Systemic Approaches, NutriOmics, Sorbonne Université, INSERM, Paris, France
- Department of Diabetology, AP-HP Pitié-Salpêtrière University Hospital, Sorbonne Université, Paris, France
| | - Judith Aron-Wisnewsky
- Nutrition and Obesity: Systemic Approaches, NutriOmics, Sorbonne Université, INSERM, Paris, France
- Department of Nutrition, Sorbonne Université, Assistance Publique- Hôpitaux de Paris, AP-HP, Pitié-Salpêtrière University Hospital, 47-83 Boulevard de l'Hôpital, 75013 Paris, France
| | - Stéphane N Hatem
- Institute of Cardiology, Foundation for Innovation in Cardiometabolism and Nutrition—ICAN, INSERM UMRS 1166, Sorbonne Université, AP-HP Pitié-Salpêtrière University Hospital, 47-83, Boulevard de l’Hôpital, 75013 Paris, France
- Foundation for Innovation in Cardiometabolism and Nutrition (IHU-ICAN, ANR-10-IAHU-05), 47-83, Boulevard de l’Hôpital, 75013 Paris, France
| | - Alban Redheuil
- Institute of Cardiometabolism and Nutrition—ICAN, INSERM UMR 1146, Laboratoire d’Imagerie Biomédicale, Unité D’Imagerie Cardiovasculaire et Thoracique, Sorbonne Université, AP-HP Hôpital Pitié-Salpêtrière, Paris, France
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3
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Kraft M, Ryger S, Berman BP, Downs ME, Jordanova KV, Poorman ME, Oberdick SD, Ogier SE, Russek SE, Dagher J, Keenan KE. Towards a barrier-free anthropomorphic brain phantom for quantitative magnetic resonance imaging: Design, first construction attempt, and challenges. PLoS One 2023; 18:e0285432. [PMID: 37437022 DOI: 10.1371/journal.pone.0285432] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2023] [Accepted: 04/21/2023] [Indexed: 07/14/2023] Open
Abstract
Existing magnetic resonance imaging (MRI) reference objects, or phantoms, are typically constructed from simple liquid or gel solutions in containers with specific geometric configurations to enable multi-year stability. However, there is a need for phantoms that better mimic the human anatomy without barriers between the tissues. Barriers result in regions without MRI signal between the different tissue mimics, which is an artificial image artifact. We created an anatomically representative 3D structure of the brain that mimicked the T1 and T2 relaxation properties of white and gray matter at 3 T. While the goal was to avoid barriers between tissues, the 3D printed barrier between white and gray matter and other flaws in the construction were visible at 3 T. Stability measurements were made using a portable MRI system operating at 64 mT, and T2 relaxation time was stable from 0 to 22 weeks. The phantom T1 relaxation properties did change from 0 to 10 weeks; however, they did not substantially change between 10 weeks and 22 weeks. The anthropomorphic phantom used a dissolvable mold construction method to better mimic anatomy, which worked in small test objects. The construction process, though, had many challenges. We share this work with the hope that the community can build on our experience.
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Affiliation(s)
- Mikail Kraft
- National Institute of Standards and Technology, Physical Measurement Laboratory, Boulder, Colorado, United States of America
| | - Slavka Ryger
- National Institute of Standards and Technology, Physical Measurement Laboratory, Boulder, Colorado, United States of America
| | - Ben P Berman
- The MITRE Corporation, McLean, Virginia, United States of America
| | - Matthew E Downs
- The MITRE Corporation, McLean, Virginia, United States of America
| | - Kalina V Jordanova
- National Institute of Standards and Technology, Physical Measurement Laboratory, Boulder, Colorado, United States of America
| | - Megan E Poorman
- Hyperfine, Inc, Guilford, Connecticut, United States of America
| | - Samuel D Oberdick
- National Institute of Standards and Technology, Physical Measurement Laboratory, Boulder, Colorado, United States of America
- Department of Physics, University of Colorado, Boulder, Colorado, United States of America
| | - Stephen E Ogier
- National Institute of Standards and Technology, Physical Measurement Laboratory, Boulder, Colorado, United States of America
- Department of Physics, University of Colorado, Boulder, Colorado, United States of America
| | - Stephen E Russek
- National Institute of Standards and Technology, Physical Measurement Laboratory, Boulder, Colorado, United States of America
| | - Joseph Dagher
- The MITRE Corporation, McLean, Virginia, United States of America
| | - Kathryn E Keenan
- National Institute of Standards and Technology, Physical Measurement Laboratory, Boulder, Colorado, United States of America
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Viltužnik R, Kaučič A, Blinc A, Vidmar J, Serša I. Comparing CT and MR Properties of Artificial Thrombi According to Their Composition. Diagnostics (Basel) 2023; 13:diagnostics13101802. [PMID: 37238289 DOI: 10.3390/diagnostics13101802] [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: 03/19/2023] [Revised: 05/09/2023] [Accepted: 05/16/2023] [Indexed: 05/28/2023] Open
Abstract
This study aims to determine whether and to what extent the structure and composition of thrombi can be assessed using NMR and CT measurements. Seven different thrombus models, namely, six RBC thrombi with hematocrit levels (HTs) of 0%, 20%, 40%, 60%, 80% and 100% and one platelet thrombus model, were analyzed using proton NMR at 100 MHz and 400 MHz, with measurements of T1 and T2 NMR relaxation times and measurements of the apparent diffusion coefficient (ADC). In addition, the thrombus models were CT-scanned in a dual-energy mode (80 kV and 140 kV) and in a single-energy mode (80 kV) to measure their CT numbers. The results confirmed that RBC thrombi can be distinguished from platelet thrombi by using ADC and CT number measurements in all three settings, while they cannot be distinguished by using T1 and T2 measurements. All measured parameters allowed for the differentiation of RBC thrombi according to their HT values, but the best sensitivity to HT was obtained with ADC and single-energy CT measurements. The importance of this study also lies in the potential application of its results for the characterization of actual thrombi in vivo.
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Affiliation(s)
- Rebeka Viltužnik
- Jožef Stefan Institute, 1000 Ljubljana, Slovenia
- Institute of Physiology, Faculty of Medicine, University of Ljubljana, 1000 Ljubljana, Slovenia
| | - Aleš Kaučič
- Clinical Institute of Radiology, University Medical Centre Ljubljana, 1000 Ljubljana, Slovenia
| | - Aleš Blinc
- Department of Vascular Diseases, University Medical Centre Ljubljana, 1000 Ljubljana, Slovenia
- Division of Internal Medicine, Faculty of Medicine, University of Ljubljana, 1000 Ljubljana, Slovenia
| | - Jernej Vidmar
- Jožef Stefan Institute, 1000 Ljubljana, Slovenia
- Institute of Physiology, Faculty of Medicine, University of Ljubljana, 1000 Ljubljana, Slovenia
- Clinical Institute of Radiology, University Medical Centre Ljubljana, 1000 Ljubljana, Slovenia
| | - Igor Serša
- Jožef Stefan Institute, 1000 Ljubljana, Slovenia
- Institute of Anatomy, Faculty of Medicine, University of Ljubljana, 1000 Ljubljana, Slovenia
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5
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Fortier V, Levesque IR. Longitudinal relaxation in fat-water mixtures and its dependence on fat content at 3 T. NMR IN BIOMEDICINE 2022; 35:e4629. [PMID: 34636097 DOI: 10.1002/nbm.4629] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2020] [Revised: 08/27/2021] [Accepted: 09/14/2021] [Indexed: 06/13/2023]
Abstract
Longitudinal (T1 ) relaxation of triglyceride molecules and water is of interest for fat-water separation and fat quantification. A better understanding of T1 relaxation could benefit modeling for applications in fat quantification and relaxation mapping. This work investigated T1 relaxation of spectral resonances of triglyceride molecules and water in liquid fat-water mixtures and its dependence on the fat fraction. Dairy cream and a safflower oil emulsion were used. These were diluted with distilled water to produce a variety of fat mass fractions (4.4% to 35% in dairy cream and 6.3% to 52.3% in safflower oil emulsion). T1 was measured at room temperature at 3 T using an inversion recovery STimulated Echo Acquisition Mode (STEAM) MR spectroscopy method with a series of inversion times. T1 variations as a function of fat fraction were investigated for various resonances. A two-component model was developed to describe the relaxation in a fat-water mixture as a function of the fat fraction. The T1 of water and of all fat resonances studied in this work decreased as the fat fraction increased. The relative variation in T1 was different for each fat resonance. The T1 of the methylene resonance showed the least variation as a function of the fat fraction. The proposed two-component model closely fits the observed T1 variations. In conclusion, this work clarifies how the T1 of major and minor fat resonances and of the water resonance varies as a function of the fat fraction in fat-water mixtures. Knowledge of these variations could serve modeling, analysis of MRI measurements in fat-water mixtures, and phantom preparation.
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Affiliation(s)
- Véronique Fortier
- Medical Physics Unit, McGill University, Montréal, QC, Canada
- Biomedical Engineering, McGill University, Montréal, QC, Canada
| | - Ives R Levesque
- Medical Physics Unit, McGill University, Montréal, QC, Canada
- Biomedical Engineering, McGill University, Montréal, QC, Canada
- Research Institute of the McGill University Health Centre, Montréal, QC, Canada
- Gerald Bronfman Department of Oncology, McGill University, Montréal, Canada
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Fritz V, Martirosian P, Machann J, Daniels R, Schick F. A comparison of emulsifiers for the formation of oil-in-water emulsions: stability of the emulsions within 9 h after production and MR signal properties. MAGNETIC RESONANCE MATERIALS IN PHYSICS BIOLOGY AND MEDICINE 2021; 35:401-410. [PMID: 34698962 PMCID: PMC9188495 DOI: 10.1007/s10334-021-00970-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/24/2021] [Revised: 10/12/2021] [Accepted: 10/13/2021] [Indexed: 11/21/2022]
Abstract
Objective To provide a basis for the selection of suitable emulsifiers in oil-in-water emulsions used as tissue analogs for MRI experiments. Three different emulsifiers were investigated with regard to their ability to stabilize tissue-like oil-in-water emulsions. Furthermore, MR signal properties of the emulsifiers themselves and influences on relaxation times and ADC values of the aqueous phase were investigated. Materials and methods Polysorbate 60, sodium dodecyl sulfate (SDS) and soy lecithin were used as emulsifiers. MR characteristics of emulsifiers were assessed in aqueous solutions and their function as a stabilizer was examined in oil-in-water emulsions of varying fat content (10, 20, 30, 40, 50%). Stability and homogeneity of the oil-in-water emulsions were evaluated with a delay of 3 h and 9 h after preparation using T1 mapping and visual control. Signal properties of the emulsifiers were investigated by 1H-MRS in aqueous emulsifier solutions. Relaxometry and diffusion weighted MRI (DWI) were performed to investigate the effect of various emulsifier concentrations on relaxation times (T1 and T2) and ADC values of aqueous solutions. Results Emulsions stabilized by polysorbate 60 or soy lecithin were stable and homogeneous across all tested fat fractions. In contrast, emulsions with SDS showed a significantly lower stability and homogeneity. Recorded T1 maps revealed marked creaming of oil droplets in almost all of the emulsions with SDS. The spectral analysis showed several additional signals for polysorbate and SDS. However, lecithin remained invisible in 1H-MRS. Relaxometry and DWI revealed different influences of the emulsifiers on water: Polysorbate and SDS showed only minor effects on relaxation times and ADC values of aqueous solutions, whereas lecithin showed a strong decrease in both relaxation times (r1,lecithin = 0.11 wt.%−1 s−1, r2,lecithin = 0.57 wt.%−1 s−1) and ADC value (Δ(ADC)lecithin = − 0.18 × 10–3 mm2/s⋅wt.%) with increasing concentration. Conclusion Lecithin is suggested as the preferred emulsifier of oil-in-water emulsions in MRI as it shows a high stabilizing ability and remains invisible in MRI experiments. In addition, lecithin is suitable as an alternative means of adjusting relaxation times and ADC values of water.
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Affiliation(s)
- Victor Fritz
- Section on Experimental Radiology, Department of Diagnostic and Interventional Radiology, University of Tuebingen, Tuebingen, Germany.
| | - Petros Martirosian
- Section on Experimental Radiology, Department of Diagnostic and Interventional Radiology, University of Tuebingen, Tuebingen, Germany
| | - Jürgen Machann
- Section on Experimental Radiology, Department of Diagnostic and Interventional Radiology, University of Tuebingen, Tuebingen, Germany.,Institute for Diabetes Research and Metabolic Diseases of the Helmholtz Centre Munich at the University of Tuebingen, Tuebingen, Germany.,German Center for Diabetes Research (DZD), Neuherberg, Germany
| | - Rolf Daniels
- Institute of Pharmaceutical Technology, University of Tuebingen, Tuebingen, Germany
| | - Fritz Schick
- Section on Experimental Radiology, Department of Diagnostic and Interventional Radiology, University of Tuebingen, Tuebingen, Germany.,Institute for Diabetes Research and Metabolic Diseases of the Helmholtz Centre Munich at the University of Tuebingen, Tuebingen, Germany
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Bachrata B, Strasser B, Bogner W, Schmid AI, Korinek R, Krššák M, Trattnig S, Robinson SD. Simultaneous Multiple Resonance Frequency imaging (SMURF): Fat-water imaging using multi-band principles. Magn Reson Med 2021; 85:1379-1396. [PMID: 32981114 PMCID: PMC7756227 DOI: 10.1002/mrm.28519] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2019] [Revised: 07/31/2020] [Accepted: 08/24/2020] [Indexed: 12/15/2022]
Abstract
PURPOSE To develop a fat-water imaging method that allows reliable separation of the two tissues, uses established robust reconstruction methods, and requires only one single-echo acquisition. THEORY AND METHODS The proposed method uses spectrally selective dual-band excitation in combination with CAIPIRINHA to generate separate images of fat and water simultaneously. Spatially selective excitation without cross-contamination is made possible by the use of spatial-spectral pulses. Fat and water images can either be visualized separately, or the fat images can be corrected for chemical shift displacement and, in gradient echo imaging, for chemical shift-related phase discrepancy, and recombined with water images, generating fat-water images free of chemical shift effects. Gradient echo and turbo spin echo sequences were developed based on this Simultaneous Multiple Resonance Frequency imaging (SMURF) approach and their performance was assessed at 3Tesla in imaging of the knee, breasts, and abdomen. RESULTS The proposed method generated well-separated fat and water images with minimal unaliasing artefacts or cross-excitation, evidenced by the near absence of water signal attributed to the fat image and vice versa. The separation achieved was similar to or better than that using separate acquisitions with water- and fat-saturation or Dixon methods. The recombined fat-water images provided similar image contrast to conventional images, but the chemical shift effects were eliminated. CONCLUSION Simultaneous Multiple Resonance Frequency imaging is a robust fat-water imaging technique that offers a solution to imaging of body regions with significant amounts of fat.
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Affiliation(s)
- Beata Bachrata
- High Field MR Centre, Department of Biomedical Imaging and Image‐Guided TherapyMedical University of ViennaViennaAustria,Christian Doppler Laboratory for Clinical Molecular MR ImagingViennaAustria
| | - Bernhard Strasser
- High Field MR Centre, Department of Biomedical Imaging and Image‐Guided TherapyMedical University of ViennaViennaAustria,Athinoula A. Martinos Center for Biomedical Imaging, Department of RadiologyMassachusetts General Hospital, Harvard Medical SchoolBostonMAUSA
| | - Wolfgang Bogner
- High Field MR Centre, Department of Biomedical Imaging and Image‐Guided TherapyMedical University of ViennaViennaAustria
| | - Albrecht Ingo Schmid
- High Field MR Centre, Center for Medical Physics and Biomedical EngineeringMedical University of ViennaViennaAustria
| | - Radim Korinek
- Institute of Scientific Instruments of the CASBrnoCzech Republic
| | - Martin Krššák
- High Field MR Centre, Department of Biomedical Imaging and Image‐Guided TherapyMedical University of ViennaViennaAustria,Christian Doppler Laboratory for Clinical Molecular MR ImagingViennaAustria,Department of Internal Medicine III, Division of Endocrinology and MetabolismMedical University of ViennaViennaAustria
| | - Siegfried Trattnig
- High Field MR Centre, Department of Biomedical Imaging and Image‐Guided TherapyMedical University of ViennaViennaAustria,Christian Doppler Laboratory for Clinical Molecular MR ImagingViennaAustria
| | - Simon Daniel Robinson
- High Field MR Centre, Department of Biomedical Imaging and Image‐Guided TherapyMedical University of ViennaViennaAustria,Centre of Advanced ImagingUniversity of QueenslandBrisbaneQLDAustralia,Department of NeurologyMedical University of GrazGrazAustria
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8
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Steenkjaer CH, Mencagli RA, Vaeggemose M, Andersen H. Isokinetic strength and degeneration of lower extremity muscles in patients with myotonic dystrophy; an MRI study. Neuromuscul Disord 2021; 31:198-211. [PMID: 33568272 DOI: 10.1016/j.nmd.2020.12.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2020] [Revised: 12/21/2020] [Accepted: 12/22/2020] [Indexed: 01/10/2023]
Abstract
Our aim was to determine isokinetic strength and degeneration of lower extremity muscles in patients with Myotonic Dystrophy (DM1). In 19 patients with DM1 and 19 matched controls, strength measured by isokinetic dynamometry was expressed as percentage of expected strength (ePct), adjusted for age, height, weight and gender. MRI of the hip, thigh and calf muscles were obtained. Fat fraction (FF), mean contractile cross-sectional area (cCSA) and specific strength (Nm/cm2) were calculated. Patients' ankle plantar flexors, knee flexors and extensors had higher FF (Δ: 0.08 - 0.42) and lower cCSA (Δ: 3.2 -17.1 cm2) compared to controls (p ≤ 0.005). EPct (Δ: 19.5 - 41.6%) and specific strength (Δ: 0.27 - 0.96 Nm/cm2) were lower in the majority of patients muscle groups (p˂0.05). Close correlations were found for patients when relating ePct to; FF for plantar flexors (R2=0.742, p<0.001) and knee extensors (R2=0.732, p<0.001), cCSA for plantar flexors (R2=0.696, p<0.001) and knee extensors (R2=0.633, p<0.001), and specific strength for dorsal flexors (ρ=0.855, p = 0.008). In conclusion, patients had weaker lower extremity muscles with higher FF, lower cCSA and specific strength compared to controls. Muscle degeneration determined by quantitative MRI strongly correlated to strength supporting its feasibility to quantify muscle dysfunction in DM1.
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Affiliation(s)
- C H Steenkjaer
- Department of Neurology, Aarhus University Hospital, Aarhus, Denmark.
| | - R A Mencagli
- Department of Neurology, Aarhus University Hospital, Aarhus, Denmark
| | - M Vaeggemose
- Department of Neurology, Aarhus University Hospital, Aarhus, Denmark
| | - H Andersen
- Department of Neurology, Aarhus University Hospital, Aarhus, Denmark
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9
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Functional characterization of human brown adipose tissue metabolism. Biochem J 2020; 477:1261-1286. [PMID: 32271883 DOI: 10.1042/bcj20190464] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2020] [Revised: 03/13/2020] [Accepted: 03/16/2020] [Indexed: 02/07/2023]
Abstract
Brown adipose tissue (BAT) has long been described according to its histological features as a multilocular, lipid-containing tissue, light brown in color, that is also responsive to the cold and found especially in hibernating mammals and human infants. Its presence in both hibernators and human infants, combined with its function as a heat-generating organ, raised many questions about its role in humans. Early characterizations of the tissue in humans focused on its progressive atrophy with age and its apparent importance for cold-exposed workers. However, the use of positron emission tomography (PET) with the glucose tracer [18F]fluorodeoxyglucose ([18F]FDG) made it possible to begin characterizing the possible function of BAT in adult humans, and whether it could play a role in the prevention or treatment of obesity and type 2 diabetes (T2D). This review focuses on the in vivo functional characterization of human BAT, the methodological approaches applied to examine these features and addresses critical gaps that remain in moving the field forward. Specifically, we describe the anatomical and biomolecular features of human BAT, the modalities and applications of non-invasive tools such as PET and magnetic resonance imaging coupled with spectroscopy (MRI/MRS) to study BAT morphology and function in vivo, and finally describe the functional characteristics of human BAT that have only been possible through the development and application of such tools.
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10
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Marage L, Gambarota G, Lasbleiz J, Lederlin M, Saint-Jalmes H. Confounding factors in multi-parametric q-MRI protocol: A study of bone marrow biomarkers at 1.5 T. Magn Reson Imaging 2020; 74:96-104. [PMID: 32858181 DOI: 10.1016/j.mri.2020.08.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2019] [Revised: 07/23/2020] [Accepted: 08/20/2020] [Indexed: 10/23/2022]
Abstract
OBJECT The MRI tissue characterization of vertebral bone marrow includes the measurement of proton density fat fraction (PDFF), T1 and T2* relaxation times of the water and fat components (T1W, T1F, T2*W, T2*F), IVIM diffusion D, perfusion fraction f and pseudo-diffusion coefficient D*. However, the measurement of these vertebral bone marrow biomarkers (VBMBs) is affected with several confounding factors. In the current study, we investigated these confounding factors including the regional variation taking the example of variation between the anterior and posterior area in lumbar vertebrae, B1 inhomogeneity and the effect of fat suppression on f. MATERIALS AND METHODS A fat suppressed diffusion-weighted sequence and two 3D gradient multi-echo sequences were used for the measurements of the seven VBMBs. A turbo flash B1 map sequence was used to estimate B1 inhomogeneities and thus, to correct flip angle for T1 quantification. We introduced a correction to perfusion fraction f measured with fat suppression, namely fPDFF. RESULTS A significant difference in the values of PDFF, f and fPDFF, T1F, T2*W and D was observed between the anterior and posterior region. Although, little variations of flip angle were observed in this anterior-posterior direction in one vertebra but larger variations were observed in head-feet direction from L1 to L5 vertebrae. DISCUSSION The regional difference in PDFF, fPDFF and T2*W can be ascribed to differences in the trabecular bone density and vascular network within vertebrae. The regional variation of VBMBs shows that care should be taken in reproducing the same region-of-interest location along a longitudinal study. The same attention should be taken while measuring f in fatty environment, and measuring T1. Furthermore, the MRI-protocol presented here allows for measurements of seven VBMBs in less than 6 min and is of interest for longitudinal studies of bone marrow diseases.
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Affiliation(s)
- Louis Marage
- Univ Rennes, CHU Rennes, CLCC Eugène Marquis, Inserm, LTSI - UMR 1099, F-35000 Rennes, France.
| | - Giulio Gambarota
- Univ Rennes, CHU Rennes, CLCC Eugène Marquis, Inserm, LTSI - UMR 1099, F-35000 Rennes, France
| | - Jeremy Lasbleiz
- Univ Rennes, CHU Rennes, CLCC Eugène Marquis, Inserm, LTSI - UMR 1099, F-35000 Rennes, France
| | - Mathieu Lederlin
- Univ Rennes, CHU Rennes, CLCC Eugène Marquis, Inserm, LTSI - UMR 1099, F-35000 Rennes, France
| | - Hervé Saint-Jalmes
- Univ Rennes, CHU Rennes, CLCC Eugène Marquis, Inserm, LTSI - UMR 1099, F-35000 Rennes, France
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11
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Thompson RB, Chow K, Mager D, Pagano JJ, Grenier J. Simultaneous proton density fat-fraction and R 2 ∗ imaging with water-specific T 1 mapping (PROFIT 1 ): application in liver. Magn Reson Med 2020; 85:223-238. [PMID: 32754942 DOI: 10.1002/mrm.28434] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2020] [Revised: 06/22/2020] [Accepted: 06/23/2020] [Indexed: 12/17/2022]
Abstract
PURPOSE To describe and validate a simultaneous proton density fat-fraction (PDFF) imaging and water-specific T1 mapping (T1(Water) ) approach for the liver (PROFIT1 ) with R 2 ∗ mapping and low sensitivity to B 1 + calibration or inhomogeneity. METHODS A multiecho gradient-echo sequence, with and without saturation preparation, was designed for simultaneous imaging of liver PDFF, R 2 ∗ , and T1(Water) (three slices in ~13 seconds). Chemical-shift-encoded MRI processing yielded fat-water separated images and R 2 ∗ maps. T1(Water) calculation utilized saturation and nonsaturation-recovery water-separated images. Several variable flip angle schemes across k-space (increasing flip angles in sequential RF pulses) were evaluated for minimization of T1 weighting, to reduce the B 1 + dependence of T1(Water) and PDFF (reduced flip angle dependence). T1(Water) accuracy was validated in mixed fat-water phantoms, with various PDFF and T1 values (3T). In vivo application was illustrated in five volunteers and five patients with nonalcoholic fatty liver disease (PDFF, T1(Water) , R 2 ∗ ). RESULTS A sin3 (θ) flip angle pattern (0 < θ < π/2 over k-space) yielded the largest PROFIT1 signal yield with negligible B 1 + dependence for both T1(Water) and PDFF. Mixed fat-water phantom experiments illustrated excellent agreement between PROFIT1 and gold-standard spectroscopic evaluation of PDFF and T1(Water) (<1% T1 error). In vivo PDFF, T1(Water) , and R 2 ∗ maps illustrated independence of the PROFIT1 values from B 1 + inhomogeneity and significant differences between volunteers and patients with nonalcoholic fatty liver disease for T1(Water) (927 ± 56 ms vs. 1033 ± 23 ms; P < .05) and PDFF (2.0% ± 0.8% vs. 13.4% ± 5.0%, P < .05). R 2 ∗ was similar between groups. CONCLUSION The PROFIT1 pulse sequence provides fast simultaneous quantification of PDFF, T1(Water) , and R 2 ∗ with minimal sensitivity to B 1 + miscalibration or inhomogeneity.
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Affiliation(s)
- Richard B Thompson
- Department of Biomedical Engineering, University of Alberta, Edmonton, AB, Canada
| | - Kelvin Chow
- Cardiovascular MR R&D, Siemens Medical Solutions USA, Inc., Chicago, IL, USA
| | - Diana Mager
- Department of Agriculture Food and Nutrition Science, University of Alberta, Edmonton, AB, Canada
| | - Joseph J Pagano
- Department of Biomedical Engineering, University of Alberta, Edmonton, AB, Canada
| | - Justin Grenier
- Department of Biomedical Engineering, University of Alberta, Edmonton, AB, Canada
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12
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Ma YJ, Fan S, Shao H, Du J, Szeverenyi NM, Young IR, Bydder GM. Use of Multiplied, Added, Subtracted and/or FiTted Inversion Recovery (MASTIR) pulse sequences. Quant Imaging Med Surg 2020; 10:1334-1369. [PMID: 32550142 DOI: 10.21037/qims-20-568] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
The group of Multiplied, Added, Subtracted and/or fiTted Inversion Recovery (MASTIR) pulse sequences in which usually two or more inversion recovery (IR) images of different types are combined is described, and uses for this type of sequence are outlined. IR sequences of different types can be multiplied, added, subtracted, and/or fitted together to produce variants of the MASTIR sequence. The sequences provide a range of options for increasing image contrast, demonstrating specific tissues and fluids of interest, and suppressing unwanted signals. A formalism using the concept of pulse sequences as tissue property filters is used to explain the signal, contrast and weighting of the pulse sequences with both univariate and multivariate filter models. Subtraction of one magnitude reconstructed IR image from another with a shorter TI can produce very high T1 dependent positive contrast from small increases in T1. The reverse subtracted IR sequence can provide high positive contrast enhancement with gadolinium chelates and iron deposition which decrease T1. Additional contrast to that arising from increases in T1 can be produced by supplementing this with contrast arising from concurrent increases in ρm and T2, as well as increases or decreases in diffusion using subtraction IR with echo subtraction and/or diffusion subtraction. Phase images may show 180º differences as a result of rotating into the transverse plane both positive and negative longitudinal magnetization. Phase images with contrast arising in this way, or other ways, can be multiplied by magnitude IR images to increase the contrast of the latter. Magnetization Transfer (MT) and susceptibility can be used with IR sequences to improve contrast. Selective images of white and brown adipose tissue lipid and water components can be produced using different TIs and in and out-of-phase TEs. Selective images of ultrashort and short T2 tissue components can be produced by nulling long T2 tissue components with an inversion pulse and subtraction of images with longer TEs from images with ultrashort TEs. The Double Echo Sliding IR (DESIRE) sequence provides images with a wide range of TIs from which it is possible to choose values of TI to achieve particular types of tissue and/or fluid contrast (e.g., for subtraction with different TIs, as described above, and for long T2 tissue signal nulling with UTE sequences). Unwanted tissue and fluid signals can be suppressed by addition and subtraction of phase-sensitive (ps) and magnitude reconstructed images. The sequence also offers options for synergistic use of the changes in blood and tissue ρm, T1, T2/T2*, D* and perfusion that can be seen with fMRI of the brain. In-vivo and ex-vivo illustrative examples of normal brain, cartilage, multiple sclerosis, Alzheimer's disease, and peripheral nerve imaged with different forms of the MASTIR sequence are included.
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Affiliation(s)
- Ya-Jun Ma
- Department of Radiology, University of California, San Diego, San Diego, CA, USA
| | - Shujuan Fan
- Department of Radiology, University of California, San Diego, San Diego, CA, USA
| | - Hongda Shao
- Department of Radiology, University of California, San Diego, San Diego, CA, USA
| | - Jiang Du
- Department of Radiology, University of California, San Diego, San Diego, CA, USA
| | | | - Ian R Young
- Formerly Department of Electrical Engineering, Imperial College, London, UK
| | - Graeme M Bydder
- Department of Radiology, University of California, San Diego, San Diego, CA, USA
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13
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Koolstra K, Webb AG, Veeger TTJ, Kan HE, Koken P, Börnert P. Water-fat separation in spiral magnetic resonance fingerprinting for high temporal resolution tissue relaxation time quantification in muscle. Magn Reson Med 2020; 84:646-662. [PMID: 31898834 PMCID: PMC7217066 DOI: 10.1002/mrm.28143] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2019] [Revised: 11/27/2019] [Accepted: 12/02/2019] [Indexed: 12/16/2022]
Abstract
Purpose To minimize the known biases introduced by fat in rapid T1 and T2 quantification in muscle using a single‐run magnetic resonance fingerprinting (MRF) water–fat separation sequence. Methods The single‐run MRF acquisition uses an alternating in‐phase/out‐of‐phase TE pattern to achieve water–fat separation based on a 2‐point DIXON method. Conjugate phase reconstruction and fat deblurring were applied to correct for B0 inhomogeneities and chemical shift blurring. Water and fat signals were matched to the on‐resonance MRF dictionary. The method was first tested in a multicompartment phantom. To test whether the approach is capable of measuring small in vivo dynamic changes in relaxation times, experiments were run in 9 healthy volunteers; parameter values were compared with and without water–fat separation during muscle recovery after plantar flexion exercise. Results Phantom results show the robustness of the water–fat resolving MRF approach to undersampling. Parameter maps in volunteers show a significant (P < .01) increase in T1 (105 ± 94 ms) and decrease in T2 (14 ± 6 ms) when using water–fat‐separated MRF, suggesting improved parameter quantification by reducing the well‐known biases introduced by fat. Exercise results showed smooth T1 and T2 recovery curves. Conclusion Water–fat separation using conjugate phase reconstruction is possible within a single‐run MRF scan. This technique can be used to rapidly map relaxation times in studies requiring dynamic scanning, in which the presence of fat is problematic.
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Affiliation(s)
- Kirsten Koolstra
- C.J. Gorter Center for High Field MRI, Radiology, Leiden University Medical Center, Leiden, Netherlands
| | - Andrew G Webb
- C.J. Gorter Center for High Field MRI, Radiology, Leiden University Medical Center, Leiden, Netherlands
| | - Thom T J Veeger
- C.J. Gorter Center for High Field MRI, Radiology, Leiden University Medical Center, Leiden, Netherlands
| | - Hermien E Kan
- C.J. Gorter Center for High Field MRI, Radiology, Leiden University Medical Center, Leiden, Netherlands
| | | | - Peter Börnert
- C.J. Gorter Center for High Field MRI, Radiology, Leiden University Medical Center, Leiden, Netherlands.,Philips Research, Hamburg, Germany
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14
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Ikeno H, Sakai K, Imai H, Mizuta M, Nakagawa T, Goto M, Kishida T, Mazda O, Yamada K. Effects of different fat-suppression methods on T1 values in dynamic contrast-enhanced magnetic resonance imaging: a phantom study. Radiol Phys Technol 2019; 12:335-342. [PMID: 31278594 DOI: 10.1007/s12194-019-00521-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2018] [Revised: 06/20/2019] [Accepted: 06/26/2019] [Indexed: 11/28/2022]
Abstract
Dynamic contrast-enhanced MRI may yield variable longitudinal-relaxation time (T1) values depending on the precision of the fat-suppression (FS) technique. This study aimed to investigate the influences of FS methods on T1 value measurements on phantoms containing test tubes filled with mixtures of five volumes of fat, six amounts of contrast agent, and water. Volumetric interpolated images were obtained using several FS methods and flip angles. T1 maps were created based on the variable flip angle approach. The T1 values of water obtained by point-resolved single-voxel spectroscopy (SVS) were used as reference values. Notably, FS methods were shown to have substantial effects on the measurement of T1 values. Among the tested FS methods, the Dixon (water) method produced T1 values most similar to SVS, which can be considered as a reference value for clinical practice.
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Affiliation(s)
- Hiroyasu Ikeno
- Department of Radiology, Kyoto Prefectural University of Medicine, 465 Kawaramachi-Hirokoji, Kamigyo-ku, Kyoto, 602-8566, Japan.
| | - Koji Sakai
- Department of Radiology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, 465 Kawaramachi-Hirokoji, Kamigyo-ku, Kyoto, 602-8566, Japan
| | - Hiroshi Imai
- MR Research and Collaboration Department, Siemens Healthcare K.K, Gate City Osaki West Tower 1-11-1 Osaki, Shinagawa-ku, Tokyo, 141-8644, Japan
| | - Masayoshi Mizuta
- Department of Radiological Technology, Faculty of Medical Science, Kyoto College of Medical Science, 1-3 Imakita, Oyama-higashi, Sonobe, Nantan City, Kyoto, 622-0041, Japan
| | - Toshiaki Nakagawa
- Department of Radiology, Kyoto Prefectural University of Medicine, 465 Kawaramachi-Hirokoji, Kamigyo-ku, Kyoto, 602-8566, Japan
| | - Mariko Goto
- Department of Radiology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, 465 Kawaramachi-Hirokoji, Kamigyo-ku, Kyoto, 602-8566, Japan
| | - Tsunao Kishida
- Department of Immunology, Kyoto Prefectural University of Medicine, 465 Kawaramachi-Hirokoji, Kamigyo-ku, Kyoto, 602-8566, Japan
| | - Osam Mazda
- Department of Immunology, Kyoto Prefectural University of Medicine, 465 Kawaramachi-Hirokoji, Kamigyo-ku, Kyoto, 602-8566, Japan
| | - Kei Yamada
- Department of Radiology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, 465 Kawaramachi-Hirokoji, Kamigyo-ku, Kyoto, 602-8566, Japan
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15
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Yamashiro A, Kobayashi M, Saito T. Cerebrospinal fluid T1 value phantom reproduction at scan room temperature. J Appl Clin Med Phys 2019; 20:166-175. [PMID: 31179645 PMCID: PMC6612700 DOI: 10.1002/acm2.12659] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2018] [Revised: 05/16/2019] [Accepted: 05/21/2019] [Indexed: 01/05/2023] Open
Abstract
The T1 value of pure water, which is often used as a phantom to simulate cerebrospinal fluid, is significantly different from that of in-vivo cerebrospinal fluid. The purpose of this study was to develop a phantom with a T1 value equivalent to that of in-vivo cerebrospinal fluid under examination room temperature (23°C-25°C). In this study, 1.5 and 3.0 T magnetic resonance imaging scanners were used. We examined the signal intensity change in relation to pure water temperature, the T1 values of acetone-diluted solutions (0-100 v/v%, in 10 steps), and the correlation coefficients obtained from volunteers and the prepared phantoms. The T1 value was close to the value reported in the literature for cerebrospinal fluid when the acetone-diluted solution was 70 v/v% or higher at scan room temperature. The value at that time was 3532.81-4704.57 ms at 1.5 T and it ranged from 4052.41 to 5701.61 ms at 3.0 T. The highest correlation with the values obtained from the volunteers was r = 0.993 with pure acetone at 1.5 T and r = 0.991 with acetone 90 v/v% at 3.0 T. The relative error of the best phantom-volunteer match was 32.61 (%) ± 6.71 at 1.5 T and 46.67 (%) ± 4.31 at 3.0 T. The T1 value measured by the null point method did not detect a significant difference between in vivo CSF and acetone 100 v/v% at 1.5 T and acetone 90 v/v% at 3.0 T. The T1 value of cerebrospinal fluid in the living body at scan room temperature was reproduced with acetone. The optimum concentration of acetone for cerebrospinal-fluid reproduction was pure acetone at 1.5 T and 90 v/v% at 3.0 T.
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Affiliation(s)
- Akihiro Yamashiro
- Department of Radiology, Nagano Red Cross Hospital, Nagano-City, Nagano-ken, Japan
| | - Masato Kobayashi
- Department of Radiology, Shinano Town Shin-Etsu Hospital, Kamiminochi-gun, Nagano-ken, Japan
| | - Takaaki Saito
- Department of Radiology, Iiyama Red Cross Hospital, Iiyama-City, Nagano-ken, Japan
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16
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Franz D, Diefenbach MN, Treibel F, Weidlich D, Syväri J, Ruschke S, Wu M, Holzapfel C, Drabsch T, Baum T, Eggers H, Rummeny EJ, Hauner H, Karampinos DC. Differentiating supraclavicular from gluteal adipose tissue based on simultaneous PDFF and T 2 * mapping using a 20-echo gradient-echo acquisition. J Magn Reson Imaging 2019; 50:424-434. [PMID: 30684282 PMCID: PMC6767392 DOI: 10.1002/jmri.26661] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2018] [Revised: 01/08/2019] [Accepted: 01/09/2019] [Indexed: 01/15/2023] Open
Abstract
Background Adipose tissue (AT) can be classified into white and brown/beige subtypes. Chemical shift encoding‐based water–fat MRI‐techniques allowing simultaneous mapping of proton density fat fraction (PDFF) and T2* result in a lower PDFF and a shorter T2* in brown compared with white AT. However, AT T2* values vary widely in the literature and are primarily based on 6‐echo data. Increasing the number of echoes in a multiecho gradient‐echo acquisition is expected to increase the precision of AT T2* mapping. Purpose 1) To mitigate issues of current T2*‐measurement techniques through experimental design, and 2) to investigate gluteal and supraclavicular AT T2* and PDFF and their relationship using a 20‐echo gradient‐echo acquisition. Study Type Prospective. Subjects Twenty‐one healthy subjects. Field Strength/Sequence Assessment First, a ground truth signal evolution was simulated from a single‐T2* water–fat model. Second, a time‐interleaved 20‐echo gradient‐echo sequence with monopolar gradients of neck and abdomen/pelvis at 3 T was performed in vivo to determine supraclavicular and gluteal PDFF and T2*. Complex‐based water–fat separation was performed for the first 6 echoes and the full 20 echoes. AT depots were segmented. Statistical Tests Mann‐Whitney test, Wilcoxon signed‐rank test and simple linear regression analysis. Results Both PDFF and T2* differed significantly between supraclavicular and gluteal AT with 6 and 20 echoes (PDFF: P < 0.0001 each, T2*: P = 0.03 / P < 0.0001 for 6/20 echoes). 6‐echo T2* demonstrated higher standard deviations and broader ranges than 20‐echo T2*. Regression analyses revealed a strong relationship between PDFF and T2* values per AT compartment (R2 = 0.63 supraclavicular, R2 = 0.86 gluteal, P < 0.0001 each). Data Conclusion The present findings suggest that an increase in the number of sampled echoes beyond 6 does not affect AT PDFF quantification, whereas AT T2* is considerably affected. Thus, a 20‐echo gradient‐echo acquisition enables a multiparametric analysis of both AT PDFF and T2* and may therefore improve MR‐based differentiation between white and brown fat. Level of Evidence: 2 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2019;50:424–434.
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Affiliation(s)
- Daniela Franz
- Department of Diagnostic and Interventional Radiology, Klinikum rechts der Isar, Technical University of Munich, Munich, Germany
| | - Maximilian N Diefenbach
- Department of Diagnostic and Interventional Radiology, Klinikum rechts der Isar, Technical University of Munich, Munich, Germany
| | - Franziska Treibel
- Department of Diagnostic and Interventional Radiology, Klinikum rechts der Isar, Technical University of Munich, Munich, Germany
| | - Dominik Weidlich
- Department of Diagnostic and Interventional Radiology, Klinikum rechts der Isar, Technical University of Munich, Munich, Germany
| | - Jan Syväri
- Department of Diagnostic and Interventional Radiology, Klinikum rechts der Isar, Technical University of Munich, Munich, Germany
| | - Stefan Ruschke
- Department of Diagnostic and Interventional Radiology, Klinikum rechts der Isar, Technical University of Munich, Munich, Germany
| | - Mingming Wu
- Department of Diagnostic and Interventional Radiology, Klinikum rechts der Isar, Technical University of Munich, Munich, Germany
| | - Christina Holzapfel
- Institute for Nutritional Medicine, Klinikum rechts der Isar, Technical University of Munich, Munich, Germany
| | - Theresa Drabsch
- Institute for Nutritional Medicine, Klinikum rechts der Isar, Technical University of Munich, Munich, Germany
| | - Thomas Baum
- Department of Diagnostic and Interventional Neuroradiology, Klinikum rechts der Isar, Technical University of Munich, Munich, Germany
| | | | - Ernst J Rummeny
- Department of Diagnostic and Interventional Radiology, Klinikum rechts der Isar, Technical University of Munich, Munich, Germany
| | - Hans Hauner
- Institute for Nutritional Medicine, Klinikum rechts der Isar, Technical University of Munich, Munich, Germany
| | - Dimitrios C Karampinos
- Department of Diagnostic and Interventional Radiology, Klinikum rechts der Isar, Technical University of Munich, Munich, Germany
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Neumayer B, Widek T, Stollberger R, Scheurer E. Reproducibility of relaxometry of human lumbar vertebrae at 3 Tesla using 1
H MR spectroscopy. J Magn Reson Imaging 2017; 48:153-159. [DOI: 10.1002/jmri.25912] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2017] [Accepted: 11/14/2017] [Indexed: 02/04/2023] Open
Affiliation(s)
- Bernhard Neumayer
- Ludwig Boltzmann Institute for Clinical Forensic Imaging; Graz Austria
- BioTechMed-Graz; Austria
| | - Thomas Widek
- Ludwig Boltzmann Institute for Clinical Forensic Imaging; Graz Austria
- BioTechMed-Graz; Austria
| | - Rudolf Stollberger
- BioTechMed-Graz; Austria
- Institute of Medical Engineering; Graz University of Technology; Graz Austria
| | - Eva Scheurer
- Institute of Forensic Medicine; University of Basel; Basel Switzerland
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18
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Burakiewicz J, Sinclair CDJ, Fischer D, Walter GA, Kan HE, Hollingsworth KG. Quantifying fat replacement of muscle by quantitative MRI in muscular dystrophy. J Neurol 2017; 264:2053-2067. [PMID: 28669118 PMCID: PMC5617883 DOI: 10.1007/s00415-017-8547-3] [Citation(s) in RCA: 137] [Impact Index Per Article: 19.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2017] [Revised: 06/12/2017] [Accepted: 06/13/2017] [Indexed: 12/15/2022]
Abstract
The muscular dystrophies are rare orphan diseases, characterized by progressive muscle weakness: the most common and well known is Duchenne muscular dystrophy which affects young boys and progresses quickly during childhood. However, over 70 distinct variants have been identified to date, with different rates of progression, implications for morbidity, mortality, and quality of life. There are presently no curative therapies for these diseases, but a range of potential therapies are presently reaching the stage of multi-centre, multi-national first-in-man clinical trials. There is a need for sensitive, objective end-points to assess the efficacy of the proposed therapies. Present clinical measurements are often too dependent on patient effort or motivation, and lack sensitivity to small changes, or are invasive. Quantitative MRI to measure the fat replacement of skeletal muscle by either chemical shift imaging methods (Dixon or IDEAL) or spectroscopy has been demonstrated to provide such a sensitive, objective end-point in a number of studies. This review considers the importance of the outcome measures, discusses the considerations required to make robust measurements and appropriate quality assurance measures, and draws together the existing literature for cross-sectional and longitudinal cohort studies using these methods in muscular dystrophy.
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Affiliation(s)
- Jedrzej Burakiewicz
- Department of Radiology, C. J. Gorter Center for High Field MRI, Leiden University Medical Centre, Leiden, The Netherlands
| | - Christopher D J Sinclair
- MRC Centre for Neuromuscular Diseases, UCL Institute of Neurology, London, UK.,Neuroradiological Academic Unit, UCL Institute of Neurology, London, UK
| | - Dirk Fischer
- Division of Neuropaediatrics, University of Basel Children's Hospital, Spitalstrasse 33, Postfach, Basel, 4031, Switzerland.,Department of Neurology, University of Basel Hospital, Petersgraben 4, Basel, 4031, Switzerland
| | - Glenn A Walter
- Department of Physiology and Functional Genomics, University of Florida, Gainesville, FL, 32610, USA
| | - Hermien E Kan
- Department of Radiology, C. J. Gorter Center for High Field MRI, Leiden University Medical Centre, Leiden, The Netherlands
| | - Kieren G Hollingsworth
- Newcastle Magnetic Resonance Centre, Institute of Cellular Medicine, Newcastle University, Newcastle-upon-Tyne, UK.
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19
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A fast method for the quantification of fat fraction and relaxation times: Comparison of five sites of bone marrow. Magn Reson Imaging 2017; 39:157-161. [PMID: 28263827 DOI: 10.1016/j.mri.2017.03.001] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2016] [Revised: 02/24/2017] [Accepted: 03/01/2017] [Indexed: 01/29/2023]
Abstract
PURPOSE Bone marrow is found either as red bone marrow, which mainly contains haematopoietic cells, or yellow bone marrow, which mainly contains adipocytes. In adults, red bone marrow is principally located in the axial skeleton. A recent study has introduced a method to simultaneously estimate the fat fraction (FF), the T1 and T2* relaxation times of water (T1w, T2*w) and fat (T1f and T2*f) in the vertebral bone marrow. The aim of the current study was to measure FF, T1w, T1f, T2*w and T2*f in five sites of bone marrow, and to assess the presence of regional variations. METHODS MRI experiments were performed at 1.5T on five healthy volunteers (31.6±15.6years) using a prototype chemical-shift-encoded 3D multi-gradient-echo sequence (VIBE) acquired with two flip angles. Acquisitions were performed in the shoulders, lumbar spine and pelvis, with acquisition times of <25seconds per sequence. Signal intensities of magnitude images of the individual echoes were used to fit the signal and compute FF, T1w, T1f, T2*w and T2*f in the humerus, sternum, vertebra, ilium and femur. RESULTS Regional variations of fat fraction and relaxation times were observed in these sites, with higher fat fraction and longer T1w in the epiphyses of long bones. A high correlation between FF and T1w was measured in these bones (R=0.84 in the humerus and R=0.84 in the femur). In most sites, there was a significant difference between water and fat relaxation times, attesting the relevance of measuring these parameters separately. CONCLUSION The method proposed in the current study allowed for measurements of FF, T1w, T1f, T2*w and T2*f in five sites of bone marrow. Regional variations of these parameters were observed and a strong negative correlation between the T1 of water and the fat fraction in bones with high fat fractions was found.
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Yoo SP, Pineda F, Barrett JC, Poon C, Tirrell M, Chung EJ. Gadolinium-Functionalized Peptide Amphiphile Micelles for Multimodal Imaging of Atherosclerotic Lesions. ACS OMEGA 2016; 1:996-1003. [PMID: 27917409 PMCID: PMC5131325 DOI: 10.1021/acsomega.6b00210] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/26/2016] [Accepted: 11/09/2016] [Indexed: 05/23/2023]
Abstract
The leading causes of morbidity and mortality globally are cardiovascular diseases, and nanomedicine can provide many improvements including disease-specific targeting, early detection, and local delivery of diagnostic agents. To this end, we designed fibrin-binding, peptide amphiphile micelles (PAMs), achieved by incorporating the targeting peptide cysteine-arginine-glutamic acid-lysine-alanine (CREKA), with two types of amphiphilic molecules containing the gadoliniuim (Gd) chelator diethylenetriaminepentaacetic acid (DTPA), DTPA-bis(stearylamide)(Gd), and 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-[(poly(ethylene glycol) (PEG))-2000]-DTPA(Gd) (DSPE-PEG2000-DTPA(Gd)). The material characteristics of the resulting nanoparticle diagnostic probes, clot-binding properties in vitro, and contrast enhancement and safety for dual, optical imaging-magnetic resonance imaging (MRI) were evaluated in the atherosclerotic mouse model. Transmission electron micrographs showed a homogenous population of spherical micelles for formulations containing DSPE-PEG2000-DTPA(Gd), whereas both spherical and cylindrical micelles were formed upon mixing DTPA-BSA(Gd) and CREKA amphiphiles. Clot-binding assays confirmed DSPE-PEG2000-DTPA(Gd)-based CREKA micelles targeted clots over 8-fold higher than nontargeting (NT) counterpart micelles, whereas no difference was found between CREKA and NT, DTPA-BSA(Gd) micelles. However, in vivo MRI and optical imaging studies of the aortas and hearts showed fibrin specificity was conferred by the peptide ligand without much difference between the nanoparticle formulations or shapes. Biodistribution studies confirmed that all micelles were cleared through both the reticuloendothelial system and renal clearance, and histology showed no signs of necrosis. In summary, these studies demonstrate the successful synthesis, and the molecular imaging capabilities of two types of CREKA-Gd PAMs for atherosclerosis. Moreover, we demonstrate the differences in micelle formulations and shapes and their outcomes in vitro versus in vivo for site-specific, diagnostic strategies, and provide the groundwork for the detection of thrombosis via contrast-enhancing agents and concurrent therapeutic delivery for theranostic applications.
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Affiliation(s)
- Sang Pil Yoo
- Institute
for Molecular Engineering, University of
Chicago, 5747 South Ellis Avenue, Chicago, Illinois, 60637, United States
| | - Federico Pineda
- Department
of Radiology, University of Chicago, 5841 South Maryland Avenue, MC2026, Chicago, Illinois 60637, United States
| | - John C. Barrett
- Institute
for Molecular Engineering, University of
Chicago, 5747 South Ellis Avenue, Chicago, Illinois, 60637, United States
| | - Christopher Poon
- Department
of Chemistry, University of Chicago, 929 E. 57th Street, Chicago, Illinois 60637, United States
| | - Matthew Tirrell
- Institute
for Molecular Engineering, University of
Chicago, 5747 South Ellis Avenue, Chicago, Illinois, 60637, United States
| | - Eun Ji Chung
- Institute
for Molecular Engineering, University of
Chicago, 5747 South Ellis Avenue, Chicago, Illinois, 60637, United States
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Le Ster C, Gambarota G, Lasbleiz J, Guillin R, Decaux O, Saint-Jalmes H. Breath-hold MR measurements of fat fraction,T1, andT2* of water and fat in vertebral bone marrow. J Magn Reson Imaging 2016; 44:549-55. [DOI: 10.1002/jmri.25205] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2015] [Accepted: 02/05/2016] [Indexed: 01/23/2023] Open
Affiliation(s)
- Caroline Le Ster
- INSERM, UMR 1099; Rennes France
- Université de Rennes 1, LTSI; Rennes France
- Siemens Healthcare; Saint-Denis France
| | - Giulio Gambarota
- INSERM, UMR 1099; Rennes France
- Université de Rennes 1, LTSI; Rennes France
| | - Jérémy Lasbleiz
- INSERM, UMR 1099; Rennes France
- Université de Rennes 1, LTSI; Rennes France
| | - Raphaël Guillin
- Department of Imaging; Rennes University Hospital; Rennes France
| | - Olivier Decaux
- Department of Imaging; Rennes University Hospital; Rennes France
| | - Hervé Saint-Jalmes
- INSERM, UMR 1099; Rennes France
- Université de Rennes 1, LTSI; Rennes France
- CRLCC, Centre Eugène Marquis; Rennes France
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Bhanu Prakash KN, Srour H, Velan SS, Chuang KH. A method for the automatic segmentation of brown adipose tissue. MAGNETIC RESONANCE MATERIALS IN PHYSICS BIOLOGY AND MEDICINE 2016; 29:287-99. [DOI: 10.1007/s10334-015-0517-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/17/2015] [Revised: 12/02/2015] [Accepted: 12/03/2015] [Indexed: 01/24/2023]
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Le Y, Dale B, Akisik F, Koons K, Lin C. Improved T1, contrast concentration, and pharmacokinetic parameter quantification in the presence of fat with two-point Dixon for dynamic contrast-enhanced magnetic resonance imaging. Magn Reson Med 2015; 75:1677-84. [PMID: 25988338 DOI: 10.1002/mrm.25639] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2014] [Revised: 01/06/2015] [Accepted: 01/07/2015] [Indexed: 11/06/2022]
Abstract
PURPOSE To evaluate the impact of fat and fat-suppression on the quantification of T1, gadolinium concentration, and pharmacokinetic parameters in DCE-MRI. METHODS T1 values were measured in fat-free phantoms using variable flip angle with no fat suppression, quick or interleaved fat saturation (QFS), or two-point Dixon and were compared with reference values measured with inversion recovery-prepared turbo spin echo. Relaxivity of gadolinium-benzyloxypropionictetraacetate (Gd-BOPTA) was measured in emulsions of Gd-BOPTA solution and fat using Dixon in-phase and water-only images. Liver T1 and pharmacokinetic parameters of 15 patients were calculated from Dixon in-phase and water-only images and were correlated with liver fat signal fraction. RESULTS T1 values measured using Dixon water-only and non-fat-suppressed images matched the reference values; while T1 values measured using QFS showed large deviations. Relaxivities and Gd measured in the Dixon water-only images were less affected by the fat than those measured in the in-phase images. The correlation between liver fat fraction and the differences in measured pharmacokinetic parameters using Dixon in-phase and water-only images were significant (P < 0.05) for T1, K(trans), and incremental area under the curve, but not Ve (P = 0.1). CONCLUSION Dixon water-only images provided more reliable estimation of T1, Gd, and pharmacokinetic parameters when fat was present.
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Affiliation(s)
- Yuan Le
- Department of Radiology and Imaging Science, Indiana University School of Medicine, Indianapolis, Indiana, USA
| | - Brian Dale
- Siemens Medical Solutions, USA, MR R&D, Morrisville, North Carolina, USA
| | - Fatih Akisik
- Department of Radiology and Imaging Science, Indiana University School of Medicine, Indianapolis, Indiana, USA
| | - Karen Koons
- Department of Radiology, Indiana University Health, Indianapolis, Indiana, USA
| | - Chen Lin
- Department of Radiology and Imaging Science, Indiana University School of Medicine, Indianapolis, Indiana, USA
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Abstract
In this review, we will first discuss the concept of bone strength and introduce how fat at different locations, including the bone marrow, directly or indirectly regulates bone turnover. We will then review the current literature supporting the mechanistic relationship between marrow fat and bone and our understanding of the relationship between body fat, body weight, and bone with emphasis on its hormonal regulation. Finally, we will briefly discuss the importance and challenges of accurately measuring the fat compartments using non-invasive methods. This review highlights the complex relationship between fat and bone and how these new concepts will impact our diagnostic and therapeutic approaches in the very near future.
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Affiliation(s)
- Richard Kremer
- McGill University, Montreal, QC, Canada
- *Correspondence: Richard Kremer,
| | - Vicente Gilsanz
- Children’s Hospital Los Angeles, Keck School of Medicine of the University of Southern California, Los Angeles, CA, USA
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25
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Garnov N, Linder N, Schaudinn A, Blüher M, Karlas T, Schütz T, Dietrich A, Kahn T, Busse H. Comparison of T1 relaxation times in adipose tissue of severely obese patients and healthy lean subjects measured by 1.5 T MRI. NMR IN BIOMEDICINE 2014; 27:1123-1128. [PMID: 25066754 DOI: 10.1002/nbm.3166] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/23/2013] [Revised: 06/17/2014] [Accepted: 06/22/2014] [Indexed: 06/03/2023]
Abstract
Subcutaneous (SAT) and visceral adipose tissue (VAT) differ in composition, endocrine function and localization in the body. VAT is considered to play a role in the pathogenesis of insulin resistance, type 2 diabetes, fatty liver disease, and other obesity-related disorders. It has been shown that the amount, distribution, and (cellular) composition of adipose tissue (AT) correlate well with metabolic conditions. In this study, T1 relaxation times of AT were measured in severely obese subjects and compared with those of healthy lean controls. Here, we tested the hypothesis that T1 relaxation times of AT differ between lean and obese individuals, but also between VAT and SAT as well as superficial (sSAT) and deep SAT (dSAT) in the same individual. Twenty severely obese subjects (BMI 41.4 ± 4.8 kg/m(2) ) and ten healthy lean controls matched for age (BMI 21.5 ± 1.9 kg/m(2) ) underwent MRI at 1.5 T using a single-shot fast spin-echo sequence (short-tau inversion recovery) at six different inversion times (TI range 100-1000 ms). T1 relaxation times were computed for all subjects by fitting the TI -dependent MR signal intensities of user-defined regions of interest in both SAT and VAT to a model function. T1 times in sSAT and dSAT were only measured in obese patients. For both obese patients and controls, the T1 times of SAT (275 ± 14 and 301 ± 12 ms) were significantly (p < 0.01) shorter than the respective values in VAT (294 ± 20 and 360 ± 35 ms). Obese subjects also showed significant (p < 0.01) T1 differences between sSAT (268 ± 11 ms) and dSAT (281 ± 19 ms). More important, T1 differences in both SAT and VAT were highly significant (p < 0.001) between obese patients and healthy subjects. The results of our pilot study suggest that T1 relaxation times differ between severely obese patients and lean controls, and may potentially provide an additional means for the non-invasive assessment of AT conditions and dysfunction.
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Affiliation(s)
- Nikita Garnov
- Department of Diagnostic and Interventional Radiology, Leipzig University Hospital, Leipzig, Germany; Integrated Research and Treatment Center (IFB) Adiposity Diseases, Leipzig University Medical Center, Leipzig, Germany
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Peterson P, Svensson J, Månsson S. Relaxation effects in MRI-based quantification of fat content and fatty acid composition. Magn Reson Med 2013; 72:1320-9. [PMID: 24327547 DOI: 10.1002/mrm.25048] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2013] [Revised: 10/14/2013] [Accepted: 10/28/2013] [Indexed: 12/26/2022]
Abstract
PURPOSE To investigate various sources of bias in MRI-based quantification of fat fraction (FF) and fatty acid composition (FAC) using chemical shift-encoded techniques. METHODS Signals from various FFs and FACs and individual relaxation rates of all signal components were simulated. From these signals, FF and FAC parameters were estimated with and without correction for differences in individual relaxation rates. In addition, phantom experiments were conducted with various flip angles and number of echoes to validate the simulations. RESULTS As expected, T(1) weighting resulted in an overestimation of the FF, but had much smaller impact on the FAC parameters. Differences in T(2) values of the signal components resulted in overestimation of the FAC parameters in fat/water mixtures, whereas the estimation in pure oil was largely unaffected. This bias was corrected using a simplified signal model with different T(2) values of water and fat, where the accuracy of the modeled T(2) of water was critical. The results of the phantom experiment were in agreement with simulations. CONCLUSION T(1) weighting has only a minor effect on FAC quantification in both fat/water mixtures and pure oils. T(2) weighting is mainly a concern in fat/water mixtures but may be corrected using a simplified model.
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Affiliation(s)
- Pernilla Peterson
- Department of Medical Radiation Physics, Malmö, Department of Clinical Sciences, Malmö, Lund University, Skåne University Hospital, Malmö, Sweden
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Lin JS, Hwang KP, Jackson EF, Hazle JD, Stafford RJ, Taylor BA. Multiparametric fat-water separation method for fast chemical-shift imaging guidance of thermal therapies. Med Phys 2013; 40:103302. [PMID: 24089932 DOI: 10.1118/1.4819815] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
PURPOSE A k-means-based classification algorithm is investigated to assess suitability for rapidly separating and classifying fat/water spectral peaks from a fast chemical shift imaging technique for magnetic resonance temperature imaging. Algorithm testing is performed in simulated mathematical phantoms and agar gel phantoms containing mixed fat/water regions. METHODS Proton resonance frequencies (PRFs), apparent spin-spin relaxation (T2*) times, and T1-weighted (T1-W) amplitude values were calculated for each voxel using a single-peak autoregressive moving average (ARMA) signal model. These parameters were then used as criteria for k-means sorting, with the results used to determine PRF ranges of each chemical species cluster for further classification. To detect the presence of secondary chemical species, spectral parameters were recalculated when needed using a two-peak ARMA signal model during the subsequent classification steps. Mathematical phantom simulations involved the modulation of signal-to-noise ratios (SNR), maximum PRF shift (MPS) values, analysis window sizes, and frequency expansion factor sizes in order to characterize the algorithm performance across a variety of conditions. In agar, images were collected on a 1.5T clinical MR scanner using acquisition parameters close to simulation, and algorithm performance was assessed by comparing classification results to manually segmented maps of the fat/water regions. RESULTS Performance was characterized quantitatively using the Dice Similarity Coefficient (DSC), sensitivity, and specificity. The simulated mathematical phantom experiments demonstrated good fat/water separation depending on conditions, specifically high SNR, moderate MPS value, small analysis window size, and low but nonzero frequency expansion factor size. Physical phantom results demonstrated good identification for both water (0.997 ± 0.001, 0.999 ± 0.001, and 0.986 ± 0.001 for DSC, sensitivity, and specificity, respectively) and fat (0.763 ± 0.006, 0.980 ± 0.004, and 0.941 ± 0.002 for DSC, sensitivity, and specificity, respectively). Temperature uncertainties, based on PRF uncertainties from a 5 × 5-voxel ROI, were 0.342 and 0.351°C for pure and mixed fat/water regions, respectively. Algorithm speed was tested using 25 × 25-voxel and whole image ROIs containing both fat and water, resulting in average processing times per acquisition of 2.00 ± 0.07 s and 146 ± 1 s, respectively, using uncompiled MATLAB scripts running on a shared CPU server with eight Intel Xeon(TM) E5640 quad-core processors (2.66 GHz, 12 MB cache) and 12 GB RAM. CONCLUSIONS Results from both the mathematical and physical phantom suggest the k-means-based classification algorithm could be useful for rapid, dynamic imaging in an ROI for thermal interventions. Successful separation of fat/water information would aid in reducing errors from the nontemperature sensitive fat PRF, as well as potentially facilitate using fat as an internal reference for PRF shift thermometry when appropriate. Additionally, the T1-W or R2* signals may be used for monitoring temperature in surrounding adipose tissue.
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Affiliation(s)
- Jonathan S Lin
- Department of Bioengineering, Rice University, 6100 Main Street, Houston, Texas 77005 and Department of Imaging Physics, The University of Texas MD Anderson Cancer Center, 1515 Holcombe Boulevard, Houston, Texas 77030
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Holstila M, Virtanen KA, Grönroos TJ, Laine J, Lepomäki V, Saunavaara J, Lisinen I, Komu M, Hannukainen JC, Nuutila P, Parkkola R, Borra RJH. Measurement of brown adipose tissue mass using a novel dual-echo magnetic resonance imaging approach: a validation study. Metabolism 2013; 62:1189-98. [PMID: 23587549 DOI: 10.1016/j.metabol.2013.03.002] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/24/2012] [Revised: 02/22/2013] [Accepted: 03/11/2013] [Indexed: 11/22/2022]
Abstract
OBJECTIVE The aim of this study was to evaluate and validate magnetic resonance imaging (MRI) for the visualization and quantification of brown adipose tissue (BAT) in vivo in a rat model. We hypothesized that, based on differences in tissue water and lipid content, MRI could reliably differentiate between BAT and white adipose tissue (WAT) and could therefore be a possible alternative for (18)F-Fluorodeoxyglucose Positron Emission Tomography ((18)FDG-PET), the current gold standard for non-invasive BAT quantification. MATERIALS/METHODS Eleven rats were studied using both (18)FDG-PET/CT and MRI (1.5 T). A dual echo (in-and-out-of-phase) sequence was used, both with and without spectral presaturation inversion recovery (SPIR) fat suppression (DUAL-SPIR) to visualize BAT, after which all BAT was surgically excised. The BAT volume measurements obtained via (18)FDG-PET/CT and DUAL-SPIR MR were quantitatively compared with the histological findings. All study protocols were reviewed and approved by the local ethics committee. RESULTS The BAT mass measurements that were obtained using DUAL-SPIR MR subtraction images correlated better with the histological findings (P=0.017, R=0.89) than did the measurements obtained using (18)FDG-PET/CT (P=0.78, R=0.15), regardless of the BAT metabolic activation state. Additionally, the basic feasibility of the DUAL-SPIR method was demonstrated in three human pilot subjects. CONCLUSIONS This study demonstrates the potential for MRI to reliably detect and quantify BAT in vivo. MRI can provide information beyond that provided by (18)FDG-PET imaging, and its ability to detect BAT is independent of its metabolic activation state. Additionally, MRI is a low-cost alternative that does not require radiation.
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Affiliation(s)
- Milja Holstila
- Medical Imaging Centre of Southwest Finland, Turku University Hospital, Turku, Finland
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Hu HH, Börnert P, Hernando D, Kellman P, Ma J, Reeder S, Sirlin C. ISMRM workshop on fat-water separation: insights, applications and progress in MRI. Magn Reson Med 2012; 68:378-88. [PMID: 22693111 PMCID: PMC3575097 DOI: 10.1002/mrm.24369] [Citation(s) in RCA: 134] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2012] [Revised: 05/14/2012] [Accepted: 05/16/2012] [Indexed: 12/12/2022]
Abstract
Approximately 130 attendees convened on February 19-22, 2012 for the first ISMRM-sponsored workshop on water-fat imaging. The motivation to host this meeting was driven by the increasing number of research publications on this topic over the past decade. The scientific program included an historical perspective and a discussion of the clinical relevance of water-fat MRI, a technical description of multiecho pulse sequences, a review of data acquisition and reconstruction algorithms, a summary of the confounding factors that influence quantitative fat measurements and the importance of MRI-based biomarkers, a description of applications in the heart, liver, pancreas, abdomen, spine, pelvis, and muscles, an overview of the implications of fat in diabetes and obesity, a discussion on MR spectroscopy, a review of childhood obesity, the efficacy of lifestyle interventional studies, and the role of brown adipose tissue, and an outlook on federal funding opportunities from the National Institutes of Health.
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Affiliation(s)
- Houchun Harry Hu
- Departments of Radiology and Electrical Engineering, Children's Hospital Los Angeles, University of Southern California, Los Angeles, California 90027, USA.
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Hamilton G, Smith DL, Bydder M, Nayak KS, Hu HH. MR properties of brown and white adipose tissues. J Magn Reson Imaging 2012; 34:468-73. [PMID: 21780237 DOI: 10.1002/jmri.22623] [Citation(s) in RCA: 94] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
PURPOSE To explore the MR signatures of brown adipose tissue (BAT) compared with white adipose tissue (WAT) using single-voxel MR spectroscopy. MATERIALS AND METHODS (1) H MR STEAM spectra were acquired from a 3 Tesla clinical whole body scanner from seven excised murine adipose tissue samples of BAT (n=4) and WAT (n=3). Spectra were acquired at multiple echo times (TEs) and inversion times (TIs) to measure the T1, T2, and T2-corrected peak areas. A theoretical triglyceride model characterized the fat in terms of number of double bonds (ndb) and number of methylene-interrupted double bonds (nmidb). RESULTS Negligible differences between WAT and BAT were seen in the T1 and T2 of fat and the T2 of water. However, the water fraction in BAT was higher (48.5%) compared with WAT (7.1%) and the T1 of water was lower in BAT (618 ms) compared with WAT (1053 ms). The fat spectrum also differed, indicating lower levels of unsaturated triglycerides in BAT (ndb=2.7, nmidb=0.7) compared with WAT (ndb=3.3, nmidb=1.0). CONCLUSION We have demonstrated that there are several key MR-based signatures of BAT and WAT that may allow differentiation on MR imaging.
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Affiliation(s)
- Gavin Hamilton
- Department of Radiology, University of California, San Diego, San Diego, California, USA
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Karampinos DC, Yu H, Shimakawa A, Link TM, Majumdar S. T₁-corrected fat quantification using chemical shift-based water/fat separation: application to skeletal muscle. Magn Reson Med 2011; 66:1312-26. [PMID: 21452279 PMCID: PMC3150641 DOI: 10.1002/mrm.22925] [Citation(s) in RCA: 91] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2010] [Revised: 01/25/2011] [Accepted: 02/21/2011] [Indexed: 12/11/2022]
Abstract
Chemical shift-based water/fat separation, like iterative decomposition of water and fat with echo asymmetry and least-squares estimation, has been proposed for quantifying intermuscular adipose tissue. An important confounding factor in iterative decomposition of water and fat with echo asymmetry and least-squares estimation-based intermuscular adipose tissue quantification is the large difference in T(1) between muscle and fat, which can cause significant overestimation in the fat fraction. This T(1) bias effect is usually reduced by using small flip angles. T(1) -correction can be performed by using at least two different flip angles and fitting for T(1) of water and fat. In this work, a novel approach for the water/fat separation problem in a dual flip angle experiment is introduced and a new approach for the selection of the two flip angles, labeled as the unequal small flip angle approach, is developed, aiming to improve the noise efficiency of the T(1) -correction step relative to existing approaches. It is shown that the use of flip angles, selected such the muscle water signal is assumed to be T(1) -independent for the first flip angle and the fat signal is assumed to be T(1) -independent for the second flip angle, has superior noise performance to the use of equal small flip angles (no T(1) estimation required) and the use of large flip angles (T(1) estimation required).
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Affiliation(s)
- Dimitrios C Karampinos
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, California, USA.
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32
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Optimized in-phase and opposed-phase MR imaging for accurate detection of small fat or water fractions: theoretical considerations and experimental application in emulsions. MAGNETIC RESONANCE MATERIALS IN PHYSICS BIOLOGY AND MEDICINE 2011; 24:167-78. [DOI: 10.1007/s10334-011-0248-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/06/2010] [Revised: 03/09/2011] [Accepted: 03/09/2011] [Indexed: 12/21/2022]
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Hernando D, Liang ZP, Kellman P. Chemical shift-based water/fat separation: a comparison of signal models. Magn Reson Med 2011; 64:811-22. [PMID: 20593375 DOI: 10.1002/mrm.22455] [Citation(s) in RCA: 108] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Quantitative water/fat separation in MRI requires careful modeling of the acquired signal. Multiple signal models have been proposed in recent years, but their relative performance has not yet been established. This article presents a comparative study of 12 signal models for quantitative water/fat separation. These models were selected according to three main criteria: magnitude or complex fitting, use of single-peak or multipeak fat spectrum, and modeling of T(2)(*) decay. The models were compared based on an analysis of the bias and standard deviation of their resulting estimates. Results from theoretical analysis, simulation, phantom experiments, and in vivo data were in good agreement. These results show that (a) complex fitting is uniformly superior to magnitude fitting, (b) multipeak fat modeling is able to remove the bias present in single-peak fat modeling, and (c) a single-T(2)(*) model performs best over a range of clinically relevant signal-to-noise ratios (SNRs) and water/fat ratios.
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Affiliation(s)
- Diego Hernando
- Department of Electrical and Computer Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA.
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Branca RT, Warren WS. In vivo brown adipose tissue detection and characterization using water-lipid intermolecular zero-quantum coherences. Magn Reson Med 2010; 65:313-9. [PMID: 20939093 DOI: 10.1002/mrm.22622] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2010] [Revised: 08/02/2010] [Accepted: 08/06/2010] [Indexed: 11/07/2022]
Abstract
Brown adipose tissue and white adipose tissue depots are noninvasively characterized in vitro and in vivo in healthy and obese mice using intermolecular zero-quantum coherence transitions between lipid and water spins. Intermolecular zero-quantum coherences enable selective detection of spatial correlation between water and lipid spins and thereby the hydration of fatty deposits with subvoxel resolution. At about a 100 mm distance scale, the major observed peaks are between water, methylene protons at 1.3 ppm, and olefinic protons at 5.3 ppm. Our in vitro results show that the methylene-olefinic intermolecular zero-quantum coherence signal is strong both in brown and white adipose tissues, but that the water-methylene intermolecular zero-quantum coherence signal is characteristic only of brown adipose tissue. In vivo, the ratio of these peaks is substantially higher in lean or young mice than in old or obese mice.
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Affiliation(s)
- Rosa T Branca
- Center for Molecular and Biomolecular Imaging, 2220 French Family Science Center, Duke University, Chemistry Department, Durham, North Carolina 27708-0346, USA.
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Bortolotti V, Fantazzini P, Gombia M, Greco D, Rinaldin G, Sykora S. PERFIDI filters to suppress and/or quantify relaxation time components in multi-component systems: an example for fat-water systems. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2010; 206:219-226. [PMID: 20702125 DOI: 10.1016/j.jmr.2010.07.010] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2010] [Revised: 07/08/2010] [Accepted: 07/15/2010] [Indexed: 05/29/2023]
Abstract
Parametrically Enabled Relaxation FIlters with Double and multiple Inversion (PERFIDI) is an experimental NMR/MRI technique devised to analyze samples/voxels characterized by multi-exponential longitudinal relaxation. It is based on a linear combination of NMR sequences with suitable preambles composed of inversion pulses. Given any standard NMR/MRI sequence, it permits one to modify it in a way which will attenuate, in a predictable manner and before data acquisition, signals arising from components with different r rates (r=1/T1). Consequently, it is possible to define relatively simple protocols to suppress and/or to quantify signals of different components. This article describes a simple way to construct low-pass, high-pass and band-pass PERFIDI filters. Experimental data are presented in which the method has been used to separate fat and water proton signals. We also present a novel protocol for very fast determination of the ratio between the fat signal and the total signal which avoids any time-consuming magnetization recovery multi-array data acquisition. The method has been validated also for MRI, producing well T1-contrasted images.
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Affiliation(s)
- V Bortolotti
- Department DICAM, University of Bologna, Viale Risorgimento 2, 40136 Bologna, Italy
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