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In-phase simultaneous spectral editing of lactate and alanine with suppression of J-coupled lipids by the modified selective multiple quantum coherence sequences. Magn Reson Imaging 2022; 94:127-143. [PMID: 36089181 DOI: 10.1016/j.mri.2022.08.020] [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: 07/28/2022] [Revised: 08/24/2022] [Accepted: 08/31/2022] [Indexed: 11/21/2022]
Abstract
1H magnetic resonance spectroscopy (MRS) with the multiple quantum coherence (MQC) technique allows for the detection of lactate, an end product of glycolysis, in the environment of lipids. The method can also be used to detect alanine, a byproduct of glutaminolysis. An issue is that when both lactate and alanine are detected together by the MQC technique, a phase mismatch arises between lactate and alanine signals due to off-resonance rotations and the difference in double quantum coherence frequencies between the two molecules. Such phase mismatch can cause errors in spectral fitting and metabolite quantification. In this study, we designed two pulse sequences that eliminate such phase differences of lactate and alanine while suppressing lipid signals by modifications of the Selective Multiple Quantum Coherence (Sel-MQC) sequence, a well-known MQC technique. Using the product operator formalism and the off-resonance rotation matrices, the phase evolutions of lactate and alanine during the spectrally selective pulses and the free precession times of the sequence at the single quantum, double quantum and zero quantum coherence states of these molecules were calculated. The multiple quantum (MQ) evolution time t1 that can remove the phase difference of lactate and alanine at the echo was calculated and fine-tuned with experiments. The lactate and alanine signal intensities and the editing efficiencies from the two modified Sel-MQC sequences were theoretically predicted by using the product operator evolutions and compared with the experimental data. The J-coupled lipid signals were successfully suppressed by both sequences. One of the two developed sequences was applied to a human body with a phantom of lactate and alanine, which resulted in successful in-phase editing of lactate and alanine and suppression of the lipid signals from the body. The study sets an important foundation for the noninvasive detection of lactate and alanine from tumors of cancer patients.
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Lee SC, Hariharan H, Arias-Mendoza F, Mizsei G, Nath K, Chawla S, Elliott M, Reddy R, Glickson J. Coherence pathway analysis of J-coupled lipids and lactate and effective suppression of lipids upon the selective multiple quantum coherence lactate editing sequence. Biomed Phys Eng Express 2022; 8. [PMID: 35193126 DOI: 10.1088/2057-1976/ac57ad] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2021] [Accepted: 02/21/2022] [Indexed: 11/11/2022]
Abstract
Objective:The selective multiple quantum coherence (Sel-MQC) sequence is a magnetic resonance spectroscopy (MRS) technique used to detect lactate and suppress co-resonant lipid signalsin vivo. The coherence pathways of J-coupled lipids upon the sequence, however, have not been studied, hindering a logical design of the sequence to fully attenuate lipid signals. The objective of this study is to elucidate the coherence pathways of J-coupled lipids upon the Sel-MQC sequence and find a strategy to effectively suppress lipid signals from these pathways while keeping the lactate signal.Approach:The product operator formalism was used to express the evolutions of the J-coupled spins of lipids and lactate. The transformations of the product operators by the spectrally selective pulses of the sequence were calculated by using the off-resonance rotation matrices. The coherence pathways and the conversion rates of the individual pathways were derived from them. Experiments were performed on phantoms and two human subjects at 3T.Main results:The coherence pathways contributing to the various lipid resonance signals by the Sel-MQC sequence depending on the gradient ratios and RF pulse lengths were identified. Theoretical calculations of the signals from the determined coherence pathways and signal attenuations by gradients matched the experimental data very well. Lipid signals from fatty tissues of the subjects were successfully suppressed to the noise level by using the gradient ratio -0.8:-1:2 or 1:0.8:2. The new gradient ratios kept the lactate signal the same as with the previously used gradient ratio 0:-1:2.Significance:The study has elucidated the coherence pathways of J-coupled lipids upon the Sel-MQC sequence and demonstrated how lipid signals can be effectively suppressed while keeping lactate signals by using information from the coherence pathway analysis. The findings enable applying the Sel-MQC sequence to lactate detection in an environment of high concentrations of lipids.
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Affiliation(s)
- Seung-Cheol Lee
- University of Pennsylvania, 423 Guardian Dr., Philadelphia, Pennsylvania, 19104-6243, UNITED STATES
| | - Hari Hariharan
- University of Pennsylvania, 422 Curie Boulevard, Philadelphia, Pennsylvania, 19104, UNITED STATES
| | - Fernando Arias-Mendoza
- University of Pennsylvania, 423 Guardian Dr., Philadelphia, Pennsylvania, 19104, UNITED STATES
| | - Gabor Mizsei
- University of Pennsylvania, 423 Guardian Dr., Philadelphia, Pennsylvania, 19104, UNITED STATES
| | - Kavindra Nath
- University of Pennsylvania, 423 Guardian Dr., Philadelphia, Pennsylvania, 19014, UNITED STATES
| | - Sanjeev Chawla
- University of Pennsylvania, 3400 Spruce Street, Philadelphia, Pennsylvania, 19104, UNITED STATES
| | - Mark Elliott
- University of Pennsylvania, 422 Curie Boulevard, Philadelphia, Pennsylvania, 19104, UNITED STATES
| | - Ravinder Reddy
- University of Pennsylvania, 422 Curie Boulevard, Philadelphia, Pennsylvania, 19104, UNITED STATES
| | - Jerry Glickson
- University of Pennsylvania, 423 Guardian Dr., Philadelphia, Pennsylvania, 19104, UNITED STATES
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Fat unsaturation measures in tibial, subcutaneous and breast adipose tissue using short and long TE MRS at 3 T. Magn Reson Imaging 2021; 86:61-69. [PMID: 34808305 DOI: 10.1016/j.mri.2021.11.007] [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: 03/30/2021] [Revised: 09/30/2021] [Accepted: 11/15/2021] [Indexed: 11/22/2022]
Abstract
Fat unsaturation and poly-unsaturation measures can be obtained in vivo with magnetic resonance spectroscopy (MRS) through the olefinic (≈5.4 ppm) and diallylic (≈2.8 ppm) resonances, respectively. Long echo time (TE) MRS sequences have been previously optimized for olefinic/methylene (≈1.3 ppm) or olefinic/methyl (≈0.9 ppm) measures. The objectives of this work, using a Point RESolved Spectroscopy (PRESS) sequence, are to: 1) Investigate olefinic, methyl and methylene resonance decay in subcutaneous, tibial, and breast adipose tissue to determine if a direct comparison of unsaturation measures can be made without correction for T2 losses. 2) Assess intra-individual fat unsaturation and poly-unsaturation measures in the three adipose tissues. 3) Estimate correction factors for olefinic to methylene ratios to compensate for J-coupling and T2 relaxation losses that take place when increasing PRESS TE from 40 ms to 200 ms (previously optimized long-TE). 4) Investigate the utility of an inversion recovery for resolving the olefinic resonance from water in adipose tissue. PRESS spectra were acquired from the three adipose regions (breast in female only) in healthy volunteers at 3 T. It was found that olefinic and methyl signal decays faster in breast tissue compared to in tibial bone marrow. Poly-unsaturation measures (diallylic/methylene) differ for tibial bone marrow compared to subcutaneous and breast adipose tissue, with average values of 1.7 ± 0.4, 2.2 ± 0.4, and 2.3 ± 0.8%, respectively. PRESS (TE = 40 ms) with an inversion recovery resolves the olefinic and water resonances in breast tissue with a signal to noise ratio approximately six times greater than that using PRESS with a TE of 200 ms. Stimulated Echo Acquisition Mode (STEAM) with a TE of 20 ms (mixing time of 20 ms) was also combined with IR to resolve the olefinic resonance from that of water is spinal bone marrow.
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Bao J, Zhuang Y, Chen Z, Cheng J, Zhong J. Detection of fatty acid composition of trabecular bone marrow by localized iDQC MRS at 3 T: A pilot study in healthy volunteers. Magn Reson Imaging 2020; 77:28-35. [PMID: 32926992 DOI: 10.1016/j.mri.2020.09.007] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2020] [Revised: 09/08/2020] [Accepted: 09/08/2020] [Indexed: 10/23/2022]
Abstract
BACKGROUND Although a growing body of research shows that the bone marrow adipose tissue (BMAT) may play an essential role in bone inflammation and energy metabolism, available noninvasive methods for distinguishing different fatty acids in BMAT are still limited, in spite of their potential to provide novel biomarkers for bone related diseases. PURPOSE To assess the ability of a localized intermolecular double quantum coherence (iDQC) spectroscopy sequence to resolve more fatty acid peaks than conventional MR spectroscopy (MRS), like polyunsaturated fatty acids (PUFA), from the human BMAT in the presence of trabecular bone; To preliminarily investigate whether the fatty acids composition is different between different regions and groups. RESULTS Compared with conventional MRS results, additional four fatty acids peaks were well resolved using the proposed method in human BMAT in the presence of trabecular bone. In addition, a different fat composition was found between distal femur and proximal tibia: fat was more unsaturated (vinyl, *p < 0.01; diallylic, *p < 0.01) in distal femur bone marrow than in proximal tibia, and this higher unsaturation level was caused by PUFA (r = 0.67, diallylic, *p < 0.01). No significant difference in fatty acid composition were found either between left and right legs, or between female and male in the healthy young subjects studied. CONCLUSION This study demonstrated that the unsaturated fatty acids information of human BMAT in the presence of trabecular bone can be clearly identified with the localized iDQC at 3 T. The resolved peaks, especially PUFA, may serve as additional diagnostic biomarkers for BMAT related diseases in the future.
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Affiliation(s)
- Jianfeng Bao
- Department of Magnetic Resonance Imaging, The First Affiliated Hospital of Zhengzhou University, Zhengzhou University, Zhengzhou 450000, China
| | - Yuchuan Zhuang
- Department of Imaging Sciences, University of Rochester Medical Center, Rochester 14627, USA
| | - Zhong Chen
- Fujian Provincial Key Laboratory of Plasma and Magnetic Resonance Research, Xiamen University, Xiamen 361000, China
| | - Jingliang Cheng
- Department of Magnetic Resonance Imaging, The First Affiliated Hospital of Zhengzhou University, Zhengzhou University, Zhengzhou 450000, China.
| | - Jianhui Zhong
- Department of Imaging Sciences, University of Rochester Medical Center, Rochester 14627, USA.
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Alhulail AA, Patterson DA, Xia P, Zhou X, Lin C, Thomas MA, Dydak U, Emir UE. Fat-water separation by fast metabolite cycling magnetic resonance spectroscopic imaging at 3 T: A method to generate separate quantitative distribution maps of musculoskeletal lipid components. Magn Reson Med 2020; 84:1126-1139. [PMID: 32103549 DOI: 10.1002/mrm.28228] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2019] [Revised: 01/03/2020] [Accepted: 02/03/2020] [Indexed: 12/29/2022]
Abstract
PURPOSE To provide a rapid, noninvasive fat-water separation technique that allows producing quantitative maps of particular lipid components. METHODS The calf muscles in 5 healthy adolescents (age 12-16 years; body mass index = 20 ± 3 kg/m2 ) were scanned by two different fat fraction measurement methods. A density-weighted concentric-ring trajectory metabolite-cycling MRSI technique was implemented to collect data with a nominal resolution of 0.25 mL within 3 minutes and 16 seconds. For comparative purposes, the standard Dixon technique was performed. The two techniques were compared using structural similarity analysis. Additionally, the difference in the distribution of each lipid over the adolescent calf muscles was assessed based on the MRSI data. RESULTS The proposed MRSI technique provided individual fat fraction maps for eight musculoskeletal lipid components identified by LCModel analysis (IMC/L [CH3 ], EMCL [CH3 ], IMC/L [CH2 ]n , EMC/L [CH2 ]n , IMC/L [CH2 -CH], EMC/L [CH2 -CH], IMC/L [-CH=CH-], and EMC/L [-CH=CH-]) with mean structural similarity indices of 0.19, 0.04, 0.03, 0.50, 0.45, 0.04, 0.07, and 0.12, respectively, compared with the maps generated by the used Dixon method. Further analysis of voxels with zero structural similarity demonstrated an increased sensitivity of fat fraction lipid maps from the data acquired using this MRSI technique over the standard Dixon technique. The lipid spatial distribution over calf muscles was consistent with previously published findings in adults. CONCLUSION This MRSI technique can be a useful tool when individual lipid fat fraction maps are desired within a clinically acceptable time and with a nominal spatial resolution of 0.25 mL.
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Affiliation(s)
- Ahmad A Alhulail
- School of Health Sciences, Purdue University, West Lafayette, Indiana.,Department of Radiology and Medical Imaging, Prince Sattam bin Abdulaziz University, Al Kharj, Saudi Arabia
| | - Debra A Patterson
- School of Health Sciences, Purdue University, West Lafayette, Indiana.,Department of Radiology and Imaging Sciences, Indiana University School of Medicine, Indianapolis, Indiana
| | - Pingyu Xia
- School of Health Sciences, Purdue University, West Lafayette, Indiana
| | - Xiaopeng Zhou
- School of Health Sciences, Purdue University, West Lafayette, Indiana
| | - Chen Lin
- Department of Radiology and Imaging Sciences, Indiana University School of Medicine, Indianapolis, Indiana
| | - M Albert Thomas
- Department of Radiology, University of California Los Angeles, Los Angeles, California
| | - Ulrike Dydak
- School of Health Sciences, Purdue University, West Lafayette, Indiana.,Department of Radiology and Imaging Sciences, Indiana University School of Medicine, Indianapolis, Indiana
| | - Uzay E Emir
- School of Health Sciences, Purdue University, West Lafayette, Indiana.,Weldon School of Biomedical Engineering, Purdue University, West Lafayette, Indiana
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Gajdošík M, Hingerl L, Škoch A, Freudenthaler A, Krumpolec P, Ukropec J, Ukropcová B, Šedivý P, Hájek M, Itariu BK, Maier B, Baumgartner‐Parzer S, Krebs M, Trattnig S, Krššák M. Ultralong TE In Vivo 1 H MR Spectroscopy of Omega-3 Fatty Acids in Subcutaneous Adipose Tissue at 7 T. J Magn Reson Imaging 2019; 50:71-82. [PMID: 30578581 PMCID: PMC6618283 DOI: 10.1002/jmri.26605] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2018] [Revised: 11/27/2018] [Accepted: 11/28/2018] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND Omega-3 (n-3) fatty acids (FA) play and important role in neural development and other metabolic diseases such as obesity and diabetes. The knowledge about the in vivo content and distribution of n-3 FA in human body tissues is not well established and the standard quantification of FA is invasive and costly. PURPOSE To detect omega-3 (n-3 CH3 ) and non-omega-3 (CH3 ) methyl group resonance lines with echo times up to 1200 msec, in oils, for the assessment of n-3 FA content, and the n-3 FA fraction in adipose tissue in vivo. STUDY TYPE Prospective technical development. POPULATION Three oils with different n-3 FA content and 24 healthy subjects. FIELD STRENGTH/SEQUENCE Single-voxel MR spectroscopy (SVS) with a point-resolved spectroscopy (PRESS) sequence with an echo time (TE) of 1000 msec at 7 T. ASSESSMENT Knowledge about the J-coupling evolution of both CH3 resonances was used for the optimal detection of the n-3 CH3 resonance line at a TE of 1000 msec. The accuracy of the method in oils and in vivo was validated from a biopsy sample with gas chromatography analysis. STATISTICAL TESTS SVS data were compared to gas chromatography with the Pearson correlation coefficient. RESULTS T2 relaxation times in oils were assessed as follows: CH2 , 65 ± 22 msec; CH3 , 325 ± 7 msec; and n-3 CH3 , 628 ± 34 msec. The n-3 FA fractions from oil phantom experiments (n = 3) were in agreement with chromatography analysis and the comparison of in vivo obtained data with the results of chromatography analysis (n = 5) yielded a significant correlation (P = 0.029). DATA CONCLUSION PRESS with ultralong-TE can detect and quantify the n-3 CH3 signal in vivo at 7 T. LEVEL OF EVIDENCE 1 Technical Efficacy: Stage 1 J. Magn. Reson. Imaging 2019;50:71-82.
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Affiliation(s)
- Martin Gajdošík
- High‐field MR Centre, Department of Biomedical Imaging and Image‐guided TherapyMedical University of ViennaViennaAustria
- Division of Endocrinology and Metabolism, Department of Internal Medicine IIIMedical University of ViennaViennaAustria
- Bernard and Irene Schwartz Center for Biomedical Imaging, Department of RadiologyNew York University School of MedicineNew YorkNew York
| | - Lukas Hingerl
- High‐field MR Centre, Department of Biomedical Imaging and Image‐guided TherapyMedical University of ViennaViennaAustria
| | - Antonín Škoch
- National Institute of Mental HealthKlecanyCzech Republic
- MR Unit, Department of Diagnostic and Interventional RadiologyInstitute for Clinical and Experimental MedicinePragueCzech Republic
| | - Angelika Freudenthaler
- Division of Endocrinology and Metabolism, Department of Internal Medicine IIIMedical University of ViennaViennaAustria
| | - Patrik Krumpolec
- High‐field MR Centre, Department of Biomedical Imaging and Image‐guided TherapyMedical University of ViennaViennaAustria
- Institute of Experimental EndocrinologyBiomedical Research Center, Slovak Academy of SciencesBratislavaSlovakia
| | - Jozef Ukropec
- Institute of Experimental EndocrinologyBiomedical Research Center, Slovak Academy of SciencesBratislavaSlovakia
| | - Barbara Ukropcová
- Institute of Experimental EndocrinologyBiomedical Research Center, Slovak Academy of SciencesBratislavaSlovakia
| | - Petr Šedivý
- MR Unit, Department of Diagnostic and Interventional RadiologyInstitute for Clinical and Experimental MedicinePragueCzech Republic
| | - Milan Hájek
- MR Unit, Department of Diagnostic and Interventional RadiologyInstitute for Clinical and Experimental MedicinePragueCzech Republic
| | - Bianca K. Itariu
- Division of Endocrinology and Metabolism, Department of Internal Medicine IIIMedical University of ViennaViennaAustria
| | - Bernhard Maier
- University Clinic for Trauma Surgery, Medical University of ViennaViennaAustria
| | - Sabina Baumgartner‐Parzer
- Division of Endocrinology and Metabolism, Department of Internal Medicine IIIMedical University of ViennaViennaAustria
| | - Michael Krebs
- Division of Endocrinology and Metabolism, Department of Internal Medicine IIIMedical 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
| | - Martin Krššák
- High‐field MR Centre, Department of Biomedical Imaging and Image‐guided TherapyMedical University of ViennaViennaAustria
- Division of Endocrinology and Metabolism, Department of Internal Medicine IIIMedical University of ViennaViennaAustria
- Christian Doppler Laboratory for Clinical Molecular MR ImagingViennaAustria
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Improved quantitative fatty acid values with correction of T2 relaxation time in terminal methyl group: In vivo proton magnetic resonance spectroscopy at ultra high field in hepatic steatosis. Chem Phys Lipids 2018; 212:35-43. [PMID: 29337015 DOI: 10.1016/j.chemphyslip.2018.01.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2017] [Revised: 01/10/2018] [Accepted: 01/10/2018] [Indexed: 12/30/2022]
Abstract
Proton magnetic resonance spectroscopy (MRS) with optimized relaxation time is an effective method to quantify hepatic fatty acid values and characterize steatosis. The aim of this study is to quantify the difference in hepatic lipid content with metabolic changes during the progression of steatosis by using localized MRS sequence with T2 relaxation time determination. Fatty liver disease was induced in C57BL/6N mice through a high-fat diet (HFD) of pellets containing 60% fat, 20% protein, and 20% carbohydrates. We used stimulated echo acquisition mode (repetition time: 3500 ms; mixing time: 10 ms; echo time: 20 ms) sequence. Using enhanced and mono exponential curve-fitting methods, the lipid relaxation time in mice was estimated at a fixed repetition time of 5000 ms and echo time ranging from 20 to 70 ms. The calculated lipid contents with incorrect and correct relaxation times were as follows: total saturated fatty acid (4.00 ± 2.90 vs 6.74 ± 2.25, p < 0.05 at week 0; 15.23 ± 9.94 vs 25.53 ± 10.49, p < 0.05 at week 4); total unsaturated fatty acid (0.40 ± 0.49 vs 0.56 ± 0.47, p < 0.05 at week 4; 0.33 ± 0.26 vs 0.60 ± 0.21, p < 0.01 at week 7); total unsaturated bond (0.48 ± 0.52 vs 1.05 ± 0.58, p < 0.05 at week 10). Furthermore, we determined that the correct relaxation times of triglycerides between 0 and 10 weeks were significantly altered in the resonances (∼2.03 ppm: 31.07 ± 1.00 vs 27.62 ± 1.20, p < 0.01; ∼2.25 ppm: 29.10 ± 1.52 vs 26.39 ± 1.08, p < 0.05; ∼2.78 ppm: 37.67 ± 2.92 vs 29.37 ± 2.64, p < 0.001). The work presented focused on the significance of the J-coupling effect. The selection of an appropriate relaxation time considering the J-coupling effect provides an effective method for quantifying lipid contents and characterizing hepatic steatosis.
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Fisher ME, Dobberthien BJ, Tessier AG, Yahya A. Characterization of the response of taurine protons to PRESS at 9.4 T for Resolving choline and Determining taurine T2. NMR IN BIOMEDICINE 2016; 29:1427-1435. [PMID: 27496562 DOI: 10.1002/nbm.3588] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2016] [Revised: 06/13/2016] [Accepted: 06/24/2016] [Indexed: 06/06/2023]
Abstract
Point-resolved spectroscopy (PRESS), characterized by two TEs (TE1 and TE2 ), can be employed to perform animal magnetic resonance spectroscopy (MRS) studies at 9.4 T. Taurine (Tau) and choline (Cho) are relevant metabolites that can be measured by MRS. In this work, the response of the J-coupled protons of Tau as a function of PRESS TE1 and TE2 was characterized at 9.4 T to achieve two objectives. The first was to determine two TE1 and TE2 combinations that could be used to obtain T2 -corrected measures of Tau (3.42 ppm) that were minimally influenced by J coupling. The second was to exploit the Tau J coupling to find a timing combination that minimized the 3.25-ppm Tau signal to enable the Cho (3.22 ppm) resonance to be resolved from the overlapping Tau signal. The response of Tau protons was investigated both numerically and experimentally. It was numerically determined that the timings {TE1 , TE2 } = {17 ms, 10 ms} and {TE1 , TE2 } = {80 ms, 70 ms} yielded similar 3.42-ppm Tau resonance areas (5% difference), rendering them suitable for Tau T2 determination. {TE1 , TE2 } = {25 ms, 50 ms} was found to yield minimal 3.25-ppm Tau signal, reducing its interference with Cho. The efficacy of the timings was demonstrated on phantom solutions and in vivo in four Sprague Dawley rats. LCModel was employed to analyse the in vivo spectra and Tau T2 values were estimated by fitting the Tau peak areas obtained with {TE1 , TE2 } = {17 ms, 10 ms} and {TE1 , TE2 } = {80 ms, 70 ms} to a monoexponentially decaying function. An average Tau T2 of 106 ms (standard deviation, 12 ms) was obtained. LCModel analysis of rat spectra obtained with {TE1 , TE2 } = {25 ms, 50 ms} demonstrated negligible levels of Tau signal, compared with that obtained with short TE.
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Affiliation(s)
- Marissa E Fisher
- Department of Oncology, University of Alberta, Edmonton, AB, Canada
| | | | - Anthony G Tessier
- Department of Oncology, University of Alberta, Edmonton, AB, Canada
- Department of Medical Physics, Cross Cancer Institute, Edmonton, AB, Canada
| | - Atiyah Yahya
- Department of Oncology, University of Alberta, Edmonton, AB, Canada.
- Department of Medical Physics, Cross Cancer Institute, Edmonton, AB, Canada.
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Barber QM, Yahya A. Aspects of spinal bone marrow fat to water quantification with magnetic resonance spectroscopy at 3 T. Biomed Phys Eng Express 2015. [DOI: 10.1088/2057-1976/1/4/047001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
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