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Armbruster R, Wilson N, Elliott MA, Liu F, Benyard B, Jacobs P, Swain A, Nanga RPR, Reddy R. Repeatability of Lac+ measurements in healthy human brain at 3 T. NMR IN BIOMEDICINE 2024; 37:e5158. [PMID: 38584133 DOI: 10.1002/nbm.5158] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/06/2023] [Revised: 03/04/2024] [Accepted: 03/11/2024] [Indexed: 04/09/2024]
Abstract
PURPOSE In vivo quantification of lactate has numerous applications in studying the pathology of both cerebral and musculoskeletal systems. Due to its low concentration (~0.5-1 mM), and overlap with lipid signals, traditional 1H MR spectra acquired in vivo using a small voxel and short echo time often result in an inadequate signal to detect and resolve the lactate peak, especially in healthy human volunteers. METHODS In this study, using a semi-LASER acquisition with long echo time (TE = 288 ms) and large voxel size (80 × 70 × 20 mm3), we clearly visualize the combined signal of lactate and threonine. Therefore, we call the signal at 1.33 ppm Lac+ and quantify Lac+ concentration from water suppressed spectra in healthy human brains in vivo. Four participants (22-37 years old; mean age = 28 ± 5.4; three male, one female) were scanned on four separate days, and on each day four measurements were taken. Intra-day values are calculated for each participant by comparing the four measurements on a single day. Inter-day values were calculated using the mean intra-day measurements. RESULTS The mean intra-participant Lac+ concentration, standard deviation (SD), and coefficient of variation (CV) ranged from 0.49 to 0.61 mM, 0.02 to 0.07 mM, and 4% to 13%, respectively, across four volunteers. The inter-participant Lac+ concentration, SD, and CV was 0.53 mM, ±0.06 mM, and 11%. CONCLUSION Repeatability is shown in Lac+ measurement in healthy human brain using a long echo time semi-LASER sequence with a large voxel in about 3.5 min at 3 T.
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Affiliation(s)
- Ryan Armbruster
- Center for Advanced Metabolic Imaging in Precision Medicine, Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Neil Wilson
- Center for Advanced Metabolic Imaging in Precision Medicine, Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Mark A Elliott
- Center for Advanced Metabolic Imaging in Precision Medicine, Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Fang Liu
- Department of Biostatistics, Epidemiology, and Informatics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Blake Benyard
- Center for Advanced Metabolic Imaging in Precision Medicine, Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Paul Jacobs
- Center for Advanced Metabolic Imaging in Precision Medicine, Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Anshuman Swain
- Center for Advanced Metabolic Imaging in Precision Medicine, Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Ravi Prakash Reddy Nanga
- Center for Advanced Metabolic Imaging in Precision Medicine, Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Ravinder Reddy
- Center for Advanced Metabolic Imaging in Precision Medicine, Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
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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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Lacroix R, Rozeman EA, Kreutz M, Renner K, Blank CU. Targeting tumor-associated acidity in cancer immunotherapy. Cancer Immunol Immunother 2018; 67:1331-1348. [PMID: 29974196 PMCID: PMC11028141 DOI: 10.1007/s00262-018-2195-z] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2018] [Accepted: 06/29/2018] [Indexed: 12/21/2022]
Abstract
Checkpoint inhibitors, such as cytotoxic T-lymphocyte-associated protein-4 (CTLA-4) and programmed cell death-1 (PD-1) monoclonal antibodies have changed profoundly the treatment of melanoma, renal cell carcinoma, non-small cell lung cancer, Hodgkin lymphoma, and bladder cancer. Currently, they are tested in various tumor entities as monotherapy or in combination with chemotherapies or targeted therapies. However, only a subgroup of patients benefit from checkpoint blockade (combinations). This raises the question, which all mechanisms inhibit T cell function in the tumor environment, restricting the efficacy of these immunotherapeutic approaches. Serum activity of lactate dehydrogenase, likely reflecting the glycolytic activity of the tumor cells and thus acidity within the tumor microenvironment, turned out to be one of the strongest markers predicting response to checkpoint inhibition. In this review, we discuss the impact of tumor-associated acidity on the efficacy of T cell-mediated cancer immunotherapy and possible approaches to break this barrier.
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Affiliation(s)
- Ruben Lacroix
- Department of Molecular Oncology and Immunology, Netherlands Cancer Institute, Plesmanlaan 121, 1066CX, Amsterdam, The Netherlands
| | - Elisa A Rozeman
- Department of Medical Oncology, Netherlands Cancer Institute, Amsterdam, The Netherlands
| | - Marina Kreutz
- Department of Internal Medicine III, University Hospital Regensburg, Regensburg, Germany
| | - Kathrin Renner
- Department of Internal Medicine III, University Hospital Regensburg, Regensburg, Germany
| | - Christian U Blank
- Department of Molecular Oncology and Immunology, Netherlands Cancer Institute, Plesmanlaan 121, 1066CX, Amsterdam, The Netherlands.
- Department of Medical Oncology, Netherlands Cancer Institute, Amsterdam, The Netherlands.
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Beloueche-Babari M, Wantuch S, Casals Galobart T, Koniordou M, Parkes HG, Arunan V, Chung YL, Eykyn TR, Smith PD, Leach MO. MCT1 Inhibitor AZD3965 Increases Mitochondrial Metabolism, Facilitating Combination Therapy and Noninvasive Magnetic Resonance Spectroscopy. Cancer Res 2017; 77:5913-5924. [PMID: 28923861 PMCID: PMC5669455 DOI: 10.1158/0008-5472.can-16-2686] [Citation(s) in RCA: 88] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2016] [Revised: 06/01/2017] [Accepted: 09/06/2017] [Indexed: 12/31/2022]
Abstract
Monocarboxylate transporters (MCT) modulate tumor cell metabolism and offer promising therapeutic targets for cancer treatment. Understanding the impact of MCT blockade on tumor cell metabolism may help develop combination strategies or identify pharmacodynamic biomarkers to support the clinical development of MCT inhibitors now in clinical trials. In this study, we assessed the impact of the MCT1 inhibitor AZD3965 on cancer cell metabolism in vitro and in vivo Exposing human lymphoma and colon carcinoma cells to AZD3965 increased MCT4-dependent accumulation of intracellular lactate, inhibiting monocarboxylate influx and efflux. AZD3965 also increased the levels of TCA cycle-related metabolites and 13C-glucose mitochondrial metabolism, enhancing oxidative pyruvate dehydrogenase and anaplerotic pyruvate carboxylase fluxes. Increased mitochondrial metabolism was necessary to maintain cell survival under drug stress. These effects were counteracted by coadministration of the mitochondrial complex I inhibitor metformin and the mitochondrial pyruvate carrier inhibitor UK5099. Improved bioenergetics were confirmed in vivo after dosing with AZD3965 in mouse xenograft models of human lymphoma. Our results reveal new metabolic consequences of MCT1 inhibition that might be exploited for therapeutic and pharmacodynamic purposes. Cancer Res; 77(21); 5913-24. ©2017 AACR.
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Affiliation(s)
- Mounia Beloueche-Babari
- Cancer Research UK Cancer Imaging Centre, Division of Radiotherapy and Imaging, The Institute of Cancer Research, London and The Royal Marsden NHS Foundation Trust, London, United Kingdom.
| | - Slawomir Wantuch
- Cancer Research UK Cancer Imaging Centre, Division of Radiotherapy and Imaging, The Institute of Cancer Research, London and The Royal Marsden NHS Foundation Trust, London, United Kingdom
| | - Teresa Casals Galobart
- Cancer Research UK Cancer Imaging Centre, Division of Radiotherapy and Imaging, The Institute of Cancer Research, London and The Royal Marsden NHS Foundation Trust, London, United Kingdom
| | - Markella Koniordou
- Cancer Research UK Cancer Imaging Centre, Division of Radiotherapy and Imaging, The Institute of Cancer Research, London and The Royal Marsden NHS Foundation Trust, London, United Kingdom
| | - Harold G Parkes
- Cancer Research UK Cancer Imaging Centre, Division of Radiotherapy and Imaging, The Institute of Cancer Research, London and The Royal Marsden NHS Foundation Trust, London, United Kingdom
| | - Vaitha Arunan
- Cancer Research UK Cancer Imaging Centre, Division of Radiotherapy and Imaging, The Institute of Cancer Research, London and The Royal Marsden NHS Foundation Trust, London, United Kingdom
| | - Yuen-Li Chung
- Cancer Research UK Cancer Imaging Centre, Division of Radiotherapy and Imaging, The Institute of Cancer Research, London and The Royal Marsden NHS Foundation Trust, London, United Kingdom
| | - Thomas R Eykyn
- Cancer Research UK Cancer Imaging Centre, Division of Radiotherapy and Imaging, The Institute of Cancer Research, London and The Royal Marsden NHS Foundation Trust, London, United Kingdom
| | - Paul D Smith
- AstraZeneca, Cancer Biosciences, Cancer Research UK Cambridge Institute, Cambridge, United Kingdom
| | - Martin O Leach
- Cancer Research UK Cancer Imaging Centre, Division of Radiotherapy and Imaging, The Institute of Cancer Research, London and The Royal Marsden NHS Foundation Trust, London, United Kingdom
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Magnetic Resonance Spectroscopy and its Clinical Applications: A Review. J Med Imaging Radiat Sci 2017; 48:233-253. [PMID: 31047406 DOI: 10.1016/j.jmir.2017.06.004] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2017] [Revised: 04/30/2017] [Accepted: 06/22/2017] [Indexed: 12/25/2022]
Abstract
In vivo NMR spectroscopy is known as magnetic resonance spectroscopy (MRS). MRS has been applied as both a research and a clinical tool in order to detect visible or nonvisible abnormalities. The adaptability of MRS allows a technique that can probe a wide variety of metabolic uses across different tissues. Although MRS is mostly applied for brain tissue, it can be used for detection, localization, staging, tumour aggressiveness evaluation, and tumour response assessment of breast, prostate, hepatic, and other cancers. In this article, the medical applications of MRS in the brain, including tumours, neural and psychiatric disorder studies, breast, prostate, hepatic, gastrointestinal, and genitourinary investigations have been reviewed.
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Al-Saffar NMS, Agliano A, Marshall LV, Jackson LE, Balarajah G, Sidhu J, Clarke PA, Jones C, Workman P, Pearson ADJ, Leach MO. In vitro nuclear magnetic resonance spectroscopy metabolic biomarkers for the combination of temozolomide with PI3K inhibition in paediatric glioblastoma cells. PLoS One 2017; 12:e0180263. [PMID: 28704425 PMCID: PMC5509135 DOI: 10.1371/journal.pone.0180263] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2017] [Accepted: 06/13/2017] [Indexed: 11/18/2022] Open
Abstract
Recent experimental data showed that the PI3K pathway contributes to resistance to temozolomide (TMZ) in paediatric glioblastoma and that this effect is reversed by combination treatment of TMZ with a PI3K inhibitor. Our aim is to assess whether this combination results in metabolic changes that are detectable by nuclear magnetic resonance (NMR) spectroscopy, potentially providing metabolic biomarkers for PI3K inhibition and TMZ combination treatment. Using two genetically distinct paediatric glioblastoma cell lines, SF188 and KNS42, in vitro 1H-NMR analysis following treatment with the dual pan-Class I PI3K/mTOR inhibitor PI-103 resulted in a decrease in lactate and phosphocholine (PC) levels (P<0.02) relative to control. In contrast, treatment with TMZ caused an increase in glycerolphosphocholine (GPC) levels (P≤0.05). Combination of PI-103 with TMZ showed metabolic effects of both agents including a decrease in the levels of lactate and PC (P<0.02) while an increase in GPC (P<0.05). We also report a decrease in the protein expression levels of HK2, LDHA and CHKA providing likely mechanisms for the depletion of lactate and PC, respectively. Our results show that our in vitro NMR-detected changes in lactate and choline metabolites may have potential as non-invasive biomarkers for monitoring response to combination of PI3K/mTOR inhibitors with TMZ during clinical trials in children with glioblastoma, subject to further in vivo validation.
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Affiliation(s)
- Nada M. S. Al-Saffar
- Cancer Research UK Cancer Imaging Centre, Division of Radiotherapy and Imaging, The Institute of Cancer Research and The Royal Marsden NHS Foundation Trust, London, United Kingdom
| | - Alice Agliano
- Cancer Research UK Cancer Imaging Centre, Division of Radiotherapy and Imaging, The Institute of Cancer Research and The Royal Marsden NHS Foundation Trust, London, United Kingdom
| | - Lynley V. Marshall
- Divisions of Cancer Therapeutics and Molecular Pathology, The Institute of Cancer Research and The Royal Marsden NHS Foundation Trust, London, United Kingdom
- Divisions of Clinical Studies and Cancer Therapeutics, The Institute of Cancer Research and The Royal Marsden NHS Foundation Trust, London, United Kingdom
| | - L. Elizabeth Jackson
- Cancer Research UK Cancer Imaging Centre, Division of Radiotherapy and Imaging, The Institute of Cancer Research and The Royal Marsden NHS Foundation Trust, London, United Kingdom
| | - Geetha Balarajah
- Cancer Research UK Cancer Imaging Centre, Division of Radiotherapy and Imaging, The Institute of Cancer Research and The Royal Marsden NHS Foundation Trust, London, United Kingdom
| | - Jasmin Sidhu
- Cancer Research UK Cancer Imaging Centre, Division of Radiotherapy and Imaging, The Institute of Cancer Research and The Royal Marsden NHS Foundation Trust, London, United Kingdom
| | - Paul A. Clarke
- Cancer Research UK Cancer Therapeutics Unit, Division of Cancer Therapeutics, The Institute of Cancer Research, London, United Kingdom
| | - Chris Jones
- Divisions of Cancer Therapeutics and Molecular Pathology, The Institute of Cancer Research and The Royal Marsden NHS Foundation Trust, London, United Kingdom
| | - Paul Workman
- Cancer Research UK Cancer Therapeutics Unit, Division of Cancer Therapeutics, The Institute of Cancer Research, London, United Kingdom
| | - Andrew D. J. Pearson
- Divisions of Clinical Studies and Cancer Therapeutics, The Institute of Cancer Research and The Royal Marsden NHS Foundation Trust, London, United Kingdom
| | - Martin O. Leach
- Cancer Research UK Cancer Imaging Centre, Division of Radiotherapy and Imaging, The Institute of Cancer Research and The Royal Marsden NHS Foundation Trust, London, United Kingdom
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Harris AD, Saleh MG, Edden RAE. Edited 1 H magnetic resonance spectroscopy in vivo: Methods and metabolites. Magn Reson Med 2017; 77:1377-1389. [PMID: 28150876 PMCID: PMC5352552 DOI: 10.1002/mrm.26619] [Citation(s) in RCA: 121] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2016] [Revised: 12/30/2016] [Accepted: 12/30/2016] [Indexed: 12/13/2022]
Abstract
The Proton magnetic resonance (1 H-MRS) spectrum contains information about the concentration of tissue metabolites within a predefined region of interest (a voxel). The conventional spectrum in some cases obscures information about less abundant metabolites due to limited separation and complex splitting of the metabolite peaks. One method to detect these metabolites is to reduce the complexity of the spectrum using editing. This review provides an overview of the one-dimensional editing methods available to interrogate these obscured metabolite peaks. These methods include sequence optimizations, echo-time averaging, J-difference editing methods (single BASING, dual BASING, and MEGA-PRESS), constant-time PRESS, and multiple quantum filtering. It then provides an overview of the brain metabolites whose detection can benefit from one or more of these editing approaches, including ascorbic acid, γ-aminobutyric acid, lactate, aspartate, N-acetyl aspartyl glutamate, 2-hydroxyglutarate, glutathione, glutamate, glycine, and serine. Magn Reson Med 77:1377-1389, 2017. © 2017 International Society for Magnetic Resonance in Medicine.
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Affiliation(s)
- Ashley D Harris
- Department of Radiology, University of Calgary, Calgary, AB T2N 1N4, Canada
- Child and Adolescent Imaging Research (CAIR) Program, Alberta Children's Hospital Research Institute, University of Calgary, Calgary, AB T3B 6A9, Canada
- Hotchkiss Brain Institute, University of Calgary, Calgary, AB T2N 1N4, Canada
| | - Muhammad G Saleh
- Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
- F.M. Kirby Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD 21205, USA
| | - Richard A E Edden
- Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
- F.M. Kirby Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD 21205, USA
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Payne GS, deSouza NM, Messiou C, Leach MO. Single-shot single-voxel lactate measurements using FOCI-LASER and a multiple-quantum filter. NMR IN BIOMEDICINE 2015; 28:496-504. [PMID: 25802214 PMCID: PMC4737099 DOI: 10.1002/nbm.3276] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/16/2014] [Revised: 01/22/2015] [Accepted: 01/23/2015] [Indexed: 05/15/2023]
Abstract
Measurement of tissue lactate using (1) H MRS is often confounded by overlap with intense lipid signals at 1.3 ppm. Single-voxel localization using PRESS is also compromised by the large chemical shift displacement between voxels for the 4.1 ppm (-CH) resonance and the 1.3 ppm -CH3 resonance, leading to subvoxels with signals of opposite phase and hence partial signal cancellation. To reduce the chemical shift displacement to negligible proportions, a modified semi-LASER sequence was written ("FOCI-LASER", abbreviated as fLASER) using FOCI pulses to permit high RF bandwidth even with the limited RF amplitude characteristic of clinical MRI scanners. A further modification, MQF-fLASER, includes a selective multiple-quantum filter to detect lactate and reject lipid signals. The sequences were implemented on a Philips 3 T Achieva TX system. In a solution of brain metabolites fLASER lactate signals were 2.7 times those of PRESS. MQF-fLASER lactate was 47% of fLASER (the theoretical maximum is 50%) but still larger than PRESS lactate. In oil, the main 1.3 ppm lipid peak was suppressed to less than 1%. Enhanced suppression was possible using increased gradient durations. The minimum detectable lactate concentration was approximately 0.5 mM. Coherence selection gradients needed to be at the magic angle to avoid large water signals derived from intermolecular multiple-quantum coherences. In pilot patient measurements, lactate peaks were often observed in brain tumours, but not in cervix tumours; lipids were effectively suppressed. In summary, compared with PRESS, the fLASER sequence yields greatly superior sensitivity for direct detection of lactate (and equivalent sensitivity for other metabolites), while the single-voxel single-shot MQF-fLASER sequence surpasses PRESS for lactate detection while eliminating substantial signals from lipids. This sequence will increase the potential for in vivo lactate measurement as a biomarker in targeted anti-cancer treatments as well as in measurements of tissue hypoxia.
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Affiliation(s)
- Geoffrey S Payne
- Cancer Research UK Cancer Imaging Centre, Royal Marsden Hospital and Institute of Cancer Research, Sutton, Surrey, UK
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