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Fedeli L, Benelli M, Busoni S, Belli G, Ciccarone A, Coniglio A, Esposito M, Nocetti L, Sghedoni R, Tarducci R, Altabella L, Belligotti E, Bettarini S, Betti M, Caivano R, Carnì M, Chiappiniello A, Cimolai S, Cretti F, Fulcheri C, Gasperi C, Giacometti M, Levrero F, Lizio D, Maieron M, Marzi S, Mascaro L, Mazzocchi S, Meliadò G, Morzenti S, Niespolo A, Noferini L, Oberhofer N, Orsingher L, Quattrocchi M, Ricci A, Savini A, Taddeucci A, Testa C, Tortoli P, Gobbi G, Gori C, Bernardi L, Giannelli M, Mazzoni LN. On the dependence of quantitative diffusion-weighted imaging on scanner system characteristics and acquisition parameters: A large multicenter and multiparametric phantom study with unsupervised clustering analysis. Phys Med 2021; 85:98-106. [PMID: 33991807 DOI: 10.1016/j.ejmp.2021.04.020] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/21/2021] [Revised: 03/31/2021] [Accepted: 04/23/2021] [Indexed: 11/25/2022] Open
Abstract
PURPOSE The purpose of this multicenter phantom study was to exploit an innovative approach, based on an extensive acquisition protocol and unsupervised clustering analysis, in order to assess any potential bias in apparent diffusion coefficient (ADC) estimation due to different scanner characteristics. Moreover, we aimed at assessing, for the first time, any effect of acquisition plan/phase encoding direction on ADC estimation. METHODS Water phantom acquisitions were carried out on 39 scanners. DWI acquisitions (b-value = 0-200-400-600-800-1000 s/mm2) with different acquisition plans (axial, coronal, sagittal) and phase encoding directions (anterior/posterior and right/left, for the axial acquisition plan), for 3 orthogonal diffusion weighting gradient directions, were performed. For each acquisition setup, ADC values were measured in-center and off-center (6 different positions), resulting in an entire dataset of 84 × 39 = 3276 ADC values. Spatial uniformity of ADC maps was assessed by means of the percentage difference between off-center and in-center ADC values (Δ). RESULTS No significant dependence of in-center ADC values on acquisition plan/phase encoding direction was found. Ward unsupervised clustering analysis showed 3 distinct clusters of scanners and an association between Δ-values and manufacturer/model, whereas no association between Δ-values and maximum gradient strength, slew rate or static magnetic field strength was revealed. Several acquisition setups showed significant differences among groups, indicating the introduction of different biases in ADC estimation. CONCLUSIONS Unsupervised clustering analysis of DWI data, obtained from several scanners using an extensive acquisition protocol, allows to reveal an association between measured ADC values and manufacturer/model of scanner, as well as to identify suboptimal DWI acquisition setups for accurate ADC estimation.
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Affiliation(s)
- Luca Fedeli
- S.O.C. Fisica Sanitaria Pistoia-Prato, A.U.S.L. Toscana Centro, Italy
| | - Matteo Benelli
- Bioinformatics Unit, Hospital of Prato, A.U.S.L. Toscana Centro, Italy
| | - Simone Busoni
- U.O.C. Fisica Sanitaria, A.O.U. Careggi, Firenze, Italy
| | - Giacomo Belli
- U.O.C. Fisica Sanitaria, A.O.U. Careggi, Firenze, Italy
| | | | - Angela Coniglio
- Department of Medical Physics, P.O. S. Filippo Neri, Roma, Italy
| | - Marco Esposito
- S.C. Fisica Sanitaria Firenze-Empoli, A.U.S.L. Toscana Centro, Firenze, Italy
| | - Luca Nocetti
- Servizio di Fisica Medica, A.O.U. Policlinico di Modena, Modena, Italy
| | - Roberto Sghedoni
- Fisica Medica, Azienda USL - IRCCS di Reggio Emilia, Reggio Emilia, Italy
| | | | - Luisa Altabella
- Medical Physics Department, Hospital of Trento, APSS, Trento, Italy
| | - Eleonora Belligotti
- Fisica Medica ed Alte Tecnologie, A.O. Ospedali Riuniti Marche Nord, Pesaro, Italy
| | - Silvia Bettarini
- U.O.C. Fisica Sanitaria, A.O.U. Careggi, Firenze, Italy; Università degli Studi di Firenze, Firenze, Italy
| | - Margherita Betti
- S.O.C. Fisica Sanitaria Pistoia-Prato, A.U.S.L. Toscana Centro, Italy
| | - Rocchina Caivano
- U.O. Radioterapia Oncologica e Fisica Sanitaria, I.R.C.C.S. CROB, Rionero in Vulture (PZ), Italy
| | - Marco Carnì
- U.O.D. Fisica Sanitaria, A.O.U. Policlinico Umberto I, Roma, Italy
| | | | - Sara Cimolai
- U.O. Fisica Sanitaria, U.L.S.S. 2 Marca Trevigiana, Treviso, Italy
| | - Fabiola Cretti
- U.S.C. Fisica Sanitaria, A.O. Papa Giovanni XXIII, Bergamo, Italy
| | | | - Chiara Gasperi
- U.O.S.D. Fisica Sanitaria Arezzo, A.U.S.L. Toscana Sud Est, Arezzo, Italy
| | - Mara Giacometti
- S.O.D. Fisica Sanitaria, A.O.U. Ospedali Riuniti di Ancona, Ancona, Italy
| | - Fabrizio Levrero
- U.O. Fisica Sanitaria, Ospedale Policlinico San Martino, Genova, Italy
| | - Domenico Lizio
- Fisica Sanitaria, A.S.S.T. Grande Ospedale Metropolitano Niguarda, Milano, Italy
| | - Marta Maieron
- S.O.C. Fisica Sanitaria, A.S.U.I. Udine S. Maria della Misericordia, Udine, Italy
| | - Simona Marzi
- S.C. Laboratorio di Fisica Medica e Sistemi Esperti, Istituto Nazionale Tumori Regina Elena, Roma, Italy
| | - Lorella Mascaro
- U.O.C. Fisica Sanitaria, A.S.S.T. Spedali Civili, Brescia, Italy
| | - Silvia Mazzocchi
- S.C. Fisica Sanitaria Firenze-Empoli, A.U.S.L. Toscana Centro, Firenze, Italy
| | - Gabriele Meliadò
- U.O.C. Fisica Sanitaria, A.O.U. Integrata di Verona, Verona, Italy
| | | | - Alessandra Niespolo
- U.O.C. Fisica Sanitaria Area Nord, A.U.S.L. Toscana Nord Ovest, Lucca, Italy
| | | | - Nadia Oberhofer
- Servizio Aziendale di Fisica Sanitaria, A.S. dell'Alto Adige, Bolzano, Italy
| | - Laura Orsingher
- U.O. Fisica Sanitaria, U.L.S.S. 2 Marca Trevigiana, Treviso, Italy
| | | | | | - Alessandro Savini
- Istituto Scientifico Romagnolo per lo Studio e la Cura dei Tumori (IRST) IRCCS, Meldola, Italy
| | | | - Claudia Testa
- Dipartimento di Fisica e Astronomia, Università di Bologna, Bologna, Italy
| | - Paolo Tortoli
- U.O.C. Fisica Sanitaria, A.O.U. Careggi, Firenze, Italy; Università degli Studi di Firenze, Firenze, Italy
| | - Gianni Gobbi
- Università degli Studi di Perugia, Perugia, Italy
| | - Cesare Gori
- Università degli Studi di Firenze, Firenze, Italy
| | - Luca Bernardi
- S.O.C. Fisica Sanitaria Pistoia-Prato, A.U.S.L. Toscana Centro, Italy
| | - Marco Giannelli
- Unit of Medical Physics, Pisa University Hospital "Azienda Ospedaliero-Universitaria Pisana", Pisa, Italy.
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Graf C, MacMillan EL, Fu E, Harris T, Traboulsee A, Vavasour IM, MacKay AL, Mädler B, Li DKB, Laule C. Intra- and inter-site reproducibility of human brain single-voxel proton MRS at 3 T. NMR IN BIOMEDICINE 2019; 32:e4083. [PMID: 30889311 DOI: 10.1002/nbm.4083] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2018] [Revised: 01/24/2019] [Accepted: 01/28/2019] [Indexed: 06/09/2023]
Abstract
INTRODUCTION Clinical trials that involve participants from multiple sites necessitate standardized and reliable quantitative MRI outcomes to detect significant group differences over time. Metabolite concentrations measured by proton MRS (1 H-MRS) provide valuable information about in vivo metabolism of the central nervous system, but can vary based on the acquisition and quantitation methods used by different MR sites. Therefore, we investigated the intra- and inter-site reproducibility of metabolite concentrations measured by 1 H-MRS on MRI scanners from a single manufacturer across six sites. METHODS Five healthy controls were scanned twice within 24 h at six participating 3 T MR sites with large single-voxel PRESS (TE/TR/NSA = 36 ms/4000 ms/56) and anatomical images for voxel positioning and correction of partial volume relaxation. Absolute metabolite concentrations were calculated relative to the T1 and T2 relaxation corrected signal from water. Intra- and inter-site reproducibility was assessed using Bland-Altman plots and intra- and inter-site coefficient of variation (CoV) as well as intra- and inter-site intra-class correlation coefficient. RESULTS The median intra-site CoVs for the five major metabolite concentrations ([NAA], [tCr], [Glu], [tCho] and [Ins]) were between 2.5 and 5.3%. Inter-site CoVs were also low, with the median CoVs for all metabolites between 3.7 and 6.4%. Metabolite concentrations were robust to small inconsistencies in voxel placement and site was not the driving factor in the variance of the measurement of any metabolite concentration. Between-subject differences accounted for the majority of the concentration variability for creatine, choline and myo-inositol (42-65% of the variance). CONCLUSION A large single-voxel 1 H-MRS acquisition from a single manufacturer's MRI scanner is highly reproducible and reliable for multi-site clinical trials.
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Affiliation(s)
- Carina Graf
- Physics & Astronomy, University of British Columbia, Vancouver, British Columbia, Canada
- International Collaboration on Repair Discoveries (ICORD), Vancouver, British Columbia, Canada
| | - Erin L MacMillan
- MR Clinical Science, Philips Canada, Markham, Ontario, Canada
- UBC MRI Research Centre, University of British Columbia, Vancouver, British Columbia, Canada
- ImageTech Lab, Simon Fraser University, Surrey, British Columbia, Canada
| | - Eric Fu
- Statistics, University of British Columbia, Vancouver, British Columbia, Canada
| | - Trudy Harris
- UBC MRI Research Centre, University of British Columbia, Vancouver, British Columbia, Canada
- Radiology, University of British Columbia, Vancouver, British Columbia, Canada
| | - Anthony Traboulsee
- Medicine (Neurology), University of British Columbia, Vancouver, British Columbia, Canada
| | - Irene M Vavasour
- UBC MRI Research Centre, University of British Columbia, Vancouver, British Columbia, Canada
- Radiology, University of British Columbia, Vancouver, British Columbia, Canada
| | - Alex L MacKay
- Physics & Astronomy, University of British Columbia, Vancouver, British Columbia, Canada
- UBC MRI Research Centre, University of British Columbia, Vancouver, British Columbia, Canada
- Radiology, University of British Columbia, Vancouver, British Columbia, Canada
| | | | - David K B Li
- UBC MRI Research Centre, University of British Columbia, Vancouver, British Columbia, Canada
- Radiology, University of British Columbia, Vancouver, British Columbia, Canada
- Medicine (Neurology), University of British Columbia, Vancouver, British Columbia, Canada
| | - Cornelia Laule
- Physics & Astronomy, University of British Columbia, Vancouver, British Columbia, Canada
- International Collaboration on Repair Discoveries (ICORD), Vancouver, British Columbia, Canada
- Radiology, University of British Columbia, Vancouver, British Columbia, Canada
- Pathology & Laboratory Medicine, University of British Columbia, Vancouver, British Columbia, Canada
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Sghedoni R, Coniglio A, Mazzoni LN, Busoni S, Belli G, Tarducci R, Nocetti L, Fedeli L, Esposito M, Ciccarone A, Altabella L, Bellini A, Binotto L, Caivano R, Carnì M, Ricci A, Cimolai S, D'Urso D, Gasperi C, Levrero F, Mangili P, Morzenti S, Nitrosi A, Oberhofer N, Parruccini N, Toncelli A, Valastro LM, Gori C, Gobbi G, Giannelli M. A straightforward multiparametric quality control protocol for proton magnetic resonance spectroscopy: Validation and comparison of various 1.5 T and 3 T clinical scanner systems. Phys Med 2018; 54:49-55. [PMID: 30337010 DOI: 10.1016/j.ejmp.2018.08.013] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/06/2018] [Revised: 07/25/2018] [Accepted: 08/13/2018] [Indexed: 02/08/2023] Open
Abstract
PURPOSE The aim of this study was to propose and validate across various clinical scanner systems a straightforward multiparametric quality assurance procedure for proton magnetic resonance spectroscopy (MRS). METHODS Eighteen clinical 1.5 T and 3 T scanner systems for MRS, from 16 centres and 3 different manufacturers, were enrolled in the study. A standard spherical water phantom was employed by all centres. The acquisition protocol included 3 sets of single (isotropic) voxel (size 20 mm) PRESS acquisitions with unsuppressed water signal and acquisition voxel position at isocenter as well as off-center, repeated 4/5 times within approximately 2 months. Water peak linewidth (LW) and area under the water peak (AP) were estimated. RESULTS LW values [mean (standard deviation)] were 1.4 (1.0) Hz and 0.8 (0.3) Hz for 3 T and 1.5 T scanners, respectively. The mean (standard deviation) (across all scanners) coefficient of variation of LW and AP for different spatial positions of acquisition voxel were 43% (20%) and 11% (11%), respectively. The mean (standard deviation) phantom T2values were 1145 (50) ms and 1010 (95) ms for 1.5 T and 3 T scanners, respectively. The mean (standard deviation) (across all scanners) coefficients of variation for repeated measurements of LW, AP and T2 were 25% (20%), 10% (14%) and 5% (2%), respectively. CONCLUSIONS We proposed a straightforward multiparametric and not time consuming quality control protocol for MRS, which can be included in routine and periodic quality assurance procedures. The protocol has been validated and proven to be feasible in a multicentre comparison study of a fairly large number of clinical 1.5 T and 3 T scanner systems.
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Affiliation(s)
| | - Angela Coniglio
- Medical Physics Unit, Ospedale San Giovanni Calibita Fatebenefratelli, Roma, Italy.
| | | | | | | | - Roberto Tarducci
- Health Physics Unit, Azienda Ospedaliera di Perugia, Perugia, Italy
| | - Luca Nocetti
- Health Physics Unit, Azienda Ospedaliera di Modena, Modena, Italy
| | - Luca Fedeli
- Physics and Astronomy Department, University of Florence, Firenze, Italy
| | - Marco Esposito
- Health Physics Unit, Azienda USL Toscana Centro, Firenze, Italy
| | | | | | | | - Luca Binotto
- Medical Physics Unit, Azienda ULSS 3 Serenissima, Mestre, Italy
| | - Rocchina Caivano
- Radiotherapy and Health Physics Unit, IRCCS CROB, Rionero in Vulture - Potenza, Italy
| | - Marco Carnì
- Health Physics Unit, Policlinico Umberto I, Roma, Italy
| | | | - Sara Cimolai
- Health Physics Unit, Azienda ULSS 2 Marca Trevigiana, Treviso, Italy
| | - Davide D'Urso
- Health Physics Unit, Azienda ULSS 2 Marca Trevigiana, Treviso, Italy
| | - Chiara Gasperi
- Health Physics Unit, Azienda USL Toscana Sud Est, Arezzo, Italy
| | - Fabrizio Levrero
- Medical and Health Physics Unit, IRCCS AOU San Martino, Genova, Italy
| | - Paola Mangili
- Medical Physics Unit, IRCCS San Raffaele, Milano, Italy
| | | | - Andrea Nitrosi
- Medical Physics Unit, Arcispedale Santa Maria Nuova - IRCCS, Reggio Emilia, Italy
| | - Nadia Oberhofer
- Health Physics, Azienda Sanitaria della Provincia Autonoma di Bolzano, Bolzano, Italy
| | | | | | | | - Cesare Gori
- Health Physics Unit, AOU Careggi, Firenze, Italy
| | - Gianni Gobbi
- Health Physics Unit, Azienda Ospedaliera di Perugia, Perugia, Italy
| | - Marco Giannelli
- Unit of Medical Physics, Pisa University Hospital "Azienda Ospedaliero-Universitaria Pisana", Pisa, Italy
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4
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Pedrosa de Barros N, Slotboom J. Quality management in in vivo proton MRS. Anal Biochem 2017; 529:98-116. [DOI: 10.1016/j.ab.2017.01.017] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2016] [Revised: 11/18/2016] [Accepted: 01/19/2017] [Indexed: 12/27/2022]
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Liu Z, Dimitrov IE, Lenkinski RE, Hajibeigi A, Vinogradov E. UCEPR: Ultrafast localized CEST-spectroscopy with PRESS in phantoms and in vivo. Magn Reson Med 2016; 75:1875-85. [PMID: 26033357 PMCID: PMC4663188 DOI: 10.1002/mrm.25780] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2015] [Revised: 04/02/2015] [Accepted: 04/27/2015] [Indexed: 11/10/2022]
Abstract
PURPOSE Chemical exchange saturation transfer (CEST) is a contrast mechanism enhancing low-concentration molecules through saturation transfer from their exchangeable protons to bulk water. Often many scans are acquired to form a Z-spectrum, making the CEST method time-consuming. Here, an ultrafast localized CEST-spectroscopy with PRESS (UCEPR) is proposed to obtain the entire Z-spectrum of a voxel using only two scans, significantly accelerating CEST. THEORY AND METHODS The approach combines ultrafast nonlocalized CEST spectroscopy with localization using PRESS. A field gradient is applied concurrently with the saturation pulse producing simultaneous saturation of all Z-spectrum frequencies that are also spatially encoded. A readout gradient during data acquisition resolves the spatial dependence of the CEST responses into frequency. UCEPR was tested on a 3T scanner both in phantoms and in vivo. RESULTS In phantoms, a fast Z-spectroscopy acquisition of multiple pH-variant iopamidol samples was achieved with four- to seven-fold acceleration as compared to the conventional CEST methods. In vivo, amide proton transfer (APT) in white matter of healthy human brain was measured rapidly in 48 s and with high frequency resolution (≤ 0.2 ppm). CONCLUSION Compared with conventional CEST methods, UCEPR has the advantage of rapidly acquiring high-resolution Z-spectra. Potential in vivo applications include ultrafast localized Z-spectroscopy, quantitative, or dynamic CEST studies.
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Affiliation(s)
- Zheng Liu
- Radiology, University of Texas Southwestern Medical Center, Dallas, Texas, USA
- Division of Neuroscience, Oregon National Primate Research Center, Oregon Health & Science University, Beaverton, Oregon, USA
| | - Ivan E. Dimitrov
- Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, Texas, USA
- Philips Medical Systems, Highland Heights, Ohio, USA
| | - Robert E. Lenkinski
- Radiology, University of Texas Southwestern Medical Center, Dallas, Texas, USA
- Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Asghar Hajibeigi
- Radiology, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Elena Vinogradov
- Radiology, University of Texas Southwestern Medical Center, Dallas, Texas, USA
- Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, Texas, USA
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Song KH, Kim SY, Lee DW, Jung JY, Lee JH, Baek HM, Choe BY. Design of a fused phantom for quantitative evaluation of brain metabolites and enhanced quality assurance testing for magnetic resonance imaging and spectroscopy. J Neurosci Methods 2015; 255:75-84. [PMID: 26277420 DOI: 10.1016/j.jneumeth.2015.08.005] [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: 10/12/2014] [Revised: 07/12/2015] [Accepted: 08/05/2015] [Indexed: 11/30/2022]
Abstract
BACKGROUND Magnetic resonance imaging and spectroscopy (MRI-MRS) is a useful tool for the identification and evaluation of chemical changes in anatomical regions. Quality assurance (QA) is performed in either images or spectra using QA phantom. Therefore, consistent and uniform technical MRI-MRS QA is crucial. NEW METHOD Here we developed an MRI-MRS fused phantom along with the inserts for metabolite quantification to simultaneously optimize QA parameters for both MRI and MRS. T1- and T2-weighted images were obtained and MRS was performed with point-resolved spectroscopy. RESULTS Using the fused phantom, the results of measuring MRI factors were: geometric distortion, <2% and ± 2 mm; image intensity uniformity, 83.09 ± 1.33%; percent-signal ghosting, 0.025 ± 0.004; low-contrast object detectability, 27.85 ± 0.80. In addition, the signal-to-noise ratio of N-acetyl-aspartate was consistently high (42.00 ± 5.66). COMPARISON WITH EXISTING METHODS In previous studies, MR phantoms could not obtain information from both images and spectra in the MR scanner simultaneously. Here we designed and developed a phantom for accurate and consistent QA within the acceptance range. It is important to take into account variations in the QA value using the MRI-MRS phantom, when comparing to other clinical or research MR scanners. CONCLUSIONS The MRI-MRS QA factors obtained simultaneously using the phantom can facilitate evaluation of both images and spectra, and provide guidelines for obtaining MRI and MRS QA factors simultaneously.
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Affiliation(s)
- Kyu-Ho Song
- Department of Biomedical Engineering, Research Institute of Biomedical Engineering, College of Medicine, The Catholic University of Korea, Seoul 137-701, Republic of Korea
| | - Sang-Young Kim
- Department of Biomedical Engineering, Research Institute of Biomedical Engineering, College of Medicine, The Catholic University of Korea, Seoul 137-701, Republic of Korea
| | - Do-Wan Lee
- Department of Biomedical Engineering, Research Institute of Biomedical Engineering, College of Medicine, The Catholic University of Korea, Seoul 137-701, Republic of Korea
| | - Jin-Young Jung
- Department of Biomedical Engineering, Research Institute of Biomedical Engineering, College of Medicine, The Catholic University of Korea, Seoul 137-701, Republic of Korea
| | - Jung-Hoon Lee
- Department of Biomedical Engineering, Research Institute of Biomedical Engineering, College of Medicine, The Catholic University of Korea, Seoul 137-701, Republic of Korea
| | - Hyeon-Man Baek
- Center for Magnetic Resonance Research, Korea Basic Science Institute, Chungbuk 363-883, Republic of Korea; Department of Bio-Analytical Science, Korea University of Science and Technology, Daejeon 305-333, Republic of Korea
| | - Bo-Young Choe
- Department of Biomedical Engineering, Research Institute of Biomedical Engineering, College of Medicine, The Catholic University of Korea, Seoul 137-701, Republic of Korea.
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Schneider E, NessAiver M. The Osteoarthritis Initiative (OAI) magnetic resonance imaging quality assurance update. Osteoarthritis Cartilage 2013; 21:110-6. [PMID: 23092792 PMCID: PMC3629918 DOI: 10.1016/j.joca.2012.10.011] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/20/2012] [Revised: 10/10/2012] [Accepted: 10/14/2012] [Indexed: 02/02/2023]
Abstract
OBJECTIVE Longitudinal quantitative evaluation of cartilage disease requires reproducible measurements over time. We report 8 years of quality assurance (QA) metrics for quantitative magnetic resonance (MR) knee analyses from the Osteoarthritis Initiative (OAI) and show the impact of MR system, phantom, and acquisition protocol changes. METHOD Key 3T MR QA metrics, including signal-to-noise, signal uniformity, T2 relaxation times, and geometric distortion, were quantified monthly on two different phantoms using an automated program. RESULTS Over 8 years, phantom measurements showed root-mean-square coefficient-of-variation reproducibility of <0.25% (190.0 mm diameter) and <0.20% (148.0 mm length), resulting in spherical volume reproducibility of <0.35%. T2 relaxation time reproducibility varied from 1.5% to 5.3%; seasonal fluctuations were observed at two sites. All other QA goals were met except: slice thicknesses were consistently larger than nominal on turbo spin echo images; knee coil signal uniformity and signal level varied significantly over time. CONCLUSIONS The longitudinal variations for a spherical volume should have minimal impact on the accuracy and reproducibility of cartilage volume and thickness measurements as they are an order of magnitude smaller than reported for either unpaired or paired (repositioning and reanalysis) precision errors. This stability should enable direct comparison of baseline and follow-up images. Cross-comparison of the geometric results from all four OAI sites reveal that the MR systems do not statistically differ and enable results to be pooled. MR QA results identified similar technical issues as previously published. Geometric accuracy stability should have the greatest impact on quantitative analysis of longitudinal change in cartilage volume and thickness precision.
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Affiliation(s)
- E. Schneider
- Imaging Institute, Cleveland Clinic Foundation, Cleveland, OH, USA,SciTrials, LLC, Rocky River, OH, USA,Address correspondence and reprint requests to: E. Schneider, Imaging Institute, L10, Cleveland Clinic Foundation, 9500 Euclid Avenue, Cleveland, OH 44116, USA. Tel: 1-216-444-7915; Fax: 1-216-445-1492. (E. Schneider)
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Tofts PS, Collins DJ. Multicentre imaging measurements for oncology and in the brain. Br J Radiol 2012; 84 Spec No 2:S213-26. [PMID: 22433831 DOI: 10.1259/bjr/74316620] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Multicentre imaging studies of brain tumours (and other tumour and brain studies) can enable a large group of patients to be studied, yet they present challenging technical problems. Differences between centres can be characterised, understood and minimised by use of phantoms (test objects) and normal control subjects. Normal white matter forms an excellent standard for some MRI parameters (e.g. diffusion or magnetisation transfer) because the normal biological range is low (<2-3%) and the measurements will reflect this, provided the acquisition sequence is controlled. MR phantoms have benefits and they are necessary for some parameters (e.g. tumour volume). Techniques for temperature monitoring and control are given. In a multicentre study or treatment trial, between-centre variation should be minimised. In a cross-sectional study, all groups should be represented at each centre and the effect of centre added as a covariate in the statistical analysis. In a serial study of disease progression or treatment effect, individual patients should receive all of their scans at the same centre; the power is then limited by the within-subject reproducibility. Sources of variation that are generic to any imaging method and analysis parameters include MR sequence mismatch, B(1) errors, CT effective tube potential, region of interest generation and segmentation procedure. Specific tissue parameters are analysed in detail to identify the major sources of variation and the most appropriate phantoms or normal studies. These include dynamic contrast-enhanced and dynamic susceptibility contrast gadolinium imaging, T(1), diffusion, magnetisation transfer, spectroscopy, tumour volume, arterial spin labelling and CT perfusion.
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Affiliation(s)
- P S Tofts
- Brighton and Sussex Medical School, Brighton, UK.
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Germuska M, Tunariu N, Leach MO, Xu J, Payne GS. An evaluation of motion compensation strategies and repeatability for abdominal (1)H MR spectroscopy measurements in volunteer studies and clinical trials. NMR IN BIOMEDICINE 2012; 25:859-865. [PMID: 22190219 DOI: 10.1002/nbm.1802] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2011] [Revised: 09/14/2011] [Accepted: 09/16/2011] [Indexed: 05/31/2023]
Abstract
Increased expression of choline kinase has frequently been shown in tumours and is thought to be associated with disease progression. Studies using magnetic resonance spectroscopy have shown an increase in total choline-containing metabolites (tCho) in tumour compared with healthy tissue. Subsequent reductions in tCho following successful treatment support the use of tCho as a biomarker of disease and response. However, accurate measurement of tCho using MRS in abdominal tumours is complicated by respiratory motion, blurring the acquisition volume and degrading the lineshape and signal-to-noise ratio (SNR) of metabolites. Motion compensation using prospectively gated acquisitions or offline correction of phase and frequency distortions can help restore the SNR and linewidth of metabolites. Prospectively gated acquisitions have the advantage of confining the volume of acquisition to the prescribed volume but are constrained by the repetition time (TR) of the respiratory motion. In contrast, data acquired for offline correction may use a shorter repetition time and therefore yield an increased SNR per unit time. In this study abdominal spectra acquired from single-voxel 'free-breathing' measurements in liver of healthy volunteers and in abdominal tumours of cancer patients were compared with those of prospective gating and with an implementation of offline correction. The two motion compensation methodologies were assessed in terms of SNR, linewidth and repeatability. Our experiments show that prospective gating and offline correction result in a 12-22% reduction in median tCho linewidth, while offline correction also provides a significant increase in SNR. The repeatability coefficient (the expected interval for 95% of repeat measurements) for tCho/water ratio was reduced by 37% (prospective gating) and 41% (offline correction). Both methods of motion compensation substantially improved the reproducibility of the tCho/water measurement and the tCho linewidth. While offline correction also leads to a significant improvement in SNR, it may suffer more from out-of-voxel contamination.
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Affiliation(s)
- M Germuska
- Royal Marsden Hospital and Institute of Cancer Research, Downs Road, Sutton, Surrey, SM2 5PT, UK.
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10
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The osteoarthritis initiative (OAI) magnetic resonance imaging quality assurance methods and results. Osteoarthritis Cartilage 2008; 16:994-1004. [PMID: 18424108 PMCID: PMC2584336 DOI: 10.1016/j.joca.2008.02.010] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/13/2007] [Accepted: 02/08/2008] [Indexed: 02/02/2023]
Abstract
OBJECTIVE To outline the osteoarthritis initiative's (OAI) magnetic resonance (MR) system quality assurance (QA) processes and present the first 3 years' results. METHOD OAI MR QA included acquisitions evaluated manually at each of the four sites and other acquisitions assessed by an automated computer program. Key image characteristics such as signal-to-noise, contrast-to-noise, signal uniformity, T2 relaxation times, local and global geometric distortion were quantified monthly using the automated program. RESULTS Uniformly high quality, artifact-free subject images were obtained from all four OAI 3 tesla MR facilities. Over a 3-year period, key criteria for quantitative cartilage morphometry were excellent with a 190.0 mm diameter and 148.0 mm length object having reproducible diameter (0.04% RMS CV) and length (0.56% RMS CV). This resulted in spherical volume reproducibility of 0.46% RMS CV. Ghost levels were consistently <0.2%. T2 relaxation time varied longitudinally site-by-site from 2.3 to 18.8% RMS CV. All other measures of MR system stability were met except: 3.0 mm and 5.0 mm slice thicknesses were consistently larger than expected; knee coil signal uniformity and signal level varied significantly over time. CONCLUSIONS OAI MR QA results compared favorably to prior publications and identified similar technical issues for geometric measurements. The longitudinal variations measured in the OAI QA process should have minimal impact on the accuracy and reproducibility of cartilage thickness and volume quantification. This stability should enable direct comparison of baseline and follow-up images. Cross-comparison of the results from all four OAI sites reveals that the MR systems are sufficiently uniform to enable results to be combined.
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11
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van der Graaf M, Julià-Sapé M, Howe FA, Ziegler A, Majós C, Moreno-Torres A, Rijpkema M, Acosta D, Opstad KS, van der Meulen YM, Arús C, Heerschap A. MRS quality assessment in a multicentre study on MRS-based classification of brain tumours. NMR IN BIOMEDICINE 2008; 21:148-58. [PMID: 17458918 DOI: 10.1002/nbm.1172] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
This paper reports on quality assessment of MRS in the European Union-funded multicentre project INTERPRET (International Network for Pattern Recognition of Tumours Using Magnetic Resonance; http://azizu.uab.es/INTERPRET), which has developed brain tumour classification software using in vivo proton MR spectra. The quality assessment consisted of both MR system quality assurance (SQA) and quality control (QC) of spectral data acquired from patients and healthy volunteers. The system performance of the MR spectrometers at all participating centres was checked bimonthly by a short measurement protocol using a specially designed INTERPRET phantom. In addition, a more extended SQA protocol was performed yearly and after each hardware or software upgrade. To compare the system performance for in vivo measurements, each centre acquired MR spectra from the brain of five healthy volunteers. All MR systems fulfilled generally accepted minimal system performance for brain MRS during the entire data acquisition period. The QC procedure of the MR spectra in the database comprised automatic determination of the signal-to-noise ratio (SNR) in a water-suppressed spectrum and of the line width of the water resonance (water band width, WBW) in the corresponding non-suppressed spectrum. Values of SNR > 10 and WBW < 8 Hz at 1.5 T were determined empirically as conservative threshold levels required for spectra to be of acceptable quality. These thresholds only hold for SNR and WBW values using the definitions and data processing described in this article. A final QC check consisted of visual inspection of each clinically validated water-suppressed metabolite spectrum by two, or, in the case of disagreement, three, experienced MR spectroscopists, to detect artefacts such as large baseline distortions, exceptionally broadened metabolite peaks, insufficient removal of the water line, large phase errors, and signals originating from outside the voxel. In the end, 10% of 889 spectra with completed spectroscopic judgement were discarded.
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Affiliation(s)
- Marinette van der Graaf
- Department of Radiology, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands.
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12
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Abstract
The ability to select a discrete region within the body for signal acquisition is a fundamental requirement of in vivo NMR spectroscopy. Ideally, it should be possible to tailor the selected volume to coincide exactly with the lesion or tissue of interest, without loss of signal from within this volume or contamination with extraneous signals. Many techniques have been developed over the past 25 years employing a combination of RF coil properties, static magnetic field gradients and pulse sequence design in an attempt to meet these goals. This review presents a comprehensive survey of these techniques, their various advantages and disadvantages, and implications for clinical applications. Particular emphasis is placed on the reliability of the techniques in terms of signal loss, contamination and the effect of nuclear relaxation and J-coupling. The survey includes techniques based on RF coil and pulse design alone, those using static magnetic field gradients, and magnetic resonance spectroscopic imaging. Although there is an emphasis on techniques currently in widespread use (PRESS, STEAM, ISIS and MRSI), the review also includes earlier techniques, in order to provide historical context, and techniques that are promising for future use in clinical and biomedical applications.
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Affiliation(s)
- Stephen F Keevil
- Department of Medical Physics, Guy's and St Thomas' NHS Foundation Trust, Guy's Hospital, London, SE1 9RT, UK.
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13
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Leach MO. Magnetic resonance spectroscopy (MRS) in the investigation of cancer at The Royal Marsden Hospital and The Institute of Cancer Research. Phys Med Biol 2006; 51:R61-82. [PMID: 16790921 DOI: 10.1088/0031-9155/51/13/r05] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Developments in magnetic resonance spectroscopy (MRS) at The Royal Marsden Hospital and The Institute of Cancer Research are reviewed in the context of preceding developments in nuclear magnetic resonance (NMR) and MRS, and some of the early developments in this field, particularly those leading to human measurements. The early development of technology, and associated techniques for human measurement and assessment will be discussed, with particular reference to experience at out institutions. Applications using particular nuclei will then be described and related to other experimental work where appropriate. Contributions to the development of MRS that have been published in Physics in Medicine and Biology will be discussed.
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Affiliation(s)
- M O Leach
- Cancer Research UK Clinical Magnetic Resonance Research Group, Institute of Cancer Research and Royal Marsden NHS Foundation Trust, Sutton, Surrey, SM2 5PT, UK
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14
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Keevil SF, Newbold MC. The performance of volume selection sequences for in vivo NMR spectroscopy: implications for quantitative MRS. Magn Reson Imaging 2001; 19:1217-26. [PMID: 11755732 DOI: 10.1016/s0730-725x(01)00449-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Previous work has demonstrated that deficiencies in volume selection sequences used in magnetic resonance spectroscopy may compromise the quality of the spectra obtained. In this paper, further studies on the ISIS and PRESS sequences are presented. Under conditions of partial saturation, ISIS can exhibit serious contamination with extraneous signal, particularly when a small volume of interest (VOI) is selected. ISIS protocols should therefore use VOIs that are large relative to the target volume, and repetition times that are as long as practicable. In PRESS, contamination is found to be minimised by using a VOI that is small relative to the target volume, and to be independent of repetition time. PRESS performance is also independent of echo time, except when very short echo times are used. These results are consistent with previously published work on ISIS and PRESS, and it is now possible to establish generic features of these sequences and to understand the implications for quantitative spectroscopy. T(1)-weighting of contamination in ISIS can compromise both relative and absolute quantification techniques in several respects. Contamination in PRESS is largely independent of relaxation times and would be easier to model and correct for in the context of quantitative spectroscopy.
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Affiliation(s)
- S F Keevil
- Department of Radiological Sciences, Guy's, King's and St Thomas' School of Medicine, King's College London, Guy's Campus, London, SE1 9RT, UK.
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15
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Brooks JC, Roberts N, Kemp GJ, Gosney MA, Lye M, Whitehouse GH. A proton magnetic resonance spectroscopy study of age-related changes in frontal lobe metabolite concentrations. Cereb Cortex 2001; 11:598-605. [PMID: 11415962 DOI: 10.1093/cercor/11.7.598] [Citation(s) in RCA: 116] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Ageing is associated with reduction of grey matter volume and it is reported that the frontal lobes are preferentially affected. We have applied quantitative magnetic resonance spectroscopy (MRS), incorporating measurement of brain tissue water content and metabolite T(2) relaxation times, to determine absolute concentrations of the putative neuronal marker N-acetylaspartate (NAA), creatine (Cr) and choline (Cho) compounds in the frontal lobe of 50 male subjects aged between 20 and 70 years (10 per decade). The fractional brain water content (beta(MR)) did not change significantly as a function of age (r = 0.07, P = 0.65) and had a mean value of 81% (CV = 2%). The concentration (in millimoles per litre brain tissue) of NAA decreased significantly with age (r = -0.42, P = 0.003), with an overall decrease of 12% between the third and seventh decades. The concentrations of Cr and Cho did not change significantly with age. The interpretation of the age-dependent decrease in NAA concentration as reflecting either a reduction in neuronal volume, number or function is discussed.
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Affiliation(s)
- J C Brooks
- Magnetic Resonance and Image Analysis Research Centre, Department of Musculoskeletal Science, University of Liverpool, Liverpool, UK.
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16
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Burtscher IM, Johansson E, Holtås S, Ståhlberg F. Quality assessment of localization technique performance in small volume in vivo 1H MR spectroscopy. Magn Reson Imaging 1999; 17:1511-9. [PMID: 10610000 DOI: 10.1016/s0730-725x(99)00076-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
A new phantom and evaluation method for experimental evaluation of 1H-magnetic resonance spectroscopy single volume localization techniques regarding signal contamination (C), defined as the part of the signal originating outside the volume of interest, is presented. The quality assessment method is based on a spherical phantom with an oil/water interface in order to reduce susceptibility effects, and applied for stimulated-echo acquisition method (STEAM) and spin-echo (SE) sequences, echo times of 270, 135, and 10 ms, and cubic volumes of interest (VOI) of 1(3), 1.5(3), 2(3), 2.5(3), and 3(3) cm3. To be able to mimic measurements of the contamination in three dimensions the physical gradients representing the three orthogonal directions for slice selection were shifted in the pulse sequences. Contamination values in one dimension differed between 6.5% and 8.4% in SE sequences, and between 0.7% and 13.8% in STEAM sequences. In STEAM sequences a decrease of C with increasing VOI size was observed while SE sequences showed comparable C values for the different VOI sizes tested. The total contamination in three dimensions were 19% and 18% in SE and STEAM sequences with a TE of 270 ms, and 7% in a STEAM sequence with a TE of 10 ms, respectively. The presented evaluation method is easily applied to the new phantom and showed high reproducibility.
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Affiliation(s)
- I M Burtscher
- Department of Radiology, University Hospital, Lund, Sweden.
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17
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Abstract
Following the impetus of early clinical and experimental investigations, in vivo and in vitro MRS studies of tumours pointed in the eighties to the possible significance of signals arising from phospholipid (PL) precursors and catabolites as novel biochemical indicators of in vivo tumour progression and response to therapy. In the present decade, MRS analyses of individual components contributing to the 31P PME (phosphomonoester) and PDE (phosphodiester) resonances, as well as to the 1H 'choline peak', have reinforced some of these expectations. Moreover, the absolute quantification of these signals provided the basis for addressing more specific (although still open) questions on the biochemical mechanisms responsible for the formation of intracellular pools of PL derivatives in tumours, under different conditions of cell proliferative status and/or malignancy level. This article is aimed at providing an overview on: (a) quantitative MRS measurements on the contents of phosphocholine (PCho), phosphoethanolamine (PEtn) and their glycerol derivatives ģlycerol 3-phosphocholine (GPC) and glycerol 3-phosphoethanolamine (GPE)[ in human tumours and cells (with particular attention to breast and brain cancer and lymphomas), as well as in normal mammalian tissues (including developing organs and rapidly proliferating tissues); (b) possible correlations of MRS parameters like PEtn/PCho and PCho/GPC ratios with in vitro cell growth status and/or cell tumorigenicity; and (c) current and new hypotheses on the role and interplay of biosynthetic and catabolic pathways of the choline and ethanolamine cycles in modulating the intracellular sizes of PCho and PEtn pools, either in response to mitogenic stimuli or in relation to malignant transformation.
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Affiliation(s)
- F Podo
- Laboratory of Cell Biology, Istituto Superiore di Sanità, Rome,
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18
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Chong VF, Rumpel H, Aw YS, Ho GL, Fan YF, Chua EJ. Temporal lobe necrosis following radiation therapy for nasopharyngeal carcinoma: 1H MR spectroscopic findings. Int J Radiat Oncol Biol Phys 1999; 45:699-705. [PMID: 10524425 DOI: 10.1016/s0360-3016(99)00236-9] [Citation(s) in RCA: 48] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
PURPOSE To observe the patterns of radiation-induced temporal lobe necrosis (TLN) following radiation therapy for nasopharyngeal carcinoma (NPC). METHODS AND MATERIALS Twenty-five proton magnetic resonance spectroscopic (1H MRS) examinations were acquired from 13 healthy adult volunteers for comparison with data from the patient population. There were 18 patients (28 spectra) with radiologic evidence of TLN and all patients were confirmed cases of NPC treated with radiation therapy. Six patients (33%) had a single treatment while 12 (67%) patients had two treatments. All 1H MRS examinations were performed on a 2-T whole body system (Bruker) using the point-resolved spectroscopy (PRESS) method with TE = 135 ms, TR = 3000 ms, and data processed automatically using the LCModel software package for metabolite quantification. RESULTS The N-acetyl-aspartate (NAA) levels were reduced in all except one spectrum (96%). Choline (Cho) was increased in 3 (11%), normal in 4 (14%), and reduced in 21 (75%) spectra. The creatine (Cr) level was normal in 8 (29%) spectra and reduced in 20 (71%) spectra. In four patients with normal imaging findings 1H MRS was abnormal. CONCLUSION 1H MRS can characterize radiation-induced TLN. Spectra with increased Cho can be mistaken for neoplasm. Spectroscopy can also identify metabolic derangement before imaging.
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Affiliation(s)
- V F Chong
- Department of Diagnostic Radiology, Singapore General Hospital, Singapore.
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19
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Vikhoff-Baaz B, Ljungberg M, Starck G, Forssell-Aronsson E, Jönsson L, Alpsten M, Ekholm S. Performance of 2D 1H spectroscopic imaging of the brain: some practical considerations regarding the measurement procedure. Magn Reson Imaging 1999; 17:919-31. [PMID: 10402599 DOI: 10.1016/s0730-725x(99)00023-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
This paper deals with some of the practical considerations in the planning and performance of chemical shift imaging (MRSI or CSI) of the brain. It contains some aspects of 1) the imaging procedure (MRI), i.e., suggestions of an imaging protocol useful for the spectroscopic planning, 2) the planning of the spectroscopic volume, i.e., size and position, 3) evaluation and judgment of the preparation results, and 4) evaluation of the MRSI images. The paper also contains suggestions of developmental work and quality assessment to be done before patient studies are begun. Examples are given for MRSI studies of temporal lobe epilepsy. Several of the aspects described are obvious for the experienced spectroscopist but may be useful in the initiation of MRSI. The goal of this paper was to share our experiences of how to achieve high quality MRSI, experiences that we would had been grateful for in our prelude of MRSI experiments.
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Affiliation(s)
- B Vikhoff-Baaz
- Department of Radiation Physics, Göteborg University, Sweden.
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20
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Bovée W, Canese R, Decorps M, Forssell-Aronsson E, Le Fur Y, Howe F, Karlsen O, Knijn A, Kontaxis G, Kügel H, McLean M, Podo F, Slotboom J, Vikhoff B, Ziegler A. Absolute metabolite quantification by in vivo NMR spectroscopy: IV. Multicentre trial on MRSI localisation tests. Magn Reson Imaging 1998; 16:1113-25. [PMID: 9839995 DOI: 10.1016/s0730-725x(98)00120-9] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
The difference between the experimental and theoretical spatial response function (SRF) of a narrow tube with water is used for a localization test for magnetic resonance spectroscopic imaging (MRSI). From this difference a quantitative performance parameter is derived for the relative amount of signal within a limited region in the field of view. The total signal loss by the MRSI experiment and eddy currents is described by a parameter SL derived from the signal intensities of two echoes. Results of a European multi-centre trial show that this approach is suited for assessment of MRSI localization performance.
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Affiliation(s)
- W Bovée
- Department of Applied Physics, University of Technology, Delft, The Netherlands.
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21
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Keevil SF, Barbiroli B, Brooks JC, Cady EB, Canese R, Carlier P, Collins DJ, Gilligan P, Gobbi G, Hennig J, Kügel H, Leach MO, Metzler D, Mlynárik V, Moser E, Newbold MC, Payne GS, Ring P, Roberts JN, Rowland IJ, Thiel T, Tkác I, Topp S, Wittsack HJ, Podo F. Absolute metabolite quantification by in vivo NMR spectroscopy: II. A multicentre trial of protocols for in vivo localised proton studies of human brain. Magn Reson Imaging 1998; 16:1093-106. [PMID: 9839993 DOI: 10.1016/s0730-725x(98)00118-0] [Citation(s) in RCA: 78] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
We have performed a multicentre trial to assess the performance of three techniques for absolute quantification of cerebral metabolites using in vivo proton nuclear magnetic resonance (NMR). The techniques included were 1) an internal water standard method, 2) an external standard method based on phantom replacement, and 3) a more sophisticated method incorporating elements of both the internal and external standard approaches, together with compartmental analysis of brain water. Only the internal water standard technique could be readily implemented at all participating sites and gave acceptable precision and interlaboratory reproducibility. This method was insensitive to many of the experimental factors affecting the performance of the alternative techniques, including effects related to loading, standing waves and B1 inhomogeneities; and practical issues of phantom positioning, user expertise and examination duration. However, the internal water standard method assumes a value for the concentration of NMR-visible water within the spectroscopic volume of interest. In general, it is necessary to modify this assumed concentration on the basis of the grey matter, white matter and cerebrospinal fluid (CSF) content of the volume, and the NMR-visible water content of the grey and white matter fractions. Combining data from 11 sites, the concentrations of the principal NMR-visible metabolites in the brains of healthy subjects (age range 20-35 years) determined using the internal water standard method were (mean+/-SD): [NAA]=10.0+/-3.4 mM (n=53), [tCho]=1.9+/-1.0 mM (n=51), [Cr + PCr]=6.5+/-3.7 mM (n=51). Evidence of system instability and other sources of error at some participating sites reinforces the need for rigorous quality assurance in quantitative spectroscopy.
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Affiliation(s)
- S F Keevil
- United Medical and Dental Schools of Guy's Hospital, London, UK.
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22
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Ljungberg M, Starck G, Vikhoff-Baaz B, Forssell-Aronsson E, Alpsten M, Ekholm S. Signal profile measurements of single- and double-volume acquisitions with image-selected in vivo spectroscopy for 31P magnetic resonance spectroscopy. Magn Reson Imaging 1998; 16:829-37. [PMID: 9811147 DOI: 10.1016/s0730-725x(98)00007-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
Abstract
The volume-selection performance was studied for single- and double-volume-of-interest (VOI) acquisition with the volume-selection method image-selected in vivo spectroscopy for 31P magnetic resonance spectroscopy. High-resolution signal profiles were measured using a phantom simulating a brain. Inside the phantom there was a small, remotely controlled, movable signal source filled with ortho-phosphoric acid. Signal profiles of the VOI were measured in three perpendicular directions for 1VOI (single VOI) and 2VOI (double VOI) acquisition. The measured signal profiles for both acquisitions were very similar, but they showed a discrepancy with regard to the intended VOI (iVOI). The transition regions were on average 3.8 mm and the average full width at half maximum of the signal profile was 30 mm for an iVOI size of 30*30*30 (mm3). No displacement was observed in the signal profiles. To avoid overlapping signal profiles, the minimum separation between two iVOIs was found to be 10 mm in our magnetic resonance (MR) system. A substantial negative signal contribution from regions outside the iVOI was measured in the y-direction for 1VOI acquisition and one of the two VOIs in 2VOI acquisition. The other VOI in 2VOI acquisition exhibited only minor contamination. The measurements presented underline the importance of detailed knowledge on the volume selection performance in in vivo magnetic resonance spectroscopy.
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Affiliation(s)
- M Ljungberg
- Department of Radiation Physics, Göteborg University, Sahlgrenska University Hospital, Sweden.
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23
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Vikhoff B, Stubgaard M, Stensgaard A, Ståhlberg F, Henriksen O. A two-compartment phantom for VOI profile measurements in small-bore 31P MR spectroscopy. Phys Med Biol 1998; 43:1761-70. [PMID: 9651038 DOI: 10.1088/0031-9155/43/6/027] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
A two-compartment gel phantom for VOI profile measurements in volume-selective 31P spectroscopy in small-bore units is presented. The phantom is cylindrical with two compartments divided by a very thin (30 microm) polyethene film. This thin film permits measurements with a minimum of susceptibility influences from the partition wall. The phantom was used for evaluation of the volume selection method ISIS (image-selected in vivo spectroscopy). The position of the phantom was fixed in the magnet during the measurements, while the volume of interest (VOI) was moved stepwise over the border. The signal from the two compartments was measured for each position and the data were evaluated following differentiation. We have found this phantom suitable for VOI profile measurements of ISIS in small-bore systems. The phantom forms a useful complement to recommended phantoms for small bore-spectroscopy.
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Affiliation(s)
- B Vikhoff
- Department of Radiation Physics and Radiology, Lund University Hospital, Sweden
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24
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Duc CO, Weber OM, Trabesinger AH, Meier D, Boesiger P. Quantitative 1H MRS of the human brain in vivo based on the stimulation phantom calibration strategy. Magn Reson Med 1998; 39:491-6. [PMID: 9498606 DOI: 10.1002/mrm.1910390320] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Normal metabolite concentrations were determined in five different brain regions of healthy adult volunteers using proton magnetic resonance spectroscopy (1H MRS) in vivo. The absolute in vivo concentrations of N-acetylaspartate (NAA), creatine and phosphocreatine (Cre), and choline containing compounds (Cho) were quantified from measurements obtained with a head-shaped simulation phantom. Scanner performance and calibration accuracy were assessed by phantom experiments. Localized spectra were acquired on clinical 1.5 T systems using the PRESS localization sequence with frequency selective water suppression. Comparison of the results obtained from phantom experiments and human brain in vivo strongly suggests that reproducibility in vivo mainly depends on the topologic metabolite heterogeneity of brain tissue in combination with relative volume dislocalization.
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Affiliation(s)
- C O Duc
- Institute of Biomedical Engineering and Medical Informatics, University and Swiss Federal Institute of Technology, Zurich
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25
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Lowry M, Liney GP, Turnbull LW, Manton DJ, Blackband SJ, Horsman A. Quantification of citrate concentration in the prostate by proton magnetic resonance spectroscopy: zonal and age-related differences. Magn Reson Med 1996; 36:352-8. [PMID: 8875404 DOI: 10.1002/mrm.1910360305] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
A commercial phased-array multicoil was used to acquire water-suppressed localized proton spectra of the two major anatomical regions of the prostate. The signal-to-noise ratio and spectral resolution allowed identification of peaks from choline and creatine, as well as a major peak from citrate. Quantification of the citrate peak using experimentally determined relaxation parameters with tissue water as an internal concentration reference revealed a marked variability between different volunteers. Nevertheless, in each case, the citrate concentration was up to fourfold greater in the peripheral zone than in the central gland. Furthermore, the difference in citrate concentration between these two regions was positively correlated with the subjects age. The results indicate a consistent difference in cellular function between the major anatomical regions within the prostate and may have important consequences for the application of magnetic resonance spectroscopy to the diagnosis of prostatic pathology.
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Affiliation(s)
- M Lowry
- Centre for Magnetic Resonance Investigations, University of Hull, United Kingdom
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26
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Brunetti A, Alfano B, Soricelli A, Tedeschi E, Mainolfi C, Covelli EM, Aloj L, Panico MR, Bazzicalupo L, Salvatore M. Functional characterization of brain tumors: an overview of the potential clinical value. Nucl Med Biol 1996; 23:699-715. [PMID: 8940713 DOI: 10.1016/0969-8051(96)00069-8] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Early detection and characterization are still challenging issues in the diagnostic approach to brain tumors. Among functional imaging techniques, a clinical role for positron emission tomography studies with [18F]-fluorodeoxyglucose and for single photon emission computed tomography studies with [201Tl]-thallium-chloride has emerged. The clinical role of magnetic resonance spectroscopy is still being defined, whereas functional magnetic resonance imaging seems able to provide useful data for presurgical localization of critical cortical areas. Integration of morphostructural information provided by computed tomography and magnetic resonance imaging, with functional characterization and cyto-histologic evaluation of biologic markers, may assist in answering the open diagnostic questions concerning brain tumors.
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Affiliation(s)
- A Brunetti
- Centro CNR Per La Medicina Nucleare, Università Degli Studi Federico II, Napoli, Italy
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Cox IJ. Development and applications of in vivo clinical magnetic resonance spectroscopy. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 1996; 65:45-81. [PMID: 9029941 DOI: 10.1016/s0079-6107(96)00006-5] [Citation(s) in RCA: 54] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
4.1 CURRENT STATUS. While an extensive clinical literature of MRS of muscle, brain, heart and liver has been achieved, the MRS technique is not considered essential for routine diagnosis because it is inherently insensitive and metabolic changes tend to be small. However, MRS techniques have proven to be of considerable value for prognosis in some circumstances, notably for predicting outcome following hypoxic-ischaemic injury in the newborn and also in predicting graft viability following organ transplantation. The chemical specificity of MRS has been illustrated, and exploiting the non-invasive nature of the technique, metabolic fingerprinting of pathophysiological processes throughout the natural history of a wide variety of diseases is now being accomplished. Particularly exciting are the applications of 13C MRS for measuring hepatic and muscle glycogen levels, for example in diabetics, and the use of hepatic 31P MRS for assessing liver function in cirrhosis. Other areas of excitement are the applications of 1H MRS in assessing neuronal function in epilepsy and stroke, and for measuring the evolution of lactate in stroke and hypoxic-ischaemic encephalopathy. Emphasis on technique development continues, and applications still tend to be technology-led. The availability of routine clinical MRI systems with spectroscopy capabilities has given MRS studies wider applicability. The recent improvements in spatial resolution have been impressive and the technique is slowly becoming more quantitative. 4.2. FUTURE PERSPECTIVES. Given the flexibility of clinical magnetic resonance techniques, particularly magnetic resonance imaging, it is likely that MRI will be the diagnostic tool of choice in a wider range of diseases, such as multiple sclerosis, stroke, neurodegenerative conditions, sports injuries and in staging malignancies. Since proton magnetic resonance spectroscopy packages have become a routine addition to many MRI systems, it is feasible to select the MRI sequences of most value in highlighting anatomical and pathological abnormalities and to incorporate specifically selected MRS sequences to emphasize biochemical differences. Improvements in technical methodologies are central to further developments. For example, use of internal coils, such as implantable or endoscopic coils, will enable small regions of tissue to be studied in considerable detail, which may otherwise be inaccessible to measurement. Chemical MRS studies have benefited from the use of higher magnetic fields, and the same may be expected for clinical MRS studies. Whole-body magnets up to 4 T have been used in a few centres, and certainly 3 T systems are becoming more widely available with the recent tremendous interest in functional imaging. Certainly, better control of artefacts can be expected; for example, improved definition of spectral changes due to voluntary or involuntary movements. Wider use of proton decoupling methods will improve the specificity of the spectra, by allowing definitive assignments of overlapping resonances, as well as the sensitivity. Comparing PET and MRS studies, it is becoming increasingly obvious that both will be required in parallel to explore parameters of brain metabolism and function. The ability to measure 13C MR signals in the brain has been demonstrated, which allows measurements of glutamate and glucose turnover. MRS measurements have the advantage of not requiring a radioactive isotope, as well as being insensitive to activity-related changes in regional cerebral blood flow. Also the study of cerebral glucose metabolism by MRS is very promising, allowing a resolution and sensitivity comparable to PET. A combination of MRS and PET studies will allow the pathogenesis of neuropsychiatric disorders to be better understood. (ABSTRACT TRUNCATED)
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Affiliation(s)
- I J Cox
- Robert Steiner Magnetic Resonance Unit, Royal Postgraduate Medical School, London, U.K
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Ljungberg M, Starck G, Forssell-Aronsson E, Alpsten M, Ekholm S. Signal profile measurements for evaluation of the volume-selection performance of ISIS. NMR IN BIOMEDICINE 1995; 8:271-277. [PMID: 8732183 DOI: 10.1002/nbm.1940080607] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
High-resolution signal profiles obtained with a test phantom were used in this study to evaluate the volume-selection performance of an implementation of ISIS (Image Selected In vivo Spectroscopy). The phantom simulated the brain with regard to volume and loading of coil. A remotely controlled, movable signal source inside the phantom was filled with orthophosphoric acid. Signal profiles of the volume of interest (VOI) were measured in three perpendicular directions. Special interest was focused on the transition zones, the position of the profiles, and the effects of off-resonance and T1 smearing. The transition zones were on average 5.6 mm wide and the full width at half maximum (FWHM) was 35 mm for a VOI of 40 x 40 x 40 mm3. The positions of the centre of the signal profiles were x = 3.2, y = -0.7 and z = 3.3 mm off-centre. The deviation of the volume position could be explained by off-resonance effects during imaging and spectroscopy. These data illustrate the importance of detailed knowledge of the volume-selection performance when attempting precision measurements using image-guided in vivo MRS.
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Affiliation(s)
- M Ljungberg
- Department of Radiation Physics, Göteborg University, Sahlgrenska University Hospital, Sweden
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29
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Yongbi NM, Payne GS, Collins DJ, Leach MO. Quantification of signal selection efficiency, extra volume suppression and contamination for ISIS, STEAM and PRESS localized 1H NMR spectroscopy using an EEC localization test object. Phys Med Biol 1995; 40:1293-303. [PMID: 7568384 DOI: 10.1088/0031-9155/40/7/011] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The three most widely used single-volume NMR localization techniques (ISIS, STEAM and PRESS) are assessed quantitatively for 1H spectroscopy using an EEC localization test object. Signal selection efficiency, suppression of outer volume signals and contamination are measured on a 1.5 T whole-body Siemens GBS1 system. The ISIS signal selection efficiency (volume of interest (VOI), 1-125 cm3) ranged from 90% to 95%, with T1 relaxation during the sequence shown to account for the observed 5-10% signal loss. Contamination for ISIS was found to be higher for smaller VOIS and ranged from approximately 45% (VOI = 1 cm3) to approximately 9% (VOI = 125 cm3). For PRESS, contamination ranged from 7% to 12% and it was between 3% and 8% for STEAM. However, the maximum signal selection efficiency for the latter two techniques (echo time, 270 ms) was relatively low (10-17%), and limited by T2 losses and the non-rectangular slice profiles of sinc pulses.
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Affiliation(s)
- N M Yongbi
- CRC Clinical Magnetic Resonance Research Group, Institute of Cancer Research, Sutton, Surrey, UK
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Henriksen O. In vivo quantitation of metabolite concentrations in the brain by means of proton MRS. NMR IN BIOMEDICINE 1995; 8:139-148. [PMID: 8771088 DOI: 10.1002/nbm.1940080402] [Citation(s) in RCA: 48] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
MRS offers unique possibilities for non-invasive studies of biochemistry in the human brain in vivo. A growing body of evidence suggests that proton MRS may contribute to the clinical evaluation of a number of pathologies including ischaemia, tumours, epilepsy, metabolic and neuropaediatric disorders. In most cases results are expressed as ratios between metabolite signals obtained at certain experimental conditions. Presenting the results as metabolite signal ratios may lead to misinterpretation because such alterations can be due to changes in the content of either one of the metabolites or both, or may simply be due to changes in relaxation behaviour. Absolute quantitation of metabolite concentrations is therefore warranted. A number of studies using single volume proton MRS indicate that absolute quantitation of metabolite concentration is possible with respect to N-acetyl aspartate (NAA), total creatine, choline containing compounds, (Cho) and inositols (Ins). Internal standards (unsaturated water signal) as well as external standards have been used for signal calibration. Quality control with respect to signal linearity with concentration or with size of selected volume, selection efficiency, outer volume depression and signal contamination is essential for validation of the measurements. Furthermore, corrections for the influence of relaxation behavior are necessary. The results published so far indicate that the concentrations of NAA, total creatine, Cho and Ins in mmoles (kg wet weight)-1 range between 8.2 and 17.2 (mean 10.2), 5.9 and 11.6 (mean 7.2), 1.1 and 2.0 (mean 1.5) and 3.9 and 8.1 (mean 6.1), respectively. So far only a limited number of clinical studies has been published including studies of acute stroke, multiple sclerosis and Alzheimer's disease. The results are promising and encourage further exploitation of the utility of quantitative proton MRS in clinical practise.
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Affiliation(s)
- O Henriksen
- Danish Research Centre of Magnetic Resonance, Hvidovre University Hospital, Denmark
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Howe FA, Canese R, Podo F, Vikhoff B, Slotboom J, Griffiths JR, Henriksen O, Bovée WM. Quality assessment in in vivo NMR spectroscopy: V. Multicentre evaluation of prototype test objects and protocols for performance assessment in small bore MRS equipment. Magn Reson Imaging 1995; 13:159-67. [PMID: 7898275 DOI: 10.1016/0730-725x(94)00091-g] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
This paper reports the results of multicentre studies aimed at designing, constructing, and evaluating prototype test objects for performance assessment in small-bore MRS systems, by utilizing the test protocols already proposed by the EEC COMAC-BME Concerted Action for clinical MRS equipment. Three classes of test objects were considered: (1) a multicompartment test object for 31P MRS measurements performed with slice-selective sequences; (2) a two-compartment test object for volume-selection 1H MRS; and (3) two-compartment test objects for assessing the performance of experimental systems using ISIS as volume localization sequence in 31P MRS. The results suggested the interest of adopting some of these prototypes for improving the comparison of spectroscopy data obtained from different sites, for providing useful means of quality assurance in experimental MRS, and facilitating the validation of new localization sequences.
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Affiliation(s)
- F A Howe
- Division of Cellular and Molecular Sciences, St. George's Hospital Medical School, London, UK
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32
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Leach MO, Collins DJ, Keevil S, Rowland I, Smith MA, Henriksen O, Bovée WM, Podo F. Quality assessment in in vivo NMR spectroscopy: III. Clinical test objects: design, construction, and solutions. Magn Reson Imaging 1995; 13:131-7. [PMID: 7898273 DOI: 10.1016/0730-725x(94)00089-l] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Based on the requirements of test protocols developed to evaluate clinical MRS single slice and volume localisation sequences, two clinical test objects, STO1 and STO2 have been developed. The properties of a range of potential construction materials have been assessed, demonstrating that the water/Perspex interface produced minimum susceptibility effects. The design of the objects has been evaluated in trials on different magnetic resonance instruments, with size and loading being adjusted to allow use on currently available equipment. Appropriate test solutions for 31P and 1H measurements have been developed and their properties evaluated.
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Affiliation(s)
- M O Leach
- CRC Clinical Magnetic Resonance Research Group, Institute of Cancer Research, Sutton, Surrey, UK
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Podo F, Bovée WM, de Certaines J, Leibfritz D, Orr JS. Quality assessment in in vivo NMR spectroscopy: I. Introduction, objectives, and activities. Magn Reson Imaging 1995; 13:117-21. [PMID: 7898271 DOI: 10.1016/0730-725x(94)00087-j] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
By enabling noninvasive measurements of tissue biochemistry, nuclear magnetic resonance spectroscopy (MRS) provides a unique means of characterizing tissues. Differences in equipment, techniques, and methodology between different laboratories cause major difficulties when comparing results, whether from measurements of tissue metabolism, or from the effects of different therapies. This is of concern in critically evaluating work from different laboratories and centres, causing potential difficulties in reproducing results, limiting the establishment of MRS as a standard method of diagnosis and of characterising disease and response to therapy in the laboratory and clinic. It also poses particular problems in establishing the multicentre clinical trials of MRS that are now required to provide adequate statistical power in confirming the encouraging preliminary clinical observations. These difficulties arise principally from imperfect localization of signal from selected regions of interest in the body, and from the subsequent analyses of the MRS spectra. Improvement is possible by establishing agreed procedures for test measurements and for data analysis, and by using appropriate test objects and test substances to establish the quality of measurements. A concerted research project on characterisation of biological tissues by NMR, principally concerned with MR imaging (MRI), was activated in 1984 by the European Economic Community as part of its third Medical and Health Research Programme, under the auspices of the Biomedical Engineering Concerted Actions' Committee (COMAC-BME). In 1988, this project was prolonged for 5 years, when the programme was expanded to encompass MRS.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- F Podo
- Laboratory of Cell Biology, Istituto Superiore di Sanità, Rome, Italy
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