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Wichtmann B, Fan Q, Witzel T, Pieper C, Attenberger U, Rosen B, Wald L, Huang S, Nummenma A. Linear Multi-scale Modeling von diffusionsgewichteter MRT-Bildgebung zur mikrostrukturellen Charakterisierung von Gewebe in vivo. ROFO-FORTSCHR RONTG 2022. [DOI: 10.1055/s-0042-1749763] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- B Wichtmann
- Universitätsklinikum Bonn, Klinik f. Diagn. u. Interv. Radiologie, Bonn
| | - Q Fan
- A. A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Charlestown, MA, United States
| | - T Witzel
- A. A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Charlestown, MA, United States
| | - C Pieper
- Klinik für diagnostische und interventionelle Radiologie, Universitätsklinikum Bonn, Bonn, Deutschland
| | - U Attenberger
- Klinik für diagnostische und interventionelle Radiologie, Universitätsklinikum Bonn, Bonn, Deutschland
| | - B Rosen
- A. A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Charlestown, MA, United States
| | - L Wald
- A. A. Martinos Center for Biomedical Imaging, Department of Radiology / Harvard-MIT Division of Health Sciences and Technology, Massachusetts General Hospital / Massachusetts Institute of Technology, Charlestown / Cambridge, MA, United States
| | - S Huang
- A. A. Martinos Center for Biomedical Imaging, Department of Radiology / Harvard-MIT Division of Health Sciences and Technology, Massachusetts General Hospital / Massachusetts Institute of Technology, Charlestown / Cambridge, MA, United States
| | - A Nummenma
- A. A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Charlestown, MA, United States
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Thapa B, Mareyam A, Stockmann J, Strasser B, Keil B, Hoecht P, Carp SA, Li X, Wang Z, Chang YV, Dietrich J, Uhlmann E, Cahill DP, Batchelor T, Wald L, Andronesi OC. In Vivo Absolute Metabolite Quantification Using a Multiplexed ERETIC‐RX Array Coil for Whole‐Brain MR Spectroscopic Imaging. J Magn Reson Imaging 2022. [DOI: 10.1002/jmri.27716] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
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Dong Z, Wang F, Wald L, Setsompop K. SNR
‐efficient distortion‐free diffusion relaxometry imaging using accelerated echo‐train shifted echo‐planar time‐resolving imaging (
ACE‐EPTI
). Magn Reson Med 2022; 88:164-179. [DOI: 10.1002/mrm.29198] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2021] [Revised: 01/23/2022] [Accepted: 01/24/2022] [Indexed: 11/08/2022]
Affiliation(s)
- Zijing Dong
- Athinoula A. Martinos Center for Biomedical Imaging Massachusetts General Hospital Charlestown Massachusetts USA
- Department of Electrical Engineering and Computer Science MIT Cambridge Massachusetts USA
| | - Fuyixue Wang
- Athinoula A. Martinos Center for Biomedical Imaging Massachusetts General Hospital Charlestown Massachusetts USA
- Harvard‐MIT Health Sciences and Technology, MIT Cambridge Massachusetts USA
| | - Lawrence Wald
- Athinoula A. Martinos Center for Biomedical Imaging Massachusetts General Hospital Charlestown Massachusetts USA
- Harvard‐MIT Health Sciences and Technology, MIT Cambridge Massachusetts USA
| | - Kawin Setsompop
- Department of Radiology Stanford University Stanford California USA
- Department of Electrical Engineering Stanford University Stanford California USA
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Thapa B, Mareyam A, Stockmann J, Strasser B, Keil B, Hoecht P, Carp S, Li X, Wang Z, Chang YV, Dietrich J, Uhlmann E, Cahill DP, Batchelor T, Wald L, Andronesi OC. In Vivo Absolute Metabolite Quantification Using a Multiplexed ERETIC-RX Array Coil for Whole-Brain MR Spectroscopic Imaging. J Magn Reson Imaging 2021; 56:121-133. [PMID: 34958166 DOI: 10.1002/jmri.28028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2021] [Revised: 12/01/2021] [Accepted: 12/03/2021] [Indexed: 11/06/2022] Open
Abstract
BACKGROUND Absolute quantification of metabolites in MR spectroscopic imaging (MRSI) requires a stable reference signal of known concentration. The Electronic REference To access In vivo Concentrations (ERETIC) has shown great promise but has not been applied in patients and 3D MRSI. ERETIC hardware has not been integrated with receive arrays due to technical challenges, such as coil combination and unwanted coupling between multiple ERETIC and receive channels, for which we developed mitigation strategies. PURPOSE To develop absolute quantification for whole-brain MRSI in glioma patients. STUDY TYPE Prospective. POPULATION Five healthy volunteers and three patients with isocitrate dehydrogenase mutant glioma (27% female). Calibration and coil loading phantoms. FIELD STRENGTH/SEQUENCE A 3 T; Adiabatic spin-echo spiral 3D MRSI with real-time motion correction, Fluid Attenuated Inversion Recovery (FLAIR), Gradient Recalled Echo (GRE), Multi-echo Magnetization Prepared Rapid Acquisition of Gradient Echo (MEMPRAGE). ASSESSMENT Absolute quantification was performed for five brain metabolites (total N-acetyl-aspartate [NAA]/creatine/choline, glutamine + glutamate, myo-inositol) and the oncometabolite 2-hydroxyglutarate using a custom-built 4x-ERETIC/8x-receive array coil. Metabolite quantification was performed with both EREIC and internal water reference methods. ERETIC signal was transmitted via optical link and used to correct coil loading. Inductive and radiative coupling between ERETIC and receive channels were measured. STATISTICAL TESTS ERETIC and internal water methods for metabolite quantification were compared using Bland-Altman (BA) analysis and the nonparametric Mann-Whitney test. P < 0.05 was considered statistically significant. RESULTS ERETIC could be integrated in receive arrays and inductive coupling dominated (5-886 times) radiative coupling. Phantoms show proportional scaling of the ERETIC signal with coil loading. The BA analysis demonstrated very good agreement (3.3% ± 1.6%) in healthy volunteers, while there was a large difference (36.1% ± 3.8%) in glioma tumors between metabolite concentrations by ERETIC and internal water quantification. CONCLUSION Our results indicate that ERETIC integrated with receive arrays and whole-brain MRSI is feasible for brain metabolites quantification. Further validation is required to probe that ERETIC provides more accurate metabolite concentration in glioma patients. EVIDENCE LEVEL 2 TECHNICAL EFFICACY: Stage 1.
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Affiliation(s)
- Bijaya Thapa
- A. A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Charlestown, Massachusetts, USA.,Harvard Medical School, Boston, Massachusetts, USA
| | - Azma Mareyam
- A. A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Charlestown, Massachusetts, USA
| | - Jason Stockmann
- A. A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Charlestown, Massachusetts, USA.,Harvard Medical School, Boston, Massachusetts, USA
| | - Bernhard Strasser
- A. A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Charlestown, Massachusetts, USA.,Harvard Medical School, Boston, Massachusetts, USA
| | - Boris Keil
- Institute of Medical Physics and Radiation Protection, TH-Mittelhessen University of Applied Sciences (THM), Giessen, Germany
| | | | - Stefan Carp
- A. A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Charlestown, Massachusetts, USA.,Harvard Medical School, Boston, Massachusetts, USA
| | - Xianqi Li
- A. A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Charlestown, Massachusetts, USA.,Harvard Medical School, Boston, Massachusetts, USA
| | - Zhe Wang
- Siemens Medical Solutions USA, Boston, Massachusetts, USA
| | - Yulin V Chang
- Siemens Medical Solutions USA, Boston, Massachusetts, USA
| | - Jorg Dietrich
- Harvard Medical School, Boston, Massachusetts, USA.,Division of Neuro-Oncology, Department of Neurology, Massachusetts General Hospital, Boston, Massachusetts, USA
| | - Erik Uhlmann
- Harvard Medical School, Boston, Massachusetts, USA.,Department of Neurology, Beth Israel Deaconess Medical Center, Boston, Massachusetts, USA
| | - Daniel P Cahill
- Harvard Medical School, Boston, Massachusetts, USA.,Department of Neurosurgery, Massachusetts General Hospital, Boston, Massachusetts, USA
| | - Tracy Batchelor
- Harvard Medical School, Boston, Massachusetts, USA.,Department of Neurology, Brigham's and Women Hospital, Boston, Massachusetts, USA.,Dana Farber Cancer Institute, Boston, Massachusetts, USA
| | - Lawrence Wald
- A. A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Charlestown, Massachusetts, USA.,Harvard Medical School, Boston, Massachusetts, USA
| | - Ovidiu C Andronesi
- A. A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Charlestown, Massachusetts, USA.,Harvard Medical School, Boston, Massachusetts, USA
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Esmaeili M, Stockmann J, Strasser B, Arango N, Thapa B, Wang Z, van der Kouwe A, Dietrich J, Cahill DP, Batchelor TT, White J, Adalsteinsson E, Wald L, Andronesi OC. An integrated RF-receive/B 0-shim array coil boosts performance of whole-brain MR spectroscopic imaging at 7 T. Sci Rep 2020; 10:15029. [PMID: 32929121 PMCID: PMC7490394 DOI: 10.1038/s41598-020-71623-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Accepted: 06/16/2020] [Indexed: 12/03/2022] Open
Abstract
Metabolic imaging of the human brain by in-vivo magnetic resonance spectroscopic imaging (MRSI) can non-invasively probe neurochemistry in healthy and disease conditions. MRSI at ultra-high field (≥ 7 T) provides increased sensitivity for fast high-resolution metabolic imaging, but comes with technical challenges due to non-uniform B0 field. Here, we show that an integrated RF-receive/B0-shim (AC/DC) array coil can be used to mitigate 7 T B0 inhomogeneity, which improves spectral quality and metabolite quantification over a whole-brain slab. Our results from simulations, phantoms, healthy and brain tumor human subjects indicate improvements of global B0 homogeneity by 55%, narrower spectral linewidth by 29%, higher signal-to-noise ratio by 31%, more precise metabolite quantification by 22%, and an increase by 21% of the brain volume that can be reliably analyzed. AC/DC shimming provide the highest correlation (R2 = 0.98, P = 0.001) with ground-truth values for metabolite concentration. Clinical translation of AC/DC and MRSI is demonstrated in a patient with mutant-IDH1 glioma where it enables imaging of D-2-hydroxyglutarate oncometabolite with a 2.8-fold increase in contrast-to-noise ratio at higher resolution and more brain coverage compared to previous 7 T studies. Hence, AC/DC technology may help ultra-high field MRSI become more feasible to take advantage of higher signal/contrast-to-noise in clinical applications.
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Affiliation(s)
- Morteza Esmaeili
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
- Department of Diagnostic Imaging, Akershus University Hospital, Lørenskog, Norway
| | - Jason Stockmann
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Bernhard Strasser
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Nicolas Arango
- Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Bijaya Thapa
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Zhe Wang
- Siemens Medical Solutions, USA, Charlestown, MA, USA
| | - Andre van der Kouwe
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Jorg Dietrich
- Division of Neuro-Oncology, Department Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Daniel P Cahill
- Department of Neurosurgery, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Tracy T Batchelor
- Department Neurology, Brigham's and Women Hospital, Harvard Medical School, Boston, MA, USA
| | - Jacob White
- Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Elfar Adalsteinsson
- Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Lawrence Wald
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Ovidiu C Andronesi
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA.
- Athinoula A. Martinos Center for Biomedical Imaging, Building 149, Room 2301 13th Street, Charlestown, MA, 02129, USA.
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Gao Y, Mareyam A, Sun Y, Witzel T, Arango N, Kuang I, White J, Roe AW, Wald L, Stockmann J, Zhang X. A 16-channel AC/DC array coil for anesthetized monkey whole-brain imaging at 7T. Neuroimage 2019; 207:116396. [PMID: 31778818 DOI: 10.1016/j.neuroimage.2019.116396] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2019] [Revised: 11/21/2019] [Accepted: 11/22/2019] [Indexed: 01/07/2023] Open
Abstract
Functional magnetic resonance imaging (fMRI) in monkeys is important for bridging the gap between invasive animal brain studies and non-invasive human brain studies. To resolve the finer functional structure of the monkey brain, ultra-high-field (UHF) MR is essential, and high-performance, close-fitting RF receive coils are typically desired to fully leverage the intrinsic gains provided by UHF MRI. Moreover, static field (B0) inhomogeneity arising from the tissue susceptibility interface is more severe at UHF, presenting an obstacle to achieving high-resolution fMRI. B0 shim of the monkey head is challenging due to its smaller size and more complex sources of B0 offsets in multi-modal imaging tasks. In the present work, we have customized an array coil for lightly-anesthetized monkey fMRI in the 7T human scanner that combines RF and multi-coil (MC) B0 shim functionality (also referred to as AC/DC coils) to provide high imaging SNR and high-spatial-order, rapidly switchable B0-shim capability. Additional space was retained on the coil to render it compatible with monkey multi-modal imaging studies. Both MC global (whole-volume) and dynamic (slice-optimized) shim methods were tested and evaluated, and the benefits of MC shim for fMRI experiments was also studied. A minor reduction in RF coil performance was found after introducing additional B0 shim circuitry. However, the proposed RF coil provided higher image SNR and more uniform contrast compared to a commercially available coil for human knee imaging. Compared with static 2nd-order shim, the B0 inhomogeneity was reduced by 56.8%, and 95-percentile B0 offset was reduced to within 28.2 Hz through MC shim, versus 68.7 Hz with 2nd-order static shim. As a result, functional image quality could be improved, and brain activation can be better detected using the proposed AC/DC monkey coil.
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Affiliation(s)
- Yang Gao
- Interdisciplinary Institute of Neuroscience and Technology, Key Laboratory for Biomedical Engineering of Ministry of Education, College of Biomedical Engineering & Instrument Science, Zhejiang University, Hangzhou, China; Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, MA, United States; School of Medicine, Zhejiang University, Hangzhou, China
| | - Azma Mareyam
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, MA, United States
| | - Yi Sun
- MR Collaboration, Siemens Healthcare, Shanghai, China
| | - Thomas Witzel
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, MA, United States; Harvard Medical School, Boston, MA, United States
| | - Nicolas Arango
- Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, MA, United States
| | - Irene Kuang
- Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, MA, United States
| | - Jacob White
- Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, MA, United States
| | - Anna Wang Roe
- Interdisciplinary Institute of Neuroscience and Technology, Key Laboratory for Biomedical Engineering of Ministry of Education, College of Biomedical Engineering & Instrument Science, Zhejiang University, Hangzhou, China; School of Medicine, Zhejiang University, Hangzhou, China
| | - Lawrence Wald
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, MA, United States; Harvard Medical School, Boston, MA, United States
| | - Jason Stockmann
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, MA, United States; Harvard Medical School, Boston, MA, United States
| | - Xiaotong Zhang
- Interdisciplinary Institute of Neuroscience and Technology, Key Laboratory for Biomedical Engineering of Ministry of Education, College of Biomedical Engineering & Instrument Science, Zhejiang University, Hangzhou, China; School of Medicine, Zhejiang University, Hangzhou, China.
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Kurhanewicz J, Vigneron DB, Ardenkjaer-Larsen JH, Bankson JA, Brindle K, Cunningham CH, Gallagher FA, Keshari KR, Kjaer A, Laustsen C, Mankoff DA, Merritt ME, Nelson SJ, Pauly JM, Lee P, Ronen S, Tyler DJ, Rajan SS, Spielman DM, Wald L, Zhang X, Malloy CR, Rizi R. Hyperpolarized 13C MRI: Path to Clinical Translation in Oncology. Neoplasia 2019; 21:1-16. [PMID: 30472500 PMCID: PMC6260457 DOI: 10.1016/j.neo.2018.09.006] [Citation(s) in RCA: 278] [Impact Index Per Article: 55.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2018] [Revised: 09/27/2018] [Accepted: 09/27/2018] [Indexed: 12/22/2022]
Abstract
This white paper discusses prospects for advancing hyperpolarization technology to better understand cancer metabolism, identify current obstacles to HP (hyperpolarized) 13C magnetic resonance imaging's (MRI's) widespread clinical use, and provide recommendations for overcoming them. Since the publication of the first NIH white paper on hyperpolarized 13C MRI in 2011, preclinical studies involving [1-13C]pyruvate as well a number of other 13C labeled metabolic substrates have demonstrated this technology's capacity to provide unique metabolic information. A dose-ranging study of HP [1-13C]pyruvate in patients with prostate cancer established safety and feasibility of this technique. Additional studies are ongoing in prostate, brain, breast, liver, cervical, and ovarian cancer. Technology for generating and delivering hyperpolarized agents has evolved, and new MR data acquisition sequences and improved MRI hardware have been developed. It will be important to continue investigation and development of existing and new probes in animal models. Improved polarization technology, efficient radiofrequency coils, and reliable pulse sequences are all important objectives to enable exploration of the technology in healthy control subjects and patient populations. It will be critical to determine how HP 13C MRI might fill existing needs in current clinical research and practice, and complement existing metabolic imaging modalities. Financial sponsorship and integration of academia, industry, and government efforts will be important factors in translating the technology for clinical research in oncology. This white paper is intended to provide recommendations with this goal in mind.
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Affiliation(s)
- John Kurhanewicz
- Department of Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, CA, USA.
| | - Daniel B Vigneron
- Department of Radiology and Biomedical Imaging, University of California at San Francisco, San Francisco, CA, USA
| | | | - James A Bankson
- Department of Imaging Physics, MD Anderson Medical Center, Houston, TX, USA
| | - Kevin Brindle
- Department of Biochemistry, University of Cambridge, Cambridge, UK
| | | | | | - Kayvan R Keshari
- Department of Radiology, Memorial Sloan Kettering Cancer Center, NY, New York, USA
| | - Andreas Kjaer
- Department of Clinical Physiology, Nuclear Medicine & PET and Cluster for Molecular Imaging, Rigshospitalet and University of Copenhagen, Denmark
| | | | - David A Mankoff
- Department of Radiology, University of Pennsylvania, PA, USA
| | - Matthew E Merritt
- Department of Biochemistry and Molecular Biology, University of Florida, Gainesville, FL, USA
| | - Sarah J Nelson
- Department of Radiology and Biomedical Imaging, University of California at San Francisco, San Francisco, CA, USA
| | - John M Pauly
- Department of Electric Engineering, Stanford University, USA
| | - Philips Lee
- Functional Metabolism Group, Singapore Biomedical Consortium, Agency for Science, Technology and Research, Singapore
| | - Sabrina Ronen
- Department of Radiology and Biomedical Imaging, University of California at San Francisco, San Francisco, CA, USA
| | - Damian J Tyler
- Department of Biomedical Science, University of Oxford, Oxford, UK
| | - Sunder S Rajan
- Center for Devices and Radiological Health (CDRH), FDA, White Oak, MD, USA
| | - Daniel M Spielman
- Departments of Radiology and Electric Engineering, Stanford University, USA
| | - Lawrence Wald
- Department of Radiology, Harvard Medical School, Boston, MA, USA
| | - Xiaoliang Zhang
- Department of Radiology and Biomedical Imaging, University of California at San Francisco, San Francisco, CA, USA
| | - Craig R Malloy
- Advanced Imaging Research Center, UT Southwestern Medical Center, Dallas, TX, USA
| | - Rahim Rizi
- Department of Radiology, University of Pennsylvania, PA, USA
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Savoye I, Olsen C, Wald L, Clavel-Chapelon F, Boutron-Ruault MC, Kvaskoff M. Profils d’exposition solaire et risque de cancer cutané : étude cas-témoin nichée dans E3N. Rev Epidemiol Sante Publique 2016. [DOI: 10.1016/j.respe.2016.06.216] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
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Deen B, Richardson H, Dilks D, Takahashi A, Keil B, Wald L, Kanwisher N, Saxe R. Category-sensitive visual regions in human infants. J Vis 2016. [DOI: 10.1167/16.12.204] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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Beissner F, Polimeni J, Kim J, Bianciardi M, Renvall V, Eichner C, Wald L, Napadow V. Functional magnetic resonance imaging of pain-related brainstem nuclei in single subjects at 7 Tesla. Clin Neurophysiol 2016. [DOI: 10.1016/j.clinph.2015.10.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Abstract
Abstract. Several common practices are tested for assessing the effective solar zenith angle that can be associated to each measurement in time-series of in situ or satellite-derived measurements of hourly irradiation on horizontal surface. High quality 1 min measurements of direct irradiation collected by the BSRN stations in Carpentras in France and Payerne in Switzerland, are aggregated to yield time series of hourly direct irradiation on both horizontal and normal planes. Time series of hourly direct horizontal irradiation are reconstructed from those of hourly direct normal irradiation and estimates of the effective solar zenith angle by one of the six practices. Differences between estimated and actual time series of the direct horizontal irradiation indicate the performances of six practices. Several of them yield satisfactory estimates of the effective solar angles. The most accurate results are obtained if the effective angle is computed by two time series of the direct horizontal and normal irradiations that should be observed if the sky were cloud-free. If not possible, then the most accurate results are obtained from using irradiation at the top of atmosphere. Performances show a tendency to decrease during sunrise and sunset hours. The effective solar azimuth angle is computed from the effective solar zenith angle.
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Wandji Nyamsi W, Espinar B, Blanc P, Wald L. Estimating the photosynthetically active radiation under clear skies by means of a new approach. Adv Sci Res 2015. [DOI: 10.5194/asr-12-5-2015] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Abstract. The k-distribution method and the correlated-k approximation of Kato et al. (1999) is a computationally efficient approach originally designed for calculations of the broadband solar radiation by dividing the solar spectrum in 32 specific spectral bands from 240 to 4606 nm. This paper describes a technique for an accurate assessment of the photosynthetically active radiation (PAR) from 400 to 700 nm at ground level, under clear-sky conditions using twelve of these spectral bands. It is validated against detailed spectral calculations of the PAR made by the radiative transfer model libRadtran. For the direct and global PAR irradiance, the bias is −0.4 W m−2 (−0.2%) and −4 W m−2 (−1.3%) and the root mean square error is 1.8 W m−2 (0.7%) and 4.5 W m−2 (1.5%). For the direct and global Photosynthetic Photon Flux Density, the biases are of about +10.3 μmol m−2 s−1 (+0.8%) and 1.9 μmol m−2 s−1 (−0.1%) respectively, and the root mean square error is 11.4 μmol m−2 s−1 (0.9%) and 4.0 μmol m−2 s−1 (0.3%). The correlation coefficient is greater than 0.99. This technique provides much better results than two state-of-the-art empirical methods computing the daily mean of PAR from the daily mean of broadband irradiance.
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Abstract
Abstract. New Caledonia experiences a decrease in surface solar irradiation since 2004. It is of order of 4% of the mean yearly irradiation over the 10 years period: 2004–2013, and amounts to −9 W m−2. The preeminent roles of the changes in cloud cover and to a lesser extent, those in aerosol optical depth on the decrease in yearly irradiation are evidenced. The study highlights the role of data sets offering a worldwide coverage in understanding changes in solar radiation and planning large solar energy plants such as the ICOADS (International Comprehensive Ocean-Atmosphere Data Set) of the NOAA and MACC (Monitoring Atmosphere Composition and Climate) data sets combined with the McClear model.
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Qu Z, Blanc P, Lefèvre M, Wald L, Oumbe A. Study of the MLB parameterisation for change in surface solar irradiance with sun zenith angle in clear sky. Adv Sci Res 2011. [DOI: 10.5194/asr-6-233-2011] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Abstract. The MLB parameterisation (Modified Lambert-Beer, Mueller et al., 2004) describes the change in SSI with sun zenith angle (SZA) in clear-sky conditions. It applies to the direct and global SSI as well as their spectral distribution. We assess its performances by comparing its results to the outputs of the radiative transfer model libRadtran and standard interpolation procedures. The standard two-point fitting MLB function performs very well at SZA between 0° and 60° and fairly bad from 60° to 89.9°. A parameterisation made of four MLBs for four intervals (0°, 60°), (60°, 75°), (75°, 85°) and (85°, 89.9°) is also tested. This piecewise MLB parameterisation exhibits satisfactory performances at any SZA and outperforms standard linear interpolation techniques. 95 % of errors in global SSI are less than 1 W m−2 for each band and less than 5 W m−2 for total irradiance.
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Oumbe A, Blanc P, Gschwind B, Lefevre M, Qu Z, Schroedter-Homscheidt M, Wald L. Solar irradiance in clear atmosphere: study of parameterisations of change with altitude. Adv Sci Res 2011. [DOI: 10.5194/asr-6-199-2011] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Abstract. Parameterisation of changes of the solar irradiance at ground level with a specific variable (e.g. solar zenithal angle, aerosol optical depth, altitude, etc.) is often used in operational processes because it saves computational time. This paper deals with the modelling of the vertical profile of downwelling solar irradiance for the first two kilometres above ground in clear sky conditions. Two analytical parameterisations are evaluated for direct and global irradiance in spectral bands as well as for the total irradiance. These parameterisations reproduce the vertical profile with good accuracy for global spectral irradiance and are less accurate for direct component, especially in turbid atmosphere. A piecewise linear interpolation technique using irradiance values known at surface and 4 altitudes every 500 m performs better in any case.
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Orton SM, Wald L, Confavreux C, Vukusic S, Krohn JP, Ramagopalan SV, Herrera BM, Sadovnick AD, Ebers GC. Association of UV radiation with multiple sclerosis prevalence and sex ratio in France. Neurology 2011; 76:425-31. [PMID: 21282589 DOI: 10.1212/wnl.0b013e31820a0a9f] [Citation(s) in RCA: 90] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
BACKGROUND French farmers and their families constitute an informative population to study multiple sclerosis (MS) prevalence and related epidemiology. We carried out an ecological study to evaluate the association of MS prevalence and ultraviolet (UV) radiation, a candidate climatologic risk factor. METHODS Mean annual and winter (December-March) UVB irradiation values were systematically compared to MS prevalence rates in corresponding regions of France. UVB data were obtained from the solar radiation database (SoDa) service and prevalence rates from previously published data on 2,667 MS cases registered with the national farmer health insurance system, Mutualité Sociale Agricole (MSA). Pearson correlation was used to examine the relationship of annual and winter UVB values with MS prevalence. Male and female prevalence were also analyzed separately. Linear regression was used to test for interaction of annual and winter UVB with sex in predicting MS prevalence. RESULTS There was a strong association between MS prevalence and annual mean UVB irradiation (r = -0.80, p < 0.001) and average winter UVB (r = -0.87, p < 0.001). Both female (r = -0.76, p < 0.001) and male (r = -0.46, p = 0.032) prevalence rates were correlated with annual UVB. Regression modeling showed that the effect of UVB on prevalence rates differed by sex; the interaction effect was significant for both annual UVB (p = 0.003) and winter UVB (p = 0.002). CONCLUSIONS The findings suggest that regional UVB radiation is predictive of corresponding MS prevalence rates and supports the hypothesis that sunlight exposure influences MS risk. The evidence also supports a potential role for gender-specific effects of UVB exposure.
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Affiliation(s)
- S-M Orton
- Wellcome Trust Centre for Human Genetics and Department of Clinical Neurology, University of Oxford, Oxford, UK
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Baker C, Williams M, Reddy L, Wald L, Wiggins G, Dickerson B, Triantafyllou C, Kanwisher N. Fine-grained analysis of functional selectivity in human occipitotemporal cortex. J Vis 2010. [DOI: 10.1167/7.9.1029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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Beaulant AL, Perron G, Kleinpeter J, Weber C, Ranchin T, Wald L. Adding virtual measuring stations to a network for urban air pollution mapping. Environ Int 2008; 34:599-605. [PMID: 18550171 DOI: 10.1016/j.envint.2007.12.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Maps of pollutants concentration are usually generated by means of interpolation and extrapolation methods. The quality of the results depends mainly of the number of permanent or temporary measuring stations. This paper deals with a method for the virtual densification of the network of stations. The method creates "virtual measuring stations". It aims at improving the quality of interpolation by increasing the number of data on pollutant concentration. The virtual stations are determined by the means of a classification method applied to each pixel of the area under concern. Discriminating elements are pollutants emission classes, land cover types, urban morphological indicators created to this purpose and distance to major roads. A first implementation was made for particulate matter (PM) for the city of Strasbourg (France) using thin-plates spline interpolation method in Arcview 9 GIS. The relative Root Mean Square Error decreases from 49% for five input stations down to 15% for the virtual stations.
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Affiliation(s)
- A L Beaulant
- Center for Energy and Processes, Paris School of Mines, Sophia Antipolis Cedex, France.
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Otazo R, Mueller B, Ugurbil K, Wald L, Posse S. Signal-to-noise ratio and spectral linewidth improvements between 1.5 and 7 Tesla in proton echo-planar spectroscopic imaging. Magn Reson Med 2007; 56:1200-10. [PMID: 17094090 DOI: 10.1002/mrm.21067] [Citation(s) in RCA: 107] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
This study characterizes gains in sensitivity and spectral resolution of proton echo-planar spectroscopic imaging (PEPSI) with increasing magnetic field strength (B(0)). Signal-to-noise ratio (SNR) per unit volume and unit time, and intrinsic linewidth (LW) of N-acetyl-aspartate (NAA), creatine (Cr), and choline (Cho) were measured with PEPSI at 1.5, 3, 4, and 7 Tesla on scanners that shared a similar software and hardware platform, using circularly polarized (CP) and eight-channel phased-array (PA) head coils. Data were corrected for relaxation effects and processed with a time-domain matched filter (MF) adapted to each B(0). The SNR and LW measured with PEPSI were very similar to those measured with conventional point-resolved spectroscopy (PRESS) SI. Measurements with the CP coil demonstrated a nearly linear SNR gain with respect to B(0) in central brain regions. For the PA coil, the SNR-B(0) relationship was less than linear, but there was a substantial SNR increase in comparison to the CP coil. The LW in units of ppm decreased with B(0), resulting in improved spectral resolution. These studies using PEPSI demonstrated linear gains in SNR with respect to B(0), consistent with theoretical expectations, and a decrease in ppm LW with increasing B(0).
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Abstract
Imaging of endothelial-specific markers is critically important in non-invasive detection of early signs of vascular pathologies (eg inflammation, atherosclerosis and angiogenesis). A model of adoptive human endothelial cell (HUVEC) transfer was used to test-specific imaging probes for human vascular disease consisting of cross-linked iron oxide (CLIO) nanoparticles conjugated to anti-human E-selectin (CLIO-F(ab')(2)). To perform in vivo imaging of E-selectin expression in functional blood vessels, human vascular endothelium cells (HUVECs) were implanted in athymic mice in Matrigel solution, which served as a temporary neovascularization scaffold after the solidification. The formation of HUVEC-containing vessels was established by histology and microscopy. CLIO-F(ab')(2) probes were administered via an i.v. injection following the induction of E-selectin expression by IL-1beta. High-resolution MR images were obtained before and after the administration of CLIO-F(ab')(2), which showed specific hypointensity only if treated with IL-1beta. A three-times higher CLIO-induced MR signal decrease on T2(*) images was measured in HUVEC implants in response to IL-1beta treatment. Image signal intensity did not change in control animals that: (1) harbored Matrigel alone, (2) in the absence of IL-1beta treatment or (3) in animals injected with CLIO linked to the idiotype-matched control F(ab')(2). Experiments in an adoptive transfer model demonstrated that HUVEC-containing neovessels are perfused and that IL-1beta inducible E-selectin expression in these vessels is detectable with non-invasive imaging by using targeted nanoparticles.
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Affiliation(s)
- Hye Won Kang
- Department of Radiology, Center for Molecular Imaging Research, Massachusetts General Hospital and Harvard Medical School, Charlestown, USA
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Baker CI, Knouf N, Wald L, Kwong K, Benner T, Fischl B, Kanwisher N. Functional selectivity of human extrastriate visual cortex at high resolution. J Vis 2004. [DOI: 10.1167/4.8.88] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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Liu J, Jovicich J, Baker CI, Mangini M, Wald L, Kanwisher N. A left fusiform region that responds selectively to letter strings. J Vis 2004. [DOI: 10.1167/4.8.97] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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Knake S, Grant PE, Stufflebeam S, Shiraishi H, Wald L, Salat D, Tuch D, Hamer HM, Rosenow F, Oertel WH, Fischl B, Dale AM, Halgren E. Multimodale Bildgebung verbessert die prächirurgische Diagnostik (3 T MRT, 3 T DTI, automatisierte quantitative Analysemethoden, 306-channel MEG und EEG) von Patienten mit fokalen Epilepsien - eine prospektive Studie mit 70 Patienten. Akt Neurol 2004. [DOI: 10.1055/s-2004-833121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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Jaaskelainen IP, Bonmassar G, Melcher H, Stufflebeam S, Hawley M, May P, Wald L, Tiitinen H, Belliveau JW. Cortical mechanisms of pre-attentive auditory “Gating”. Neuroimage 2001. [DOI: 10.1016/s1053-8119(01)91664-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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Vigneron D, Bollen A, McDermott M, Wald L, Day M, Moyher-Noworolski S, Henry R, Chang S, Berger M, Dillon W, Nelson S. Three-dimensional magnetic resonance spectroscopic imaging of histologically confirmed brain tumors. Magn Reson Imaging 2001; 19:89-101. [PMID: 11295350 DOI: 10.1016/s0730-725x(01)00225-9] [Citation(s) in RCA: 78] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The goal of this study was to determine whether presurgical metabolite levels measured by 3D MR Spectroscopic Imaging (MRSI) can accurately detect viable cancer within human brain tumor masses. A total of 31 patients (33 exams, 39 pathology correlations) with brain tumors were studied prior to surgical biopsy and/or resection. The 3D MRSI was obtained with a spatial resolution of 0.2 to 1 cc throughout the majority of the mass and adjacent brain tissue using PRESS-CSI localization. Levels of choline, creatine and NAA were estimated from the locations of the resected tissue and normalized to normal appearing brain tissue. The data were correlated with subsequent histologic analysis of the biopsy tissue samples. Although there were large variations in the metabolite ratios, all regions of confirmed cancer demonstrated significant choline levels and a mean choline/NAA ratio of 5.84 + 2.58 with the lowest value being 1.3. This lowest value is greater than 4 standard deviations above the mean (0.52 +/- 0.13) found in 8 normal volunteers. The choline signal intensities in confirmed cancers were significantly elevated compared to normal appearing brain tissue with a mean ratio of 1.71 +/- 0.69. Spectra with no significant metabolite levels were observed in the non-enhancing necrotic core of the tumor masses. The results of this study indicate that 3D MRSI of brain tumors can detect abnormal metabolite levels in regions of viable cancer and grades and can differentiate cancer from necrosis and/or normal brain tissue.
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Affiliation(s)
- D Vigneron
- Department of Radiology, University of California, San Francisco, CA 94143, USA.
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Siemiatycki J, Wacholder S, Dewar R, Wald L, Bégin D, Richardson L, Rosenman K, Gérin M. Smoking and degree of occupational exposure: are internal analyses in cohort studies likely to be confounded by smoking status? Am J Ind Med 1988; 13:59-69. [PMID: 3344756 DOI: 10.1002/ajim.4700130105] [Citation(s) in RCA: 50] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Occupational cohort studies are usually carried out without the benefit of information on smoking habits of cohort members. One common approach to avoid confounding bias related to smoking habits is to carry out an internal analysis, comparing workers with different degrees of occupational exposure. The premise behind this approach is that within a cohort there is unlikely to be correlation between degree of exposure and smoking habits. If this were untrue, smoking could confound the disease-exposure relationships. Our purpose was to verify the premise. The study sample consisted of 857 French-Canadian men born between 1910 and 1930, with 11 or fewer years of education, and interviewed around 1980 in the context of an occupational cancer case-control study. For each man we had information on smoking habits, job history, and a history of the chemicals he was exposed to in each of his jobs. We computed two indices of the dirtiness of workers' job histories: one based on the job titles held by the man and a second based on the degree of exposures to workplace substances. There was no correlation between these indices of job dirtiness and smoking history. We also examined the smoking-exposure relationship among the subsets of men who had been occupationally exposed to ten especially noticeable substances. Within the subsets, there was no indication of a consistent difference among the smoking subgroups in level or duration of exposure to these index substances. These findings do not support the view that nonsmokers sought out cleaner job environments than smokers; they imply that internal analyses of "dose-response" in cohort studies are unlikely to be seriously confounded by smoking habits.
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Affiliation(s)
- J Siemiatycki
- Epidemiology and Preventive Medicine Research Centre, Institut Armand-Frappier, Laval-des-Rapides, Quebec, Canada
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