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Bonde JPE, Begtrup LM, Jensen JH, Flachs EM, Jakobsson K, Nielsen C, Nilsson K, Rylander L, Vilhelmsson A, Petersen KU, Tøttenborg SS. Occupational risk of COVID-19 in foreign-born employees in Denmark. Occup Med (Lond) 2024; 74:63-70. [PMID: 37133767 DOI: 10.1093/occmed/kqad044] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [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: 05/04/2023] Open
Abstract
BACKGROUND Foreign-born workers in high-income countries experience higher rates of COVID-19 but the causes are only partially known. AIMS To examine if the occupational risk of COVID-19 in foreign-born workers deviates from the risk in native-born employees in Denmark. METHODS Within a registry-based cohort of all residents employed in Denmark (n = 2 451 542), we identified four-digit DISCO-08 occupations associated with an increased incidence of COVID-19-related hospital admission during 2020-21 (at-risk occupations). The sex-specific prevalence of at-risk employment in foreign born was compared with the prevalence in native born. Moreover, we examined if the country of birth modified the risk of a positive SARS-CoV-2 polymerase chain reaction (PCR) test and COVID-19-related hospital admission in at-risk occupations. RESULTS Workers born in low-income countries and male workers from Eastern Europe more often worked in at-risk occupations (relative risks between 1.16 [95% confidence interval {CI} 1.14-1.17] and 1.87 [95% CI 1.82-1.90]). Being foreign-born modified the adjusted risk of PCR test positivity (test for interaction P < 0.0001), primarily because of higher risk in at-risk occupations among men born in Eastern European countries (incidence rate ratio [IRR] 2.39 [95% CI 2.09-2.72] versus IRR 1.19 [95% CI 1.14-1.23] in native-born men). For COVID-19-related hospital admission, no overall interaction was seen, and in women, country of birth did not consistently modify the occupational risk. CONCLUSIONS Workplace viral transmission may contribute to an excess risk of COVID-19 in male workers born in Eastern Europe, but most foreign-born employees in at-risk occupations seem not to be at higher occupational risk than native born.
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Affiliation(s)
- J P E Bonde
- Department of Occupational and Environmental Medicine, Copenhagen University Hospital Bispebjerg and Frederiksberg, Copenhagen 2400, Denmark
- Department of Public Health, University of Copenhagen, Copenhagen 1500, Denmark
| | - L M Begtrup
- Department of Occupational and Environmental Medicine, Copenhagen University Hospital Bispebjerg and Frederiksberg, Copenhagen 2400, Denmark
- Department of Public Health, University of Copenhagen, Copenhagen 1500, Denmark
| | - J H Jensen
- Department of Occupational and Environmental Medicine, Copenhagen University Hospital Bispebjerg and Frederiksberg, Copenhagen 2400, Denmark
| | - E M Flachs
- Department of Occupational and Environmental Medicine, Copenhagen University Hospital Bispebjerg and Frederiksberg, Copenhagen 2400, Denmark
| | - K Jakobsson
- School of Public Health and Community Medicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg 405 30, Sweden
| | - C Nielsen
- Division of Occupational and Environmental Medicine, Department of Laboratory Medicine, Lund University, Lund 22363, Sweden
- Clinical Pharmacology, Pharmacy and Environmental Medicine, University of Southern Denmark, Odense 5000, Denmark
| | - K Nilsson
- Division of Occupational and Environmental Medicine, Department of Laboratory Medicine, Lund University, Lund 22363, Sweden
- Division of Public Health, Kristianstad University, Kristianstad 29188, Sweden
| | - L Rylander
- Division of Occupational and Environmental Medicine, Department of Laboratory Medicine, Lund University, Lund 22363, Sweden
| | - A Vilhelmsson
- Division of Occupational and Environmental Medicine, Department of Laboratory Medicine, Lund University, Lund 22363, Sweden
| | - K U Petersen
- Department of Occupational and Environmental Medicine, Copenhagen University Hospital Bispebjerg and Frederiksberg, Copenhagen 2400, Denmark
| | - S S Tøttenborg
- Department of Occupational and Environmental Medicine, Copenhagen University Hospital Bispebjerg and Frederiksberg, Copenhagen 2400, Denmark
- Department of Public Health, University of Copenhagen, Copenhagen 1500, Denmark
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2
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Moss HG, Wolf LG, Coker-Bolt P, Ramakrishnan V, Aljuhani T, Yazdani M, Brown TR, Jensen JH, Jenkins DD. Quantitative Diffusion and Spectroscopic Neuroimaging Combined with a Novel Early-Developmental Assessment Improves Models for 1-Year Developmental Outcomes. AJNR Am J Neuroradiol 2022; 43:139-145. [PMID: 34949592 PMCID: PMC8757543 DOI: 10.3174/ajnr.a7370] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [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] [Received: 06/17/2021] [Accepted: 09/27/2021] [Indexed: 01/03/2023]
Abstract
BACKGROUND AND PURPOSE Preterm infants are at risk for overt and silent CNS injury, with developmental consequences that are difficult to predict. The novel Specific Test of Early Infant Motor Performance, administered in preterm infants at term age, is indicative of later developmental gross motor and cognitive scores at 12 months. Here, we assessed whether functional performance on this early assessment correlates with CNS integrity via MR spectroscopy or diffusional kurtosis imaging and whether these quantitative neuroimaging methods improve predictions for future 12-month developmental scores. MATERIALS AND METHODS MR spectroscopy and quantitative diffusion MR imaging data were acquired in preterm infants (n = 16) at term. Testing was performed at term and 3 months using the Specific Test of Early Infant Motor Performance and the Bayley Scales of Infant and Toddler Development, Third Edition, at 12 months. We modeled the relationship of MR spectroscopy and diffusion MR imaging data with both test scores via multiple linear regression. RESULTS MR spectroscopy NAA ratios at a TE of 270 ms in the frontal WM and basal ganglia and kurtosis metrics in major WM tracts correlated strongly with total Specific Test of Early Infant Motor Performance scores. The addition of MR spectroscopy and diffusion separately improved the functional predictions of 12-month outcomes. CONCLUSIONS Microstructural integrity of the major WM tracts and metabolism in the basal ganglia and frontal WM strongly correlate with early developmental performance, suggesting that the Specific Test of Early Infant Motor Performance reflects CNS integrity after preterm birth. This study demonstrates that combining quantitative neuroimaging and early functional movement improves the prediction of 12-month outcomes in premature infants.
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Affiliation(s)
- H G Moss
- From the Department of Neuroscience (H.G.M., J.H.J.)
- Center for Biomedical Imaging (H.G.M., T.R.B., J.H.J., D.D.J.)
| | - L G Wolf
- Department of Pediatrics (L.G.W., D.D.J.)
| | - P Coker-Bolt
- Division of Occupational Therapy (P.C.-B., T.A.), College of Health Sciences
| | | | - T Aljuhani
- Division of Occupational Therapy (P.C.-B., T.A.), College of Health Sciences
- Division of Public Health Sciences (V.R., T.A.)
| | - M Yazdani
- Department of Radiology and Radiological Science (M.Y., T.R.B., J.H.J.), Medical University of South Carolina, Charleston, South Carolina
| | - T R Brown
- Center for Biomedical Imaging (H.G.M., T.R.B., J.H.J., D.D.J.)
- Department of Radiology and Radiological Science (M.Y., T.R.B., J.H.J.), Medical University of South Carolina, Charleston, South Carolina
| | - J H Jensen
- From the Department of Neuroscience (H.G.M., J.H.J.)
- Center for Biomedical Imaging (H.G.M., T.R.B., J.H.J., D.D.J.)
- Department of Radiology and Radiological Science (M.Y., T.R.B., J.H.J.), Medical University of South Carolina, Charleston, South Carolina
| | - D D Jenkins
- Center for Biomedical Imaging (H.G.M., T.R.B., J.H.J., D.D.J.)
- Department of Pediatrics (L.G.W., D.D.J.)
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3
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Jensen JH, Cakal SD, Li J, Pless CJ, Radeke C, Jepsen ML, Jensen TE, Dufva M, Lind JU. Large-scale spontaneous self-organization and maturation of skeletal muscle tissues on ultra-compliant gelatin hydrogel substrates. Sci Rep 2020; 10:13305. [PMID: 32764726 PMCID: PMC7411013 DOI: 10.1038/s41598-020-69936-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2020] [Accepted: 07/15/2020] [Indexed: 11/09/2022] Open
Abstract
Cellular self-organization is the fundamental driving force behind the complex architectures of native tissue. Yet, attempts at replicating native tissue architectures in vitro often involve complex micro-fabrication methods and materials. While impressive progress has been made within engineered models of striated muscle, the wide adaptation of these models is held back by the need for specific tools and knowhow. In this report, we show that C2C12 myoblasts spontaneously organize into highly aligned myotube tissues on the mm to cm scale, when cultured on sufficiently soft yet fully isotropic gelatin hydrogel substrates. Interestingly, we only observed this phenomenon for hydrogels with Young’s modulus of 6 kPa and below. For slightly more rigid compositions, only local micrometer-scale myotube organization was observed, similar to that seen in conventional polystyrene dishes. The hydrogel-supported myotubes could be cultured for multiple weeks and matured into highly contractile phenotypes with notable upregulation of myosin heavy chain, as compared to myotubes developed in conventional petri dishes. The procedure for casting the ultra-soft gelatin hydrogels is straight forward and compatible with standardized laboratory tools. It may thus serve as a simple, yet versatile, approach to generating skeletal muscle tissue of improved physiological relevance for applied and basic research.
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Affiliation(s)
- Joen H Jensen
- Department of Health Technology, Technical University of Denmark, Building 423, 2800, Kgs. Lyngby, Denmark
| | - Selgin D Cakal
- Department of Health Technology, Technical University of Denmark, Building 423, 2800, Kgs. Lyngby, Denmark
| | - Jingwen Li
- Section of Molecular Physiology, Department of Nutrition, Exercise and Sports, University of Copenhagen, 2100, København Ø, Denmark
| | - Christian J Pless
- Department of Health Technology, Technical University of Denmark, Building 423, 2800, Kgs. Lyngby, Denmark
| | - Carmen Radeke
- Department of Health Technology, Technical University of Denmark, Building 423, 2800, Kgs. Lyngby, Denmark
| | - Morten Leth Jepsen
- Department of Health Technology, Technical University of Denmark, Building 423, 2800, Kgs. Lyngby, Denmark.,The Danish National Research Foundation and Villum Foundation's Center for Intelligent Drug Delivery and Sensing Using Microcontainers and Nanomechanics (IDUN), Technical University of Denmark, Building 423, 2800, Kgs. Lyngby, Denmark
| | - Thomas E Jensen
- Section of Molecular Physiology, Department of Nutrition, Exercise and Sports, University of Copenhagen, 2100, København Ø, Denmark
| | - Martin Dufva
- Department of Health Technology, Technical University of Denmark, Building 423, 2800, Kgs. Lyngby, Denmark. .,The Danish National Research Foundation and Villum Foundation's Center for Intelligent Drug Delivery and Sensing Using Microcontainers and Nanomechanics (IDUN), Technical University of Denmark, Building 423, 2800, Kgs. Lyngby, Denmark.
| | - Johan U Lind
- Department of Health Technology, Technical University of Denmark, Building 423, 2800, Kgs. Lyngby, Denmark.
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Kirsebom OS, Tengblad O, Lica R, Munch M, Riisager K, Fynbo HOU, Borge MJG, Madurga M, Marroquin I, Andreyev AN, Berry TA, Christensen ER, Fernández PD, Doherty DT, Van Duppen P, Fraile LM, Gallardo MC, Greenlees PT, Harkness-Brennan LJ, Hubbard N, Huyse M, Jensen JH, Johansson H, Jonson B, Judson DS, Konki J, Lazarus I, Lund MV, Marginean N, Marginean R, Perea A, Mihai C, Negret A, Page RD, Pucknell V, Rahkila P, Sorlin O, Sotty C, Swartz JA, Sørensen HB, Törnqvist H, Vedia V, Warr N, De Witte H. First Accurate Normalization of the β-delayed α Decay of ^{16}N and Implications for the ^{12}C(α,γ)^{16}O Astrophysical Reaction Rate. Phys Rev Lett 2018; 121:142701. [PMID: 30339438 DOI: 10.1103/physrevlett.121.142701] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/09/2018] [Revised: 06/22/2018] [Indexed: 06/08/2023]
Abstract
The ^{12}C(α,γ)^{16}O reaction plays a central role in astrophysics, but its cross section at energies relevant for astrophysical applications is only poorly constrained by laboratory data. The reduced α width, γ_{11}, of the bound 1^{-} level in ^{16}O is particularly important to determine the cross section. The magnitude of γ_{11} is determined via sub-Coulomb α-transfer reactions or the β-delayed α decay of ^{16}N, but the latter approach is presently hampered by the lack of sufficiently precise data on the β-decay branching ratios. Here we report improved branching ratios for the bound 1^{-} level [b_{β,11}=(5.02±0.10)×10^{-2}] and for β-delayed α emission [b_{βα}=(1.59±0.06)×10^{-5}]. Our value for b_{βα} is 33% larger than previously held, leading to a substantial increase in γ_{11}. Our revised value for γ_{11} is in good agreement with the value obtained in α-transfer studies and the weighted average of the two gives a robust and precise determination of γ_{11}, which provides significantly improved constraints on the ^{12}C(α,γ) cross section in the energy range relevant to hydrostatic He burning.
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Affiliation(s)
- O S Kirsebom
- Department of Physics and Astronomy, Aarhus University, DK-8000 Aarhus C, Denmark
| | - O Tengblad
- Instituto de Estructura de la Materia, CSIC, E-28006 Madrid, Spain
| | - R Lica
- CERN, CH-1211 Geneva 23, Switzerland
- Horia Hulubei National Institute for Physics and Nuclear Engineering (IFIN-HH), RO-077125 Bucharest-Magurele, Romania
| | - M Munch
- Department of Physics and Astronomy, Aarhus University, DK-8000 Aarhus C, Denmark
| | - K Riisager
- Department of Physics and Astronomy, Aarhus University, DK-8000 Aarhus C, Denmark
| | - H O U Fynbo
- Department of Physics and Astronomy, Aarhus University, DK-8000 Aarhus C, Denmark
| | - M J G Borge
- Instituto de Estructura de la Materia, CSIC, E-28006 Madrid, Spain
- CERN, CH-1211 Geneva 23, Switzerland
| | - M Madurga
- CERN, CH-1211 Geneva 23, Switzerland
| | - I Marroquin
- Instituto de Estructura de la Materia, CSIC, E-28006 Madrid, Spain
| | - A N Andreyev
- Department of Physics, University of York, York YO10 5DD, United Kingdom
- Advanced Science Research Centre (ASRC), Japan Atomic Energy Agency (JAEA), Tokai-mura, Ibaraki 319-1195, Japan
| | - T A Berry
- Department of Physics, University of Surrey, Guildford, GU2 7XH, United Kingdom
| | - E R Christensen
- Department of Physics and Astronomy, Aarhus University, DK-8000 Aarhus C, Denmark
| | - P Díaz Fernández
- Department of Physics, Chalmers University of Technology, S-41296 Göteborg, Sweden
| | - D T Doherty
- Department of Physics, University of York, York YO10 5DD, United Kingdom
| | - P Van Duppen
- KU Leuven, Instituut voor Kern- en Stralingsfysica, 3001 Leuven, Belgium
| | - L M Fraile
- Grupo de Física Nuclear, Universidad Complutense de Madrid, E-28040 Madrid, Spain
| | - M C Gallardo
- Grupo de Física Nuclear, Universidad Complutense de Madrid, E-28040 Madrid, Spain
| | - P T Greenlees
- University of Jyvaskyla, Department of Physics, P.O. Box 35, FI-40014 University of Jyvaskyla, Finland
- Helsinki Institute of Physics, University of Helsinki, P.O. Box 64, FI-00014 Helsinki, Finland
| | - L J Harkness-Brennan
- Oliver Lodge Laboratory, University of Liverpool, Liverpool L69 7ZE, United Kingdom
| | - N Hubbard
- Department of Physics and Astronomy, Aarhus University, DK-8000 Aarhus C, Denmark
- Department of Physics, University of York, York YO10 5DD, United Kingdom
| | - M Huyse
- KU Leuven, Instituut voor Kern- en Stralingsfysica, 3001 Leuven, Belgium
| | - J H Jensen
- Department of Physics and Astronomy, Aarhus University, DK-8000 Aarhus C, Denmark
| | - H Johansson
- Department of Physics, Chalmers University of Technology, S-41296 Göteborg, Sweden
| | - B Jonson
- Department of Physics, Chalmers University of Technology, S-41296 Göteborg, Sweden
| | - D S Judson
- Oliver Lodge Laboratory, University of Liverpool, Liverpool L69 7ZE, United Kingdom
| | - J Konki
- CERN, CH-1211 Geneva 23, Switzerland
- University of Jyvaskyla, Department of Physics, P.O. Box 35, FI-40014 University of Jyvaskyla, Finland
- Helsinki Institute of Physics, University of Helsinki, P.O. Box 64, FI-00014 Helsinki, Finland
| | - I Lazarus
- STFC Daresbury, Daresbury, Warrington WA4 4AD, United Kingdom
| | - M V Lund
- Department of Physics and Astronomy, Aarhus University, DK-8000 Aarhus C, Denmark
| | - N Marginean
- Horia Hulubei National Institute for Physics and Nuclear Engineering (IFIN-HH), RO-077125 Bucharest-Magurele, Romania
| | - R Marginean
- Horia Hulubei National Institute for Physics and Nuclear Engineering (IFIN-HH), RO-077125 Bucharest-Magurele, Romania
| | - A Perea
- Instituto de Estructura de la Materia, CSIC, E-28006 Madrid, Spain
| | - C Mihai
- Horia Hulubei National Institute for Physics and Nuclear Engineering (IFIN-HH), RO-077125 Bucharest-Magurele, Romania
| | - A Negret
- Horia Hulubei National Institute for Physics and Nuclear Engineering (IFIN-HH), RO-077125 Bucharest-Magurele, Romania
| | - R D Page
- Oliver Lodge Laboratory, University of Liverpool, Liverpool L69 7ZE, United Kingdom
| | - V Pucknell
- STFC Daresbury, Daresbury, Warrington WA4 4AD, United Kingdom
| | - P Rahkila
- University of Jyvaskyla, Department of Physics, P.O. Box 35, FI-40014 University of Jyvaskyla, Finland
- Helsinki Institute of Physics, University of Helsinki, P.O. Box 64, FI-00014 Helsinki, Finland
| | - O Sorlin
- CERN, CH-1211 Geneva 23, Switzerland
- GANIL, CEA/DSM-CNRS/IN2P3, Bvd Henri Becquerel, 14076 Caen, France
| | - C Sotty
- Horia Hulubei National Institute for Physics and Nuclear Engineering (IFIN-HH), RO-077125 Bucharest-Magurele, Romania
| | - J A Swartz
- Department of Physics and Astronomy, Aarhus University, DK-8000 Aarhus C, Denmark
| | - H B Sørensen
- Department of Physics and Astronomy, Aarhus University, DK-8000 Aarhus C, Denmark
| | - H Törnqvist
- Institut für Kernphysik, Technische Universität Darmstadt, Darmstadt, Germany
- GSI Helmholtzzentrum für Schwerionenforschung, Darmstadt, Germany
| | - V Vedia
- Grupo de Física Nuclear, Universidad Complutense de Madrid, E-28040 Madrid, Spain
| | - N Warr
- Institut für Kernphysik, Universität zu Köln, D-50937 Köln, Germany
| | - H De Witte
- KU Leuven, Instituut voor Kern- en Stralingsfysica, 3001 Leuven, Belgium
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Spampinato MV, Kocher MR, Jensen JH, Helpern JA, Collins HR, Hatch NU. Diffusional Kurtosis Imaging of the Corticospinal Tract in Multiple Sclerosis: Association with Neurologic Disability. AJNR Am J Neuroradiol 2017; 38:1494-1500. [PMID: 28572153 DOI: 10.3174/ajnr.a5225] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2016] [Accepted: 03/14/2017] [Indexed: 11/07/2022]
Abstract
BACKGROUND AND PURPOSE Multiple sclerosis is an autoimmune disorder resulting in progressive neurologic disability. Our aim was to evaluate the associations between diffusional kurtosis imaging-derived metrics for the corticospinal tract and disability in multiple sclerosis. MATERIALS AND METHODS Forty patients with MS underwent brain MR imaging including diffusional kurtosis imaging. After we masked out T2 hyperintense lesions, the fractional anisotropy, mean diffusivity, radial diffusivity, axial diffusivity, mean kurtosis, radial kurtosis, and axial kurtosis were estimated for the corticospinal tract. Disability was quantified by using the Expanded Disability Status Scale at the time of MR imaging and 12 months post-MR imaging. The Pearson correlation coefficient and linear regression analyses were conducted to evaluate the associations between diffusion metrics and disability. RESULTS Significant correlations were found between the Expanded Disability Status Scale scores during the baseline visit and age (r = 0.47), T2 lesion volume (r = 0.38), corticospinal tract mean diffusivity (r = 0.41), radial diffusivity (r = 0.41), axial diffusivity (r = 0.34), fractional anisotropy (r = -0.36), and radial kurtosis (r = -0.42). Significant correlations were also found between the Expanded Disability Status Scale scores at 12-month follow-up and age (r = 0.38), mean diffusivity (r = 0.45), radial diffusivity (r = 0.41), axial diffusivity (r = 0.45), mean kurtosis (r = -0.42), radial kurtosis (r = -0.56), and axial kurtosis (r = -0.36). Linear regression analyses demonstrated significant associations among radial kurtosis, age, and Expanded Disability Status Scale score during the baseline visit, while radial kurtosis was the only variable associated with Expanded Disability Status Scale score for the 12-month follow-up. CONCLUSIONS Radial kurtosis of the corticospinal tract may have an association with neurologic disability in MS.
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Affiliation(s)
- M V Spampinato
- From the Department of Radiology and Radiological Science (M.V.S., M.R.K., J.H.J., J.A.H., H.R.C., N.U.H.) .,Center for Biomedical Imaging (M.V.S., J.H.J., J.A.H.), Medical University of South Carolina, Charleston, South Carolina
| | - M R Kocher
- From the Department of Radiology and Radiological Science (M.V.S., M.R.K., J.H.J., J.A.H., H.R.C., N.U.H.)
| | - J H Jensen
- From the Department of Radiology and Radiological Science (M.V.S., M.R.K., J.H.J., J.A.H., H.R.C., N.U.H.).,Center for Biomedical Imaging (M.V.S., J.H.J., J.A.H.), Medical University of South Carolina, Charleston, South Carolina
| | - J A Helpern
- From the Department of Radiology and Radiological Science (M.V.S., M.R.K., J.H.J., J.A.H., H.R.C., N.U.H.).,Center for Biomedical Imaging (M.V.S., J.H.J., J.A.H.), Medical University of South Carolina, Charleston, South Carolina
| | - H R Collins
- From the Department of Radiology and Radiological Science (M.V.S., M.R.K., J.H.J., J.A.H., H.R.C., N.U.H.)
| | - N U Hatch
- From the Department of Radiology and Radiological Science (M.V.S., M.R.K., J.H.J., J.A.H., H.R.C., N.U.H.)
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Spampinato MV, Chan C, Jensen JH, Helpern JA, Bonilha L, Kautz SA, Nietert PJ, Feng W. Diffusional Kurtosis Imaging and Motor Outcome in Acute Ischemic Stroke. AJNR Am J Neuroradiol 2017; 38:1328-1334. [PMID: 28473339 DOI: 10.3174/ajnr.a5180] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2016] [Accepted: 02/13/2017] [Indexed: 12/23/2022]
Abstract
BACKGROUND AND PURPOSE Motor impairment is the most common deficit after stroke. Our aim was to evaluate whether diffusional kurtosis imaging can detect corticospinal tract microstructural changes in the acute phase for patients with first-ever ischemic stroke and motor impairment and to assess the correlations between diffusional kurtosis imaging-derived diffusion metrics for the corticospinal tract and motor impairment 3 months poststroke. MATERIALS AND METHODS We evaluated 17 patients with stroke who underwent brain MR imaging including diffusional kurtosis imaging within 4 days after the onset of symptoms. Neurologic evaluation included the Fugl-Meyer Upper Extremity Motor scale in the acute phase and 3 months poststroke. For the corticospinal tract in the lesioned and contralateral hemispheres, we estimated with diffusional kurtosis imaging both pure diffusion metrics, such as the mean diffusivity and mean kurtosis, and model-dependent quantities, such as the axonal water fraction. We evaluated the correlations between corticospinal tract diffusion metrics and the Fugl-Meyer Upper Extremity Motor scale at 3 months. RESULTS Among all the diffusion metrics, the largest percentage signal changes of the lesioned hemisphere corticospinal tract were observed with axial kurtosis, with an average 12% increase compared with the contralateral corticospinal tract. The strongest associations between the 3-month Fugl-Meyer Upper Extremity Motor scale score and diffusion metrics were found for the lesioned/contralateral hemisphere corticospinal tract mean kurtosis (ρ = -0.85) and axial kurtosis (ρ = -0.78) ratios. CONCLUSIONS This study was designed to be one of hypothesis generation. Diffusion metrics related to kurtosis were found to be more sensitive than conventional diffusivity metrics to early poststroke corticospinal tract microstructural changes and may have potential value in the prediction of motor impairment at 3 months.
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Affiliation(s)
- M V Spampinato
- From the Department of Radiology and Radiological Science (M.V.S., C.C., J.H.J., J.A.H.) .,Center for Biomedical Imaging (M.V.S., C.C., J.H.J., J.A.H.)
| | - C Chan
- From the Department of Radiology and Radiological Science (M.V.S., C.C., J.H.J., J.A.H.).,Center for Biomedical Imaging (M.V.S., C.C., J.H.J., J.A.H.)
| | - J H Jensen
- From the Department of Radiology and Radiological Science (M.V.S., C.C., J.H.J., J.A.H.).,Center for Biomedical Imaging (M.V.S., C.C., J.H.J., J.A.H.)
| | - J A Helpern
- From the Department of Radiology and Radiological Science (M.V.S., C.C., J.H.J., J.A.H.).,Center for Biomedical Imaging (M.V.S., C.C., J.H.J., J.A.H.).,Department of Neurology (L.B., W.F., J.A.H.), Medical University of South Carolina, Charleston, South Carolina
| | - L Bonilha
- Department of Neurology (L.B., W.F., J.A.H.), Medical University of South Carolina, Charleston, South Carolina
| | - S A Kautz
- Department of Health Sciences and Research (S.A.K.).,Ralph H. Johnson VA Medical Center (S.A.K.), Charleston, South Carolina
| | - P J Nietert
- Department of Public Health Sciences (P.J.N., W.F.)
| | - W Feng
- Department of Public Health Sciences (P.J.N., W.F.).,Department of Neurology (L.B., W.F., J.A.H.), Medical University of South Carolina, Charleston, South Carolina
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Glenn GR, Kuo LW, Chao YP, Lee CY, Helpern JA, Jensen JH. Mapping the Orientation of White Matter Fiber Bundles: A Comparative Study of Diffusion Tensor Imaging, Diffusional Kurtosis Imaging, and Diffusion Spectrum Imaging. AJNR Am J Neuroradiol 2016; 37:1216-22. [PMID: 26939628 DOI: 10.3174/ajnr.a4714] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [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] [Received: 09/02/2015] [Accepted: 12/30/2015] [Indexed: 01/20/2023]
Abstract
BACKGROUND AND PURPOSE White matter fiber tractography relies on fiber bundle orientation estimates from diffusion MR imaging. However, clinically feasible techniques such as DTI and diffusional kurtosis imaging use assumptions, which may introduce error into in vivo orientation estimates. In this study, fiber bundle orientations from DTI and diffusional kurtosis imaging are compared with diffusion spectrum imaging as a criterion standard to assess the performance of each technique. MATERIALS AND METHODS For each subject, full DTI, diffusional kurtosis imaging, and diffusion spectrum imaging datasets were acquired during 2 independent sessions, and fiber bundle orientations were estimated by using the specific theoretic assumptions of each technique. Angular variability and angular error measures were assessed by comparing the orientation estimates. Tractography generated with each of the 3 reconstructions was also examined and contrasted. RESULTS Orientation estimates from all 3 techniques had comparable angular reproducibility, but diffusional kurtosis imaging decreased angular error throughout the white matter compared with DTI. Diffusion spectrum imaging and diffusional kurtosis imaging enabled the detection of crossing-fiber bundles, which had pronounced effects on tractography relative to DTI. Diffusion spectrum imaging had the highest sensitivity for detecting crossing fibers; however, the diffusion spectrum imaging and diffusional kurtosis imaging tracts were qualitatively similar. CONCLUSIONS Fiber bundle orientation estimates from diffusional kurtosis imaging have less systematic error than those from DTI, which can noticeably affect tractography. Moreover, tractography obtained with diffusional kurtosis imaging is qualitatively comparable with that of diffusion spectrum imaging. Because diffusional kurtosis imaging has a shorter typical scan time than diffusion spectrum imaging, diffusional kurtosis imaging is potentially more suitable for a variety of clinical and research applications.
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Affiliation(s)
- G R Glenn
- From the Center for Biomedical Imaging (G.R.G., C.-Y.L., J.A.H., J.H.J.) Department of Neurosciences (G.R.G., J.A.H.) Department of Radiology and Radiological Science (G.R.G., C.-Y.L., J.A.H., J.H.J.), Medical University of South Carolina, Charleston, South Carolina
| | - L-W Kuo
- Institute of Biomedical Engineering and Nanomedicine (L.-W.K.), National Health Research Institutes, Miaoli County, Taiwan
| | - Y-P Chao
- Graduate Institute of Medical Mechatronics (Y.-P.C.), Chang Gung University, Taoyuan, Taiwan
| | - C-Y Lee
- From the Center for Biomedical Imaging (G.R.G., C.-Y.L., J.A.H., J.H.J.) Department of Radiology and Radiological Science (G.R.G., C.-Y.L., J.A.H., J.H.J.), Medical University of South Carolina, Charleston, South Carolina
| | - J A Helpern
- From the Center for Biomedical Imaging (G.R.G., C.-Y.L., J.A.H., J.H.J.) Department of Neurosciences (G.R.G., J.A.H.) Department of Radiology and Radiological Science (G.R.G., C.-Y.L., J.A.H., J.H.J.), Medical University of South Carolina, Charleston, South Carolina
| | - J H Jensen
- From the Center for Biomedical Imaging (G.R.G., C.-Y.L., J.A.H., J.H.J.) Department of Radiology and Radiological Science (G.R.G., C.-Y.L., J.A.H., J.H.J.), Medical University of South Carolina, Charleston, South Carolina
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Bonilha L, Lee CY, Jensen JH, Tabesh A, Spampinato MV, Edwards JC, Breedlove J, Helpern JA. Altered microstructure in temporal lobe epilepsy: a diffusional kurtosis imaging study. AJNR Am J Neuroradiol 2014; 36:719-24. [PMID: 25500311 DOI: 10.3174/ajnr.a4185] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2014] [Accepted: 10/19/2014] [Indexed: 11/07/2022]
Abstract
BACKGROUND AND PURPOSE Temporal lobe epilepsy is associated with regional abnormalities in tissue microstructure, as demonstrated by DTI. However, the full extent of these abnormalities has not yet been defined because DTI conveys only a fraction of the information potentially accessible with diffusion MR imaging. In this study, we assessed the added value of diffusional kurtosis imaging, an extension of DTI, to evaluate microstructural abnormalities in patients with temporal lobe epilepsy. MATERIALS AND METHODS Thirty-two patients with left temporal lobe epilepsy and 36 matched healthy subjects underwent diffusion MR imaging. To evaluate abnormalities in patients, we performed voxelwise analyses, assessing DTI-derived mean diffusivity, fractional anisotropy, and diffusional kurtosis imaging-derived mean diffusional kurtosis, as well as diffusional kurtosis imaging and DTI-derived axial and radial components, comparing patients with controls. RESULTS We replicated findings from previous studies demonstrating a reduction in fractional anisotropy and an increase in mean diffusivity preferentially affecting, but not restricted to, the temporal lobe ipsilateral to seizure onset. We also noted a pronounced pattern of diffusional kurtosis imaging abnormalities in gray and white matter tissues, often extending into regions that were not detected as abnormal by DTI measures. CONCLUSIONS Diffusional kurtosis is a sensitive and complementary measure of microstructural compromise in patients with temporal lobe epilepsy. It provides additional information regarding the anatomic distribution and degree of damage in this condition. Diffusional kurtosis imaging may be used as a biomarker for disease severity, clinical phenotypes, and treatment monitoring in epilepsy.
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Affiliation(s)
- L Bonilha
- From the Departments of Neurology and Neurosurgery (L.B., J.C.E.) Comprehensive Epilepsy Center (L.B., J.C.E., J.B.) Center for Biomedical Imaging (L.B., C.-Y.L., J.H.J., A.T., M.V.S.), Medical University of South Carolina, Charleston, South Carolina.
| | - C-Y Lee
- Radiology and Radiological Science (C.-Y.L., J.H.J., A.T., M.V.S., J.A.H.) Center for Biomedical Imaging (L.B., C.-Y.L., J.H.J., A.T., M.V.S.), Medical University of South Carolina, Charleston, South Carolina
| | - J H Jensen
- Radiology and Radiological Science (C.-Y.L., J.H.J., A.T., M.V.S., J.A.H.) Center for Biomedical Imaging (L.B., C.-Y.L., J.H.J., A.T., M.V.S.), Medical University of South Carolina, Charleston, South Carolina
| | - A Tabesh
- Radiology and Radiological Science (C.-Y.L., J.H.J., A.T., M.V.S., J.A.H.) Center for Biomedical Imaging (L.B., C.-Y.L., J.H.J., A.T., M.V.S.), Medical University of South Carolina, Charleston, South Carolina
| | - M V Spampinato
- Radiology and Radiological Science (C.-Y.L., J.H.J., A.T., M.V.S., J.A.H.) Center for Biomedical Imaging (L.B., C.-Y.L., J.H.J., A.T., M.V.S.), Medical University of South Carolina, Charleston, South Carolina
| | - J C Edwards
- From the Departments of Neurology and Neurosurgery (L.B., J.C.E.) Comprehensive Epilepsy Center (L.B., J.C.E., J.B.)
| | - J Breedlove
- Comprehensive Epilepsy Center (L.B., J.C.E., J.B.)
| | - J A Helpern
- Radiology and Radiological Science (C.-Y.L., J.H.J., A.T., M.V.S., J.A.H.)
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Bester M, Jensen JH, Babb JS, Tabesh A, Miles L, Herbert J, Grossman RI, Inglese M. Non-Gaussian diffusion MRI of gray matter is associated with cognitive impairment in multiple sclerosis. Mult Scler 2014; 21:935-44. [PMID: 25392318 DOI: 10.1177/1352458514556295] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [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: 04/16/2014] [Accepted: 09/23/2014] [Indexed: 01/13/2023]
Abstract
BACKGROUND Non-Gaussian diffusion imaging by using diffusional kurtosis imaging (DKI) allows assessment of isotropic tissue as of gray matter (GM), an important limitation of diffusion tensor imaging (DTI). OBJECTIVE In this study, we describe DKI and DTI metrics of GM in multiple sclerosis (MS) patients and their association with cognitive deficits. METHODS Thirty-four patients with relapsing-remitting MS and 17 controls underwent MRI on a 3T scanner including a sequence for DKI with 30 diffusion directions and 3b values for each direction. Mean kurtosis (MK), mean diffusivity and fractional anisotropy (FA) of cortical and subcortical GM were measured using histogram analysis. Spearman rank correlations were used to characterize associations among imaging measures and clinical/neuropsychological scores. RESULTS In cortical GM, a significant decrease of MK (0.68 vs. 0.73; p < 0.001) and increase of FA (0.16 vs. 0.13; p < 0.001) was found in patients compared to controls. Decreased cortical MK was correlated with poor performance on the Delis-Kaplan Executive Function System test (r = 0.66, p = 0.01). CONCLUSION Mean kurtosis is sensitive to abnormality in GM of MS patients and can provide information that is complementary to that of conventional DTI-derived metrics. The association between MK and cognitive deficits suggests that DKI might serve as a clinically relevant biomarker for cortical injury.
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Affiliation(s)
- M Bester
- Department of Diagnostic and Interventional Neuroradiology, University Medical Centre Hamburg-Eppendorf (UKE), Germany/ Department of Radiology, Langone Medical Center, NYU School of Medicine, NY, USA
| | - J H Jensen
- Department of Radiology and Radiological Science, Medical University of South Carolina, USA
| | - J S Babb
- Department of Radiology, Langone Medical Center, NYU School of Medicine, NY, USA
| | - A Tabesh
- Department of Radiology and Radiological Science, Medical University of South Carolina, USA
| | - L Miles
- Department of Radiology, Langone Medical Center, NYU School of Medicine, NY, USA
| | - J Herbert
- Department of Neurology, Langone Medical Center, NYU School of Medicine, NY, USA
| | - R I Grossman
- Department of Radiology, Langone Medical Center, NYU School of Medicine, NY, USA
| | - M Inglese
- Department of Radiology, Langone Medical Center, NYU School of Medicine, NY, USA/Department of Neurology, Radiology and Neuroscience, Mount Sinai School of Medicine, USA
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Paydar A, Fieremans E, Nwankwo JI, Lazar M, Sheth HD, Adisetiyo V, Helpern JA, Jensen JH, Milla SS. Diffusional kurtosis imaging of the developing brain. AJNR Am J Neuroradiol 2013; 35:808-14. [PMID: 24231848 DOI: 10.3174/ajnr.a3764] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
BACKGROUND AND PURPOSE Diffusional kurtosis imaging is an extension of DTI but includes non-Gaussian diffusion effects, allowing more comprehensive characterization of microstructural changes during brain development. Our purpose was to use diffusional kurtosis imaging to measure age-related microstructural changes in both the WM and GM of the developing human brain. MATERIALS AND METHODS Diffusional kurtosis imaging was performed in 59 subjects ranging from birth to 4 years 7 months of age. Diffusion metrics, fractional anisotropy, and mean kurtosis were collected from VOIs within multiple WM and GM structures and subsequently analyzed with respect to age. Diffusional kurtosis tractography images at various stages of development were also generated. RESULTS Fractional anisotropy and mean kurtosis both showed age-related increases in all WM regions, reflecting progression of diffusional anisotropy throughout development, predominantly in the first 2 years of life (eg, 70% and 157% increase in fractional anisotropy and mean kurtosis, respectively, from birth to 2 years for the splenium). However, mean kurtosis detected continued microstructural changes in WM past the fractional anisotropy plateau, accounting for more delayed isotropic changes (eg, 90% of maximum fractional anisotropy was reached at 5 months, whereas 90% of maximum mean kurtosis occurred at 18 months for the external capsule). Mean kurtosis may also provide greater characterization of GM maturation (eg, the putamen showed no change in fractional anisotropy but an 81% change in mean kurtosis from birth to 4 years 7 months). CONCLUSIONS Mean kurtosis detects significant microstructural changes consistent with known patterns of brain maturation. In comparison with fractional anisotropy, mean kurtosis may offer a more comprehensive evaluation of age-related microstructural changes in both WM and GM and is potentially a valuable technique for studying brain development.
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Affiliation(s)
- A Paydar
- From the Department of Radiology (A.P., E.F., J.I.N., M.L., H.D.S., V.A., S.S.M.), Center for Biomedical Imaging, New York University School of Medicine, New York, New York
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11
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Fieremans E, Benitez A, Jensen JH, Falangola MF, Tabesh A, Deardorff RL, Spampinato MVS, Babb JS, Novikov DS, Ferris SH, Helpern JA. Novel white matter tract integrity metrics sensitive to Alzheimer disease progression. AJNR Am J Neuroradiol 2013; 34:2105-12. [PMID: 23764722 DOI: 10.3174/ajnr.a3553] [Citation(s) in RCA: 111] [Impact Index Per Article: 10.1] [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: 11/07/2022]
Abstract
BACKGROUND AND PURPOSE Along with cortical abnormalities, white matter microstructural changes such as axonal loss and myelin breakdown are implicated in the pathogenesis of Alzheimer disease. Recently, a white matter model was introduced that relates non-Gaussian diffusional kurtosis imaging metrics to characteristics of white matter tract integrity, including the axonal water fraction, the intra-axonal diffusivity, and the extra-axonal axial and radial diffusivities. MATERIALS AND METHODS This study reports these white matter tract integrity metrics in subjects with amnestic mild cognitive impairment (n = 12), Alzheimer disease (n = 14), and age-matched healthy controls (n = 15) in an effort to investigate their sensitivity, diagnostic accuracy, and associations with white matter changes through the course of Alzheimer disease. RESULTS With tract-based spatial statistics and region-of-interest analyses, increased diffusivity in the extra-axonal space (extra-axonal axial and radial diffusivities) in several white matter tracts sensitively and accurately discriminated healthy controls from those with amnestic mild cognitive impairment (area under the receiver operating characteristic curve = 0.82-0.95), while widespread decreased axonal water fraction discriminated amnestic mild cognitive impairment from Alzheimer disease (area under the receiver operating characteristic curve = 0.84). Additionally, these white matter tract integrity metrics in the body of the corpus callosum were strongly correlated with processing speed in amnestic mild cognitive impairment (r = |0.80-0.82|, P < .001). CONCLUSIONS These findings have implications for the course and spatial progression of white matter degeneration in Alzheimer disease, suggest the mechanisms by which these changes occur, and demonstrate the viability of these white matter tract integrity metrics as potential neuroimaging biomarkers of the earliest stages of Alzheimer disease and disease progression.
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Affiliation(s)
- E Fieremans
- Department of Radiology, Center for Biomedical Imaging
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12
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Faro SH, Mohamed FB, Helpern JA, Jensen JH, Thulborn KR, Atkinson IC, Sair HI, Mikulis DJ. Hot topics in functional neuroradiology. AJNR Am J Neuroradiol 2013; 34:2241-9. [PMID: 24136644 DOI: 10.3174/ajnr.a3721] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Functional neuroradiology represents a relatively new and ever-growing subspecialty in the field of neuroradiology. Neuroradiology has evolved beyond anatomy and basic tissue signal characteristics and strives to understand the underlying physiologic processes of central nervous system disease. The American Society of Functional Neuroradiology sponsors a yearly educational and scientific meeting, and the educational committee was asked to suggest a few cutting-edge functional neuroradiology techniques (hot topics). The following is a review of several of these topics and includes "Diffusion Tensor Imaging of the Pediatric Spinal Cord"; "Diffusional Kurtosis Imaging"; "From Standardization to Quantification: Beyond Biomarkers toward Bioscales as Neuro MR Imaging Surrogates of Clinical End Points"; Resting-State Functional MR Imaging"; and "Current Use of Cerebrovascular Reserve Imaging."
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Grossman EJ, Jensen JH, Babb JS, Chen Q, Tabesh A, Fieremans E, Xia D, Inglese M, Grossman RI. Cognitive impairment in mild traumatic brain injury: a longitudinal diffusional kurtosis and perfusion imaging study. AJNR Am J Neuroradiol 2012. [PMID: 23179649 DOI: 10.3174/ajnr.a3358] [Citation(s) in RCA: 135] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
BACKGROUND AND PURPOSE Cognitive impairment is frequent among patients with mild traumatic brain injury despite the absence of detectable damage on conventional MR imaging. In this study, the quantitative MR imaging techniques DTI, DKI, and ASL were used to measure changes in the structure and function in the thalamus and WM of patients with MTBI during a short follow-up period, to determine whether these techniques can be used to investigate relationships with cognitive performance and to predict outcome. MATERIALS AND METHODS Twenty patients with MTBI and 16 controls underwent MR imaging at 3T and a neuropsychological battery designed to yield measures for attention, concentration, executive functioning, memory, learning, and information processing. MK, FA, MD, and CBF were measured in the thalamus by using region-of-interest analysis and in WM by using tract-based spatial statistics. Analyses were performed comparing regional imaging measures of subject groups and the results of testing of their associations with neuropsychological performance. RESULTS Patients with MTBI exhibited significant differences from controls for DTI, DKI, and ASL measures in the thalamus and various WM regions both within 1 month after injury and >9 months after injury. At baseline, DTI and DKI measures in the thalamus and various WM regions were significantly associated with performance in different neuropsychological domains, and cognitive impairment was significantly associated with MK in the thalamus and FA in optic radiations. CONCLUSIONS Combined application of DTI, DKI, and ASL to study MTBI might be useful for investigating dynamic changes in the thalamus and WM as well as cognitive impairment during a short follow-up period, though the small number of patients examined did not predict outcome.
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Affiliation(s)
- E J Grossman
- Department of Radiology, Center for Biomedical Imaging, New York University School of Medicine, 660 First Ave, 4th Floor, Room 420, New York, New York 10016, USA.
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Raz E, Jensen JH, Ge Y, Babb JS, Miles L, Reaume J, Grossman RI, Inglese M. Brain iron quantification in mild traumatic brain injury: a magnetic field correlation study. AJNR Am J Neuroradiol 2011; 32:1851-6. [PMID: 21885717 DOI: 10.3174/ajnr.a2637] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
BACKGROUND AND PURPOSE Experimental studies have suggested a role for iron accumulation in the pathology of TBI. Magnetic field correlation MR imaging is sensitive to the presence of non-heme iron. The aims of this study are to 1) assess the presence, if any, and the extent of iron deposition in the deep gray matter and regional white matter of patients with mTBI by using MFC MR imaging; and 2) investigate the association of regional brain iron deposition with cognitive and behavioral performance of patients with mTBI. MATERIALS AND METHODS We prospectively enrolled 28 patients with mTBI. Eighteen healthy subjects served as controls. The subjects were administered the Stroop color word test, the Verbal Fluency Task, and the Post-Concussion Symptoms Scale. The MR imaging protocol (on a 3T imager) consisted of conventional brain imaging and MFC sequences. After the calculation of parametric maps, MFC was measured by using a region of interest approach. MFC values across groups were compared by using analysis of covariance, and the relationship of MFC values and neuropsychological tests were evaluated by using Spearman correlations. RESULTS Compared with controls, patients with mTBI demonstrated significant higher MFC values in the globus pallidus (P = .002) and in the thalamus (P = .036). In patients with mTBI, Stroop test scores were associated with the MFC value in frontal white matter (r = -0.38, P = .043). CONCLUSIONS MFC values were significantly elevated in the thalamus and globus pallidus of patients with mTBI, suggesting increased accumulation of iron. This supports the hypothesis that deep gray matter is a site of injury in mTBI and suggests a possible role for iron accumulation in the pathophysiological events after mTBI.
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Affiliation(s)
- E Raz
- Department of Radiology, New York University School of Medicine, New York, USA
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Sigmund EE, Cho GY, Kim S, Finn M, Moccaldi M, Jensen JH, Sodickson DK, Goldberg JD, Formenti S, Moy L. Intravoxel incoherent motion imaging of tumor microenvironment in locally advanced breast cancer. Magn Reson Med 2011; 65:1437-47. [PMID: 21287591 DOI: 10.1002/mrm.22740] [Citation(s) in RCA: 160] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2010] [Revised: 10/06/2010] [Accepted: 11/03/2010] [Indexed: 12/17/2022]
Abstract
Diffusion-weighted imaging plays important roles in cancer diagnosis, monitoring, and treatment. Although most applications measure restricted diffusion by tumor cellularity, diffusion-weighted imaging is also sensitive to vascularity through the intravoxel incoherent motion effect. Hypervascularity can confound apparent diffusion coefficient measurements in breast cancer. We acquired multiple b-value diffusion-weighted imaging at 3 T in a cohort of breast cancer patients and performed biexponential intravoxel incoherent motion analysis to extract tissue diffusivity (D(t)), perfusion fraction (f(p)), and pseudodiffusivity (D(p)). Results indicated significant differences between normal fibroglandular tissue and malignant lesions in apparent diffusion coefficient mean (±standard deviation) values (2.44 ± 0.30 vs. 1.34 ± 0.39 μm(2)/msec, P < 0.01) and D(t) (2.36 ± 0.38 vs. 1.15 ± 0.35 μm(2)/msec, P < 0.01). Lesion diffusion-weighted imaging signals demonstrated biexponential character in comparison to monoexponential normal tissue. There is some differentiation of lesion subtypes (invasive ductal carcinoma vs. other malignant lesions) with f(p) (10.5 ± 5.0% vs. 6.9 ± 2.9%, P = 0.06), but less so with D(t) (1.14 ± 0.32 μm(2)/msec vs. 1.18 ± 0.52 μm(2)/msec, P = 0.88) and D(p) (14.9 ± 11.4 μm(2)/msec vs. 16.1 ± 5.7 μm(2)/msec, P = 0.75). Comparison of intravoxel incoherent motion biomarkers with contrast enhancement suggests moderate correlations. These results suggest the potential of intravoxel incoherent motion vascular and cellular biomarkers for initial grading, progression monitoring, or treatment assessment of breast tumors.
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Affiliation(s)
- E E Sigmund
- Department of Radiology, New York University Langone Medical Center, New York, New York, USA.
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Richardson TO, Robinson EJH, Christensen K, Jensen JH, Christensen K, Jensen HJ, Franks NR, Sendova-Franks AB. Comment on P. Nouvellet, J.P. Bacon, D. Waxman, "Testing the level of ant activity associated with quorum sensing: An empirical approach leading to the establishment and test of a null-model". J Theor Biol 2011; 269:356-8. [PMID: 21056577 DOI: 10.1016/j.jtbi.2010.11.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2010] [Revised: 11/02/2010] [Accepted: 11/02/2010] [Indexed: 10/18/2022]
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Lu H, Pollack E, Young R, Babb JS, Johnson G, Zagzag D, Carson R, Jensen JH, Helpern JA, Law M. Predicting grade of cerebral glioma using vascular-space occupancy MR imaging. AJNR Am J Neuroradiol 2007; 29:373-8. [PMID: 17974612 DOI: 10.3174/ajnr.a0794] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
BACKGROUND AND PURPOSE MR imaging can measure tissue perfusion and the integrity of the blood-brain barrier. We hypothesize that a combined measure of cerebral blood volume and vascular permeability using vascular-space occupancy (VASO) MR imaging, a recently developed imaging technique, is of diagnostic value for predicting tumor grade. MATERIALS AND METHODS Thirty-nine patients (9 World Health Organization [WHO] grade II, 20 grade III, and 10 grade IV as determined by histopathologic assessment) were examined using VASO MR imaging, and regions-of-interest analysis was performed in tumoral regions, as well as in regions contralateral to the tumor. A Mann-Whitney test was conducted on the resulting VASO indices for a pairwise comparison across tumor grades. Nominal logistic regression was used to evaluate the use of VASO parameters for predicting group membership (by the percentage of correct classifications). RESULTS The ratio between tumor side and contralateral side, VASO(Ratio), showed significant differences in all 3 of the pairwise comparisons (P < .01). VASO values in the tumoral regions, VASO(Tumor), showed significant difference between grade II and III and between II and IV but not between III and IV. Both VASO(Tumor) and VASO(Ratio) were found to be significant predictors of tumor grade, giving diagnostic accuracies of 66.7% and 71.8%, respectively. When testing to discriminate grade II tumors from higher grade tumors, the areas under the receiver operating characteristic curve were found to be 0.974 and 0.985 for VASO(Tumor) and VASO(Ratio), respectively. CONCLUSION VASO MR imaging can be used for noninvasive tumor grade prediction based on cerebral blood volume and vascular permeability. VASO is more effective in separating WHO grade II from higher grades than in separating grade III from grade IV.
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Affiliation(s)
- H Lu
- Department of Radiology, New York University School of Medicine, New York, NY, USA.
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Ge Y, Jensen JH, Lu H, Helpern JA, Miles L, Inglese M, Babb JS, Herbert J, Grossman RI. Quantitative assessment of iron accumulation in the deep gray matter of multiple sclerosis by magnetic field correlation imaging. AJNR Am J Neuroradiol 2007; 28:1639-44. [PMID: 17893225 PMCID: PMC8134218 DOI: 10.3174/ajnr.a0646] [Citation(s) in RCA: 114] [Impact Index Per Article: 6.7] [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: 11/07/2022]
Abstract
BACKGROUND AND PURPOSE Deposition of iron has been recognized recently as an important factor of pathophysiologic change including neurodegenerative processes in multiple sclerosis (MS). We propose that there is an excess accumulation of iron in the deep gray matter in patients with MS that can be measured with a newly developed quantitative MR technique--magnetic field correlation (MFC) imaging. MATERIALS AND METHODS With a 3T MR system, we studied 17 patients with relapsing-remitting MS and 14 age-matched healthy control subjects. We acquired MFC imaging using an asymmetric single-shot echo-planar imaging sequence. Regions of interest were selected in both deep gray matter and white matter regions, and the mean MFC values were compared between patients and controls. We also correlated the MFC data with lesion load and neuropsychologic tests in the patients. RESULTS MFC measured in the deep gray matter in patients with MS was significantly higher than that in the healthy controls (P < or = .03), with an average increase of 24% in the globus pallidus, 39.5% in the putamen, and 30.6% in the thalamus. The increased iron deposition measured with MFC in the deep gray matter in the patients correlated positively with the total number of MS lesions (thalamus: r = 0.61, P = .01; globus pallidus: r = 0.52, P = .02). A moderate but significant correlation between the MFC value in the deep gray matter and the neuropsychologic tests was also found. CONCLUSION Quantitative measurements of iron content with MFC demonstrate increased accumulation of iron in the deep gray matter in patients with MS, which may be associated with the disrupted iron outflow pathway by lesions. Such abnormal accumulation of iron may contribute to neuropsychologic impairment and have implications for neurodegenerative processes in MS.
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Affiliation(s)
- Y Ge
- Center for Biomedical Imaging, Department of Radiology, New York University Medical Center, New York, NY 10016, USA.
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Abstract
A quantitative theory is proposed for the nonexponential NMR proton signal decay observed in liver with iron overload or superparamagnetic iron oxide particles. This effect occurs for Carr-Purcell-Meiboom-Gill (CPMG) sequences and is argued to be a direct consequence of the strong magnetic field inhomogeneities generated by the iron, rather than being due to tissue compartments. An approximate mathematical form is given for the signal decay, which is fit to experimental data for samples of rat liver with iron oxide particles, for samples of marmoset liver with hemosiderosis, and for in vivo human liver with hereditary hemochromatosis. The fitting parameters obtained are consistent with the pattern of iron deposition determined from histology. For the case of hereditary hemochromatosis, a good correlation is found between a parameter characterizing the nonexponential decay and the iron concentration. Implications for practical MR quantification of hepatic iron are discussed.
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Affiliation(s)
- J H Jensen
- Department of Radiology, New York University School of Medicine, New York, New York 10016, USA
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Abstract
A quantitative model is proposed for computing the dependence on the interecho time of the NMR relaxation rate in iron-rich gray matter obtained with a Carr-Purcell-Meiboom-Gill sequence. The model consists of representing oligodendrocytes as identical magnetic spheres arranged in a spatially random pattern, and in approximating water diffusion as isotropic and unrestricted. Predictions of the model are calculated numerically using a Monte Carlo technique and, for the weak field limit, using an analytic formula. The model is shown to provide a good fit to experimental measurements of in vitro samples of monkey brain at field levels of 1.0 T and 1.5 T. These field levels are not sufficient to fully determine the model parameters, but it is argued that this may be possible at 3.0 T. The model is potentially of value for multiple-spin-echo MRI studies of iron-related neurodegenerative disorders, such as Parkinson's disease. In particular, the model can be applied to correlate MRI data with the cellular distribution of iron in gray matter. Magn Reson Med 46:159-165, 2001.
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Affiliation(s)
- J H Jensen
- Department of Radiology, Old Bellevue, New York University School of Medicine, 550 First Avenue, New York, NY 10016, USA
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Tos M, Jensen JH, Salomon G, Jønsson MH, Post I, Thomsen JC. Cochlear implantation of Danish prelingually deaf children. Acta Otolaryngol Suppl 2001; 543:92-4. [PMID: 10908989 DOI: 10.1080/000164800454080] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
The aim of the study was to review the indications, techniques and results of cochlear implant (CI) treatment with the Nucleus CI multi-channel electrode for the first children operated on in Denmark. The study material comprised 16 children (5 girls, 11 boys). Their median age at the time of CI operation was 27 months. Anacusis was caused by pneumococcal meningitis in 31% of the children in this relatively young prelingual material. Obliteration of the cochlea was found in two children, indicating the need for surgery as soon as possible after the verification of post-meningitis, total deafness. There were no technical difficulties with operating on the youngest children in the congenital group and the age of 2 years is optimal for implantation. These preliminary results have contributed definitively to an increase in the number of cochlear implantations being carried out in young prelingually deaf Danish children.
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Affiliation(s)
- M Tos
- ENT Department, Gentofte University Hospital, Hellerup, Denmark
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Abstract
An imaging technique is proposed in which the contrast is correlated to the morphology of capillaries and other small blood vessels. The technique is based on measurements of the relaxation rates 1/T(2) and 1/T*(2) before and after the injection of a contrast agent. An image is then formed by mapping the quantity Q identical with delta R(2)/(delta R*(2))(2/3), where delta R(2) and delta R*(2) are the changes in the relaxation rates due to the contrast agent. If the contrast agent concentration is sufficiently high, it is shown that Q is given approximately by a simple analytic formula that involves only intrinsic properties of the vascular network and the rate of diffusion. In particular, Q is sensitive to the histologic vessel density. Theoretical predictions for Q are shown to be consistent with experimental data obtained with a rat glioma model and normal cerebral cortex. The imaging technique may be useful in characterizing tumor angiogenesis. Magn Reson Med 44:224-230, 2000.
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Affiliation(s)
- J H Jensen
- Department of Radiology, New York University School of Medicine, New York, NY, USA
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Jensen JH, Chandra R. NMR relaxation in tissues with weak magnetic inhomogeneities. Magn Reson Med 2000; 44:144-56. [PMID: 10893533] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/17/2023]
Abstract
A theory is presented for describing the effect on the transverse NMR relaxation rate of microscopic spatial inhomogeneities in the static magnetic field. The theory applies when the inhomogeneities are weak in magnitude and the nuclear spins diffuse a significant distance in comparison with a length scale characterizing the inhomogeneities. It is shown that the relaxation rate is determined by a temporal correlation function and depends quadratically on the magnitude of the inhomogeneities. For the case of unrestricted diffusion, a simple algebraic approximation for the temporal correlation function is derived. The theory is illustrated by applying it to a model of randomly distributed magnetized spheres. The theory is also used to fit experimental data for the dependence of the relaxation rate on the interecho time for a Carr-Purcell-Meiboom-Gill pulse sequence. The experimental systems considered are in vitro red blood cell suspensions and samples of human gray matter and rat liver. Magn Reson Med 44:144-156, 2000.
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Affiliation(s)
- J H Jensen
- Department of Radiology, New York University School of Medicine, New York, New York, USA
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Abstract
A theory for the behavior of the nuclear magnetic resonance (NMR) signal obtained from magnetically heterogeneous tissues is developed for the limit of a strong external magnetic field. If BO is the magnitude of the external magnetic field, it is found that a free-induction signal decays in a time scaling as 1/Bo, a single-spin echo signal decays in a time scaling as 1/Bo(2/3), and a multiple-spin echo signal decays in a time scaling as 1/Bo(2). Moreover, it is shown that the form of the signal decay for a multiple-spin echo sequence may deviate significantly from an exponential. Numerical results for a model consisting of randomly distributed magnetic spheres are used to confirm the theory. In addition, good agreement is demonstrated between the theory and experimental measurements obtained with particle suspensions. The validity and application of the theory to biological tissues are discussed.
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Affiliation(s)
- J H Jensen
- New York University School of Medicine, Department of Radiology, New York 10016, USA
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Barling D, de Vriend H, Cornelese JA, Ekstrand B, Hecker EF, Howlett J, Jensen JH, Lang T, Mayer S, Staer KB, Top R. The social aspects of food biotechnology: a European view. Environ Toxicol Pharmacol 1999; 7:85-93. [PMID: 21781913 DOI: 10.1016/s1382-6689(99)00009-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/13/1999] [Revised: 02/01/1999] [Accepted: 02/01/1999] [Indexed: 05/31/2023]
Abstract
The application of the modern biotechnology to food, notably through the use of GM, has raised concern amongst the European public. Values that underlie this public concern about food biotechnology, include perceptions of: trust, choice, need, and care for a sustainable society and natural balance. Recommendations are advocated for addressing these social aspects, in terms of improving consumer choice, promoting greater public involvement in decision making and achieving a sustainable society. A model of risk analysis for genetically modified organisms (GMOs) and genetically modified food that incorporates this social dimension, through the integration of risk analysis with a social impact analysis is proposed, in order to build greater popular trust into the decision making processes.
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Affiliation(s)
- D Barling
- Centre for Food Policy, Thames Valley University, London, UK
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Tos M, Jensen JH, Salomon G, Jønsson MH, Post I, Thomsen JC. [Cochlear implantation in children. The first Danish results]. Ugeskr Laeger 1999; 161:27-30. [PMID: 9922684] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/10/2023]
Abstract
The aim of this study is to review indication, technique and results of cochlear implant (CI) treatment with Nucleus CI-multi-electrode of the first ten children operated in Denmark (five children with congenital deafness and five with acquired prelingual deafness due to meningitis). In the literature, the importance of early referral and operation at the age 2-3 (4) years for congenital deafness and as soon as possible on suspicion of acquired deafness (meningitis) is stressed. A short survey of our indications, technique and rehabilitation is presented. The results of treatment after 11-44 months' use of CI are that one child has language almost matching age, four use words and short sentences accompanied by support signing, three have sound reaction and say single words without sentence building, but of these two children have only used CI for a very short time and are improving. Two meningitis sequelae cases had cochlear ossification, which made the implantation difficult. Both patients had to be operated, and one of them is not using the processor.
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Affiliation(s)
- M Tos
- Ore-naese-halsafdelingen, Amtssygehuset i Gentofte
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Drewes AM, Arendt-Nielsen L, Jensen JH, Hansen JB, Krarup HB, Tage-Jensen U. Experimental pain in the stomach: a model based on electrical stimulation guided by gastroscopy. Gut 1997; 41:753-7. [PMID: 9462207 PMCID: PMC1891591 DOI: 10.1136/gut.41.6.753] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
BACKGROUND Abdominal pain is often variable in intensity and difficult to characterise due to its referred pain pattern. Clinical pain is furthermore confounded by various emotional and cognitive factors. AIMS To develop and apply an experimental model to induce localised gastric pain. SUBJECTS Twelve healthy male volunteers. METHODS Stimulating electrodes were mounted on a biopsy forceps and electric stimuli were delivered during gastroscopy. Single, five repeated, and continuous stimuli were given at four locations in the stomach. Pain detection thresholds and pain intensities were assessed together with localisation of the referred pain area. RESULTS Pain detection thresholds were higher in the prepyloric region compared with those obtained at the lesser and greater curvature. Increasing stimulus intensity resulted in augmented pain perception and repeated stimuli elicited pain at a lower stimulus intensity than single stimuli. Continuous stimuli evoked constant (33%), increasing (33%), or decreasing (33%) pain. The localisation of referred pain varied considerably in the subjects. CONCLUSIONS The model seems relevant to study basic pain mechanisms elicited by localised stimuli in the stomach. The experimental data support the premise that a gastric focus should always be suspected in patients referred with different kinds of abdominal pain.
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Affiliation(s)
- A M Drewes
- Department of Medical Gastroenterology, Aalborg Hospital, Denmark
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Jensen JH. Accuracy of the semiclassical approximation for chaotic scattering. Phys Rev E Stat Phys Plasmas Fluids Relat Interdiscip Topics 1995; 51:1576-1578. [PMID: 9962802 DOI: 10.1103/physreve.51.1576] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Dyrlund O, Henningsen LB, Bisgaard N, Jensen JH. Digital feedback suppression (DFS). Characterization of feedback-margin improvements in a DFS hearing instrument. Scand Audiol 1994; 23:135-8. [PMID: 8085114 DOI: 10.3109/01050399409047498] [Citation(s) in RCA: 12] [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: 01/28/2023]
Abstract
The introduction of a new power behind-the-ear hearing instrument equipped with an integrated digital feedback suppression (DFS) system, based on adaptive, digital signal processing, creates the need for new methods for evaluating the characteristics of this new technology. A special measuring method based on determination of the complex loop gain of the DFS instrument and the associated feedback path is described. This method yields information about the static feedback-margin improvement due to the DFS system, and the method is usable especially in connection with measurements on real ears. It requires fairly advanced test facilities, including a dual-channel FFT analyzer and, by preference, an anechoic room. Loop gain measurements on the new DFS power behind-the-ear hearing instrument show encouraging results. Groups of profoundly hearing-impaired children and adults were tested, and static feedback-margin improvements in the order of 10 dB for the new DFS power hearing instrument were seen. Variations were largest for groups using own ear moulds and individually fitted instruments.
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Affiliation(s)
- O Dyrlund
- Technical-Audiological Laboratory, Odense, Denmark
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Jensen JH, Sørensen JL, Hauge EN, Sejrsen P, Bojsen J. A semiconductor silicon PIN diode matrix detector for measurement of 133Xe washout in small regional skin areas. Physiol Meas 1993; 14:205-16. [PMID: 8334415 DOI: 10.1088/0967-3334/14/2/011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [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: 01/29/2023]
Abstract
Local variations in microvascularization are expected in lesions and lesion-free skin of patients with pressure sores. To investigate these variations, methods for studies of the regional blood flow rate within small skin areas are needed. Regional blood flow can be estimated by measuring the washout of 133Xe from the tissue. This study describes a 2 x 12 Si PIN diode matrix detector capable of 133Xe detection, and equipped with a collimator to improve the spatial resolution. Thus the regional blood flow in subcutaneous skin areas down to about 2 cm2 can be investigated when the atraumatic epicutaneous labelling technique is used. The capability of the matrix detector and its collimator is described by laboratory investigations. In pilot investigations three normal subjects and three paraplegics with pressure sores were studied. In each individual study the detector matrix was divided into six square areas containing four diode detectors each. Thus six 133Xe disappearance rate constants from adjacent subcutaneous tissue could be determined simultaneously.
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Affiliation(s)
- J H Jensen
- Department of Biomedical and Clinical Engineering, University Hospital, Rigshospitalet, Copenhagen, Denmark
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Abstract
The size of the overpressure in the ear canal which causes rupture of the tympanic membrane (TM) in man (rupture pressure, RP) was determined in 90 subjects 7-112 h post mortem in connection with the autopsy. The equipment allowed an overpressure in the ear canal to be applied either gradually or suddenly. In 144 normal TMs it was demonstrated that the tensile strength of the TM increases post mortem. Corrected to the time 0 post mortem, RP of normal TMs ranged 0.5-2.1 kp/cm2, median 1.2 kp/cm2. It was found to be correlated to the age of the patient, i.e. RP decreased with increasing age. No correlation was found between RP and the application speed of the overpressure. Ninety-nine percent of the ruptures were localized to the pars tensa (63% to the anterior part of this structure) and typically had the shape of a minor tear. The RP of 23 TMs with atrophic scars was significantly lower, 0.3-0.8 kp/cm2, and the rupture typically had the shape of a larger defect. The results of this study indicate large intersubject variability of the tensile strength of the human TM. Some individuals are at increased risk of TM rupture at minor overpressures in the ear canal (e.g. during certain watersports, such as diving) which may carry medicolegal implications.
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Affiliation(s)
- J H Jensen
- Department of Otolaryngology, Glostrup Hospital, Copenhagen, Denmark
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Jensen JH. Erratum: Semiclassical approximation of cross sections with many rainbow peaks. Phys Rev A 1992; 46:4453-4454. [PMID: 9920619 DOI: 10.1103/physreva.46.4453.3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
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Abstract
The failure of treatment with penicillin in patients suffering from acute beta-haemolytic streptococcus Group A tonsillitis, may be due to the presence of beta-lactamase-producing bacteria. Several studies indicate that treatment with clindamycin may prevent recurrence and thereby eliminate the need for tonsillectomy. In this prospective study, 54 patients with recurrent acute tonsillitis were investigated. 29 patients were treated with clindamycin, 150 mg 4 times daily for 10 days, while 25 patients received no antibiotic treatment and served as a control group. A significantly reduced number of episodes of acute tonsillitis (P less than 0.01) and of tonsillectomy (P less than 0.001) was found in the group of patients treated with clindamycin.
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Affiliation(s)
- J H Jensen
- University Department of Otolaryngology, Hvidovre Hospital, Denmark
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Jensen RL, Jensen JH. Peri-implant maintenance. Northwest Dent 1991; 70:14-23. [PMID: 1923748] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
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Jensen JH, Ostri BJ. [Brain stem audiometry and unconventional audiometry in small children--a comparison with pure-tone audiometry performed at a later time]. Ugeskr Laeger 1991; 153:1055-7. [PMID: 2024330] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Auditory brain-stem responses (ABR) was performed in the determination of hearing threshold in 71 infants and children born 1980-1985, all belonging to high risk groups or difficult-to-test children (median age 17 months, range 2-80). In a follow up study, 41 of the children were tested with pure tone audiometry approximately 2 1/2 years later. A significant correlation was revealed between the threshold obtained by ABR and the pure tone threshold at 2 kHz (Kendall tau C = 0.59, p less than 0.00005). Compared to pure tone audiometry, the threshold had been estimated correctly by ABR in 81% of the patients (+/- 20 dB HL), in 2% the threshold had been estimated to be more than 20 dB better (false negative), while 17% had the threshold estimated more than 20 dB worse (false positive). The median difference between the thresholds obtained was -10 dB HL, the 25% percentile -20 dB HL and the 75% percentile 0 dB HL. In 28 children, behavioural audiometry and pure tone audiometry could be analyzed. 21% were false negative and 50% false positive. The result of the study indicates that ABR is a reliable testing procedure in the estimation of hearing thresholds in children who cannot cooperate sufficiently for pure tone audiometry. ABR gives a more valid estimation of the hearing than behavioural audiometry and is therefore a most valuable testing procedure in paediatric audiology.
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Affiliation(s)
- J H Jensen
- Audiologisk afdeling, Bispebjerg Hospital, København
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Jensen JH, Leth N, Bonding P. Topical application of decongestant in dysfunction of the Eustachian tube: a randomized, double-blind, placebo-controlled trial. Clin Otolaryngol 1990; 15:197-201. [PMID: 1697515 DOI: 10.1111/j.1365-2273.1990.tb00775.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.5] [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: 12/28/2022]
Abstract
Thirty-six patients, aged 12-75 years, with dry, central tympanic membrane perforations and a negative Valsalva manouevre and/or a negative aspiration/deflation test, were included in a randomized, double-blind, placebo-controlled trial on the effect of a decongestant agent (xylometazoline chloride 0.1%) and placebo (saline 0.9%) applied directly to the pharyngeal opening of the Eustachian tube. Judged by the Valsalva manouevre, tubal patency was significantly improved after application of the active drug (P less than 0.003). In contrast, no effect was demonstrated by the aspiration test (P = 0.80) or the deflation test (P = 0.51). It is concluded that a topical decongestant improves Eustachian tube function but only at unphysiologically high pressures.
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Affiliation(s)
- J H Jensen
- Department of Otolaryngology, Glostrup Hospital, Denmark
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Abstract
Na,K-ATPase, or the Na,K-pump, is essential for the excitability and contractility of muscle tissue. Hypothyroidism in associated with a marked decrease in the Na,K-pump concentration in skeletal muscle and myocardium. In 7 patients on long-term amiodarone treatment there was a 36% reduction in the concentration of 3H-ouabain binding sites in skeletal muscle biopsies compared to 7 healthy subjects. This decrease during long-term amiodarone treatment may represent an equivalent reduction in the concentration of the functional Na,K-pump and it may be important in the adverse effect of amiodarone on muscle.
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Affiliation(s)
- A Nørgaard
- Department of Cardiology, Aarhus University Hospital, Denmark
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Jensen RL, Jensen JH, Krauser JT, Schulte JK. Hydroxylapatite coated dental implants. Northwest Dent 1989; 68:14-25. [PMID: 2561194] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
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Jensen JH, Noring E. [Torticollis--an unusual origin]. Ugeskr Laeger 1989; 151:950-1. [PMID: 2711514] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
On account of left-sided chronic otitis with cholesteatoma an otherwise healthy eight year-old girl underwent an otological operation lasting five hours. The course was technically uncomplicated. Postoperatively, persistent torticollis with turning of the head to the right was observed. X-ray and CT-scanning revealed atlanto-axial subluxation. No other cause than the rotation of the head during the operation was demonstrated. It is concluded that subluxation should be considered if torticollis is present after operations during which the head has been rotated.
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