3D cine DENSE MRI: ventricular segmentation and myocardial stratin analysis

Includes abstract. Includes bibliographical references

Magnetic resonance imaging of myocardial strain after acute ST-segment-elevation myocardial infarction: a systematic review

The purpose of this systematic review is to provide a clinically relevant, disease-based perspective on myocardial strain imaging in patients with acute myocardial infarction or stable ischemic heart disease. Cardiac magnetic resonance imaging uniquely integrates myocardial function with pathology. Therefore, this review focuses on strain imaging with cardiac magnetic resonance. We have specifically considered the relationships between left ventricular (LV) strain, infarct pathologies, and their associations with prognosis. A comprehensive literature review was conducted in accordance with the PRISMA guidelines. Publications were identified that (1) described the relationship between strain and infarct pathologies, (2) assessed the relationship between strain and subsequent LV outcomes, and (3) assessed the relationship between strain and health outcomes. In patients with acute myocardial infarction, circumferential strain predicts the recovery of LV systolic function in the longer term. The prognostic value of longitudinal strain is less certain. Strain differentiates between infarcted versus noninfarcted myocardium, even in patients with stable ischemic heart disease with preserved LV ejection fraction. Strain recovery is impaired in infarcted segments with intramyocardial hemorrhage or microvascular obstruction. There are practical limitations to measuring strain with cardiac magnetic resonance in the acute setting, and knowledge gaps, including the lack of data showing incremental value in clinical practice. Critically, studies of cardiac magnetic resonance strain imaging in patients with ischemic heart disease have been limited by sample size and design. Strain imaging has potential as a tool to assess for early or subclinical changes in LV function, and strain is now being included as a surrogate measure of outcome in therapeutic trials

Mapping right ventricular myocardial mechanics using 3D cine DENSE cardiovascular magnetic resonance

<p>Abstract</p> <p>Background</p> <p>The mechanics of the right ventricle (RV) are not well understood as studies of the RV have been limited. This is, in part, due to the RV's thin wall, asymmetric geometry and irregular motion. However, the RV plays an important role in cardiovascular function. This study aims to describe the complex mechanics of the healthy RV using three dimensional (3D) cine displacement encoding with stimulated echoes (DENSE) cardiovascular magnetic resonance (CMR).</p> <p>Methods</p> <p>Whole heart 3D cine DENSE data were acquired from five healthy volunteers. Tailored post-processing algorithms for RV mid-wall tissue tracking and strain estimation are presented. A method for sub-dividing the RV into four regions according to anatomical land marks is proposed, and the temporal evolution of strain was assessed in these regions.</p> <p>Results</p> <p>The 3D cine DENSE tissue tracking methods successfully capture the motion and deformation of the RV at a high spatial resolution in all volunteers. The regional Lagrangian peak surface strain and time to peak values correspond with previous studies using myocardial tagging, DENSE and strain encoded CMR. The inflow region consistently displays lower peak strains than the apical and outflow regions, and the time to peak strains suggest RV mechanical activation in the following order: inflow, outflow, mid, then apex.</p> <p>Conclusions</p> <p>Model-free techniques have been developed to study the myocardial mechanics of the RV at a high spatial resolution using 3D cine DENSE CMR. The consistency of the regional RV strain patterns across healthy subjects is encouraging and the techniques may have clinical utility in assessing disrupted RV mechanics in the diseased heart.</p

Assessment of left atrial volume before and after pulmonary thromboendarterectomy in chronic thromboembolic pulmonary hypertension.

BackgroundImpaired left ventricular diastolic filling is common in chronic thromboembolic pulmonary hypertension (CTEPH), and recent studies support left ventricular underfilling as a cause. To investigate this further, we assessed left atrial volume index (LAVI) in patients with CTEPH before and after pulmonary thromboendarterectomy (PTE).MethodsForty-eight consecutive CTEPH patients had pre- &amp; post-PTE echocardiograms and right heart catheterizations. Parameters included mean pulmonary artery pressure (mPAP), pulmonary vascular resistance (PVR), cardiac index, LAVI, &amp; mitral E/A ratio. Echocardiograms were performed 6 ± 3 days pre-PTE and 10 ± 4 days post-PTE. Regression analyses compared pre- and post-PTE LAVI with other parameters.ResultsPre-op LAVI (mean 19.0 ± 7 mL/m2) correlated significantly with pre-op PVR (R = -0.45, p = 0.001), mPAP (R = -0.28, p = 0.05) and cardiac index (R = 0.38, p = 0.006). Post-PTE, LAVI increased by 18% to 22.4 ± 7 mL/m2 (p = 0.003). This change correlated with change in PVR (765 to 311 dyne-s/cm5, p = 0.01), cardiac index (2.6 to 3.2 L/min/m2, p = 0.02), and E/A (.95 to 1.44, p = 0.002).ConclusionIn CTEPH, smaller LAVI is associated with lower cardiac output, higher mPAP, and higher PVR. LAVI increases by ~20% after PTE, and this change correlates with changes in PVR and mitral E/A. The rapid increase in LAVI supports the concept that left ventricular diastolic impairment and low E/A pre-PTE are due to left heart underfilling rather than inherent left ventricular diastolic dysfunction

Quantifying right ventricular motion and strain using 3D cine DENSE MRI

Background: The RV is difficult to image because of its thin wall, asymmetric geometry and complex motion. DENSE is a quantitative MRI technique for measuring myocardial displacement and strain at high spatial and temporal resolutions [1,2]. DENSE encodes tissue displacement directly into the image phase, allowing for the direct extraction of motion data at a pixel resolution. A free-breathing navigator-gated spiral 3D cine DENSE sequence was recently developed [3], providing an MRI technique which is well suited to quantifying RV mechanics. Methods: Whole heart 3D cine DENSE data were acquired from two normal volunteers, after informed consent was obtained and in accordance with protocols approved by the University of Virginia institutional review board. The endocardial and epicardial contours were manually delineated to identify the myocardium from surrounding anatomical structures. A 3D spatiotemporal phase unwrapping algorithm was used to remove phase aliasing [4], and 3D Lagrangian displacement fields were derived for all cardiac phases. Midline contours were calculated from the epicardial and endocardial contours, and tissue tracking seed points were defined at pixel spaced intervals. A 3D tracking algorithm was implemented as a direct extension of the 2D tracking algorithm presented in [4], producing midline motion trajectories from which strain was calculated. Tangential 1D strain was calculated in the longitudinal and circumferential cardiac directions. Strain time curves are computed representing the free wall of the RV. Results: Figure 1 illustrates the RV free wall mean tangential 1D strain time curves for approximately 3/4 of the cardiac cycle over the apical-mid section of the heart for one volunteer. Results show measurements ranging between -0.1 and -0.25, and further illustrate a greater displacement in the longitudinal direction. Results compare favorably with studies using myocardial tagging and DENSE[5,6]

Search for Spatial Correlations of Neutrinos with Ultra-high-energy Cosmic Rays

For several decades, the origin of ultra-high-energy cosmic rays (UHECRs) has been an unsolved question of highenergy astrophysics. One approach for solving this puzzle is to correlate UHECRs with high-energy neutrinos, since neutrinos are a direct probe of hadronic interactions of cosmic rays and are not deflected by magnetic fields. In this paper, we present three different approaches for correlating the arrival directions of neutrinos with the arrival directions of UHECRs. The neutrino data are provided by the IceCube Neutrino Observatory and ANTARES, while the UHECR data with energies above ∼50 EeV are provided by the Pierre Auger Observatory and the Telescope Array. All experiments provide increased statistics and improved reconstructions with respect to our previous results reported in 2015. The first analysis uses a high-statistics neutrino sample optimized for pointsource searches to search for excesses of neutrino clustering in the vicinity of UHECR directions. The second analysis searches for an excess of UHECRs in the direction of the highest-energy neutrinos. The third analysis searches for an excess of pairs of UHECRs and highest-energy neutrinos on different angular scales. None of the analyses have found a significant excess, and previously reported overfluctuations are reduced in significance. Based on these results, we further constrain the neutrino flux spatially correlated with UHECRs.Centre National de la Recherche Scientifique (CNRS), Commissariat à l’énergie atomique et aux énergies alternatives (CEA), Commission Européenne (FEDER fund and Marie Curie Program), Institut Universitaire de France (IUF), LabEx UnivEarthS (ANR-10- LABX-0023 and ANR-18-IDEX-0001), Région Île-de-France (DIM-ACAV), Région Alsace (contrat CPER), Région Provence- Alpes-Côte d’Azur, Département du Var and Ville de La Seyne-sur-Mer, FranceBundesministerium für Bildung und Forschung (BMBF), GermanyIstituto Nazionale di Fisica Nucleare (INFN), ItalyNederlandse organisatie voor Wetenschappelijk Onderzoek (NWO), the NetherlandsCouncil of the President of the Russian Federation for young scientists and leading scientific schools supporting grants, RussiaExecutive Unit for Financing Higher Education, Research, Development and Innovation (UEFISCDI), RomaniaMinisterio de Ciencia, Innovación, Investigación y Universidades (MCIU): Programa Estatal de Generación de Conocimiento (refs. PGC2018-096663-B-C41, -A-C42, -BC43, -B-C44) (MCIU/FEDER), Generalitat Valenciana: Prometeo (PROMETEO/2020/019), Grisolía (refs. GRISOLIA/ 2018/119, /2021/192) and GenT (refs. CIDEGENT/2018/ 034, /2019/043, /2020/049, /2021/023) programs, Junta de Andalucía (ref. A-FQM-053-UGR18), La Caixa Foundation (ref. LCF/BQ/IN17/11620019), EU: MSC program (ref. 101025085), SpainMinistry of Higher Education, Scientific Research and Innovation, Morocco, and the Arab Fund for Economic and Social Development, KuwaitU.S. National Science Foundation-Office of Polar Programs, U.S. National Science Foundation-Physics Division, U.S. National Science Foundation-EPSCoR, Wisconsin Alumni Research Foundation, Center for High Throughput Computing (CHTC) at the University of Wisconsin−Madison, Open Science Grid (OSG), Extreme Science and Engineering Discovery Environment (XSEDE), Frontera computing project at the Texas Advanced Computing Center, U.S. Department of Energy−National Energy Research Scientific Computing Center, Particle astrophysics research computing center at the University of Maryland, Institute for Cyber-Enabled Research at Michigan State University, and Astroparticle physics computational facility at Marquette UniversityBelgium—Funds for Scientific Research (FRS-FNRS and FWO), FWO Odysseus and Big Science programmes, and Belgian Federal Science Policy Office (Belspo)Germany—Bundesministerium für Bildung und Forschung (BMBF), Deutsche Forschungsgemeinschaft (DFG), Helmholtz Alliance for Astroparticle Physics (HAP), Initiative and Networking Fund of the Helmholtz Association, Deutsches Elektronen Synchrotron (DESY), and High Performance Computing cluster of the RWTH AachenSweden—Swedish Research Council, Swedish Polar Research Secretariat, Swedish National Infrastructure for Computing (SNIC), and Knut and Alice Wallenberg FoundationAustralia—Australian Research CouncilCanada— Natural Sciences and Engineering Research Council of Canada, Calcul Québec, Compute Ontario, Canada Foundation for Innovation, WestGrid, and Compute CanadaDenmark—Villum Fonden and Carlsberg FoundationNew Zealand—Marsden FundJapan—Japan Society for Promotion of Science (JSPS) and Institute for Global Prominent Research (IGPR) of Chiba UniversityKorea—National Research Foundation of Korea (NRF)Switzerland—Swiss National Science Foundation (SNSF)United Kingdom—Department of Physics, University of OxfordArgentina—Comisión Nacional de Energía Atómica; Agencia Nacional de Promoción Científica y Tecnológica (ANPCyT); Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET); Gobierno de la Provincia de Mendoza; Municipalidad de Malargüe; NDM Holdings and Valle Las Leñas; in gratitude for their continuing cooperation over land access; Australia—the Australian Research Council;Belgium—Fonds de la Recherche Scientifique (FNRS); Research Foundation Flanders (FWO)Brazil—Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Financiadora de Estudos e Projetos (FINEP)Fundação de Amparo à Pesquisa do Estado de Rio de Janeiro (FAPERJ); São Paulo Research Foundation (FAPESP) Grants No. 2019/10151-2, No. 2010/07359-6 and No. 1999/ 05404-3; Ministério da Ciência, Tecnologia, Inovações e Comunicações (MCTIC)Czech Republic—Grant No. MSMT CR LTT18004, LM2015038, LM2018102, CZ.02.1.01/0.0/0.0/ 16_013/0001402, CZ.02.1.01/0.0/0.0/18_046/0016010, and CZ.02.1.01/0.0/0.0/17_049/0008422France—Centre de Calcul IN2P3/CNRSCentre National de la Recherche Scientifique (CNRS); Conseil Régional Ile-de-France; Département Physique Nucléaire et Corpusculaire (PNC-IN2P3/CNRS); Département Sciences de l’Univers (SDU-INSU/CNRS); Institut Lagrange de Paris (ILP) Grant No. LABEX ANR-10-LABX-63 within the Investissements d’Avenir Programme Grant No. ANR-11-IDEX- 0004-02Germany—Bundesministerium für Bildung und Forschung (BMBF); Deutsche Forschungsgemeinschaft (DFG); Finanzministerium Baden-Württemberg; Helmholtz Alliance for Astroparticle Physics (HAP); Helmholtz-Gemeinschaft Deutscher Forschungszentren (HGF); Ministerium für Innovation, Wissenschaft und Forschung des Landes Nordrhein-Westfalen; Ministerium für Wissenschaft, Forschung und Kunst des Landes Baden-WürttembergItaly—Istituto Nazionale di Fisica Nucleare (INFN); Istituto Nazionale di Astrofisica (INAF); Ministero dell’Istruzione, dell’Universitá e della Ricerca (MIUR); CETEMPS Center of Excellence; Ministero degli Affari Esteri (MAE)México—Consejo Nacional de Ciencia y Tecnología (CONACYT) No. 167733; Universidad Nacional Autónoma de México (UNAM)PAPIIT DGAPA-UNAMThe Netherlands— Ministry of Education, Culture and Science; Netherlands Organisation for Scientific Research (NWO); Dutch national e-infrastructure with the support of SURF CooperativePoland —Ministry of Education and Science, grant No. DIR/WK/ 2018/11National Science Centre, Grants No. 2016/22/M/ ST9/00198, 2016/23/B/ST9/01635, and 2020/39/B/ST9/ 01398Portugal—Portuguese national funds and FEDER funds within Programa Operacional Factores de Competitividade through Fundação para a Ciência e a Tecnologia (COMPETE)Romania—Ministry of Research, Innovation and Digitization, CNCS/CCCDI—UEFISCDI, projects PN19150201/16N/ 2019, PN1906010, TE128 and PED289, within PNCDI IIISlovenia—Slovenian Research Agency, grants P1-0031, P1- 0385, I0-0033, N1-0111Spain—Ministerio de Economía, Industria y Competitividad (FPA2017-85114-P and PID2019- 104676GB-C32), Xunta de Galicia (ED431C 2017/07), Junta de Andalucía (SOMM17/6104/UGR, P18-FR-4314) Feder Funds, RENATA Red Nacional Temática de Astropartículas (FPA2015-68783-REDT) and María de Maeztu Unit of Excellence (MDM-2016-0692)USA—Department of Energy, Contracts No. DE-AC02-07CH11359, No. DE-FR02-04ER41 300, No. DE-FG02-99ER41107, and No. DE-SC0011689; National Science Foundation, Grant No. 0450696; The Grainger Foundation; Marie Curie-IRSES/EPLANET; European Particle Physics Latin American Network; and UNESCO.Japan Society for the Promotion of Science (JSPS) through Grants-in- Aid for Priority Area 431, for Specially Promoted Research JP21000002, for Scientific Research (S) JP19104006, for Specially Promoted Research JP15H05693, for Scientific Research (S) JP15H05741, for Science Research (A) JP18H03705, for Young Scientists (A) JPH26707011, and for Fostering Joint International Research (B) JP19KK0074, by the joint research program of the Institute for Cosmic Ray Research (ICRR), The University of Tokyo; by the Pioneering Program of RIKEN for the Evolution of Matter in the Universe (r-EMU)U.S. National Science Foundation awards PHY-1404495, PHY-1404502, PHY-1607727, PHY-1712517, PHY-1806797, PHY-2012934, and PHY-2112904National Research Foundation of Korea (2017K1A4A3015188, 2020R1A2C1 008230, and 2020R1A2C2102800)Ministry of Science and Higher Education of the Russian Federation under the contract 075-15-2020-778, IISN project No. 4.4501.18Belgian Science Policy under IUAP VII/37 (ULB

Electric potential across epidermis and its role during wound healing can be studied by using an in vitro reconstructed human skin

Background : After human epidermis wounding, transepithelial potential (TEP) present in nonlesional epidermis decreases and induces an endogenous direct current epithelial electric field (EEF) that could be implicated in the wound re-epithelialization. Some studies suggest that exogenous electric stimulation of wounds can stimulate healing, although the mechanisms remain to be determined. The Problem : Little is known concerning the exact action of the EEF during healing. The mechanism responsible for TEP and EEF is unknown due to the lack of an in vitro model to study this phenomenon. Basic Science Advances : We carried out studies by using a wound created in a human tissue-engineered skin and determined that TEP undergoes ascending and decreasing phases during the epithelium formation. The in vitro TEP measurements over time in the wound were corroborated with histological changes and with in vivo TEP variations during porcine skin wound healing. The expression of a crucial element implicated in Na+ transport, Na+/K+ ATPase pumps, was also evaluated at the same time points during the re-epithelialization process. The ascending and decreasing TEP values were correlated with changes in the expression of these pumps. The distribution of Na+/K+ ATPase pumps also varied according to epidermal differentiation. Further, inhibition of the pump activity induced a significant decrease of the TEP and of the re-epithelization rate. Clinical Care Relevance : A better comprehension of the role of EEF could have important future medical applications regarding the treatment of chronic wound healing. Conclusion : This study brings a new perspective to understand the formation and restoration of TEP during the cutaneous wound healing process

Semi-automated left ventricular segmentation based on a guide point model approach for 3D cine DENSE cardiovascular magnetic resonance

Abstract Background The most time consuming and limiting step in three dimensional (3D) cine displacement encoding with stimulated echoes (DENSE) MR image analysis is the demarcation of the left ventricle (LV) from its surrounding anatomical structures. The aim of this study is to implement a semi-automated segmentation algorithm for 3D cine DENSE CMR using a guide point model approach. Methods A 3D mathematical model is fitted to guide points which were interactively placed along the LV borders at a single time frame. An algorithm is presented to robustly propagate LV epicardial and endocardial surfaces of the model using the displacement information encoded in the phase images of DENSE data. The accuracy, precision and efficiency of the algorithm are tested. Results The model-defined contours show good accuracy when compared to the corresponding manually defined contours as similarity coefficients Dice and Jaccard consist of values above 0.7, while false positive and false negative measures show low percentage values. This is based on a measure of segmentation error on intra- and inter-observer spatial overlap variability. The segmentation algorithm offers a 10-fold reduction in the time required to identify LV epicardial and endocardial borders for a single 3D DENSE data set. Conclusion A semi-automated segmentation method has been developed for 3D cine DENSE CMR. The algorithm allows for contouring of the first cardiac frame where blood-myocardium contrast is almost nonexistent and reduces the time required to segment a 3D DENSE data set significantly

A Keck Adaptive Optics Survey of a Representative Sample of Gravitationally-Lensed Star-Forming Galaxies: High Spatial Resolution Studies of Kinematics and Metallicity Gradients

We discuss spatially resolved emission line spectroscopy secured for a total sample of 15 gravitationally lensed star-forming galaxies at a mean redshift of z≃2 based on Keck laser-assisted adaptive optics observations undertaken with the recently improved OSIRIS integral field unit (IFU) spectrograph. By exploiting gravitationally lensed sources drawn primarily from the CASSOWARY survey, we sample these sub-L^* galaxies with source-plane resolutions of a few hundred parsecs ensuring well-sampled 2D velocity data and resolved variations in the gas-phase metallicity. Such high spatial resolution data offer a critical check on the structural properties of larger samples derived with coarser sampling using multiple-IFU instruments. We demonstrate how kinematic complexities essential to understanding the maturity of an early star-forming galaxy can often only be revealed with better sampled data. Although we include four sources from our earlier work, the present study provides a more representative sample unbiased with respect to emission line strength. Contrary to earlier suggestions, our data indicate a more diverse range of kinematic and metal gradient behavior inconsistent with a simple picture of well-ordered rotation developing concurrently with established steep metal gradients in all but merging systems. Comparing our observations with the predictions of hydrodynamical simulations suggests that gas and metals have been mixed by outflows or other strong feedback processes, flattening the metal gradients in early star-forming galaxies