Michael Schar

Summary

Publications

  1. pmc Two repetition time saturation transfer (TwiST) with spill-over correction to measure creatine kinase reaction rates in human hearts
    Michael Schar
    Division of MR Research, Russell H Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
    J Cardiovasc Magn Reson 17:70. 2015
  2. pmc Robust volume-targeted balanced steady-state free-precession coronary magnetic resonance angiography in a breathhold at 3.0 Tesla: a reproducibility study
    Sahar Soleimanifard
    Russell H, Morgan Department of Radiology and Radiological Science, Division of Magnetic Resonance Research, Johns Hopkins University, Baltimore, MD, USA
    J Cardiovasc Magn Reson 16:27. 2014
  3. pmc Triple repetition time saturation transfer (TRiST) 31P spectroscopy for measuring human creatine kinase reaction kinetics
    Michael Schar
    Russell H Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21287, USA
    Magn Reson Med 63:1493-501. 2010
  4. pmc Simultaneous B(0)- and B(1)+-map acquisition for fast localized shim, frequency, and RF power determination in the heart at 3 T
    Michael Schar
    Russell H Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21287, USA
    Magn Reson Med 63:419-26. 2010
  5. pmc Magnetic resonance Spectroscopy with Linear Algebraic Modeling (SLAM) for higher speed and sensitivity
    Yi Zhang
    Department of Radiology and Radiological Science, Johns Hopkins University, Baltimore, MD 21287, USA
    J Magn Reson 218:66-76. 2012
  6. pmc Spatially selective implementation of the adiabatic T2Prep sequence for magnetic resonance angiography of the coronary arteries
    Sahar Soleimanifard
    Department of Electrical and Computer Engineering, Johns Hopkins University, Baltimore, Maryland, USA
    Magn Reson Med 70:97-105. 2013
  7. pmc On the dual contrast enhancement mechanism in frequency-selective inversion-recovery magnetic resonance angiography (IRON-MRA)
    Evert Jan Vonken
    Russell H Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
    Magn Reson Med 62:314-24. 2009
  8. pmc Off-resonance angiography: a new method to depict vessels--phantom and rabbit studies
    Grigorios Korosoglou
    Russell H Morgan Department of Radiology and Radiological Science, Division of Cardiology, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
    Radiology 249:501-9. 2008
  9. pmc Regional coronary endothelial function is closely related to local early coronary atherosclerosis in patients with mild coronary artery disease: pilot study
    Allison G Hays
    Department of Medicine, Johns Hopkins University, Baltimore, MD 21287, USA
    Circ Cardiovasc Imaging 5:341-8. 2012
  10. pmc Non-invasive detection of coronary endothelial response to sequential handgrip exercise in coronary artery disease patients and healthy adults
    Allison G Hays
    Department of Medicine, Division of Cardiology, Johns Hopkins University, Baltimore, Maryland, United States of America
    PLoS ONE 8:e58047. 2013

Collaborators

Detail Information

Publications38

  1. pmc Two repetition time saturation transfer (TwiST) with spill-over correction to measure creatine kinase reaction rates in human hearts
    Michael Schar
    Division of MR Research, Russell H Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
    J Cardiovasc Magn Reson 17:70. 2015
    ..Instead of measuring T1`, an intrinsic relaxation time T1 for PCr, T1 (intrinsic), is assumed. The objective was to validate TwiST measurements of CK kinetics in healthy subjects and patients with heart failure (HF)...
  2. pmc Robust volume-targeted balanced steady-state free-precession coronary magnetic resonance angiography in a breathhold at 3.0 Tesla: a reproducibility study
    Sahar Soleimanifard
    Russell H, Morgan Department of Radiology and Radiological Science, Division of Magnetic Resonance Research, Johns Hopkins University, Baltimore, MD, USA
    J Cardiovasc Magn Reson 16:27. 2014
    ..The purpose of this work was to refine, implement, and test a robust, practical single-breathhold bSSFP coronary MRA sequence at 3.0 T and to test the reproducibility of the technique...
  3. pmc Triple repetition time saturation transfer (TRiST) 31P spectroscopy for measuring human creatine kinase reaction kinetics
    Michael Schar
    Russell H Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21287, USA
    Magn Reson Med 63:1493-501. 2010
    ..The first 3-T TRiST measurements of creatine kinase k(f) in the human calf (n = 6), chest muscle, and heart (n = 8) are 0.26 +/- 0.04 s(-1), 0.23 +/- 0.03 s(-1), and 0.32 +/- 0.07 s(-1), respectively, consistent with prior 1.5 T values...
  4. pmc Simultaneous B(0)- and B(1)+-map acquisition for fast localized shim, frequency, and RF power determination in the heart at 3 T
    Michael Schar
    Russell H Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21287, USA
    Magn Reson Med 63:419-26. 2010
    ....
  5. pmc Magnetic resonance Spectroscopy with Linear Algebraic Modeling (SLAM) for higher speed and sensitivity
    Yi Zhang
    Department of Radiology and Radiological Science, Johns Hopkins University, Baltimore, MD 21287, USA
    J Magn Reson 218:66-76. 2012
    ..Both SLAM and fSLAM are simple to implement and reduce the minimum scan-time for CSI, which otherwise limits the translation of higher SNR achievable at higher field strengths to faster scanning...
  6. pmc Spatially selective implementation of the adiabatic T2Prep sequence for magnetic resonance angiography of the coronary arteries
    Sahar Soleimanifard
    Department of Electrical and Computer Engineering, Johns Hopkins University, Baltimore, Maryland, USA
    Magn Reson Med 70:97-105. 2013
    ..Additionally, a segmental analysis demonstrated that the spatially selective T2Prep was most beneficial in proximal and mid segments where the in-flowing blood volume was largest compared to the distal segments...
  7. pmc On the dual contrast enhancement mechanism in frequency-selective inversion-recovery magnetic resonance angiography (IRON-MRA)
    Evert Jan Vonken
    Russell H Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
    Magn Reson Med 62:314-24. 2009
    ..First results obtained in an in vivo rabbit model are presented...
  8. pmc Off-resonance angiography: a new method to depict vessels--phantom and rabbit studies
    Grigorios Korosoglou
    Russell H Morgan Department of Radiology and Radiological Science, Division of Cardiology, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
    Radiology 249:501-9. 2008
    ....
  9. pmc Regional coronary endothelial function is closely related to local early coronary atherosclerosis in patients with mild coronary artery disease: pilot study
    Allison G Hays
    Department of Medicine, Johns Hopkins University, Baltimore, MD 21287, USA
    Circ Cardiovasc Imaging 5:341-8. 2012
    ..We tested the hypothesis that abnormal coronary endothelial function is related to measures of early atherosclerosis such as increased coronary wall thickness...
  10. pmc Non-invasive detection of coronary endothelial response to sequential handgrip exercise in coronary artery disease patients and healthy adults
    Allison G Hays
    Department of Medicine, Division of Cardiology, Johns Hopkins University, Baltimore, Maryland, United States of America
    PLoS ONE 8:e58047. 2013
    ..Our objective is to test the hypothesis that coronary endothelial function (CorEndoFx) does not change with repeated isometric handgrip (IHG) stress in CAD patients or healthy subjects...
  11. pmc Transperineal prostate intervention: robot for fully automated MR imaging--system description and proof of principle in a canine model
    Michael Muntener
    URobotics Laboratory, Department of Urology, Johns Hopkins Medical Institutions, JHBMC, MFL W115, 5200 Eastern Ave, Baltimore, MD 21224, USA
    Radiology 247:543-9. 2008
    ..02 mm (range, 0.86-3.18 mm) and 2.50 mm (range, 1.45-10.54 mm), respectively. The robotic system is capable of accurate MR imaging-guided prostatic needle intervention within a standard MR imager in vivo in a canine model...
  12. pmc Monitoring and correcting spatio-temporal variations of the MR scanner's static magnetic field
    AbdEl Monem El-Sharkawy
    The Department of Electrical Engineering, Johns Hopkins University, Baltimore, MD 21218, USA
    MAGMA 19:223-36. 2006
    ..It is demonstrated that serial field mapping and phased difference imaging correction protocols can substantially compensate for the drift effects observed in the MR thermometry and spectroscopy experiments...
  13. doi request reprint Improved SNR efficiency in gradient echo coronary MRA with high temporal resolution using parallel imaging
    Jing Yu
    Russell H Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21287, USA
    Magn Reson Med 62:1211-20. 2009
    ..This method is most suitable for spoiled gradient echo coronary magnetic resonance angiography in which a high temporal and spatial resolution is required...
  14. pmc Simultaneous Noninvasive Assessment of Systemic and Coronary Endothelial Function
    Micaela Iantorno
    From the Division of Cardiology, Department of Medicine M I, A G H, R K, A s, G G, R G W, Division of Magnetic Resonance Research, Department of Radiology M S, S S, M S, R G W, Department of Electrical and Computer Engineering S S, Johns Hopkins University, Baltimore, MD Critical Care Medicine Department, National Institutes of Health, Bethesda, MD M I and Department of Radiology, Centre Hospitalier Universitaire Vaudois, Center for Biomedical Imaging CIBM, University of Lausanne, Lausanne, Switzerland M S
    Circ Cardiovasc Imaging 9:e003954. 2016
    ..Because the internal mammary artery (IMA) is often visualized during coronary MRI, we propose the strategy of simultaneously assessing systemic and coronary endothelial function noninvasively by MRI during IHE...
  15. doi request reprint Quantification of human high-energy phosphate metabolite concentrations at 3 T with partial volume and sensitivity corrections
    AbdEl Monem M El-Sharkawy
    Russell H Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
    NMR Biomed 26:1363-71. 2013
    ..The method enables, for the first time, the efficient, semi-automated quantification of high-energy phosphate metabolites in humans at 3 T with nonuniform excitation and detection...
  16. pmc MRI dynamic range and its compatibility with signal transmission media
    Refaat E Gabr
    Division of MR Research, Department of Radiology, Johns Hopkins School of Medicine, 600 N Wolfe St, Park 328, Baltimore, MD, USA
    J Magn Reson 198:137-45. 2009
    ..However, combining analog links with signal compression might make non-coaxial cable signal transmission viable...
  17. pmc High-energy phosphate transfer in human muscle: diffusion of phosphocreatine
    Refaat E Gabr
    Division of MR Research, Department of Radiology, Johns Hopkins University, Baltimore, Maryland, USA
    Am J Physiol Cell Physiol 301:C234-41. 2011
    ..Thus these first measurements of PCr diffusion in human muscle in vivo support the view that PCr diffusion is not a factor limiting high-energy phosphate transport between the mitochondria and the myofibrils in healthy resting myocytes...
  18. pmc On restoring motion-induced signal loss in single-voxel magnetic resonance spectra
    Refaat E Gabr
    Division of MR Research, Department of Radiology, Johns Hopkins University, Baltimore, Maryland 21287 0843, USA
    Magn Reson Med 56:754-60. 2006
    ..Constructive averaging should be incorporated as a routine tool for in vivo (1)H MRS...
  19. pmc Coronary vasomotor responses to isometric handgrip exercise are primarily mediated by nitric oxide: a noninvasive MRI test of coronary endothelial function
    Allison G Hays
    Division of Cardiology, Department of Medicine, Johns Hopkins University, Baltimore, Maryland
    Am J Physiol Heart Circ Physiol 308:H1343-50. 2015
    ..This noninvasive, reproducible MRI-IHE exam of NO-mediated CEF promises to be useful for studying CAD pathogenesis in low-risk populations and for evaluating translational strategies designed to alter CAD in patients...
  20. pmc Towards real-time intravascular endoscopic magnetic resonance imaging
    Shashank Sathyanarayana
    Division of MR Research, Department of Radiology, Johns Hopkins University, Baltimore, Maryland, USA
    JACC Cardiovasc Imaging 3:1158-65. 2010
    ....
  21. pmc Quantitative cardiac 31P spectroscopy at 3 Tesla using adiabatic pulses
    AbdEl Monem El-Sharkawy
    Russell H Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, Maryland 21287, USA
    Magn Reson Med 61:785-95. 2009
    ..8+/-0.3 s and 5.4+/-0.6 s, respectively. For heart (n=10) the values are 5.8+/-0.5 s (PCr) and 3.1+/-0.6 s (gamma-ATP). The 2TR protocol measurements agreed with those obtained by conventional methods to within 10%...
  22. pmc Impaired ATP kinetics in failing in vivo mouse heart
    Ashish Gupta
    Department of Medicine, Division of Cardiology, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
    Circ Cardiovasc Imaging 4:42-50. 2011
    ..The purpose of this work was to exploit noninvasive spatially localized magnetic resonance spectroscopy techniques to measure ATP flux through CK in in vivo mouse hearts and determine the extent of any reductions in murine HF...
  23. pmc "MRI Stealth" robot for prostate interventions
    Dan Stoianovici
    Urology Robotics, Johns Hopkins Medicine, Baltimore, MD 21224, USA
    Minim Invasive Ther Allied Technol 16:241-8. 2007
    ..Its multi-imager compatibility and other preclinical tests are included. The robot shows the technical feasibility of MRI-guided prostate interventions, yet its clinical utility is still to be determined...
  24. ncbi request reprint Positive contrast visualization of iron oxide-labeled stem cells using inversion-recovery with ON-resonant water suppression (IRON)
    Matthias Stuber
    Russell H Morgan Department of Radiology and Radiological Science, Division of MR Research, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21287, USA
    Magn Reson Med 58:1072-7. 2007
    ..The first successful use of IRON to produce positive contrast in areas of metallic spheres and SPIO-labeled stem cells in vitro and in vivo is presented...
  25. pmc Direct in vitro comparison of six three-dimensional positive contrast methods for susceptibility marker imaging
    Evert jan P A Vonken
    Russell H Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA evertjan isi uu nl
    J Magn Reson Imaging 38:344-57. 2013
    ....
  26. pmc Practical signal-to-noise ratio quantification for sensitivity encoding: application to coronary MR angiography
    Jing Yu
    Department of Biomedical Engineering, Johns Hopkins University, Baltimore, Maryland 21287, USA
    J Magn Reson Imaging 33:1330-40. 2011
    ..To develop and evaluate a practical method for the quantification of signal-to-noise ratio (SNR) on coronary MR angiograms (MRA) acquired with parallel imaging...
  27. ncbi request reprint Automated identification of minimal myocardial motion for improved image quality on MR angiography at 3 T
    Ali Ustun
    Department of Radiology, Johns Hopkins University Medical School, JHOC 4223, 601 N Caroline St, Baltimore, MD 21287, USA
    AJR Am J Roentgenol 188:W283-90. 2007
    ..5 T and 10 healthy adults (nine men, one woman; mean age, 24.9 years; age range, 21-32 years) at 3 T...
  28. pmc Nuclear Overhauser enhancement (NOE) imaging in the human brain at 7T
    Craig K Jones
    Division of MR Research, Russell H Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, USA
    Neuroimage 77:114-24. 2013
    ....
  29. ncbi request reprint Improved myocardial tagging contrast in cine balanced SSFP images
    El Sayed H Ibrahim
    Department of Electrical and Computer Engineering, Johns Hopkins University, Baltimore, Maryland 21287, USA
    J Magn Reson Imaging 24:1159-67. 2006
    ..To improve the tag persistence throughout the whole cardiac cycle by providing a constant tag-contrast throughout all the cardiac phases when using balanced steady-state free precession (bSSFP) imaging...
  30. pmc Spin-echo magnetic resonance spectroscopic imaging at 7 T with frequency-modulated refocusing pulses
    He Zhu
    Russell H Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, Maryland 21287, USA
    Magn Reson Med 69:1217-25. 2013
    ..2±0.5 compared to Hahn-MRSI at the same spatial resolution, pulse repetition time, echo time, and SENSE-acceleration factor. An interleaved two-slice Hahn-MRSI sequence is also demonstrated to be experimentally feasible...
  31. ncbi request reprint Hind limb ischemia in rabbit model: T2-prepared versus time-of-flight MR angiography at 3 T
    Grigorios Korosoglou
    Russell H Morgan Department of Radiology and Radiological Science, JHOC 4223, The Johns Hopkins University School of Medicine, 601 N Caroline St, Baltimore, MD, 21287, USA
    Radiology 245:761-9. 2007
    ..To prospectively compare various parameters of vessels imaged at 3 T by using time-of-flight (TOF) and T2-prepared magnetic resonance (MR) angiography in a rabbit model of hind limb ischemia...
  32. doi request reprint Magnetic resonance imaging overestimates ferumoxide-labeled stem cell survival after transplantation in the heart
    John Terrovitis
    Johns Hopkins University, Division of Cardiology, Department of Medicine, Rutland Ave, Baltimore, MD 21205, USA
    Circulation 117:1555-62. 2008
    ..We sought to determine the relationship between the persistence of iron-dependent MRI signals and cell survival 3 weeks after injection of syngeneic or xenogeneic ferumoxides-labeled stem cells (cardiac-derived stem cells) in rats...
  33. pmc Positive contrast visualization of nitinol devices using susceptibility gradient mapping
    Evert jan P A Vonken
    Russell H Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
    Magn Reson Med 60:588-94. 2008
    ..The positive signal response of this method depends only on the choice of the voxel neighborhood size. The properties of the method are explained and the visualizations of a nitinol wire and two stents are shown for illustration...
  34. pmc Velocity-selective magnetization-prepared non-contrast-enhanced cerebral MR angiography at 3 Tesla: Improved immunity to B0/B1 inhomogeneity
    Qin Qin
    The Russell H Morgan Department of Radiology and Radiological Science, Division of MR Research, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
    Magn Reson Med 75:1232-41. 2016
    ..To develop a Fourier-transform based velocity-selective (VS) pulse train that offers improved robustness to B0/B1 inhomogeneity for non-contrast-enhanced cerebral MR angiography (MRA) at 3 Tesla (T)...
  35. pmc Clinical applications for cardiovascular magnetic resonance imaging at 3 tesla
    Allison G Hays
    Department of Medicine, Division of Cardiology, Johns Hopkins University, Baltimore, Maryland, USA
    Curr Cardiol Rev 5:237-42. 2009
    ..5 T. This review will focus on the benefits and limitations of 3 T CMR for common clinical applications and examine areas in development for potential clinical use...
  36. pmc Automatic brachytherapy seed placement under MRI guidance
    Alexandru Patriciu
    Urology Department, URobotics Laboratory, The Johns Hopkins University School of Medicine, Baltimore, MD 21224, USA
    IEEE Trans Biomed Eng 54:1499-506. 2007
    ..Under the ideal conditions of the in vitro experiments, results show outstanding image-guided needle and seed placement accuracy...
  37. doi request reprint Intracranial arterial wall imaging using three-dimensional high isotropic resolution black blood MRI at 3.0 Tesla
    Ye Qiao
    The Russell H Morgan Department of Radiology and Radiological Sciences, The Johns Hopkins Hospital, Baltimore, Maryland, USA
    J Magn Reson Imaging 34:22-30. 2011
    ..To develop a high isotropic-resolution sequence to evaluate intracranial vessels at 3.0 Tesla (T)...
  38. ncbi request reprint Optimized detection of lactate at high fields using inner volume saturation
    Richard A E Edden
    Russell H Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, Maryland 21287, USA
    Magn Reson Med 56:912-7. 2006
    ..The method should be feasible at magnetic fields above 3 Tesla, and may also be applied to other coupled spin systems in which modulation effects are important...