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Search Publications by: Karl Stupic (Fed)

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Displaying 1 - 25 of 64

Relaxation measurements of an MRI system phantom at low magnetic field strengths

May 20, 2023
Author(s)
Michele Martin, Kalina Jordanova, Anthony Kos, Stephen E. Russek, Katy Keenan, Karl Stupic
Abstract Objective Temperature controlled T 1 and T 2 relaxation times are measured on NiCl 2 and MnCl 2 solutions from the ISMRM/NIST system phantom at low magnetic field strengths of 6.5 mT, 64 mT and 550 mT. Materials and methods The T 1 and T 2 were

Magnetic Resonance Imaging Biomarker Calibration Service: NMR Measurement of Isotropic Water Diffusion Coefficient

March 30, 2023
Author(s)
Stephen E. Russek, Katy Keenan, Karl Stupic, Nikki Rentz, Michael Boss, Kevin J. Coakley, Amanda Koepke, Cassandra Stoffer
This document describes a calibration service to measure the water diffusion coefficient, or diffusivity, in reference materials and tissue mimics using nuclear magnetic resonance (NMR) techniques. This calibration is restricted to materials which exhibit

Design and Demonstration of a Low Field Magnetic Resonance Imaging Rhizotron for In-Field Imaging of Energy Sorghum Roots

March 21, 2022
Author(s)
George Bagnall, Stephen Altobelli, Mark Conradi, Hilary Fabich, Eiichi Fukushima, Neha Koonjoo, Dean Kuethe, William Rooney, Karl Stupic, Bragi Sveinsson, Brock Weers, NITHYA RAJAN, Matthew Rosen, Cristine Morgan
Advances in plant root phenotyping will play a crucial role in the development of modern crop varieties for fostering sustainable agriculture. Root phenotyping provides critical information to plant breeders for developing varieties with improved drought

Imaging of Magnetic Excitations in Nanostructures with Microwave Near-Field Microscopy

November 25, 2021
Author(s)
Samuel Berweger, Robert Tyrrell-Ead, Houchen Chang, Mingzhong Wu, Hong Tang, Hans Nembach, Karl Stupic, Stephen E. Russek, Thomas Mitchell (Mitch) Wallis, Pavel Kabos
We present images of spin-wave excitations in a patterned yttrium iron garnet (YIG) thin film obtained by use of near-field microwave microscopy, which can achieve spatial resolution as high as 50 nm. Visualization of magnetic excitations is an enticing

A Standard System Phantom for Magnetic Resonance Imaging

April 13, 2021
Author(s)
Maureen Ainslie, Michael A. Boss, Cecil Charles, Laurence Clarke, Jeffrey L. Evelhoch, Paul Finn, Derek L. Hill, Katy Keenan, Guoying Liu, Karl Stupic, Chun Yuan, Michele Martin, Maureen Ainslie, Nikki Rentz
A standard MRI system phantom has been designed and fabricated to assess scanner performance, scanner stability, scanner inter-comparability and accuracy of quantitative relaxation time imaging. The phantom is unique in having SI-traceability, a high level

Characterization of 3-Dimensional Printing and Casting Materials for use in Computed Tomography and X-ray Imaging Phantoms

September 15, 2020
Author(s)
Bryan E. Yunker, Andrew Holmgren, Karl Stupic, J. L. Wagner, S Huddle, R Shandas, R. F. Weir, Katy Keenan, Edward Garboczi, Stephen E. Russek
Imaging phantoms are used to calibrate and validate the performance of medical computed tomography (CT) systems. Many new materials developed for three-dimensional (3D) printing processes may be useful in the direct printing or casting of biomimetic and

Characterization of 3-Dimensional Printing and Casting Materials for use in Magnetic Resonance Imaging Phantoms at 3 T

September 15, 2020
Author(s)
Bryan E. Yunker, Karl Stupic, J. L. Wagner, S Huddle, R Shandas, R. F. Weir, Stephen E. Russek, Katy Keenan
Imaging phantoms are used to calibrate and validate the performance of magnetic resonance imaging (MRI) systems. Many new materials have been developed for additive manufacturing (three-dimensional [3D] printing) processes that may be useful in the direct

Electromagnetics for Quantitative Magnetic Resonance Imaging

July 20, 2020
Author(s)
Stephen E. Russek, Karl F. Stupic, Joshua R. Biller, Michael A. Boss, Kathryn E. Keenan, Elizabeth Mirowski
Magnetic Resonance Imaging (MRI) is based on radio frequency (RF) interrogation of the human body at frequencies between 40 MHz to 300 MHz. An RF transmitter excites proton spin precession and then, in a manner analogous to an RF ID tag, the proton’s

Low-Field Magnetic Resonance Imaging of Roots in Intact Clayey and Silty Soils

July 1, 2020
Author(s)
George Bagnall, Cristine` Morgan, Matthew Rosen, Mark Conradi, Stephen Altobelli, Dean Kuethe, Haly Neely, Neha Koonjoo, Bo Zhu, Karl Stupic, John Mullet, Brock Weers, Eiichi Fukushima, William Rooney
The development of a robust method to non-invasively visualize root morphology in natural soils has been hampered by the opaque, physical, and structural properties of soils. In this work we describe a novel technology, low field magnetic resonance imaging