Skip to main content
U.S. flag

An official website of the United States government

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.


Search Publications by Kathryn Keenan

Search Title, Abstract, Conference, Citation, Keyword or Author
Displaying 1 - 17 of 17

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

September 15, 2020
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
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
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

Progress Towards Standards for Quantitative MRI (qMRI) and Outstanding Needs

January 24, 2019
Kathryn E. Keenan, Joshua R. Biller, Michael A. Boss, Adele P. Peskin, Karl F. Stupic, Stephen E. Russek, Jana Delfino, Mark Does, Jeffrey L. Evelhoch, Mark Griswold, Jeffrey Gunter, R Scott Hinks, Stuart Hoffman, Geena Kim, Riccardo Lattanzi, Xiaojuan Li, Luca Marinelli, Pratik Mukherjee, Robert J. Nordstrom, Elena Perez, Berkman Sahiner, Natalie J. Serkova, Amita Shukla-Dave, Michael Steckner, Lisa J. Wilmes, Holden Wu, Huiming Zhang, Edward F. Jackson, Daniel Sullivan
The National Institute of Standards and Technology (NIST) MRI Standards project held a one-day workshop on August 4, 2017 on campus in Boulder, CO. The goal of the workshop was to evaluate the advances in quantitative MRI (qMRI) since the last NIST

Large T1 contrast enhancement using superparamagnetic nanoparticles in ultra-low field MRI

June 5, 2018
Xiaolu Yin, Stephen E. Russek, Gary Zabow, Fan Sun, Jeotikanta Mohapatra, Kathryn E. Keenan, Michael A. Boss, Hao Zeng, Sy-Hwang Liou, John M. Moreland
Superparamagnetic iron oxide nanoparticles (SPIONs) are widely investigated and utilized as magnetic resonance imaging (MRI) contrast and therapy agents due to their large magnetic moments. Local field inhomogeneities caused by these high magnetic moments

Magnetic Resonance Imaging Biomarker Calibration Service: Proton Spin Relaxation Times

May 3, 2018
Michael A. Boss, Andrew M. Dienstfrey, Zydrunas Gimbutas, Kathryn E. Keenan, Jolene D. Splett, Karl F. Stupic, Stephen E. Russek
This document describes the calibration service to measure proton spin relaxation times, T1 and T2, of materials used in phantoms (calibration artifacts) to verify the accuracy of MRI-based quantitative measurements. Proton spin relaxation times are used

Quantitative Magnetic Resonance Imaging Phantoms: A Review and the Need for a System Phantom

October 4, 2017
Kathryn E. Keenan, Maureen Ainslie, Alexander J. Barker, Michael A. Boss, Kim M. Cecil, Cecil Charles, Thomas L. Chenevert, Laurence Clarke, Jeffrey L. Evelhoch, Paul Finn, Guoying Liu, Stephen E. Russek, Karl F. Stupic, Joshua D. Trzasko, Chun Yuan, Jie Zheng
The MRI community is using quantitative mapping techniques to complement qualitative imaging. For quantitative imaging to reach its full potential, it is necessary to analyze measurements across systems and longitudinally. Clinical use of quantitative

Accuracy, repeatability and interplatform reproducibility measurements of T 1 quantification methods used for DCE-MRI: results from a multicenter phantom study.

August 16, 2017
Octavia Bane, Stefanie J. Hectors, Mathilde Wagner, Lori L. Arlinghaus, Madhava P. Aryal, Yue Cao, Thomas L. Chenevert, Fiona Fennessy, Wei Huang, Nola M. Hylton, Jayashree Kalpathy-Cramer, Katy Keenan, Dariya I. Malyarenko, Robert V. Mulkern, David C. Newitt, Stephen E. Russek, Karl Stupic, Michael A. Boss
Purpose: To determine the in vitro accuracy, test-retest repeatability, and interplatform reproducibility of T1 quantification protocols used for dynamic contrast-enhanced MRI at 1.5 and 3 T. Methods: A T1 phantom with 14 samples was imaged at eight

Accuracy of magnetic resonance based susceptibility measurements

February 6, 2017
Hannah E. Erdevig, Stephen E. Russek, Slavka Carnicka, Karl F. Stupic, Kathryn E. Keenan
Magnetic Resonance Imaging (MRI) is increasingly used to map the magnetic susceptibility of tissue to identify cerebral microbleeds associated with traumatic brain injury and pathological iron deposits associated with neurodegenerative diseases such as

A medical device-grade T1 and ECV phantom for global T1 mapping quality assurance - The T 1 Mapping and ECV Standardization in cardiovascular magnetic resonance (T1MES) program

September 22, 2016
Gabriella Captur, Peter Gatehouse, Katy Keenan, Friso Heslinga, Ruediger Bruehl, Marcel Prothmann, Martin J. Graves, Richard J. Eames, Camilla Torlasco, Giulia Benedetti, Jacqueline Donovan, Bernd Ittermann, Redha Boubertakh, Andrew Bathgate, Celine Royet, Wenjie Pang, Reza Nezafat, Michael Salerno, Peter Kellman, James C. Moon
Background: T1 mapping and extracellular volume (ECV) have the potential to guide patient care and serve as surrogate end-points in clinical trials, but measurements differ between cardiovascular magnetic resonance (CMR) scanners and pulse sequences. To

Comparison of T1 measurement using ISMRM/NIST system phantom

May 9, 2016
Kathryn E. Keenan, Karl F. Stupic, Michael A. Boss, Stephen E. Russek, Thomas L. Chenevert, Pottumarthi V. Prasad, Wilburn E. Reddick, Jie Zheng, Peng Hu, Edward F. Jackson
We used the ISMRM/NIST system phantom to assess variations of T1 measurements across MRI systems at 1.5 T and 3 T, to determine the repeatability and reproducibility of the T1 measurements. This study demonstrates that T1 variations from NMR-measured value

Variability and bias assessment in breast ADC measurement across multiple systems

February 29, 2016
Kathryn E. Keenan, Sheye O. Aliu, Lisa J. Wilmes, David C. Newitt, Ella F. Jones, Wen Li, Michael A. Boss, Karl F. Stupic, Stephen E. Russek, Nola M. Hylton
Purpose: To assess the ability of a recent, anatomically designed breast phantom incorporating T1 and diffusion elements to serve as a quality control device for quantitative comparison of apparent diffusion coefficient (ADC) measurements calculated from

Design of a breast phantom for quantitative MRI

January 1, 2016
Kathryn E. Keenan, Sheye O. Aliu, Lisa J. Wilmes, David C. Newitt, Ella F. Jones, Wen Li, Michael A. Boss, Nola M. Hylton
Purpose: We present a breast phantom designed to enable quantitative assessment of measurements of T1 relaxation time, apparent diffusion coefficient (ADC), and other attributes of breast tissue, with long-term support from a national metrology institute

A Design-of-Experiments Approach to FEM Uncertainty Analysis for Optimizing Magnetic Resonance Imaging RF Coil Design

October 10, 2014
Jeffrey T. Fong, Nathanael A. Heckert, James J. Filliben, Li Ma, Karl F. Stupic, Kathryn E. Keenan, Stephen E. Russek
Using the RF module of COMSOL, we compute the magnetic flux density norm (BN) profiles for frequencies in the 76 to 100 MHz range, inside of a prototype birdcage coil, courtesy of Japan's National Institute of Radiological Sciences (NIRS), loaded with a