Kathryn E. Keenan

Physical Measurement Laboratory

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Karl F. Stupic

National Institute of Standards and Technology

Stephen E. Russek

National Institute of Standards and Technology

Michael A. Boss

American College of Radiology

Megan Poorman

University of Stavanger

Kalina V. Jordanova

Physical Measurement Laboratory

Michele N. Martin

National Institute of Standards and Technology

Stephen Ogier

National Institute of Standards and Technology

Mark A. Griswold

Case Western Reserve University

Lisa J. Wilmes

University of California, San Francisco

Andrew Dienstfrey

National Institute of Standards and Technology

Cooperative Institutions

Harvard University

National Institute of Standards and Technology

Massachusetts General Hospital

Physical Measurement Laboratory

University of California, San Francisco

National Institute of Standards

University College London

Stanford University

Athinoula A. Martinos Center for Biomedical Imaging

Resonance Research (United States)

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Comparison of T1 measurement using ISMRM/NIST system phantom | NIST

Kathryn E. Keenan Karl F. Stupic Michael A. Boss Stephen E. Russek Thomas L. Chenevert

NIST

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Citations (17)

Magnetic resonance imaging biomarker calibration service: proton spin relaxation times

Michael A. Boss Andrew Dienstfrey Zydrunas Gimbutas Kathryn E. Keenan A. B. Kos

Certain commercial entities, equipment, or materials may be identified in this document in order to describe an experimental procedural or concept adequately.Such identification is not intended to imply recommendation or

Proton magnetic resonance

10.6028/nist.sp.250-97

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Citations (18)

A Viscoelastic Constitutive Model Can Accurately Represent Entire Creep Indentation Tests of Human Patella Cartilage

Journal of Applied Biomechanics (2013)

Kathryn E. Keenan Saikat Pal Derek P. Lindsey Thor F. Besier Gary S. Beaupré

Cartilage material properties provide important insights into joint health, and cartilage material models are used in whole-joint finite element models. Although the biphasic model representing experimental creep indentation tests is commonly used to characterize cartilage, cartilage short-term response to loading is generally not characterized using the biphasic model. The purpose of this study was to determine the short-term and equilibrium material properties of human patella cartilage using a viscoelastic model representation of creep indentation tests. We performed 24 experimental creep indentation tests from 14 human patellar specimens ranging in age from 20 to 90 years (median age 61 years). We used a finite element model to reproduce the experimental tests and determined cartilage material properties from viscoelastic and biphasic representations of cartilage. The viscoelastic model consistently provided excellent representation of the short-term and equilibrium creep displacements. We determined initial elastic modulus, equilibrium elastic modulus, and equilibrium Poisson’s ratio using the viscoelastic model. The viscoelastic model can represent the short-term and equilibrium response of cartilage and may easily be implemented in whole-joint finite element models.

Indentation

10.1123/jab.29.3.292

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Citations (39)

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

Jeffrey T. Fong Nathanael A. Heckert James J. Filliben Li Ma Karl F. Stupic

NIST

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Breast Coil Optimization for Low Field MRI and future MR-guided Proton Therapy

IEEE Transactions on Biomedical Engineering (2024)

Torben P.P. Hornung Néha Koonjoo Sheng Shen Friderike K. Longarino Kathryn E. Keenan

Biomagnetism

10.1109/tbme.2024.3520895

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Comparison of Phase Estimation Methods for Quantitative Susceptibility Mapping Using a Rotating-Tube Phantom

Radiology Research and Practice (2021)

Kathryn E. Keenan Ben P. Berman Slávka Rýger Stephen E. Russek Wen‐Tung Wang

Quantitative Susceptibility Mapping (QSM) is an MRI tool with the potential to reveal pathological changes from magnetic susceptibility measurements. Before phase data can be used to recover susceptibility (

Δ χ

), the QSM process begins with two steps: data acquisition and phase estimation. We assess the performance of these steps, when applied without user intervention, on several variations of a phantom imaging task. We used a rotating-tube phantom with five tubes ranging from

Δ χ = 0.05

ppm to

Δ χ = 0.336

ppm. MRI data was acquired at nine angles of rotation for four different pulse sequences. The images were processed by 10 phase estimation algorithms including Laplacian, region-growing, branch-cut, temporal unwrapping, and maximum-likelihood methods, resulting in approximately 90 different combinations of data acquisition and phase estimation methods. We analyzed errors between measured and expected phases using the probability mass function and Cumulative Distribution Function. Repeatable acquisition and estimation methods were identified based on the probability of relative phase errors. For single-echo GRE and segmented EPI sequences, a region-growing method was most reliable with Pr (relative error <0.1) = 0.95 and 0.90, respectively. For multiecho sequences, a maximum-likelihood method was most reliable with Pr (relative error <0.1) = 0.97. The most repeatable multiecho methods outperformed the most repeatable single-echo methods. We found a wide range of repeatability and reproducibility for off-the-shelf MRI acquisition and phase estimation approaches, and this variability may prevent the techniques from being widely integrated in clinical workflows. The error was dominated in many cases by spatially discontinuous phase unwrapping errors. Any postprocessing applied on erroneous phase estimates, such as QSM’s background field removal and dipole inversion, would suffer from error propagation. Our paradigm identifies methods that yield consistent and accurate phase estimates that would ultimately yield consistent and accurate

Δ χ

estimates.

Quantitative Susceptibility Mapping

10.1155/2021/1898461

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Development of a musculoskeletal relaxometry phantom for T1, T2, and T1rho measurements

Proceedings on CD-ROM - International Society for Magnetic Resonance in Medicine. Scientific Meeting and Exhibition/Proceedings of the International Society for Magnetic Resonance in Medicine, Scientific Meeting and Exhibition (2024)

Jeehun Kim Stephen E. Russek Karl F. Stupic Cassandra Stoffer Kathryn E. Keenan

Motivation: There is not a commercially available musculoskeletal (MSK) relaxometry phantom. Goal(s): Develop a dedicated MSK relaxometry phantom for T1, T2, and T1rho measurement quality assurance. Approach: A cylindrical phantom with 12 vials containing modulated T1 and T2 samples was created, with an MR-visible thermometer for temperature tracking. Phantom stands were used for consistent positioning. MRI/NMR measurements were collected for longitudinal stability and temperature dependence. Results: MRI measurements were in good agreement between two vendors with CVs<3% and demonstrated longitudinal stability with CVs<3% over a 3-month period. NMR measurements showed clear changes in T1, T2, and T1rho with changing temperature. Impact: A stable MSK relaxometry phantom prototype was successfully developed and characterized, including changes with temperature. With harmonized measurement protocols, this phantom will facilitate the use of quantitative relaxometry MRI in large-scale multi-site multi-vendor trials.

10.58530/2024/1317

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Multi-site, longitudinal assessment of quantitative breast MRI variability using the CaliberMRI phantom

Jessica Gibbs Nu N. Le T. Karaulanov Lisa J. Wilmes David C. Newitt

Quantitative breast MRI data was acquired at seven clinical sites using the CaliberMRI phantom. T1 and DWI data were acquired, and the qCal software was used for analysis. Protocol adherence was assessed, quantitative measures were automatically derived, and variability between measurements was evaluated. Going forward, the phantom will be used for calibration as part of a program to assess quantitative accuracy in a large multi-site clinical trial. The phantom program will be expanded to other sites in the trial, with standardized reporting used to understand variability across sites.

10.58530/2022/3995

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Real-time automated quality control for quantitative MRI

Magnetic Resonance Materials in Physics Biology and Medicine (2024)

Andrew Dupuis Rasim Boyacıoğlu Kathryn E. Keenan Mark A. Griswold

10.1007/s10334-024-01205-3

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Color-map recommendation for MR relaxometry maps

arXiv (Cornell University) (2024)

Miha Fuderer Barbara Wichtmann Fabio Crameri Nandita M. deSouza Bettina Baeßler

Purpose: To harmonize the use of color for MR relaxometry maps and therefore recommend the use of specific color-maps for representing T1 and T2 maps. Methods: Perceptually linearized color-maps were chosen to have similar color settings as those proposed by Griswold et al. in 2018. A Delphi process, polling the opinion of a panel of 81 experts, was used to generate consensus on the suitability of these maps. Results: Consensus was reached on the suitability of the logarithm-processed Lipari color-map for T1 and the logarithm-processed Navia color-map for T2. There was consensus on color bars being mandatory and on the use of a specific value indicating invalidity. There was no consensus on whether the ranges should be fixed per anatomy. Conclusion: The authors recommend the use of the logarithm-processed Lipari color map for displaying quantitative T1 maps and R1 maps; likewise, the authors recommend the logarithm-processed Navia color-map for displaying T2, T2*, R2 and R2* maps.

10.48550/arxiv.2407.03906

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Citations (2)