Imaging-based characterization of convective tissue properties

Fuentes, David; Thompson, Emily; Jacobsen, Megan C.; Crouch, A. Colleen; Layman, Rick R.; Rivière, Béatrice; Cressman, Erik N.K.

doi:10.1080/02656736.2020.1845403

Cited by 5 publications

(3 citation statements)

References 52 publications

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“…Nonlinear pyruvate-to-lactate conversion parameters such as from a Michaelis-Menten relationship may also be considered. Additional formulations may also consider the impact of blood flow in the simulations directly though Dirichlet boundary conditions, as convective transport through porous media 59 , or as a sophisticated 3D-1D coupling with vasculature treated as 1D curvilinear segments 60 , 61 .…”

Section: Discussionmentioning

confidence: 99%

Mutual-information based optimal experimental design for hyperpolarized $$^{13}$$C-pyruvate MRI

Jha,

Walker,

Mitchell

et al. 2023

Sci Rep

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A key parameter of interest recovered from hyperpolarized (HP) MRI measurements is the apparent pyruvate-to-lactate exchange rate, $$k_{{\textrm PL}}$$ k P L , for measuring tumor metabolism. This manuscript presents an information-theory-based optimal experimental design approach that minimizes the uncertainty in the rate parameter, $$k_{{\textrm PL}}$$ k P L , recovered from HP-MRI measurements. Mutual information is employed to measure the information content of the HP measurements with respect to the first-order exchange kinetics of the pyruvate conversion to lactate. Flip angles of the pulse sequence acquisition are optimized with respect to the mutual information. A time-varying flip angle scheme leads to a higher parameter optimization that can further improve the quantitative value of mutual information over a constant flip angle scheme. However, the constant flip angle scheme, 35 and 28 degrees for pyruvate and lactate measurements, leads to an accuracy and precision comparable to the variable flip angle schemes obtained from our method. Combining the comparable performance and practical implementation, optimized pyruvate and lactate flip angles of 35 and 28 degrees, respectively, are recommended.

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Section: Discussionmentioning

confidence: 99%

Mutual-information based optimal experimental design for hyperpolarized $$^{13}$$C-pyruvate MRI

Jha,

Walker,

Mitchell

et al. 2023

Sci Rep

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“…Intravascular, extracellular, and intracellular species may also be considered. Additional formulations may also consider the impact of blood flow in the simulations directly though Dirichlet boundary conditions, as convective transport through porous media [47], or as a sophisticated 3D-1D coupling with vasculature treated as 1D curvilinear segments [48,49].…”

Section: Discussionmentioning

confidence: 99%

Mutual-Information Based Optimal Experimental Design for Hyperpolarized $^{13}$C-Pyruvate MRI

Jha¹,

Walker²,

Mitchell³

et al. 2022

Preprint

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Background. Hyperpolarized (HP) 13 C-Pyruvate MR imaging provides unique information about metabolic alterations indicative of the aggressiveness of certain cancer types. The information content of the HP-MRI data is fundamentally limited by the physics and chemistry of specific processes that take place at an atomic scale during a well-defined chemical reaction. The HP signal (magnetization of pyruvate and lactate) is a fixed resource that is established at the polarizer and naturally decays over time, and cannot be renewed after injection. The signal is further reduced with every radio-frequency excitation by the MR pulse sequence. Therefore, optimal experimental design (OED) for data acquisition is fundamentally important. A key parameter of interest recovered from HP-MRI measurements is the apparent pyruvate-to-lactate exchange rate, kP L, for measuring tumor metabolism. This manuscript presents an information-theory-based OED approach that minimizes the uncertainty in the rate parameter, kP L, recovered from the HP-MRI measurements.Methods. Mutual information (MI) is a statistical property employed here to measure the information content of the HP measurements with respect to the first-order exchange kinetics of the pyruvate conversion to lactate. An optimal experimental design formulation based on the maximization of the mutual information as a function of the MRI design parameters is proposed. The optimized MRI design parameters include flip angles of the pulse sequence acquisition. Further, a spatially varying model (high-fidelity) based on the Block -Torrey equations is proposed and utilized as a control for the OED formulation.Results. Within the mutual-information-based optimal experimental design formulation, a time-varying flip angle scheme is seen to provide significant differences in the flip angles compared to when excitation angles are fixed to a constant value. The varying flip angle scheme leads to a higher parameter optimization that can further improve the quantitative value of mutual information over the constant flip angle scheme. However, the constant flip angle scheme leads to the best accuracy and precision when considering inference from noise-corrupted data. Conclusion.Results suggest that the mutual information-based optimal data acquisition strategy is likely to improve the precision of the measurements. For the particular MRI data examined here, pyruvate and lactate flip angles of 35 and 28 degrees, respectively, were the best choice in terms of accuracy and precision of the parameter recovery. Moreover, the recovery of rate parameter kP L from the data generated from the high-fidelity model highlights the influence of diffusion and strength of vascular source on the recovered rate parameter. Since the existing pharmacokinetic models for HP-MRI do not account for spatial variation, the optimized design parameters may not be fully optimal in a more general 3D setting.

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“…Characterizing and predicting the mechanical properties of soft tissues is critical to our understanding of health and disease [8,34,18]. These properties are often driven by soft tissues' complex, heterogeneous composition and structure [3,7,9]. That is, soft tissues are usually organized in layers with each layer showing distinct and spatially-varying properties.…”

Section: Introductionmentioning

confidence: 99%

The impact of thickness heterogeneity on soft tissue biomechanics: a novel measurement technique and a demonstration on heart valve tissue

Lin

Mathur

Malinowski

et al. 2022

Biomech Model Mechanobiol

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The mechanical properties of soft tissues are driven by their complex, heterogeneous composition and structure. Interestingly, studies of soft tissue biomechanics often ignore spatial heterogeneity. In our work, we are therefore interested in exploring the impact of tissue heterogeneity on the mechanical properties of soft tissues. Therein, we specifically focus on soft tissue heterogeneity arising from spatially-varying thickness. To this end, our first goal is to develop a non-destructive measurement technique that has a high spatial resolution, provides continuous thickness maps, and is fast. Our secondary goal is to demonstrate that including spatial variation in thickness is important to the accuracy of biomechanical analyses. To this end, we use mitral valve leaflet tissue as our model system. To attain our first goal, we identify a soft tissue-specific contrast protocol that enables thickness measurements

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Imaging-based characterization of convective tissue properties

Cited by 5 publications

References 52 publications

Mutual-information based optimal experimental design for hyperpolarized $$^{13}$$C-pyruvate MRI

Mutual-information based optimal experimental design for hyperpolarized $$^{13}$$C-pyruvate MRI

Mutual-Information Based Optimal Experimental Design for Hyperpolarized $^{13}$C-Pyruvate MRI

The impact of thickness heterogeneity on soft tissue biomechanics: a novel measurement technique and a demonstration on heart valve tissue

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