The Experts below are selected from a list of 60 Experts worldwide ranked by ideXlab platform

Christopher T Rodgers - One of the best experts on this subject based on the ideXlab platform.

  • rapid b1 insensitive dual band quasi Adiabatic Saturation transfer with optimal control for complete quantification of myocardial atp flux
    Magnetic Resonance in Medicine, 2021
    Co-Authors: Jack J Miller, Ladislav Valkovic, M Kerr, Kerstin N Timm, William Watson, Andrew Tyler, Lau Jyc, Christopher T Rodgers
    Abstract:

    PURPOSE Phosphorus Saturation-transfer experiments can quantify metabolic fluxes noninvasively. Typically, the forward flux through the creatine kinase reaction is investigated by observing the decrease in phosphocreatine (PCr) after Saturation of γ-ATP. The quantification of total ATP utilization is currently underexplored, as it requires simultaneous Saturation of inorganic phosphate ( Pi ) and PCr. This is challenging, as currently available Saturation pulses reduce the already-low γ-ATP signal present. METHODS Using a hybrid optimal-control and Shinnar-Le Roux method, a quasi-Adiabatic RF pulse was designed for the dual Saturation of PCr and Pi to enable determination of total ATP utilization. The pulses were evaluated in Bloch equation simulations, compared with a conventional hard-cosine DANTE Saturation sequence, before being applied to perfused rat hearts at 11.7 T. RESULTS The quasi-Adiabatic pulse was insensitive to a >2.5-fold variation in B1 , producing equivalent Saturation with a 53% reduction in delivered pulse power and a 33-fold reduction in spillover at the minimum effective B1 . This enabled the complete quantification of the synthesis and degradation fluxes for ATP in 30-45 minutes in the perfused rat heart. While the net synthesis flux (4.24 ± 0.8 mM/s, SEM) was not significantly different from degradation flux (6.88 ± 2 mM/s, P = .06) and both measures are consistent with prior work, nonlinear error analysis highlights uncertainties in the Pi -to-ATP measurement that may explain a trend suggesting a possible imbalance. CONCLUSIONS This work demonstrates a novel quasi-Adiabatic dual-Saturation RF pulse with significantly improved performance that can be used to measure ATP turnover in the heart in vivo.

  • rapid b_1 insensitive dual band quasi Adiabatic Saturation transfer with optimal control for complete quantification of myocardial atp flux
    arXiv: Medical Physics, 2020
    Co-Authors: Jack J Miller, Ladislav Valkovic, M Kerr, Kerstin N Timm, William Watson, Justin Y C Lau, Andrew Tyler, Christopher T Rodgers, Paul A Bottomley, Lisa C Heather
    Abstract:

    Purpose: Phosphorus Saturation-transfer experiments can quantify metabolic fluxes non-invasively. Typically, the forward flux through the creatine-kinase reaction is investigated by observing the decrease in phosphocreatine (PCr) after Saturation of $\gamma$-ATP. The quantification of total ATP utilisation is currently under-explored, as it requires simultaneous Saturation of inorganic phosphate (Pi) and PCr. This is challenging, as currently available Saturation pulses reduce the already-low $\gamma$-ATP signal present. Methods: Using a hybrid optimal-control and Shinnar-Le-Roux method, a quasi-Adiabatic RF pulse was designed for the dual-Saturation of PCr and Pi to enable determination of total ATP utilisation. The pulses were evaluated in Bloch equation simulations, compared with a conventional hard-cosine DANTE Saturation sequence, before application to perfused rat hearts at 11.7 Tesla. Results: The quasi-Adiabatic pulse was insensitive to a $>2.5$-fold variation in $B_1$, producing equivalent Saturation with a 53% reduction in delivered pulse power and a 33-fold reduction in spillover at the minimum effective $B_1$. This enabled the complete quantification of the synthesis and degradation fluxes for ATP in 30-45 minutes in the perfused rat heart. While the net synthesis flux ($3.3\pm0.4$ mM/s, SEM) was not significantly different from degradation flux ($8\pm2$ mM/s) and both measures are consistent with prior work, nonlinear error analysis highlights uncertainties in the Pi-to-ATP measurement that may explain the possible imbalance. Conclusion: This work demonstrates a novel quasi-Adiabatic dual-Saturation RF pulse with significantly improved performance that can be used to measure ATP turnover in the heart in vivo.

Andrew Tyler - One of the best experts on this subject based on the ideXlab platform.

  • rapid b1 insensitive dual band quasi Adiabatic Saturation transfer with optimal control for complete quantification of myocardial atp flux
    Magnetic Resonance in Medicine, 2021
    Co-Authors: Jack J Miller, Ladislav Valkovic, M Kerr, Kerstin N Timm, William Watson, Andrew Tyler, Lau Jyc, Christopher T Rodgers
    Abstract:

    PURPOSE Phosphorus Saturation-transfer experiments can quantify metabolic fluxes noninvasively. Typically, the forward flux through the creatine kinase reaction is investigated by observing the decrease in phosphocreatine (PCr) after Saturation of γ-ATP. The quantification of total ATP utilization is currently underexplored, as it requires simultaneous Saturation of inorganic phosphate ( Pi ) and PCr. This is challenging, as currently available Saturation pulses reduce the already-low γ-ATP signal present. METHODS Using a hybrid optimal-control and Shinnar-Le Roux method, a quasi-Adiabatic RF pulse was designed for the dual Saturation of PCr and Pi to enable determination of total ATP utilization. The pulses were evaluated in Bloch equation simulations, compared with a conventional hard-cosine DANTE Saturation sequence, before being applied to perfused rat hearts at 11.7 T. RESULTS The quasi-Adiabatic pulse was insensitive to a >2.5-fold variation in B1 , producing equivalent Saturation with a 53% reduction in delivered pulse power and a 33-fold reduction in spillover at the minimum effective B1 . This enabled the complete quantification of the synthesis and degradation fluxes for ATP in 30-45 minutes in the perfused rat heart. While the net synthesis flux (4.24 ± 0.8 mM/s, SEM) was not significantly different from degradation flux (6.88 ± 2 mM/s, P = .06) and both measures are consistent with prior work, nonlinear error analysis highlights uncertainties in the Pi -to-ATP measurement that may explain a trend suggesting a possible imbalance. CONCLUSIONS This work demonstrates a novel quasi-Adiabatic dual-Saturation RF pulse with significantly improved performance that can be used to measure ATP turnover in the heart in vivo.

  • rapid b_1 insensitive dual band quasi Adiabatic Saturation transfer with optimal control for complete quantification of myocardial atp flux
    arXiv: Medical Physics, 2020
    Co-Authors: Jack J Miller, Ladislav Valkovic, M Kerr, Kerstin N Timm, William Watson, Justin Y C Lau, Andrew Tyler, Christopher T Rodgers, Paul A Bottomley, Lisa C Heather
    Abstract:

    Purpose: Phosphorus Saturation-transfer experiments can quantify metabolic fluxes non-invasively. Typically, the forward flux through the creatine-kinase reaction is investigated by observing the decrease in phosphocreatine (PCr) after Saturation of $\gamma$-ATP. The quantification of total ATP utilisation is currently under-explored, as it requires simultaneous Saturation of inorganic phosphate (Pi) and PCr. This is challenging, as currently available Saturation pulses reduce the already-low $\gamma$-ATP signal present. Methods: Using a hybrid optimal-control and Shinnar-Le-Roux method, a quasi-Adiabatic RF pulse was designed for the dual-Saturation of PCr and Pi to enable determination of total ATP utilisation. The pulses were evaluated in Bloch equation simulations, compared with a conventional hard-cosine DANTE Saturation sequence, before application to perfused rat hearts at 11.7 Tesla. Results: The quasi-Adiabatic pulse was insensitive to a $>2.5$-fold variation in $B_1$, producing equivalent Saturation with a 53% reduction in delivered pulse power and a 33-fold reduction in spillover at the minimum effective $B_1$. This enabled the complete quantification of the synthesis and degradation fluxes for ATP in 30-45 minutes in the perfused rat heart. While the net synthesis flux ($3.3\pm0.4$ mM/s, SEM) was not significantly different from degradation flux ($8\pm2$ mM/s) and both measures are consistent with prior work, nonlinear error analysis highlights uncertainties in the Pi-to-ATP measurement that may explain the possible imbalance. Conclusion: This work demonstrates a novel quasi-Adiabatic dual-Saturation RF pulse with significantly improved performance that can be used to measure ATP turnover in the heart in vivo.

Jack J Miller - One of the best experts on this subject based on the ideXlab platform.

  • rapid b1 insensitive dual band quasi Adiabatic Saturation transfer with optimal control for complete quantification of myocardial atp flux
    Magnetic Resonance in Medicine, 2021
    Co-Authors: Jack J Miller, Ladislav Valkovic, M Kerr, Kerstin N Timm, William Watson, Andrew Tyler, Lau Jyc, Christopher T Rodgers
    Abstract:

    PURPOSE Phosphorus Saturation-transfer experiments can quantify metabolic fluxes noninvasively. Typically, the forward flux through the creatine kinase reaction is investigated by observing the decrease in phosphocreatine (PCr) after Saturation of γ-ATP. The quantification of total ATP utilization is currently underexplored, as it requires simultaneous Saturation of inorganic phosphate ( Pi ) and PCr. This is challenging, as currently available Saturation pulses reduce the already-low γ-ATP signal present. METHODS Using a hybrid optimal-control and Shinnar-Le Roux method, a quasi-Adiabatic RF pulse was designed for the dual Saturation of PCr and Pi to enable determination of total ATP utilization. The pulses were evaluated in Bloch equation simulations, compared with a conventional hard-cosine DANTE Saturation sequence, before being applied to perfused rat hearts at 11.7 T. RESULTS The quasi-Adiabatic pulse was insensitive to a >2.5-fold variation in B1 , producing equivalent Saturation with a 53% reduction in delivered pulse power and a 33-fold reduction in spillover at the minimum effective B1 . This enabled the complete quantification of the synthesis and degradation fluxes for ATP in 30-45 minutes in the perfused rat heart. While the net synthesis flux (4.24 ± 0.8 mM/s, SEM) was not significantly different from degradation flux (6.88 ± 2 mM/s, P = .06) and both measures are consistent with prior work, nonlinear error analysis highlights uncertainties in the Pi -to-ATP measurement that may explain a trend suggesting a possible imbalance. CONCLUSIONS This work demonstrates a novel quasi-Adiabatic dual-Saturation RF pulse with significantly improved performance that can be used to measure ATP turnover in the heart in vivo.

  • rapid b_1 insensitive dual band quasi Adiabatic Saturation transfer with optimal control for complete quantification of myocardial atp flux
    arXiv: Medical Physics, 2020
    Co-Authors: Jack J Miller, Ladislav Valkovic, M Kerr, Kerstin N Timm, William Watson, Justin Y C Lau, Andrew Tyler, Christopher T Rodgers, Paul A Bottomley, Lisa C Heather
    Abstract:

    Purpose: Phosphorus Saturation-transfer experiments can quantify metabolic fluxes non-invasively. Typically, the forward flux through the creatine-kinase reaction is investigated by observing the decrease in phosphocreatine (PCr) after Saturation of $\gamma$-ATP. The quantification of total ATP utilisation is currently under-explored, as it requires simultaneous Saturation of inorganic phosphate (Pi) and PCr. This is challenging, as currently available Saturation pulses reduce the already-low $\gamma$-ATP signal present. Methods: Using a hybrid optimal-control and Shinnar-Le-Roux method, a quasi-Adiabatic RF pulse was designed for the dual-Saturation of PCr and Pi to enable determination of total ATP utilisation. The pulses were evaluated in Bloch equation simulations, compared with a conventional hard-cosine DANTE Saturation sequence, before application to perfused rat hearts at 11.7 Tesla. Results: The quasi-Adiabatic pulse was insensitive to a $>2.5$-fold variation in $B_1$, producing equivalent Saturation with a 53% reduction in delivered pulse power and a 33-fold reduction in spillover at the minimum effective $B_1$. This enabled the complete quantification of the synthesis and degradation fluxes for ATP in 30-45 minutes in the perfused rat heart. While the net synthesis flux ($3.3\pm0.4$ mM/s, SEM) was not significantly different from degradation flux ($8\pm2$ mM/s) and both measures are consistent with prior work, nonlinear error analysis highlights uncertainties in the Pi-to-ATP measurement that may explain the possible imbalance. Conclusion: This work demonstrates a novel quasi-Adiabatic dual-Saturation RF pulse with significantly improved performance that can be used to measure ATP turnover in the heart in vivo.

Lisa C Heather - One of the best experts on this subject based on the ideXlab platform.

  • rapid b_1 insensitive dual band quasi Adiabatic Saturation transfer with optimal control for complete quantification of myocardial atp flux
    arXiv: Medical Physics, 2020
    Co-Authors: Jack J Miller, Ladislav Valkovic, M Kerr, Kerstin N Timm, William Watson, Justin Y C Lau, Andrew Tyler, Christopher T Rodgers, Paul A Bottomley, Lisa C Heather
    Abstract:

    Purpose: Phosphorus Saturation-transfer experiments can quantify metabolic fluxes non-invasively. Typically, the forward flux through the creatine-kinase reaction is investigated by observing the decrease in phosphocreatine (PCr) after Saturation of $\gamma$-ATP. The quantification of total ATP utilisation is currently under-explored, as it requires simultaneous Saturation of inorganic phosphate (Pi) and PCr. This is challenging, as currently available Saturation pulses reduce the already-low $\gamma$-ATP signal present. Methods: Using a hybrid optimal-control and Shinnar-Le-Roux method, a quasi-Adiabatic RF pulse was designed for the dual-Saturation of PCr and Pi to enable determination of total ATP utilisation. The pulses were evaluated in Bloch equation simulations, compared with a conventional hard-cosine DANTE Saturation sequence, before application to perfused rat hearts at 11.7 Tesla. Results: The quasi-Adiabatic pulse was insensitive to a $>2.5$-fold variation in $B_1$, producing equivalent Saturation with a 53% reduction in delivered pulse power and a 33-fold reduction in spillover at the minimum effective $B_1$. This enabled the complete quantification of the synthesis and degradation fluxes for ATP in 30-45 minutes in the perfused rat heart. While the net synthesis flux ($3.3\pm0.4$ mM/s, SEM) was not significantly different from degradation flux ($8\pm2$ mM/s) and both measures are consistent with prior work, nonlinear error analysis highlights uncertainties in the Pi-to-ATP measurement that may explain the possible imbalance. Conclusion: This work demonstrates a novel quasi-Adiabatic dual-Saturation RF pulse with significantly improved performance that can be used to measure ATP turnover in the heart in vivo.

M Kerr - One of the best experts on this subject based on the ideXlab platform.

  • rapid b1 insensitive dual band quasi Adiabatic Saturation transfer with optimal control for complete quantification of myocardial atp flux
    Magnetic Resonance in Medicine, 2021
    Co-Authors: Jack J Miller, Ladislav Valkovic, M Kerr, Kerstin N Timm, William Watson, Andrew Tyler, Lau Jyc, Christopher T Rodgers
    Abstract:

    PURPOSE Phosphorus Saturation-transfer experiments can quantify metabolic fluxes noninvasively. Typically, the forward flux through the creatine kinase reaction is investigated by observing the decrease in phosphocreatine (PCr) after Saturation of γ-ATP. The quantification of total ATP utilization is currently underexplored, as it requires simultaneous Saturation of inorganic phosphate ( Pi ) and PCr. This is challenging, as currently available Saturation pulses reduce the already-low γ-ATP signal present. METHODS Using a hybrid optimal-control and Shinnar-Le Roux method, a quasi-Adiabatic RF pulse was designed for the dual Saturation of PCr and Pi to enable determination of total ATP utilization. The pulses were evaluated in Bloch equation simulations, compared with a conventional hard-cosine DANTE Saturation sequence, before being applied to perfused rat hearts at 11.7 T. RESULTS The quasi-Adiabatic pulse was insensitive to a >2.5-fold variation in B1 , producing equivalent Saturation with a 53% reduction in delivered pulse power and a 33-fold reduction in spillover at the minimum effective B1 . This enabled the complete quantification of the synthesis and degradation fluxes for ATP in 30-45 minutes in the perfused rat heart. While the net synthesis flux (4.24 ± 0.8 mM/s, SEM) was not significantly different from degradation flux (6.88 ± 2 mM/s, P = .06) and both measures are consistent with prior work, nonlinear error analysis highlights uncertainties in the Pi -to-ATP measurement that may explain a trend suggesting a possible imbalance. CONCLUSIONS This work demonstrates a novel quasi-Adiabatic dual-Saturation RF pulse with significantly improved performance that can be used to measure ATP turnover in the heart in vivo.

  • rapid b_1 insensitive dual band quasi Adiabatic Saturation transfer with optimal control for complete quantification of myocardial atp flux
    arXiv: Medical Physics, 2020
    Co-Authors: Jack J Miller, Ladislav Valkovic, M Kerr, Kerstin N Timm, William Watson, Justin Y C Lau, Andrew Tyler, Christopher T Rodgers, Paul A Bottomley, Lisa C Heather
    Abstract:

    Purpose: Phosphorus Saturation-transfer experiments can quantify metabolic fluxes non-invasively. Typically, the forward flux through the creatine-kinase reaction is investigated by observing the decrease in phosphocreatine (PCr) after Saturation of $\gamma$-ATP. The quantification of total ATP utilisation is currently under-explored, as it requires simultaneous Saturation of inorganic phosphate (Pi) and PCr. This is challenging, as currently available Saturation pulses reduce the already-low $\gamma$-ATP signal present. Methods: Using a hybrid optimal-control and Shinnar-Le-Roux method, a quasi-Adiabatic RF pulse was designed for the dual-Saturation of PCr and Pi to enable determination of total ATP utilisation. The pulses were evaluated in Bloch equation simulations, compared with a conventional hard-cosine DANTE Saturation sequence, before application to perfused rat hearts at 11.7 Tesla. Results: The quasi-Adiabatic pulse was insensitive to a $>2.5$-fold variation in $B_1$, producing equivalent Saturation with a 53% reduction in delivered pulse power and a 33-fold reduction in spillover at the minimum effective $B_1$. This enabled the complete quantification of the synthesis and degradation fluxes for ATP in 30-45 minutes in the perfused rat heart. While the net synthesis flux ($3.3\pm0.4$ mM/s, SEM) was not significantly different from degradation flux ($8\pm2$ mM/s) and both measures are consistent with prior work, nonlinear error analysis highlights uncertainties in the Pi-to-ATP measurement that may explain the possible imbalance. Conclusion: This work demonstrates a novel quasi-Adiabatic dual-Saturation RF pulse with significantly improved performance that can be used to measure ATP turnover in the heart in vivo.