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Intratumor mapping of intracellular water lifetime: metabolic images of breast cancer?
Shutter-speed pharmacokinetic analysis of dynamic-contrast-enhanced (DCE)-MRI data allows evaluation of equilibrium inter-compartmental water interchange kinetics. The process measured here – transcytolemmal water exchange – is characterized by the mean intracellular water molecule lifetime (τ(i))....
Autores principales: | , , , , , , , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
BlackWell Publishing Ltd
2014
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4174415/ https://www.ncbi.nlm.nih.gov/pubmed/24798066 http://dx.doi.org/10.1002/nbm.3111 |
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author | Springer, Charles S Li, Xin Tudorica, Luminita A Oh, Karen Y Roy, Nicole Chui, Stephen Y-C Naik, Arpana M Holtorf, Megan L Afzal, Aneela Rooney, William D Huang, Wei |
author_facet | Springer, Charles S Li, Xin Tudorica, Luminita A Oh, Karen Y Roy, Nicole Chui, Stephen Y-C Naik, Arpana M Holtorf, Megan L Afzal, Aneela Rooney, William D Huang, Wei |
author_sort | Springer, Charles S |
collection | PubMed |
description | Shutter-speed pharmacokinetic analysis of dynamic-contrast-enhanced (DCE)-MRI data allows evaluation of equilibrium inter-compartmental water interchange kinetics. The process measured here – transcytolemmal water exchange – is characterized by the mean intracellular water molecule lifetime (τ(i)). The τ(i) biomarker is a true intensive property not accessible by any formulation of the tracer pharmacokinetic paradigm, which inherently assumes it is effectively zero when applied to DCE-MRI. We present population-averaged in vivo human breast whole tumor τ(i) changes induced by therapy, along with those of other pharmacokinetic parameters. In responding patients, the DCE parameters change significantly after only one neoadjuvant chemotherapy cycle: while K(trans) (measuring mostly contrast agent (CA) extravasation) and k(ep) (CA intravasation rate constant) decrease, τ(i) increases. However, high-resolution, (1 mm)(2), parametric maps exhibit significant intratumor heterogeneity, which is lost by averaging. A typical 400 ms τ(i) value means a trans-membrane water cycling flux of 10(13) H(2)O molecules s(−1)/cell for a 12 µm diameter cell. Analyses of intratumor variations (and therapy-induced changes) of τ(i) in combination with concomitant changes of v(e) (extracellular volume fraction) indicate that the former are dominated by alterations of the equilibrium cell membrane water permeability coefficient, P(W), not of cell size. These can be interpreted in light of literature results showing that τ(i) changes are dominated by a P(W)(active) component that reciprocally reflects the membrane driving P-type ATPase ion pump turnover. For mammalian cells, this is the Na(+),K(+)-ATPase pump. These results promise the potential to discriminate metabolic and microenvironmental states of regions within tumors in vivo, and their changes with therapy. |
format | Online Article Text |
id | pubmed-4174415 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2014 |
publisher | BlackWell Publishing Ltd |
record_format | MEDLINE/PubMed |
spelling | pubmed-41744152014-09-25 Intratumor mapping of intracellular water lifetime: metabolic images of breast cancer? Springer, Charles S Li, Xin Tudorica, Luminita A Oh, Karen Y Roy, Nicole Chui, Stephen Y-C Naik, Arpana M Holtorf, Megan L Afzal, Aneela Rooney, William D Huang, Wei NMR Biomed Research Articles Shutter-speed pharmacokinetic analysis of dynamic-contrast-enhanced (DCE)-MRI data allows evaluation of equilibrium inter-compartmental water interchange kinetics. The process measured here – transcytolemmal water exchange – is characterized by the mean intracellular water molecule lifetime (τ(i)). The τ(i) biomarker is a true intensive property not accessible by any formulation of the tracer pharmacokinetic paradigm, which inherently assumes it is effectively zero when applied to DCE-MRI. We present population-averaged in vivo human breast whole tumor τ(i) changes induced by therapy, along with those of other pharmacokinetic parameters. In responding patients, the DCE parameters change significantly after only one neoadjuvant chemotherapy cycle: while K(trans) (measuring mostly contrast agent (CA) extravasation) and k(ep) (CA intravasation rate constant) decrease, τ(i) increases. However, high-resolution, (1 mm)(2), parametric maps exhibit significant intratumor heterogeneity, which is lost by averaging. A typical 400 ms τ(i) value means a trans-membrane water cycling flux of 10(13) H(2)O molecules s(−1)/cell for a 12 µm diameter cell. Analyses of intratumor variations (and therapy-induced changes) of τ(i) in combination with concomitant changes of v(e) (extracellular volume fraction) indicate that the former are dominated by alterations of the equilibrium cell membrane water permeability coefficient, P(W), not of cell size. These can be interpreted in light of literature results showing that τ(i) changes are dominated by a P(W)(active) component that reciprocally reflects the membrane driving P-type ATPase ion pump turnover. For mammalian cells, this is the Na(+),K(+)-ATPase pump. These results promise the potential to discriminate metabolic and microenvironmental states of regions within tumors in vivo, and their changes with therapy. BlackWell Publishing Ltd 2014-07 2014-05-05 /pmc/articles/PMC4174415/ /pubmed/24798066 http://dx.doi.org/10.1002/nbm.3111 Text en © 2014 The Authors. NMR in Biomedicine published by John Wiley & Sons, Ltd. http://creativecommons.org/licenses/by-nc-nd/3.0/ This is an open access article under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non-commercial and no modifications or adaptations are made. |
spellingShingle | Research Articles Springer, Charles S Li, Xin Tudorica, Luminita A Oh, Karen Y Roy, Nicole Chui, Stephen Y-C Naik, Arpana M Holtorf, Megan L Afzal, Aneela Rooney, William D Huang, Wei Intratumor mapping of intracellular water lifetime: metabolic images of breast cancer? |
title | Intratumor mapping of intracellular water lifetime: metabolic images of breast cancer? |
title_full | Intratumor mapping of intracellular water lifetime: metabolic images of breast cancer? |
title_fullStr | Intratumor mapping of intracellular water lifetime: metabolic images of breast cancer? |
title_full_unstemmed | Intratumor mapping of intracellular water lifetime: metabolic images of breast cancer? |
title_short | Intratumor mapping of intracellular water lifetime: metabolic images of breast cancer? |
title_sort | intratumor mapping of intracellular water lifetime: metabolic images of breast cancer? |
topic | Research Articles |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4174415/ https://www.ncbi.nlm.nih.gov/pubmed/24798066 http://dx.doi.org/10.1002/nbm.3111 |
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