Recommended Citation
Lee, C.-W., Stantz, K.M. Development of a mathematical model to estimate intra-tumor oxygen concentrations through multi-parametric imaging. BioMedical Engineering Online Volume 15, Issue 1, 12 October 2016, Article number 114
DOI
10.1186/s12938-016-0235-5
Date of this Version
10-2016
Keywords
Multi-variate Krogh model, In vivo functional imaging, Dynamic contrast enhanced computed tomography, Photoacoustic spectroscopy
Abstract
Background
Tumor hypoxia is involved in every stage of solid tumor development: formation, progression, metastasis, and apoptosis. Two types of hypoxia exist in tumors—chronic hypoxia and acute hypoxia. Recent studies indicate that the regional hypoxia kinetics is closely linked to metastasis and therapeutic responses, but regional hypoxia kinetics is hard to measure. We propose a novel approach to determine the local pO2 by fusing the parameters obtained from in vivo functional imaging through the use of a modified multivariate Krogh model.
Methods
To test our idea and its potential to translate into an in vivo setting through the use of existing imaging techniques, simulation studies were performed comparing the local partial oxygen pressure (pO2) from the proposed multivariate image fusion model to the referenced pO2 derived by Green’s function, which considers the contribution from every vessel segment of an entire three-dimensional tumor vasculature to profile tumor oxygen with high spatial resolution.
Results
pO2 derived from our fusion approach were close to the referenced pO2 with regression slope near 1.0 and an r2 higher than 0.8 if the voxel size (or the spatial resolution set by functional imaging modality) was less than 200 μm. The simulation also showed that the metabolic rate, blood perfusion, and hemoglobin concentration were dominant factors in tissue oxygenation. The impact of the measurement error of functional imaging to the pO2 precision and accuracy was simulated. A Gaussian error function with FWHM equal to 20 % of blood perfusion or fractional vascular volume measurement contributed to average 7 % statistical error in pO2.
Conclusion
The simulation results indicate that the fusion of multiple parametric maps through the biophysically derived mathematical models can monitor the intra-tumor spatial variations of hypoxia in tumors with existing imaging methods, and the potential to further investigate different forms of hypoxia, such as chronic and acute hypoxia, in response to cancer therapies.
Comments
Lee, C.-W., Stantz, K.M. Development of a mathematical model to estimate intra-tumor oxygen concentrations through multi-parametric imaging. BioMedical Engineering Online Volume 15, Issue 1, 12 October 2016, Article number 114.
(CC BY 4.0)