Interdisciplinary Coupled Physic Imaging

This is a follow up initiative of the outgoing interdisciplinary Austrian excellence program NFN on Photoacoustic Imaging in Biology and Medicine, (http://www.csc.univie.ac.at/pai/), which is ending in March 2014. The new proposal is again interdisciplinary, widens the scope, and focuses on up-to-date research topics in Coupled Physics Imaging (CPI). The proposal involves research groups from Applied Mathematics, Biology and Medical Physics, which have already been successfully collaborating in the NFN. In particular, due to the expert knowledge of our team, we consider now groundbreaking topics in CPI, such as combinations of OCT, Photoacoustics, and Elastography. It is a fact that most experimental realization in CPI rely on very basic mathematical models. Overall, these simplifications of assumptions limit the resolution and imaging quality. In this proposal we show that advanced mathematical modeling can be experimentally realized to improve the image quality, can decrease the acquisition time, leads to new experimental realizations, and even allows for recovery of hidden parameters. As we show in the detailed description of the working modules below, we will discover, because we already have done so, surprising, and sometimes counter-intuitive, facts about resolution and recovery processes.

This interdisciplinary project between the Computational Science Center of the University Vienna and the Center for Medical Physics and Biomedical Engineering of the Medical University of Vienna analyses the possibilities of Optical Coherence Tomography (OCT) and Photoacoustic Tomography (PAT) for investigating microscopic data.The main objective of our research has been on the quantitative analysis and the combined use of these modalities.Already at the beginning of the project we had a multi-modal measurement device available, which performs OCT and PAT measurements in parallel. At the beginning of the project this device was internationally exclusively available in Vienna, which brought us an enormous scientific benefit and stimulus for further theoretical mathematical, transclinical and medical research. In the meantime the measurement device has been made insofar transportable that multi-modal medical investigations can be made with patients (for example at the skin).During the project we developed a number of possibilities for visualization of quantitative physical parameters (such as sound speed or compressibility) of the medium of interest. With a single modality alone these parameters cannot be visualized, and therefore are not available for a medical diagnosis. With the developed quantitative methods multi-modal quantitative Elastography has turned out to be very promising for medical applications. Thereby, based on the analysis of the visualized induced displacements (computed with the optical flow) in the medium to be analyzed, we perform a quantitative analysis of the physical parameters of the medium, such as stiffness, with methods of Computational Inverse Problems. For such a workflow one needs a sequence of complementing modalities and the evaluation of the data requires advanced computational methods of Computer Vision and Computational Inverse Problems. First practical experiments with elastic and visco-elastic test materials (for example agarose and silicon) for quantitative multi-modal Elastography are very promising.