Co-registration of optoacoustic tomography and magnetic resonance imaging data from murine tumour models
Michal R. Tomaszewski, Marcel Gehrung, Dominick McIntyre, Jonathan Disselhorst, and Sarah E. Bohndiek
CTranslational Imaging Biomarkers Department, Merck & Co.
Abstract
Optoacoustic Tomography (OT) is an emerging imaging modality which can provide valuable functional and molecular insight into the tumor, including blood oxygenation, perfusion, and exogenous contrast agent distribution. As OT becomes routinely used in preclinical models, understanding the relationship between optoacoustic and other imaging biomarkers in the context of the underlying tissue biology becomes vitally important. Complementary insight into the tumor vasculature and hypoxia can be gained using OT alongside magnetic resonance imaging (MRI)-based techniques. MRI can provide excellent anatomical information and explore multiple contrast mechanisms, with OT contributing superior sensitivity and functional capabilities. To evaluate the relative performance of the two modalities for physiological measurements and the relationship between the derived metrics co-registration of their output imaging data is required. To date, this posed a significant challenge due to differences in animal positioning during imaging and the resulting deformations. Here, we present an integrated framework for registration of OT and MR image data in mice. Our framework combines a novel MR animal holder, to improve animal positioning during imaging, and a landmark-based software co-registration algorithm. We demonstrate that our protocol significantly improves registration of both body and tumor contours between OT and MRI, enabling more precise multi-modal tumor characterization.