Spherical-view photoacoustic tomography for monitoring in vivo placental function

• Main Authors: Kristie Huda, Chengxi Wu, Jaclyn G. Sider, Carolyn L. Bayer
• Format: Article
• Language: English
• Published: Elsevier 2020-12-01
• Series: Photoacoustics
• Subjects: Photoacoustic tomography; Functional imaging; Contrast agents; Placenta; Spherical tomography; Small animal imaging
• Online Access: http://www.sciencedirect.com/science/article/pii/S2213597920300495

Photoacoustic tomography has great potential to image dynamic functional changes in vivo. Many tomographic systems are built with a circular view geometry, necessitating a linear translation along one axis of the subject to obtain a three-dimensional volume. In this work, we evaluated a prototype spherical view photoacoustic tomographic system which acquires a 3D volume in a single scan, without linear translation. We simultaneously measured relative hemoglobin oxygen saturation in multiple placentas of pregnant mice under oxygen challenge. We also synthesized a folate-conjugated indocyanine green (ICG) contrast agent to image folate kinetics in the placenta. Photoacoustic tomography performed at the wavelength of peak optical absorption of our contrast agent revealed increased ICG signal over time. Through these phantom and in vivo studies, we have demonstrated that the spherical view 3D photoacoustic tomographic system achieves high sensitivity and fast image acquisition, enabling in vivo experiments to assess physiological and molecular dynamics.