Real-time clinical clutter reduction in combined epi-optoacoustic and ultrasound imaging

Flexible imaging of the human body, a requirement for broad clinical application, is obtained by direct integration of optoacoustic (OA) imaging with echo ultrasound (US) in a multimodal epi-illumination system. Up to date, successful deep epi-OA imaging is difficult to achieve owing to clutter. Clutter signals arise from optical absorption in the region of tissue irradiation and strongly reduce contrast and imaging depth. Recently, we developed a displacement-compensated averaging (DCA) technique for clutter reduction based on the clutter decorrelation that occurs when palpating the tissue. To gain first clinical experience on the practical value of DCA, we implemented this technique in a combined clinical OA and US imaging system. Our experience with freehand scanning of human volunteers reveals that real-time feedback on the clutter-reduction outcome is a key factor for achieving superior contrast and imaging depth.