Multidirectional reception of photoacoustic signals for higher resolution imaging

The imaging of microvasculature of the synovial membrane is important for the early detection of rheumatoid arthritis (RA). Photoacoustic (PA) imaging is an imaging modality that is compatible with the advantages of high spatial resolution in optical imaging and high penetration depth in ultrasound imaging. Linear probes are mainly used in clinical PA imaging. However, it is difficult for linear probes to acquire the PA signal completely from a point sound source in tissue because the area for signal reception is limited. In the present study, high resolution PA imaging as proposed by receiving the PA signals with linear probes placed at multiple angles around the imaging target to generate a compound PA image. The proposed method was compared to the conventional method with a single linear probe by computer simulation and measurement. The proposed method showed significant improvement of resolution and contrast.