Investigation of the effects of multi-angle compounding in photoacoustic imaging

The signal-to-noise ratio (SNR) of photoacoustic (PA) images of carotid arteries is considerably low for in vivo measurements. Compounding of the acquisitions from multiple locations might improve SNR of PA images. In this study, we investigated the effects of spatial compounding based on SNR comparison of PA images of a polyvinyl alcohol (PVA) phantom and an ex vivo carotid plaque, both imaged in an experimental setting. PA and plane wave ultrasound (PUS) data were acquired in a cross-section of each sample. The sample was rotated by 10° and measurements were repeated for 36 angles. Results showed that PA compounding elevated the SNR by 28.7±5.1 dB for the PVA sample and 5.5±2.4 dB for the plaque sample. Additionally, the compounding results for the limited range of rotation as would be feasible in vivo ( −30 to +30) showed an enhancement in SNR of 7.02 ± 2.73 dB. For the future, extra characterization parameters such as resolution, contrast, and sensitivity will be investigated under in vivo conditions.