Rapid scanning wide-field clutter elimination in epi-optoacoustic imaging using comb LOVIT

Reducing artifacts in photoacoustic imaging by using multi-wavelength excitation and transducer displacement

The occurrence of artifacts is a major challenge in photoacoustic imaging. The artifacts negatively affect the quality and reliability of the images. An approach using multi-wavelength excitation has previously been reported for in-plane artifact identification. Yet, out-of-plane artifacts cannot be tackled with this method. Here we propose a new method using ultrasound transducer array displacement. By displacing the ultrasound transducer array axially, we can de-correlate out-of-plane artifacts with in-plane image features and thus remove them. Combining this new method with the previous one allows us to remove potentially completely both in-plane and out-of-plane artifacts in photoacoustic imaging. We experimentally demonstrate this with experiments in phantoms as well as in vivo.

Reflection artifact identification in photoacoustic imaging using multi-wavelength excitation

Photoacoustic imaging has been a focus of research for clinical applications owing to its ability for deep visualization with optical absorption contrast. However, there are various technical challenges remaining for this technique to find its place in clinics. One of the challenges is the occurrence of reflection artifacts. The reflection artifacts may lead to image misinterpretation. Here we propose a new method using multiple wavelengths for identifying and removing the reflection artifacts. By imaging the sample with multiple wavelengths, the spectral response of the features in the photoacoustic image is obtained. We assume that the spectral response of the reflection artifact is better correlated with the proper image feature of its corresponding absorber than with other features in the image. Based on this, the reflection artifacts can be identified and removed. Here, we experimentally demonstrated the potential of this method for real-time identification and correction of reflection artifacts in photoacoustic images in phantoms as well as in vivo using a handheld photoacoustic imaging probe.