Opto-Acoustic Image Reconstruction and Motion Tracking Using Convex Optimization

Abstract

Opto-acoustic imaging systems detect acoustic waves produced by optical absorption to visualize molecular contrast in biological tissue. This permits non-invasive vascular assessment of benign and malignant tumors. In this article, we describe a framework to iteratively determine the motion of an opto-acoustic probe during a minimization-based image reconstruction process. The probe emits light and uses an ultrasonic transducer array to acquire data for cross-sectional slices of tissue. To improve visibility, our technique uses multiple 2D slices to perform 3D volumetric reconstruction. Our model includes wavelength-specific optical absorption, position-dependent illumination and a realistic transducer element geometry. We investigate this technique using simulated, experimentally collected, and clinically acquired data. By performing 3D image reconstruction on a digital phantom, we demonstrate estimation of elevational probe motion without external sensors. We compare images of a benign lesion from a clinical breast imaging study and observe significant artifact reduction and contrast-to-background ratio improvement using our technique. The approach has potential to improve opto-acoustic image visibility for assessment of breast cancer or other diseases.

Image Quality Improvement Techniques and Assessment Adequacy in Clinical Optoacoustic Imaging: A Systematic Review

“…Considering that multiple surface measurements could be valuable in addressing a range of limitations, including interference from out-of-plane absorbers and decreased contrast at depth, Zalev and Kolios [ 87 ] implemented a framework for simultaneous 3D image reconstruction and probe motion tracking. The process is formulated as a convex optimization problem, in which the reconstructed image, as well as the probe configuration, are jointly solved via a combined minimization objective.…”

Disentangling the Frequency Content in Optoacoustics

“…Out-of-plane signals have been separated from in-plane signals by axially displacing the transducer array and by de-correlating images acquired at different out-of-plane positions with the in-plane image [18,19]. In another study [20], the probe's trajectory was incorporated into a two-stage iterative 3D model-based reconstruction leading to significant out-of-plane artefact reduction. However, such approaches are impractical since they require the displacement of the transducer and do not consider the frequency-dependence of the detector's sensitivity.…”