Improvements in time resolution of tomographic photoacoustic imaging using a priori information for multiplexed systems

We present results of investigations of the application of a priori information and sparse or limited-view algorithms to simultaneously improve imaging quality and time-resolution in photoacoustic tomography. Modified versions of existing MRI/CT algorithms such as constrained backprojection and keyhole imaging are evaluated as well as a new Wiener estimation methods for extrapolation of missing data from reference data sets. Simulations indicate the effectiveness of the approaches for accurate tracking of dynamic photoacoustic events for data sets with limited views (< 90 degrees) or tomographic views with up to 1/64 of the full data set. We present experimental data of contrast uptake and washout using a 512-element curved transducer with 1:8 electronic multiplexing that demonstrates high-resolution tomographic imaging with a temporal resolution of better than 150 milliseconds using these methods.