Hybrid Pulse-Echo Ultrasonography and Optoacoustic Tomography Using Concave Arrays
Journal
IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control
Journal Volume
62
Journal Issue
9
Pages
1651-1661
Date Issued
2015-09
Author(s)
Abstract
Implementation of hybrid imaging using optoacoustic tomography (OAT) and ultrasound (US) brings together the important advantages and complementary features of both methods. However, the fundamentally different physical contrast mechanisms of the two modalities may impose significant difficulties in the optimal tomographic data acquisition and image formation strategies. We investigate the applicability of the commonly applied imaging geometries for acquisition and reconstruction of hybrid optoacoustic tomography and pulse-echo ultrasound (OPUS) images. Optimization of the ultrasound image formation strategy using concave array geometry was implemented using a synthetic aperture method combined with spatial compounding. Experimental validation was performed using a custom-made multiplexer unit executing switching between the two modalities employing the same transducer array. A variety of array probes with different angular coverages were subsequently tested, including arrays for clinical hand-held imaging as well as stationary arrays for tomographic small animal imaging. The results demonstrate that acquisition of OAT data by mere addition of an illumination source to the common US linear array geometry may result in significant limited-view artifacts and overall loss of image quality. On the other hand, unsatisfactory US image quality is achieved with tomographic arrays solely optimized for OAT image acquisition without considering the optimal transmit-receive beamforming parameters. Optimal selection of the array pitch size, tomographic coverage and spatial compounding parameters has achieved here an accurate hybrid imaging performance, which was experimentally showcased in tissuemimicking phantoms, post-mortem mice, and hand-held imaging of a healthy volunteer. The efficient combination of the two modalities in a single imaging device reveals the true power of functional and molecular imaging capacities of OAT in addition to the morphological and functional imaging capabilities of US. ? 1986-2012 IEEE.
Subjects
Acoustics; Geometry; Image reconstruction; Tomography; Transducers; Ultrasonic imaging
SDGs
Other Subjects
Acoustics; Array processing; Data acquisition; Geometry; Image acquisition; Image processing; Image quality; Molecular imaging; Photoacoustic effect; Synthetic apertures; Tomography; Transducers; Ultrasonic imaging; Complementary features; Experimental validations; Illumination sources; Linear array geometry; Optoacoustic tomography; Pulse echo ultrasound; Small animal imaging; Tissue mimicking phantom; Image reconstruction; animal; computer simulation; echography; human; imaging phantom; Institute for Cancer Research mouse; mouse; photoacoustics; procedures; tomography; Animals; Computer Simulation; Humans; Mice; Mice, Inbred ICR; Phantoms, Imaging; Photoacoustic Techniques; Tomography; Ultrasonography
Type
journal article