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Proceedings Paper

Tracking contrast agents using real-time 2D photoacoustic imaging system for cardiac applications
Author(s): Ragnar Olafsson; Leonardo Montilla; Pier Ingram; Russell S. Witte
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Paper Abstract

Photoacoustic (PA) imaging is a rapidly developing imaging modality that can detect optical contrast agents with high sensitivity. While detectors in PA imaging have traditionally been single element ultrasound transducers, use of array systems is desirable because they potentially provide high frame rates to capture dynamic events, such as injection and distribution of contrast in clinical applications. We present preliminary data consisting of 40 second sequences of coregistered pulse-echo (PE) and PA images acquired simultaneously in real time using a clinical ultrasonic machine. Using a 7 MHz linear array, the scanner allowed simultaneous acquisition of inphase-quadrature (IQ) data on 64 elements at a rate limited by the illumination source (Q-switched laser at 20 Hz) with spatial resolution determined to be 0.6 mm (axial) and 0.4 mm (lateral). PA images had a signal-to-noise ratio of approximately 35 dB without averaging. The sequences captured the injection and distribution of an infrared-absorbing contrast agent into a cadaver rat heart. From these data, a perfusion time constant of 0.23 s-1 was estimated. After further refinement, the system will be tested in live animals. Ultimately, an integrated system in the clinic could facilitate inexpensive molecular screening for coronary artery disease.

Paper Details

Date Published: 25 February 2009
PDF: 8 pages
Proc. SPIE 7177, Photons Plus Ultrasound: Imaging and Sensing 2009, 71771R (25 February 2009); doi: 10.1117/12.811060
Show Author Affiliations
Ragnar Olafsson, The Univ. of Arizona (United States)
Leonardo Montilla, The Univ. of Arizona (United States)
Pier Ingram, The Univ. of Arizona (United States)
Russell S. Witte, The Univ. of Arizona (United States)


Published in SPIE Proceedings Vol. 7177:
Photons Plus Ultrasound: Imaging and Sensing 2009
Alexander A. Oraevsky; Lihong V. Wang, Editor(s)

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