Program Information
Acoustic Property Determination for Excised Tissue Samples
M Mclean , C Dillon , A Payne*, Department of Radiology and Imaging Sciences, University of Utah, Salt Lake City, UT
Presentations
SU-I-GPD-U-1 (Sunday, July 30, 2017) 3:00 PM - 6:00 PM Room: Exhibit Hall
Purpose: Roughly 25% of uterine fibroids appear hyperintense on T2-weighted MRI scans, a property that has been correlated with poor response to magnetic resonance-guided focused ultrasound (MRgFUS) treatment. Acoustic property characterization of fibroid tissue could help to explain this correlation and improve prediction of treatment outcomes. The purpose of this study was to develop a through-transmission testing methodology for ex vivo samples analogous to those that would be received following surgical resection of uterine fibroids.
Methods: Testing in ex vivo porcine muscle evaluated the effects of the tissue thickness, sample size and shape, and the tissue bracing method on the accuracy and precision of through-transmission speed of sound and attenuation measurements. Experimental variations included [1] varying sample thickness (1-3.5 cm), [2] evaluating a one-sided and two-sided holder with and without sample vacuum-sealing, [3] comparing whole samples to those comprised of several slices and [4] determining the effects of “morcellated” tissue.
Results: Testing demonstrated that tissue slices ≥ 2 cm in thickness had improved precision in determining attenuation. Attenuation precision also improved when the sample was vacuum-sealed in a two-sided holder, but precision was not affected when comparing whole to sliced samples. Attenuation precision in morcellated tissue improved significantly when the tissue was encased in a canister rather than placed in the two-sided holder. Speed of sound was less sensitive to the experimental conditions than attenuation.
Conclusion: It is recommended that when measuring the acoustic properties of ex vivo tissue, all samples should be 2 cm thick or greater. Whole uteri or fibroids that are secured between the two holders and vacuums sealed will yield measurements that are accurate and precise. Testing sliced or morcellated tissues that have been secured inside a rigid canister will also yield more accurate and precise measurements.
Funding Support, Disclosures, and Conflict of Interest: This work was supported by the Focused Ultrasound Foundation Global Internship Program.
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