A real-time measure of cavitation induced tissue disruption by ultrasound imaging backscatter reduction.
A feedback method for obtaining real-time information on the mechanical disruption of tissue through ultrasound cavitation is presented. This method is based on a substantial reduction in ultrasound imaging backscatter from the target volume as the tissue structure is broken down. Ex-vivo samples of porcine liver were exposed to successive high-intensity ultrasound pulses at a low duty cycle to induce mechanical disruption of tissue parenchyma through cavitation (referred to as histotripsy). At the conclusion of treatment, B-scan imaging backscatter was observed to have decreased by 22.4 +/- 2.3 dB in the target location. Treated samples of tissue were found to contain disrupted tissue corresponding to the imaged hypoechoic volume with no remaining discernable structure and a sharp boundary. The observed, substantial backscatter reduction may be an effective feedback mechanism for assessing treatment efficacy in ultrasound surgery using pulsed ultrasound to create cavitation.
Hall
Timothy L
TL
University of Michigan, Department of Biomedical Engineering, Ann Arbor, MI, USA. hallt@umich.edu
Fowlkes
J Brian
JB
Cain
Charles A
CA
D000818:Animals; D003199:Computer Systems; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D066298:In Vitro Techniques; D008099:Liver / Q000000981:diagnostic imaging* / Q000601:surgery*; D011829:Radiation Dosage; D011874:Radiometry / Q000379:methods; D012542:Scattering, Radiation; D025321:Surgery, Computer-Assisted / Q000379:methods*; D013552:Swine; D014464:Ultrasonic Therapy / Q000379:methods*; D014463:Ultrasonography / Q000379:methods*