Controlled ultrasound tissue erosion.
The ability of ultrasound to produce highly controlled tissue erosion was investigated. This study is motivated by the need to develop a noninvasive procedure to perforate the neonatal atrial septum as the first step in treatment of hypoplastic left heart syndrome. A total of 232 holes were generated in 40 pieces of excised porcine atrial wall by a 788 kHz single-element transducer. The effects of various parameters [e.g., pulse repetition frequency (PRF), pulse duration (PD), and gas content of liquid] on the erosion rate and energy efficiency were explored. An Isppa of 9000 W/cm2, PDs of 3, 6, 12, and 24 cycles; PRFs between 1.34 kHz and 66.7 kHz; and gas saturation of 40-55% and 79-85% were used. The results show that very short pulses delivered at certain PRFs could maximize the erosion rate and energy efficiency. We show that well-defined perforations can be precisely located in the atrial wall through the controlled ultrasound tissue erosion (CUTE) process. A preliminary in vivo experiment was conducted on a canine subject, and the atrial septum was perforated using CUTE.
Xu
Zhen
Z
Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI 48109, USA. zhenx@umich.edu
Ludomirsky
Achiau
A
Eun
Lucy Y
LY
Hall
Timothy L
TL
Tran
Binh C
BC
Fowlkes
J Brian
JB
Cain
Charles A
CA
D000818:Animals; D004285:Dogs; D004307:Dose-Response Relationship, Radiation; D005240:Feasibility Studies; D006325:Heart Atria / Q000528:radiation effects* / Q000601:surgery*; D006346:Heart Septum / Q000528:radiation effects* / Q000601:surgery*; D066298:In Vitro Techniques; D008096:Lithotripsy / Q000379:methods*; D019060:Minimally Invasive Surgical Procedures / Q000379:methods*; D014464:Ultrasonic Therapy / Q000379:methods*; D014465:Ultrasonics