Michael Bailey - Academia.edu (original) (raw)

Papers by Michael Bailey

Journal of the American College of Emergency Physicians Open, 2020

Proceedings of Meetings on Acoustics, 2018

Acoustics today, 2017

Ultrasound is currently the only noninvasive technology able to completely diagnose and manage ki... more Ultrasound is currently the only noninvasive technology able to completely diagnose and manage kidney stones.

Journal of Endourology, 2018

Journal of endourology, 2018

Burst wave lithotripsy (BWL) is a new technology in development to fragment urinary stones. Ultra... more Burst wave lithotripsy (BWL) is a new technology in development to fragment urinary stones. Ultrasonic propulsion (UP) is a separate technology under investigation for displacing stones. We measure the effect of propulsion pulses on stone fragmentation from BWL. Two artificial stone models (crystalline calcite, BegoStone plaster) and human calcium oxalate monohydrate (COM) stones measuring 5 to 8 mm were subjected to ultrasound exposures in a polyvinyl chloride tissue phantom within a water bath. Stones were exposed to BWL with and without propulsion pulses interleaved for set time intervals depending on stone type. Fragmentation was measured as a fraction of the initial stone mass fragmented to pieces smaller than 2 mm. BegoStone model comminution improved from 6% to 35% (p < 0.001) between BWL and BWL with interleaved propulsion in a 10-minute exposure. Propulsion alone did not fragment stones, whereas addition of propulsion after BWL slightly improved BegoStone model comminuti...

Urology, Jan 28, 2017

To evaluate in more detail the effectiveness of a new designed more efficient ultrasonic propulsi... more To evaluate in more detail the effectiveness of a new designed more efficient ultrasonic propulsion for large stones and specific stone compositions in a tissue phantom model. In the first clinical trial of noninvasive ultrasonic propulsion, urinary stones of unknown compositions and sizes up to 10 mm were successfully repositioned. The study included 8- to 12-mm stones of 4 different primary compositions (calcium oxalate monohydrate, ammonium acid urate, calcium phosphate, and struvite) and a renal calyx phantom consisting of a 12 mm × 30 mm well in a 10-cm block of tissue-mimicking material. Primary outcome was the number of times a stone was expelled over 10 attempts, with ultrasonic propulsion burst duration varying from 0.5 seconds to 5 seconds. Overall success rate at expelling stones was 95%. All calcium oxalate monohydrate and ammonium acid urate stones were expelled 100% of the time. The largest stone (12 mm) became lodged within the 12-mm phantom calyx 25% of the time rega...

World journal of urology, Jan 14, 2017

Posterior acoustic shadow width has been proposed as a more accurate measure of kidney stone size... more Posterior acoustic shadow width has been proposed as a more accurate measure of kidney stone size compared to direct measurement of stone width on ultrasound (US). Published data in humans to date have been based on a research using US system. Herein, we compared these two measurements in clinical US images. Thirty patient image sets where computed tomography (CT) and US images were captured less than 1 day apart were retrospectively reviewed. Five blinded reviewers independently assessed the largest stone in each image set for shadow presence and size. Shadow size was compared to US and CT stone sizes. Eighty percent of included stones demonstrated an acoustic shadow; 83% of stones without a shadow were ≤ 5 mm on CT. Average stone size was 6.5 ± 4.0 mm on CT, 10.3 ± 4.1 mm on US, and 7.5 ± 4.2 mm by shadow width. On average, US overestimated stone size by 3.8 ± 2.4 mm based on stone width (p < 0.001) and 1.0 ± 1.4 mm based on shadow width (p < 0.0098). Shadow measurements dec...

Physics in medicine and biology, Jan 13, 2017

The color Doppler ultrasound twinkling artifact, which highlights kidney stones with rapidly chan... more The color Doppler ultrasound twinkling artifact, which highlights kidney stones with rapidly changing color, has the potential to improve stone detection; however, its inconsistent appearance has limited its clinical utility. Recently, it was proposed stable crevice bubbles on the kidney stone surface cause twinkling; however, the hypothesis is not fully accepted because the bubbles have not been directly observed. In this paper, the micron or submicron-sized bubbles predicted by the crevice bubble hypothesis are enlarged in kidney stones of five primary compositions by exposure to acoustic rarefaction pulses or hypobaric static pressures in order to simultaneously capture their appearance by high-speed photography and ultrasound imaging. On filming stones that twinkle, consecutive rarefaction pulses from a lithotripter caused some bubbles to reproducibly grow from specific locations on the stone surface, suggesting the presence of pre-existing crevice bubbles. Hyperbaric and hypoba...

Ultrasound in Medicine & Biology, 2017

Journal of Space Safety Engineering, 2016

Journal of Endourology, 2017

The Journal of Urology, 2016

Purpose-Ultrasonic propulsion is a new technology using focused ultrasound energy applied transcu... more Purpose-Ultrasonic propulsion is a new technology using focused ultrasound energy applied transcutaneously to reposition kidney stones. We report the findings from the first human investigational trial of ultrasonic propulsion toward the applications of expelling small stones and dislodging large obstructing stones. Materials and Methods-Subjects underwent ultrasonic propulsion either awake without sedation in clinic or during ureteroscopy while anesthetized. Ultrasound imaging and a pain questionnaire were completed before, during, and after propulsion. The primary outcome was to reposition stones in the collecting system. Secondary outcomes included safety, controllable movement of stones, and movement of stones < 5 mm and ≥ 5 mm. Adverse events were assessed weekly for 3 weeks. Results-Kidney stones were repositioned in 14 of 15 subjects. Of the 43 targets, 28 (65%) showed some level of movement while 13 (30%) were displaced > 3 mm to a new location. Discomfort during the procedure was rare, mild, brief, and self-limited. Stones were moved in a controlled direction with over 30 fragments being passed by 4 of 6 subjects who previously had a lithotripsy procedure. The largest stone moved was 10 mm. One patient experienced pain relief

The Journal of the Acoustical Society of America

Although diagnostic ultrasound is now a multibillion dollar a year industry, the therapeutic appl... more Although diagnostic ultrasound is now a multibillion dollar a year industry, the therapeutic applications of ultrasound were initially thought to have more promise. Indeed, the Fry brothers were performing brain surgery on human patients in the early 1950s, and with considerable success. However, therapeutic ultrasound has still not yet gained its promising potential. Recently, there has been an enormous resurgence of interest in this topic, and several major projects are underway at various facilities around the world. Our own substantial efforts in this area at the University of Washington are reviewed, with brief discussions of topics in lithotripsy, ultrasound‐enhanced drug delivery, HIFU surgery, and acoustic hemostasis. [Work supported in part by DARPA and the NIH under Grants DK‐43881 and R43HL57739.]

2006 IEEE Ultrasonics Symposium, 2006

ABSTRACT

Ultrasound in Medicine & Biology, 2003

Lithotripsy is a common effective treatment for kidney stones. However, focal volumes are often l... more Lithotripsy is a common effective treatment for kidney stones. However, focal volumes are often larger than stones, and surrounding tissue is often injured. Our goal was to test in vitro a new lithotripter consisting of two opposing, confocal and simultaneously triggered electrohydraulic sources. The pulses superimpose at the common focus, resulting in pressure doubling and enhanced cavitation growth in a localized, approximately 1-cm wide volume. Model gypsum stones and human erythrocytes were exposed to dual pulses or single pulses. At the focus, model stones treated with 100 dual pulses at a charging voltage of 15 kV broke into 8 times the number of fragments as stones treated with 200 single pulses at 18 kV. At axial positions 2 and 4 cm away from the focus, lysis of erythrocytes was reduced or equivalent for dual pulses vs. single pulses. Hence, in half the time, dual pulses increased comminution at the focus without increasing injury in surrounding regions.

Methods in Cell Science, 1997