In vivo droplet vaporization for occlusion therapy and phase aberration correction

• Published in: IEEE transactions on ultrasonics, ferroelectrics, and frequency control Vol. 49; no. 6; pp. 726 - 738
• Main Authors: Kripfgans, O.D., Fowlkes, J.B., Woydt, M., Eldevik, O.P., Carson, P.L.
• Format: Journal Article
• Language: English
• Published: New York, NY IEEE 01.06.2002; Institute of Electrical and Electronics Engineers; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Acoustics; Albumins - chemistry; Animals; Associate members; Backscatter; Biocompatibility; Biological and medical sciences; Biomedical imaging; Biomedical materials; Blood - diagnostic imaging; Blood flow; Bubbles; Cardiovascular system; Cerebral Cortex - blood supply; Chemoembolization, Therapeutic - methods; Contrast Media; Dogs; Droplets; Emulsions - chemistry; Filtering; Fluorocarbons - chemistry; In vivo; In vivo testing; In vivo tests; Investigative techniques, diagnostic techniques (general aspects); Kidney Cortex - blood supply; Lungs; Magnetic resonance imaging; Medical sciences; Medical treatment; Other treatments; Surgical implants; Treatment. General aspects; Tumors; Ultrasonic imaging; Ultrasonic investigative techniques; Ultrasonics; Ultrasonography; Vaporization; Air embolism; Human; Therapy; Bubble; Ischemia; Medical imagery; Circulatory system; Malignant tumor; Acoustic image; Phase distortion; Contrast media; Vaporization
• ISSN: 0885-3010; 1525-8955
• DOI: 10.1109/TUFFC.2002.1009331

The objective was to determine whether a transpulmonary droplet emulsion (90%, <6 μm diameter) could be used to form large gas bubbles (>30 μm) temporarily in vivo. Such bubbles could occlude a targeted capillary bed when used in a large number density. Alternatively, for a very sparse population of droplets, the resulting gas bubbles could serve as point beacons for phase aberration corrections in ultrasonic imaging. Gas bubbles can be made in vivo by acoustic droplet vaporization (ADV) of injected, superheated, dodecafluoropentane droplets. Droplets vaporize in an acoustic field whose peak rarefactional pressure exceeds a well-defined threshold. In this new work, it has been found that intraarterial and intravenous injections can be used to introduce the emulsion into the blood stream for subsequent ADV (Band M-mode on a clinical scanner) in situ. Intravenous administration results in a lower gas bubble yield, possibly because of filtering in the lung, dilution in the blood volume, or other circulatory effects. Results show that for occlusion purposes, a reduction in regional blood flow of 34% can be achieved. Individual point beacons with a +24 dB backscatter amplitude relative to white matter were created by intravenous injection and ADV.