Bioacoustics Research Lab
University of Illinois at Urbana-Champaign | Department of Electrical and Computer Engineering | Department of Bioengineering
Department of Statistics | Coordinated Science Laboratory | Beckman Institute | Food Science and Human Nutrition | Division of Nutritional Sciences | College of Engineering
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William D. O'Brien, Jr. publications:

Michael L. Oelze publications:

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Title Hemostasis of punctured blood vessels using high-intensity focused.ultrasound.
Author Vaezy S, Martin R, Yaziji H, Kaczkowski P, Keilman G, Carter S, Caps M, Chi EY, Bailey M, Crum L.
Journal Ultrasound Med Biol
Volume
Year 1998
Abstract The hemorrhagic complications of vascular injury can be significant. The authors report on the use of high-intensity focused ultrasound (HIFU) to stop the hemorrhage of punctured blood vessels in pigs. Two HIFU transducers with frequencies of 3.5 and 2.0 MHz, each equipped with a water-filled conical housing, were used. Major blood vessels (femoral artery and vein, axillary artery, carotid artery and jugular vein), 2-10 mm in diameter, of anesthetized pigs were exposed surgically and punctured with 14- and 18-gauge needles to produce moderate to profuse bleeding. Complete hemostasis was achieved in less than 3 min of HIFU treatment in most blood vessels, and all vessels were patent after the treatment. Both HIFU frequencies were effective in producing hemostasis. Gross examination of the HIFU-treated vessels showed a consistent hardening of the soft tissue surrounding the blood vessels, providing a seal for the puncture hole. Microscopic examination of the vessels showed a remarkably localized HIFU treatment, resulting in coagulation of the adventitia, and an extensive fibrin network around the vessels and in the puncture hole. The vessel walls exhibited focal swelling, without evidence of irreversible injury. HIFU may provide a useful method for achieving hemostasis of punctured and traumatized blood vessels in a variety of clinical settings.


Title Hemostasis of punctured vessels using Doppler-guided high-intensity.ultrasound.
Author Martin RW, Vaezy S, Kaczkowski P, Keilman G, Carter S, Caps M, Beach K, Plett M, Crum L.
Journal Ultrasound Med Biol
Volume
Year 1999
Abstract The use of Doppler ultrasound was investigated to determine if it would aid in guiding the application of high-intensity focused ultrasound (HIFU) to stop bleeding from punctured vessels. Major vessels (abdominal aorta, illiac, carotid, common femoral and superficial femoral arteries and the jugular vein) were surgically exposed, punctured and treated in anesthetized pigs. Treatment was applied when the Doppler sounds indicated the focus coincided with the bleeding site. In 89 treatment trials, the average time to achieve major hemostasis (a point where bleeding was reduced to a level of only oozing) was 8 s, and for complete hemostasis was 13 s. These times were significantly shorter than those of an identical former study in which only visual guidance was used. In that study, the average times for major and complete hemostasis were 40 and 62 s, respectively. The advantage of Doppler guidance in applying HIFU in treating bleeding vessels was demonstrated.


Title Hemostasis using high intensity focused ultrasound.
Author Vaezy S, Marti R, Mourad P, Crum L.
Journal Eur J Ultrasound
Volume
Year 1999
Abstract High intensity focused ultrasound (HIFU) has been shown to be an effective method of hemostasis, in animal studies, for both solid organs and blood vessels. Two distinct effects of HIFU, thermal and mechanical, appear to contribute to hemostasis. Acoustic hemostasis may provide an effective method in surgery and prehospital settings for treating trauma and elective surgery patients. A review of the methodology is given.


Title High contrast images of defects in food package seals.
Author Frazier CH, Ozguler A, Morris SA, O'Brien WD Jr.
Journal Proc Ultrason Symp IEEE
Volume
Year 1997
Abstract Previous work to detect channels in packaging seals using pulse-echo ultrasound inspired the Backscattered Amplitude Integral (BAI) imaging technique [1]. Which could reliably identify channels with diameters larger than 15mm at a center frequency of 17.3 MHz (lambda = 86mm). However smaller channels (= 6 mm in diameter) can be easily revealed by processing the data according to a new imaging technique that displays a single time-gated pressure value from the received (not envelope-detected) rf waveform at each transducer position, that is, an rf sample image (RFS). The applicability of this technique for detecting channel defects is demonstrated for plastic and aluminum foil trilaminate films with 6, 10, 15, 38, 50, 75, and 100 mm channels filled with water or air. The images are formed with a focused ultrasound transducer (17.3 MHz, 6.35 mm in diameter, f/2, 173mm ?6 dB pulse-echo lateral beamwidth at the focus) scanned over a rectangular grid, keeping the package in the focus. Subwavelength channel defects as small as 6mm can be easily detected but appear larger than 150 mm wide, according to the focal point size of the transducer. The time-gate used to create an image is chosen based on where the maximum reflection from the back surface of the material is expected, Images created with the RFS technique demonstrate higher contrast than images formed using the BAI or ultrathin C-mode (UTC) techniques. However, RFS imaging also has higher probability of not detecting a channel that is present.


Title High contrast ultrasound images of defects in food package seals.
Author Frazier CH, Tian Q, Ozguler A, Morris SA, O'Brien WD Jr.
Journal IEEE Trans UFFC
Volume
Year 2000
Abstract Previous work to detect defects in food packaging seals using pulse-echo ultrasound inspired the backscattered amplitude integral (BAI) imaging technique, which could reliably identify channels with diameters 38 μm or larger at a center frequency of 17.3 MHz (λ=86 μm). The current study presents two new processing techniques that more reliably reveal smaller channels (≈6 μm in diameter). The RF sampling technique (RFS) displays a single, time-gated, pressure value from the received (not envelope-detected) RF waveform at each transducer position. The RF correlation technique (RFC) calculates the correlation coefficients of the RF signals with a reference signal that does not pass through a channel. The correlation coefficient can be calculated for the entire RF signal (RFCE) or over a short segment of the RF signal (RFCS). The performance of these imaging methods for detecting channel defects is investigated for plastic and aluminum foil trilaminate films with 6, 10, 15, 38, and 50 μm channels filled with water or air. Data are collected with a focused ultrasound transducer (17.3 MHz, 6.35 mm in diameter, f/2, 173 μm -6 dB pulse-echo lateral beamwidth at the focus) scanned over a rectangular grid, keeping the package in the focus. Performance is measured using detection rates, image contrast, and contrast-to-noise ratio (CNR). Both RFS and RFCS have improved detection rates relative to BAI for channels 15 μm or smaller. The RFCS technique is the most effective at smoothing the background, leading to the greatest CNR improvements.


Title High frequency quantitative ultrasound imaging of solid tumors in mice.
Author Oelze ML, O'Brien WD Jr., Zachary JF.
Journal Acoust Imaging
Volume
Year 2007
Abstract A mammary carcinoma and a sarcoma were grown in mice and imaged with ultrasound transducers operating with a center frequency of 20 MHz. Quantitative ultrasound (QUS) analysis was used to characterize the tumors using the bandwidth of 10 to 25 MHz. Initial QUS estimates of the scatterer properties (average scatterer diameter and acoustic concentration) did not reveal differences between the two kinds of tumors. Examination of the tumors using light microscopy indicated definite structural differences between the two kinds of tumors. In order to draw out the structural differences with ultrasound, a higher frequency probe (center frequency measured at 70 MHz) was used to interrogate the two kinds of tumors and new models were applied to the QUS analysis. QUS scatterer diameter images of the tumors were constructed using the high frequency probe. Several models for scattering were implemented to obtain estimates of scatterer properties in order to relate estimated scatterer properties to real tissue microstructure. The Anderson model for scattering from a fluid-filled sphere differentiated the two kinds of tumors but did not yield scatterer property estimates that resembled underlying structure. Using the Anderson model, the average estimated scatterer diameters were 25.5 ? 0.14 ?m for the carcinoma and 57.5 ? 2.90 for the sarcoma. A new cell model was developed, which was based on scattering from a cell by incorporating the effects of the cytoskeleton and nucleus. The new cell model yielded estimates that appeared to reflect underlying structure more accurately but did not separate the two kinds of tumors. Using the new cell model, the average estimated scatterer diameters were 15.6 ? 2.2 ?m for the carcinoma and 16.8 ? 3.82 ?m for the sarcoma. The new cell model yielded estimates close to the actual nuclear diameter of the cell (13 ?m)


Title High frequency ultrasonic imaging of skin: Experimental results.
Author Dines KA, Sheets PW, Brink JA, Hanke CW, Condra KA, Clendenon JL, Goss SA, Smith DJ, Franklin TD.
Journal Ultrason Imaging
Volume
Year 1984
Abstract Experimental results are presented demonstrating the application of pulse echo ultrasound to imaging the skin. A laboratory prototype B-mode mechanical scanner was employed to obtain images of human skin, both in vitro and in vivo, using broadband pulsed ultrasound at 25 MHz. Images were formed by processing digitized A-mode waveforms and displaying the resulting two-dimensional cross sections using a digital imaging system. Images obtained by rectifying the A-modes are compared to those derived using a software-based cross-correlation technique. Scans of test targets demonstrate that an axial resolution of 100 m can be achieved at 25 MHz when the digital correlation method is employed. Lateral resolution is limited by the 0.25 mm half-power focal beamwidth of the transducer. Seventeen in vitro ultrasonic scans of human skin were compared to frozen section histology. Average skin depth was well correlated between the two techniques (=0.99, p<0.001). Application of cross-correlated processing to 25 MHz in vivo images produced good delineation of epidermis, papillary, and reticular dermis. Conversion to a 50 MHz transducer did not delineate skin layers as well as the 25 MHz transducer due to inherent difficulties with transducer reverberations.


Title High frequency ultrasound evaluation of radial keratotomy incisions.
Author Lazzaro DR, Aslanides IM, Belmont SC, Silverman RH, Reinstein DZ, Muller JW, Lloyd HO, Coleman DJ.
Journal J Cataract Refract Surg
Volume
Year 1995
Abstract Radial keratotomy is a surgical procedure to correct myopia that involves placing corneal incisions of precise partial thickness to induce flattening. It has yielded positive but sometimes unpredictable results. Many surgical variables influence the final result. Among them, incision depth is probably the most difficult to control and evaluate. In this study, we used very high frequency (50 MHz) ultrasound (HFU) to image radial keratotomy incisions in post-radial keratotomy human corneas to obtain high definition images of the cornea. The images allowed us to measure the depth of incisions as a percentage of corneal thickness.


Title High frequency ultrasound imaging in pupillary block glaucoma.
Author Aslanides IM, Libre PE, Silverman RH, Reinstein DZ, Lazzaro DR, Rondeau MJ, Harmon GK, Coleman DJ.
Journal Br J Ophthalmol
Volume
Year 1995
Abstract BACKGROUND--The diagnosis of pupillary block glaucoma requires sufficient clarity of the ocular media. This is particularly important for assessment of both the presence and patency of an iridotomy, and the determination of central anterior chamber depth. METHODS--High frequency ultrasonography was used in three patients with suspected pupillary block to determine iris configuration, posterior chamber volume, and ciliary body conformation. RESULTS--All patients demonstrated high frequency ultrasonographic findings consistent with pupillary block: iris bombe, a formed posterior chamber, and a lack of anterior rotation of the ciliary processes. CONCLUSION--High frequency ultrasound imaging appears to be a valuable adjunct in making or corroborating the diagnosis of pupillary block glaucoma.


Title High frequency ultrasound imaging using an active optical detector.
Author Hamilton JD, Brooks CJ, Vossler GL, O'Donnell M.
Journal IEEE Trans Ultrason Ferroelectr Freq Control
Volume
Year 1998
Abstract Optical detection of ultrasound has numerous advantages over traditional piezoelectric methods. These systems offer noncontact inspection, rapid scanning capabilities, fine spatial sampling, and large bandwidths. In addition, difficulties associated with conventional ultrasound imaging systems such as cross-talk between elements, electrical connections, and electromechanical resonances are greatly reduced or even eliminated. Because of this, high frequency phased arrays for ultrasound detection can be emulated by accurately positioning and focusing optical beams on a suitable surface, which defines array elements. However, optical systems have lower sensitivity than their piezoelectric counterparts, limiting their widespread use in ultrasound imaging. Active optical detection offers a solution. An active ultrasound detector consisting of a neodymium-doped glass waveguide laser with an optical demodulation system, was built demonstrating enhanced sensitivity while preserving the benefits of traditional passive optical detection.


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