• Volume/Page
  • Keyword
  • DOI
  • Citation
  • Advanced
   
 
 
 

Journal of the Acoustical Society of America

SECTION LISTING

BROWSE VOLUMES

Year Range: 
Search Issue | RSS Feeds RSS
Previous Issue Next Issue

Apr 1976

Volume 59, Issue S1, pp. S1-S100

Return to All Sections
back to top
RSS Feeds
back to top Session II. Physical Acoustics V: Ultrasonic Biophysics II: Interactions
Invited Paper
FREE

Quantitative measurements of scattering from tissues (A)

J. M. Reid

J. Acoust. Soc. Am. Volume 59, Issue S1, pp. S75-S75 (1976); (1 page)

Online Publication Date: 11 Aug 2005

Full Text: | Download PDF

Show Abstract
The extraction of quantitative information on the scattering process sufficient to determine the scattering mechanism and to characterize tissues is a difficult problem which has been attacked from many viewpoints. Heterogeneous biological tissues require focused beams and short pulses to isolate waves scattered from particular structures. Analysis must be done over wide bandwidths and in field regions where analytic expressions are not available. Another complication is the frequency‐dependent absorption in both overlying tissues and in the tissue being measured. Five levels of scattering measurement have been identified. The first is the simple measurement of a scattered wave by reference to an external standard. The other levels require corrections for (1) overlying tissue absorption; (2) wave and field‐shape interactions with the measuring equipment; (3) sample‐tissue absorption; and (4) the effect of concentration to determine the per‐cell or structure scattering cross section. Measurements of redcell scattering illustrate that these methods are practical. The scattering cross‐section magnitude and angular and frequency dependence correlate with theory for scattering from compressible viscous spheres. Because the substitution methods outlined can correct for the interaction between equipment parameters and wave‐shape effects, a promising area appears to be the development of substitution standards for in vitro and in vivo measurements.
Contributed Papers
FREE

Internal proton transfer and ultrasonic absorption by proteins (A)

L. J. Slutsky and R. D. White

J. Acoust. Soc. Am. Volume 59, Issue S1, pp. S75-S75 (1976); (1 page)

Online Publication Date: 11 Aug 2005

Full Text: | Download PDF

Show Abstract
The measured pH and frequency dependence of ultrasonic absorption in aqueous solutions of proteins and model compounds are reported and compared with an estimate of the contribution of internal charge‐transfer processes to the acoustic relaxation spectrum of protein solutions based on the approximate method employed by Kirkwood and Shumaker [J. G. Kirkwood and J. B. Shumaker, Proc. Nat. Acad. Sci. 38, 855 (1952)] to compute the contribution of the fluctuation dipole moment to the dielectric relaxation spectrum. The agreement with experiment is quite good and there appears to be a reasonable case for perturbation of internal proton‐transfer equilibria as a major or principal to ultrasonic absorption in protein solutions at physiological pH.
FREE

Ultrasonic spectral analyses of ocular tissues (A)

F. L. Lizzi, M. A. Laviola, L. Franzen, and D. J. Coleman

J. Acoust. Soc. Am. Volume 59, Issue S1, pp. S75-S75 (1976); (1 page)

Online Publication Date: 11 Aug 2005

Full Text: | Download PDF

Show Abstract
Spectrum analysis is performed on signals obtained from a wideband ultrasonic system used in clinical ophthalmic examinations. Clinical data has been cataloged to form the nucleus of a digital data library to assist in delineating characteristic spectral features of specific pathologies. The spectral analysis system analyzes gated r‐f echoes from tissue segments selected with the assistance of simultaneous A‐ and B‐mode displays. On‐line averaging of spectra obtained along parallel illumination paths is provided to yield the average backscatter power spectra of tissues with heterogeneous, random interior structure. These spectra are digitized and compensated for system absolute‐gain and frequency characteristics. The shapes and absolute levels of compensated spectra are being examined to evaluate their diagnostic utility. Vitreous hemorrhages are found to exhibit spectra that increase as the fourth power of frequency as would be expected for a distribution of Rayleigh scatters. Some tumors have displayed spectral resonances indicative of an ordered spatial structure. Membranous tissues (e.g., detached retinas) produce scaloped spectral patterns that can be used to deduce membrane thickness. [Work supported by NIH.]
FREE

Attenuation and velocity in normal brain (A)

F. W. Kremkau, C. P. McGraw, and R. W. Barnes

J. Acoust. Soc. Am. Volume 59, Issue S1, pp. S75-S75 (1976); (1 page)

Online Publication Date: 11 Aug 2005

Full Text: | Download PDF

Show Abstract
Attenuation and propagation velocity at 1, 3, and 5 MHz were measured in vitro at six anatomic sites in seven normal human brains obtained at autopsy. Piezoelectric transducer method gave attenuation values about 50% higher than radiation force method. Age at death for adults (20–72 yrs) was not a significant variable. A three‐day‐old infant brain, however, showed attenuation about one third that for adult. Formalin fixing increases attenuation by about 30% and reduces velocity by less than 1%. Five‐day aging of unfixed tissue reduces attenuation by about 20%. White matter has higher attenuation (which is also a stronger function of frequency) than gray or mixed matter. Attenuation is a negative function of temperature. The magnitude of temperature coefficient or attenuation is greater for lower temperatures or higher frequencies. Velocity vs temperature curves exhibit a minimum at about 15°C. These observations indicate that for attenuation and velocity measurements in normal brain in the 1 to 5 MHz range, temperature must be closely controlled, and aging and fixing of tissue must be taken into account when analysing attenuation data. [Work supported by NINCDS.]
FREE

Influence of subarachnoid structures on transmenninges ultrasonic propagation (A)

R. L. Johnston and F. Dunn

J. Acoust. Soc. Am. Volume 59, Issue S1, pp. S76-S76 (1976); (1 page)

Online Publication Date: 11 Aug 2005

Full Text: | Download PDF

Show Abstract
The ultrasonic dose threshold for irreversible lesion production in mammalian brain exhibits a frequency dependence believed to be ascribable to the outer brain menninges. Thus, the collagenous trabeculae of the subarachnoid space, interposed between the arachnoid and the pia mater, are implicated because of increased elastic moduli associated with their structural supporting role. A three‐layer model yields acceptable agreement and provides physical parameters commensurate with these involved anatomical structures. Normalization of existing data [Dunn, Lohnes, and Fry, J. Acoust. Soc. Am. 58, S12 (1975)], by this method of analysis, provides a frequency‐independent lesion threshold describable by the relation, IT½  =  200 W/cm2/sec−½. [This study was supported by a grant from the NSF.]
FREE

Ultrasonic properties of mammalian testes (A)

J. K. Brady, R. L. Johnston, S. A. Goss, W. D. O'Brien, Jr., and F. Dunn

J. Acoust. Soc. Am. Volume 59, Issue S1, pp. S76-S76 (1976); (1 page)

Online Publication Date: 11 Aug 2005

Full Text: | Download PDF

Show Abstract
The ultrasonic absorption and reflection properties have been investigated over the frequency range of 0.7 to 7 MHz, 37° C, for in vitro preparations of freshly excised, sexually mature mouse, rabbit, and cat testes. The experimental animals were mature mice of proven fertility, 15–20 weeks of age, a young cat, and a rabbit of unknown fertility. The transient thermoelectric method of absorption measurement and the pulse‐echo reflection method were used. The absorption coefficient is approximately an order of magnitude less than other soft tissues of high water content, with a positive frequency dependence. [This work was supported by a grant from the Institute of General Medical Sciences, NIH.]
FREE

Temperature rise in tissue: Continuous and pulsed ultrasound regimes (A)

F. J. Fry and W. Erdmann

J. Acoust. Soc. Am. Volume 59, Issue S1, pp. S76-S76 (1976); (1 page)

Online Publication Date: 11 Aug 2005

Full Text: | Download PDF

Show Abstract
Temperature rise in mouse testicular tissue is a linear function of incident cw ultrasound intensity (0–130 W/cm2). Small‐diameter chromel‐constantan thermocouples are used to measure the temperature rise. The absorption coefficient for this tissue (0.029 to 0.070 cm−1 intensity absorption coefficient at 1.1 MHz) provides temperature rises not exceeding 4–5°C with our focused ultrasonic irradiators. When pulse regimes are employed, the linear relationship between temperature rise and average intensity applies in limited circumstances. With spatial peak intensity less than 100 W/cm2 and burst time 100 msec or longer (1000 Hz prf) the temperature rise seems linearly related to average ultrasound intensity. For peak intensities above 100 W/cm2, average intensities below 10 W/cm2, and burst times below 100 msec, the temperature rise is essentially linearly related to peak intensity. For peak intensities below 100 W/cm2 and average intensities below 2–3 W/cm2 the temperature rise appears to be that characteristic of the continuous wave case. Preliminary data on mouse ovarian tissue indicate the same general phenomena is operative. Various experimental configurations have been uses in an attempt to demonstrate that the observed phenomena is a tissue ultrasound interaction effect and not an artifact of the tissue‐thermocouple complex.
FREE

Tissue characterization using spectral analysis of ultrasonic waveforms (A)

J. P. Jones, E. Holasek, and E. W. Purnell

J. Acoust. Soc. Am. Volume 59, Issue S1, pp. S76-S76 (1976); (1 page) | Cited 1 time

Online Publication Date: 11 Aug 2005

Full Text: | Download PDF

Show Abstract
Many types of tissues can be uniquely classified in terms of their acoustical properties and changes in their acoustical properties can be correlated with specific pathological states. For example, the ultrasonic absorption and scattering characteristics of tissue seem to provide a useful basis for tissue differentiation. Since these properties are strongly frequency dependent, spectral analysis is suggested as a preferred measurement procedure. To present spectral information in a clinically useful way, we have developed a technique for incorporating spectral characteristics into a B‐scan ultrasonogram. The technique yields a single cross‐section echo record which is formed from a composite of data obtained from three scans at different frequency bands, each separately recorded through a different color filter. The signal from a wide‐band transducer is divided into three separate frequency bands and the response recorded on a single color photograph with the primary colors of light representing the three component frequencies. Experiments with physical models demonstrate a good correlation between this two‐dimensional display of spectral information and a true spectral analysis. Preliminary clinical trials have discovered characteristic color patterns associated with a malignant melanoma. [Work supported by NIH.]
FREE

Ultrasonic indentation of plastics and bioeffects applications (A)

H. M. Frost

J. Acoust. Soc. Am. Volume 59, Issue S1, pp. S76-S76 (1976); (1 page)

Online Publication Date: 11 Aug 2005

Full Text: | Download PDF

Show Abstract
New results with an ultrasonic indenter system for soft plastics indicate that refinements in bioeffects studies involving vibrating objects acting on biological tissue are feasible. Resonant frequency changes are digitally recorded with time for the 90 kHz, self‐excited sample‐vibrator system. These changes characterize both the contact area and the changing viscoelastic properties of the sample and correlate well with the photoelastic strain data. Typical data are presented on video tape. A regime exists where the time‐averaged acoustic force F is proportional to the indenter vibration amplitude u0 : F = Ku0. The empirical constant K of 9 × 108 dyn/cm agrees well with the value 8 × 108 dyn/cm calculated from Hertzian contact theory and is apparently insensitive to the small temperature rises of sound absorption. Potential applications in tissue‐indenter studies include reproducible acoustic and static contact conditions and measurable changes in mechanical properties. A novel test for glaucoma is also proposed. [Work supported by NIH and Hood Interdisciplinary Fellowship.]
FREE

Measuring mechanical structure of tissue from scattered ultrasonic signals (A)

J. E. Burger

J. Acoust. Soc. Am. Volume 59, Issue S1, pp. S76-S76 (1976); (1 page)

Online Publication Date: 11 Aug 2005

Full Text: | Download PDF

Show Abstract
Ultrasonic B‐scans obtained clinically of many different kinds of tissue show random clutter originating from within their boundaries. This clutter is generally due to backscatter from scattering centers within the tissue and associated with its mechanical structure. The mechanical structures of different tissues are different, and so the spatial distributions of the scattering centers are expected to be different also. The spectral density in wavenumber of the scattering centers distributed along an axis is proposed as a basis for differential tissue diagnosis by ultrasound. This signature of the randomly distributed ultrasonic scattering centers is found to be a function of frequency, scattering angle, and axis orientation. The analytical results are based on the definition of the scattering strength at a point in the tissue as the scattered pressure measured at a unit distance from the point, per unit volume and pressure of the interrogating signal. The results show how the signature is calculated from experimentally measurable quantities. These quantities include the energy spectral densities of the interrogating ultrasonic signal and of the scattered ultrasonic signals received at different scattering angles. The different signatures of quasiperiodic and diffuse tissues are qualitatively described.
FREE

In vitro thermoacoustic studies in brain (A)

Thomas D. Sachs, Peter T. Anderson, Sanford J. Wright, Jr., Ralph S. Grimes, and Clinton D. Janney

J. Acoust. Soc. Am. Volume 59, Issue S1, pp. S76-S77 (1976); (2 pages)

Online Publication Date: 11 Aug 2005

Full Text: | Download PDF

Show Abstract
The TAST system passes a burst of “thermometer” sound beam through tissue, and measures its transit time. Next, a focused heating sound field warms a small volume of tissue in the path of the thermometer beam, in proportion to its absorption. Finally, the thermometer‐beam burst is repeated and its transit time subtracted from that of the initial thermometer‐beam burst. This time difference characterizes the tissue because it depends on the absorption coefficient and the temperature coefficient of velocity. Both are apparently sensitive to tissue structure as well as other tissue characteristics. In a fixed human brain TAST distinguished among various intracranial structures with a spatial resolution of better than 3 mm. Should predictions based on the data and theory prove correct, TAST may become a noninvasive alternative to biopsy. [Work supported in part by the Sloan Foundation.]
FREE

Intensity and state dependence of acoustical absorption coefficients in mammalian tissues (A)

R. A. Handler and P. P. Lele

J. Acoust. Soc. Am. Volume 59, Issue S1, pp. S77-S77 (1976); (1 page)

Online Publication Date: 11 Aug 2005

Full Text: | Download PDF

Show Abstract
There is still considerable uncertainty regarding the mechanism(s) by which high intensity, pulsed (one or a few cycles) ultrasound can damage mammalian tissues. Thermal mechanisms, which are known to mediate damage with burst mode (hundreds of cycles) or cw insonation, are believed to be of negligible importance in pulsed insonation because of the subthreshold magnitude of temperature rise as calculated from estimates of peak acoustic intensities and “known” acoustic absorption coefficients of tissues. This has led some investigators to invoke the existence of mysterious mechanical mechanisms to explain the occurrence of tissue damage at acoustic intensity levels at which cavitation is known to be absent. Similarly, some form of nonthermal phenomena are invoked to explain differences in the results obtained from insonation with “equivalent” amounts (intensity X duration) of ultrasound in burst and pulsed modes, respectively. Implicit in these arguments is the assumption that the acoustical absorption coefficient is invariant and does not depend on the intensity of ultrasound or the state of the tissue. Thus, customarily, “known” absorption coefficients, measured with low intensity ultrasound, have been used to calculate temperature rises in tissues subjected to high intensity insonation. However, theoretical analyses, as well as experimental studies in mammalian tissues, indicate that the acoustical absorption coefficients in tissues, far from being invariant, are in fact dependent both upon the field intensity as well as the tissue state. [Work supported by the US PHS.]
FREE

Internal scattering of ultrasound in biological tissues in vitro (A)

A. B. Mansfield, N. Senapati, and P. P. Lele

J. Acoust. Soc. Am. Volume 59, Issue S1, pp. S77-S77 (1976); (1 page)

Online Publication Date: 11 Aug 2005

Full Text: | Download PDF

Show Abstract
The patterns of signal amplitude vs angular position which result when diagnostic level ultrasound is internally scattered by phantoms of precisely known geometry and various normal and pathological tissues were measured. The physical phenomenon is similar to Bragg diffraction which is seen when a wavefront impinges upon a regular array of scatterers whose size is smaller than and whose spacing is of the same order as the incident wavelength. The internal geometry of the targets and the ultrasonic wavelength determine a series of maxima and minima occurring with a specific predictable angular pattern. Matched pairs of 1–4‐MHz unfocused transducers were used as transmitter and receiver, respectively. The duration of the transmit pulse was long enough (10–20 msec) for a continuous wave approximation, but short enough to be spaced away temporally from the tank wall reflections. The signals received from the specimen were time‐gated, rectified, and integrated. The transducers were swept through an arc of ∼120°. The pattern of the scattered amplitude vs angle showed a characteristic average intermaximal separation which was a function of both the target structure and the ultrasonic wavelength. [Work supported by the US PHS.]
Return to All Sections
Close

Home Publications Meetings Contact ASA Site Map Back to Top

Copyright © Acoustical Society of America

close