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Showing papers in "Ultrasound in Medicine and Biology in 1980"


Journal ArticleDOI
TL;DR: The simplified results of several theoretical derivations are presented and employed in illustrative calculations and plots to ascertain the importance of nonlinear effects in applications involving plane waves, spherically diverging waves, and spheric converging waves.
Abstract: Some fundamentals of nonlinear acoustics are reviewed to facilitate their consideration in biomedical ultrasound. The phenomena described include acoustic nonlinearity, finite amplitude distortion, shock formation, harmonic components, nonlinearly induced absorption, saturation, and the influence of these effects on ultrasonic beams. The simplified results of several theoretical derivations are presented and employed in illustrative calculations and plots. These maybe used to ascertain the importance of nonlinear effects in applications involving plane waves, spherically diverging waves, and spherically converging (focused) waves. A discussion of relevant experiments is given, along with some comments on possible consequences in diagnostic, surgical, and theraputic applications.

279 citations


Journal ArticleDOI
TL;DR: Calculations show that a bubble of diameter small enough to get through these capillaries will totally dissolve due to surface tension effects, in a time shorter than the pulmonary capillary to left atrial circulation time.
Abstract: Peripherally injected ultrasonic contrast is removed by the lungs. The source of this contrast effect is microbubbles in the injected fluid. We studied bubble dynamics to attempt to explain their removal by the lungs. Commercially prepared precision microbubbles of 5–10 μm could be imaged using standard M-mode echocardiographic equipment. Thus, absence of contrast in left atrial echocardiogram after peripheral contrast injections implies that bubbles of this size are absent, though they are small enough to traverse the pulmonary capillary “sieve”. Calculations show that a bubble of diameter small enough to get through these capillaries (mean size 8 μm) will totally dissolve due to surface tension effects, in a time shorter than the pulmonary capillary to left atrial circulation time.

168 citations


Journal ArticleDOI
TL;DR: Examples of nonlinear acoustic phenomena in water in the range of frequencies and intensities of interest for biomedical ultrasound are provided and simple adaptation of the theory summarized in a companion paper leads to predictions which are in excellent agreement with the observations.
Abstract: Examples of nonlinear acoustic phenomena in water in the range of frequencies and intensities of interest for biomedical ultrasound are provided. Total intensities, including all harmonics generated in the medium have been measured with a spherical radiometer. The fundamental component of the waves have been measured with a miniature probe hydrophone and low pass filter. Simple adaptation of the theory summarized in a companion paper leads to predictions which are in excellent agreement with the observations. The illustrated phenomena must be considered in studies of the biological effects of ultrasound as well as in the applications of ultrasound in medicine.

162 citations


Journal ArticleDOI
TL;DR: It is demonstrated that the potassium content of rat thymocytes in vitro is decreased following exposure to 2W/cm 2, 3MHz ultrasound for 40 min at 37°C, without inducing cell lysis or gross membrane damage.
Abstract: It is demonstrated that the potassium content of rat thymocytes in vitro is decreased following exposure to 2W/cm 2 , 3MHz ultrasound for 40 min at 37°C, without inducing cell lysis or gross membrane damage. The abnormal values for potassium are maintained after completion of insonation. The changes are shown to arise from ultrasound-induced decreases in ion influx together with increases in potassium efflux. Recorded temperature changes in the media are shown to be insufficient to account for the observed decreases in cell potassium. The magnitude of cell potassium decrease at 3 MHz is shown to be similar in aerated and degassed water. Acoustic microstreaming either at the cell membrane of within the cell is suggested as the damage mechanism leading to ion flux changes.

105 citations


Journal ArticleDOI
TL;DR: A third order mathematical model is developed which describes these waveforms in patients with occlusive arterial disease and in normal volunteers, which has two complex and one real pole, and in occluded arteries with collateral circulation all the poles are real.
Abstract: A method is presented for describing the shape of the blood-velocity/time waveforms recorded at the posterior tibial artery, using Doppler-shift flowmeters. A third order mathematical model is developed which describes these waveforms in patients with occlusive arterial disease and in normal volunteers. In normals, the model has two complex and one real pole, and in occluded arteries with collateral circulation all the poles are real. The complex poles are shown to be related to the elastic modulus of the artery and also to the lumen size. The third pole is shown to be related to the degree of vasoconstriction of the peripheral circulation.

90 citations


Journal ArticleDOI
TL;DR: The results show that the Laplace transform method is a sensitive technique for determining the presence of minor stenoses in the aorto-iliac segment, for determining changes in elastic modulus of the proximal vessels, and for studying changes in distal impedance.
Abstract: The blood-velocity/time waveforms over the cardiac cycle obtained from the common femoral arteries of 44 limbs, are defined using Fourier transform and curve-fitting techniques. This results in a third order Laplace transform whose coefficients can be related to distal impedance, proximal lumen diameter and stiffness. The sensitivity of this technique has been investigated in the study of aorto-iliac disease, and compared with single plane arteriography and Pulsatility Index. The results show that the Laplace transform method is a sensitive technique for determining the presence of minor stenoses in the aorto-iliac segment, for determining changes in elastic modulus of the proximal vessels, and for studying changes in distal impedance. Pulsatility Index, is sensitive to the presence of proximal disease but it does not seem able to differentiate between stenoses of less than or greater than 50%. PI is sensitive also to changes in distal impedance, but insensitive to changes in arterial elasticity.

90 citations


Journal ArticleDOI
TL;DR: The Duplex Scanner III is described, which provides B -mode images of vascular anatomy combined with a pulsed 5 MHz Doppler to analyze blood flow within those vessels imaged.
Abstract: Ultrasound provides a convenient means for the clinical evaluation of both the anatomy and the blood velocity patterns in large peripheral blood vessels. Continued development of ultrasound techniques has reached the point of providing useful diagnostic information in a routine fashion. This paper describes the Duplex Scanner III, which provides B -mode images of vascular anatomy combined with a pulsed 5 MHz Doppler to analyze blood flow within those vessels imaged. Improvements over the Duplex Scanner II include: increased scan head reliability; additional operating features and processing techniques to more accurately evaluate anatomy and blood flow characteristics; and display and recording techniques to facilitate clinical use.

61 citations



Journal ArticleDOI
TL;DR: A third order Laplace transform whose coefficients can be related to distal impedance, proximal lumen diameter and elastic modulus is results in a blood-velocity/time waveform over the cardiac cycle from the common femoral artery investigated using Fourier transform and curve-fitting techniques.
Abstract: The blood-velocity/time waveform over the cardiac cycle from the common femoral artery is investigated using Fourier transform and curve-fitting techniques. This results in a third order Laplace transform whose coefficients can be related to distal impedance, proximal lumen diameter and elastic modulus. The validity of the method is investigated by determining the coefficients of the Laplace transform, derived from the common femoral waveform, and from these values, reconstructing the waveform and comparing with the original. The Fourier transform, curve fitting, and reconstruction procedures are shown for each waveform so that all stages of the method can be critically assessed.

58 citations


Journal ArticleDOI
TL;DR: The character of such lesions suggests that essential focal beam dimensions and temporal coherence of the sound wave were preserved with minimal distortion after transmission through this particular skull section, which has been determined to exhibit sound intensity losses of about 16 dB at 500 kHz.
Abstract: Focal lesions in lucite blocks and live brain tissue produced by an intense focused 500 kHz ultrasonic beam which had first been transmitted through an excised adult human skull section (formalin fixed) are described. The incident acoustic intensifies ranged from about 880 to 1200 W/cm 2 with exposure durations of 5–6 sec. The character of such lesions suggests that essential focal beam dimensions and temporal coherence of the sound wave were preserved with minimal distortion after transmission through this particular skull section (7–8 mm thickness over the region of sound transmission), which has been determined to exhibit sound intensity losses of about 16 dB at 500 kHz. These appears to be little heating of the skull section during irradiation at this incident intensity.

48 citations


Journal ArticleDOI
TL;DR: Suspensions of human erythrocytes in saline containing Luciferase/Luciferin were exposed to 1.6 MHz ultrasound in the presence of stable gas bodies trapped within the holes in hydrophobic Nuclepore membranes, apparently indicating that some ery Throatcytes were being disrupted.
Abstract: Suspensions of human erythrocytes in saline containing Luciferase/Luciferin (an enzyme preparation from fireflies which emits visible light in the presence of ATP) were exposed to 1.6 MHz ultrasound in the presence of stable gas bodies trapped within the holes in hydrophobic Nuclepore membranes. Ultrasonic intensities greater than 20–30 mW/cm2 (spatial peak) resulted in the emission of light, apparently indicating that some erythrocytes were being disrupted. No effects could be observed at these low intensities in the absence of the gas bodies.

Journal ArticleDOI
TL;DR: The design considerations and capabilities of a scanner with these multiple modes of operation, including compound scan as well as simple scan mode, are discussed and the initial clinical results and potential applications are presented.
Abstract: A real time scanner which images in compound scan as well as simple scan mode offers advantages over a conventional unit which only produces simple scans in one format. A linear array scanner in which the line of sight can be steered gives a variety of formats for both simple scan and compound scan imaging. The design considerations and capabilities of a scanner with these multiple modes of operation is discussed. The initial clinical results and potential applications are presented.

Journal ArticleDOI
TL;DR: It was found that the RTR was simpler to measure than other more commonly used parameters such as Pulsatility Index and at least as sensitive for the differentiation between severe arterial disease and the mildly affected or normal state.
Abstract: The common femoral to popliteal segments of 123 patients with radiologically confirmed arterial disease have been compared with those of 43 volunteers apparently free from disease. The comparisons have been based upon parameters derived from Doppler-shifted, continuous wave ultrasound. Simultaneous recordings of the Doppler signal were made from over the common femoral artery and the popliteal artery; these were analyzed subsequently to reveal variations of maximum frequency with time. Fifteen parameters were obtained from each segment. Of these the Pulsatility Index (P.I.) the Damping Factor(Δ), the pulse wave transit time(TT) the rise time ratio(RTR) from each segment were examined in detail. The Doppler results from the patient groups were compared also with the findings from arteriography. On the basis of these comparisons it was found that the RTR was simpler to measure than other more commonly used parameters such as Pulsatility Index and at least as sensitive for the differentiation between severe arterial disease and the mildly affected or normal state. However, none of these parameters was sufficiently sensitive to distinguish between mild to moderate disease and normal.

Journal ArticleDOI
TL;DR: The authors describe a pulsed-Doppler technique using a single gate which they believed enabled the identification of the vertebral artery with greater certainty than previous techniques, but critical analysis of their results show that this technique is still not satisfactory and that recordings from other arteries are still being made under the impression that the signals are arising from the vertebrae.
Abstract: The vertebral arteries have always been difficult to examine with ultrasonic Doppler systems. While a number of different techniques have been proposed none would seem to be satisfactory and all suffer from difficulty in identifying, with certainty, the signals arising from the vertebral arteries. The exception to this restriction would appear to be the identification of retrograde vertebral artery flow in “steal” syndromes. The authors raise the question however, whether clinical bias may not play a significant part in such successful examinations since “steal” syndromes can be diagnosed by means other than Doppler recording and the results of such investigations are usually known to the operator before the Doppler examination is made. An example where such clinical bias was responsible for a false diagnosis of a “steal” syndrome is given. The authors describe a pulsed-Doppler technique using a single gate which they believed enabled the identification of the vertebral artery with greater certainty than previous techniques. Critical analysis of their results however, show that this technique is still not satisfactory and that recordings from other arteries are still being made under the impression that the signals are arising from the vertebral artery.

Journal ArticleDOI
TL;DR: It is suggested that the tissue changes which collectively constitute aging may, in some instances, be predictably associated with measurable changes in the acoustic properties of those tissues.
Abstract: The propagation velocity (c) and attenuation coefficient (α) of ultrasound were measured at room temperature in skin tissues excised from twenty aged (27 months) and eight young (2 months) Bar Harbor strain female mice. Frequencies used were 2.25, 5.0, 7.5 and 10.0 MHz. Both velocity and attenuation data were obtained using a pulse-echo technique. Transit times were measured with a universal counter timer to 10 nsec resolution, and corrected for the “dead time” due to the transducer matching layer. Aged skin had significantly lower values of c and α at all frequencies than did the corresponding young tissues. This preliminary study suggests that the tissue changes which collectively constitute aging may, in some instances, be predictably associated with measurable changes in the acoustic properties of those tissues.

Journal ArticleDOI
TL;DR: Analysis of the acute oedema response of rats to intracutaneous injection of silver nitrate found significant reduction of dye leakage occurred with treatment of injection sites with ultrasound at 0.79 MHz frequency, but not with the other frequencies and durations tested.
Abstract: The effect of ultrasound at a space-averaged intensity of 0.5 W/cm2:administered for 2-5 min at frequencies of 2.9, 1.5 and 0.79 MHz and mark-space ratios of 1:4(2 ms:8 ms) and 1:1(2 ms:2 ms) was investigated on the acute oedema response of rats to intracutaneous injection of silver nitrate. Rats. anaesthetized with ether were given Evans blue intravenously and two intracutaneous injections of silver nitrate (2 × 10-6 mol) into the abdominal skin. Insonation of one skin site and mock-insonation of the other was performed immediately after the injections. Rats were killed 30 min after the injections and oedema response measured by the amount of dye leakage expressed as absorbance. Significant reduction of dye leakage occurred with treatment of injection sites with ultrasound at 0.79 MHz frequency and durations of application of 2 and 4 min for both mark-space ratios,but not with the other frequencies and durations tested. Further studies are necessary to determine the relevance of this finding to the clinical efficacy of ultrasound in certain inflammatory conditions.

Journal ArticleDOI
TL;DR: The M and S phases of the cell cycle were more resistant with respect to cell lysis and loss of reproductive integrity than were the G1 and G2 phases.
Abstract: Chinese hamster V-79 cells were exposed in suspensions for 1–15 min to 1.1 MHz continuous wave (CW) ultrasound at axial intensifies from 0.25–30 W/cm2. Cell lysis was evidenced by a decrease in the number of intact cells, and loss of reproductive integrity was evidenced by a decrease in the plating efficiency of the remaining intact cells. The magnitude of these effects was a function of both intensity and exposure duration. Mitotically synchronized cells displayed a differential sensitivity depending upon cell cycle position. The M and S phases of the cell cycle were more resistant with respect to cell lysis and loss of reproductive integrity than were the G1 and G2 phases.

Journal ArticleDOI
TL;DR: In this paper, a simple instrument for determining the total power from ultrasonic therapy equipment is described, which employs a novel method of measuring the radiation force exerted by the ultrasonic beam radiated by the equipment into a water-filled test tank.
Abstract: A simple instrument for determining the total power from ultrasonic therapy equipment is described. It employs a novel method of measuring the radiation force exerted by the ultrasonic beam radiated by the equipment into a water-filled test tank, and offers a number of advantages over established techniques with regard to simplicity, sensitivity and ease of use. Further development of the device now in progress could provide a simple means of measuring ultrasonic power at the much lower levels normally associated with diagnostic equipment.

Journal ArticleDOI
TL;DR: This study was unable to confirm earlier reports of delayed lethality as a result of exposure to ultrasound in that fraction of the population which survived beyond the egg stage.
Abstract: Eggs of the fruit fly, Drosophila melanogaster (wild type), were exposed to 1 MHz traveling and standing wave ultrasound at intensities up to 5 W/cm 2 . Traveling waves at 3 W/cm 2 and “1 W/cm 2 standing waves” killed about one third of the exposed population. Death occurred at the egg stage of development. This study was unable to confirm earlier reports of delayed lethality as a result of exposure to ultrasound in that fraction of the population which survived beyond the egg stage.

Journal ArticleDOI
TL;DR: The slowing-down or arrest of the growth of the globe indicates the severity of RLFP and a diagnosis of retinoblastoma can be ruled out with great certainty and retinal detachment, if present, is manifest also with echo-opthalmography.
Abstract: Fifteen premature babies were controlled with ultrasound because of retrolental fibroplasia (RLFP). The typical echogram shows behind the lens echoes of medium amplitudes. The posterior part of the vitreous is acoustically clear. A diagnosis of retinoblastoma can be ruled out with great certainty and retinal detachment, if present, is manifest also with echo-opthalmography. Coast's disease, uveitism, persistent hyperplastic primary vitreous and vitreal opacities may show similar echograms as in RLFP. Biometry demonstrated microphthalmos in 36% of the cases. The slowing-down or arrest of the growth of the globe indicates the severity of RLFP. Visual axis shrinkage was never observed.

Journal ArticleDOI
TL;DR: A phantom for comparative imaging of biological fluids by ultrasonic and computerized tomographic scanning is described, which incorporates a tissue-equivalent gel closely resembling human liver tissue as imaged by these two modalities.
Abstract: The construction of a phantom for comparative imaging of biological fluids by ultrasonic and computerized tomographic scanning is described. The phantom incorporates a tissue-equivalent gel closely resembling human liver tissue as imaged by these two modalities.

Journal ArticleDOI
TL;DR: An exposure of the eggs of Drosophila melanogaster to a traveling wave of 1 MHz ultrasound at 5 W/cm 2 for 30 sec has been found to kill approximately 70% of the population, and the sensitivity of the Eggs to heat alone was tested.
Abstract: An exposure of the eggs of Drosophila melanogaster to a traveling wave of 1 MHz ultrasound at 5 W/cm 2 for 30 sec has been found to kill approximately 70% of the population. To determine whether heating could be responsible for this effect, the sensitivity of the eggs to heat alone was tested. Temperature increments attributable to ultrasound were estimated by treating the eggs as heat sources in a thermally conducting medium. The absorption coefficient of the eggs was found to be very large but estimated to be less than 5 nepers/cm. The corresponding maximum temperature increments were calculated to be less than 3°C. This value is far too low to account for the observed effects on the basis of heating.

Journal ArticleDOI
TL;DR: This technique which is easily applicable to existing pulsed Dopplers, should extend the clinical applicability of these systems to long range or high velocity flows whose Doppler spectra are sufficiently narrow.
Abstract: Existing pulsed Dopplers have a fundamental limitation which makes them unable to measure a velocity v at a range R greater than that given by the limit Rv = c 2 /8 φ 0 where c is the sound velocity and f 0 the transmitted ultrasound frequency. This limit makes it impossible for conventional pulsed Dopplers to measure blood velocity transcutaneously in such locations as stenosed or regurgitant heart valves in adults. This paper described a principle using periodic changes of the repetition frequency of the transmitted signal. This increases the range limit of pulsed Doppler systems by the ratio of the Doppler spectrum enter frequency to its bandwidth. This technique which is easily applicable to existing pulsed Dopplers, should extend the clinical applicability of these systems to long range or high velocity flows whose Doppler spectra are sufficiently narrow

Journal ArticleDOI
TL;DR: Application of the 30 channel directional pulsed Doppler imaging system (MAVIS) to the investigation of patients with either vertebro-basilar symptoms or the subclavian steal syndrome is discussed.
Abstract: A 30 channel directional pulsed Doppler imaging system (MAVIS) has been used to produce images of the vertebral artery. The technique of imaging the subclavian artery in the suparaclavicular fossa, the origin of the vertebral artery and the section of this vessel up to the foramen in the transverse process of the sixth cervical vertebra is described. Further segments of the vertebral artery appearing between the cervical transverse processes can also be imaged if disease in the mid portion of the vessel is suspected. Confirmation of the identity of the insonated artery is gained from its position on the image in relation to the subclavian and common carotid arteries and from its characteristic flow velocity wave forms. Examples of the typical antero-posterior images obtained are presented. Of 60 vertebral arteries scanned, 56 have been imaged successfully. Insufficient patients have undergone conventional contrast angiography to allow data on diagnostic accuracy but the unsuccessful scans may well have been in those with occluded vessels. Application of the technique to the investigation of patients with either vertebro-basilar symptoms or the subclavian steal syndrome is discussed.


Journal ArticleDOI
TL;DR: Mitochondria appear to be the most sensitive organelle, exhibiting swelling, electron-dense condensations in the matrix, loss of cristae, and the formation of lamellar membranes, with eventual disruption of the outer membrane.
Abstract: Reproducible ultrastructural alterations in subcellular organelles have been produced with ultrasonic exposure. Mitochondria appear to be the most sensitive organelle, exhibiting swelling, electron-dense condensations in the matrix, loss of cristae, and the formation of lamellar membranes, with eventual disruption of the outer membrane. The endoplasmic reticulum is less sensitive, but also shows a graded response to increasing exposure including dilation of the cisternae, loss of ribosomes from the surface, and vesiculation. Lysomes appear to retain their structural integrity better than other cytoplasmic organelles. If the level of exposure is not lethal to the cell, most of the changes are repaired within 96 hr; however, mitochondrial changes persist for longer periods and may be irreversible. Additional studies are needed to understand the mechanism of mitochondrial injury and recovery.

Journal ArticleDOI
TL;DR: In this paper, both pulsed and continuous wave 3 MHz radiation was used to treat hamster fibrosarcomas and rates of metastasis and effectiveness in eliminating the primary tumor were approximately equal with the two methods of treatment.
Abstract: Ultrasonically induced hyperthermia (44–45°C for 10 min) and surgical excision were used in the treatment of hamster fibrosarcomas. Both pulsed and continuous wave 3 MHz radiation was used. Rates of metastasis and effectiveness in eliminating the primary tumor were approximately equal with the two methods of treatment.

Journal ArticleDOI
TL;DR: High amplitude modulated subharmonic and white noise emissions were detected, after a time delay, at intensities in excess of 22 W/cm 2 when bean root tips were exposed to ultrasound in either plane or focused fields at 1 MHz.
Abstract: High amplitude modulated subharmonic and white noise emissions were detected, after a time delay, at intensities in excess of 22 W/cm 2 when bean root tips were exposed to ultrasound in either plane or focused fields at 1 MHz. The temperature rise in the root tips on initiating exposure was 8°C at 10 W/cm 2 and 15°C at 40 W/cm 2 . A further temperature increase ranging from 5° to 20°C was observed if subharmonic emission began during the exposure. Growth inhibition occurred in root tips heated to 40°C for 3 min in the absence of sound. The temperature of the ultrasound treatment tank was maintained at about 8°C to avoid damaging temperature rises during sonication. Root growth inhibition occurred in the plane field in the absence of strong subharmonic emission at intensities as low as 3 W/cm 2 following 80-min treatment. These was a detectable increase in second harmonic emission when roots were treated in the focused field at 15 W/cm 2 for 6 min.

Journal ArticleDOI
TL;DR: A new form of automated scanning has been developed which overcomes geometric and amplitude distortion and physical scanning limitations, associated with simple arcs, and is required for ultrasound mammography of large breasts.
Abstract: A new form of automated scanning has been developed which overcomes geometric and amplitude distortion and physical scanning limitations, associated with simple arc scanning. In simple arc scanning, the transducer rotates about a point located behind the viewed object. This produces a dense concentration of scan lines around the point of rotation, resulting in a V-shaped type of geometric distortion. Remote focus arc scanning, reported in this paper, results in an arc scan which reduces this geometric distortion by substituting an imaginary focal point placed at infinity for a true point source of rotation. This is accomplished by simultaneous simple arc and sector scanning motions. This type of scan is required for ultrasound mammography of large breasts.

Journal ArticleDOI
TL;DR: The results indicated differences between children younger than 1 yr and those who are older in pediatric echocardiography, which was based on the image quality of six cardiac structures which include the aortic root, left atrium, right ventricle, interventricular septum, left Ventricle and mitral valve.
Abstract: Recently a hand-held two-dimensional linear array ultrasound diagnostic system was introduced. To assess the clinical usefulness of this non-invasive system in pediatric echocardiography, an evaluation study was carried out. For this purpose 58 children up to the age of 18 yr were examined. Several of them were known to have a congenital cardiac malformation. The assessment has been based on the image quality of six cardiac structures which include the aortic root, left atrium, right ventricle, interventricular septum, left ventricle and mitral valve. The results indicated differences between children younger than 1 yr and those who are older. Therefore the patients were divided into two groups. In the younger children, only three cardiac structures, the aortic root, left atrium and mitral valve, were recognized with a score above 80%, whereas the remaining structures received a score of 60% or lower. In the older age group the results were much better, as all six cardiac structures were visualized with a score of 80% or more.