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At least 37 records · Page 2Linked to original sources
PubMed1981

[Basic studies on ultrasonic surgery. I. Principles, status and perspectives of ultrasonic surgery].

The ultrasonic power with regard to its medical use for resection, treatment, and joining of soft and hard biologic tissues is investigated after the formation of the ultrasonic diagnostics and therapy. The situation of the ultrasonic surgery as an unconventional method for the ingenious complementation of tested operative techniques is valued after the representation of the mode of operation and the present equipment. The trend of development and prospective problems of the research are deduced from them.

Amputation Stumps↗
PubMed1977

[Perspectives of ultrasonic diagnosis for the localization of intrauterine pessaries. Ultrasonic presentation of various types of IUDs].

The authors report on their experiences with ultrasonic localization of several types of IUDs. The investigations were carried out with the ultrasonic equipment-B-scanning -- Vidoson S 635 (Siemens). The characteristics of the echosonic pictures of 6 IUDs (Szontágh-IUD, Lippes-Loop, Gravigard, Alza-T, Copper-T, Antigon were studied. It could be stated that the IUDs can be well identified by ultrasonics. In cases of IUD in situ and early pregnancy the amnion and the IUD can be exactly localized.

Amnion↗
PubMed2005

Detection and correction of aliasing in ultrasonic measurement of blood flows with Ultrasonic-Measurement-Integrated simulation.

Detailed information of real blood flows is essential to develop an accurate diagnosis or treatment for serious circulatory diseases such as aortic aneurysms. Ultrasonic-Measurement-Integrated (UMI) simulation, in which feedback signals from the ultrasonic measurement make the simulation converge to the real blood flow, is a key to solving this problem. However, aliasing in the ultrasonic blood velocity measurement causes UMI simulation to converge to an erroneous result. In this paper, we have investigated the detection and the correction of aliasing in UMI simulation. The artificial force in the feedback of UMI simulation can be used as an index to detect the aliasing. We have proposed two ways for the correction of the aliasing. Correction A, in which measurement velocity is replaced with the computational one at the monitoring point where the aliasing is detected, substantially improves the accuracy of UMI simulation. Correction B, in which measurement velocity is replaced with an estimated Doppler velocity, can provide exactly the same result as that of UMI simulation using the nonaliased standard solution. Although correction B gives the most accurate result, correction A seems more robust and, therefore, a beneficial choice considering the other artifacts in the measurement.

Doppler Effect↗
PubMed2005

Ultrasonic control of ceramic membrane fouling by particles: effect of ultrasonic factors.

Ultrasound at 20 kHz was applied to a cross-flow ultrafiltration system with gamma-alumina membranes in the presence of colloidal silica particles to systematically investigate how ultrasonic factors affect membrane cleaning. Based on imaging of the ultrasonic cavitation region, optimal cleaning occurred when the membrane was outside but close to the cavitation region. Increasing the filtration pressure increased the compressive forces driving cavitation collapse and resulted in fewer cavitation bubbles absorbing and scattering sound waves and increasing sound wave penetration. However, an increased filtration pressure also resulted in greater permeation drag, and subsequently less improvement in permeate flux compared to low filtration pressure. Finally, pulsed ultrasound with short pulse intervals resulted in permeate flux improvement close to that of continuous sonication.

Ceramics↗
PubMed1975

Ultrasonic measurement of sound velocity in whole blood. A comparison between an ultrasonic method and the conventional packed-cell-volume test for hematocrit determination.

A new ultrasonic instrument for the determination of sound velocity in tissue is described. The instrument has been used in this investigation to measure the sound velocity in heparinized whole blood samples. The corresponding hematocrit values of the blood samples were determined by the packed cell volume test. The measurements in the hematocrit range of approx. 30-55 indicate a high degree of correlation between the hematocrit value and the respective blood sound velocity (S.E.E.=1.3 and r=0.96). Repeated measurements of the same blood samples up to 1 hr after collection of the blood show very small changes in reading of sound velocity, provided the samples were kept at a constant temperature and well stirred. The ultrasonic measurement is quick and simple to perform, and the blood specimen is not changed by the measuring process.

Electronics, Medical↗
PubMed1992

A clinical evaluation of hand and ultrasonic instruments on subgingival debridement. 1. With unmodified and modified ultrasonic inserts.

This clinical investigation evaluated the effect on subgingival surfaces of three instruments: hand instruments and ultrasonic instruments with modified and unmodified inserts. Ten operators (five dentists and five dental hygienists) performed randomly assigned operative procedures. Pocket depth, instrument limit, and instrument efficiency were evaluated for each type of instrument. The results indicated that there are advantages to using modified ultrasonic inserts for scaling and root planing.

Dental Calculus↗
PubMed1994

Ultrasonic manipulation of particles and cells. Ultrasonic separation of cells.

Cells or particles suspended in a sonic standing wave field experience forces which concentrate them at positions separated by half a wavelength. The aims of the study were: (1) To optimise conditions and test theoretical predictions for ultrasonic concentration and separation of particles or cells. (2) To investigate the scale-up of experimental systems. (3) To establish the maximum acoustic pressure to which a suspension might be exposed without inducing order-disrupting cavitation. (4) To compare the efficiencies of techniques for harvesting concentrated particles. The primary outcomes were: (1) To design of an acoustic pressure distribution within cylindrical containers which led to uniformly repeating sound pressure patterns throughout the containers in the standing wave mode, concentrated suspended eukaryotic cells or latex beads in clumps on the axis of wide containers, and provided uniform response of all particle clumps to acoustic harvesting regimes. Theory for the behaviour (e.g. movement to different preferred sites) of particles as a function of specific gravity and compressibility in containers of different lateral dimensions was extended and was confirmed experimentally. Convective streaming in the container was identified as a variable requiring control in the manipulation of particles of 1 micron or smaller size. (2) Consideration of scale-up from the model 10 ml volume led to the conclusion that flow systems in intermediate volume containers have more promise than scaled up batch systems. (3) The maximum acoustic pressures applicable to a suspension without inducing order-disrupting cavitation or excessive conductive streaming at 1 MHz and 3 MHz induce a force equivalent to a centrifugal field of about 10(3) g. (4) The most efficient technique for harvesting concentrated particles was the introduction of a frequency increment between two transducers to form a slowly sweeping pseudo-standing wave. The attractive inter-droplet ultrasonic standing wave force was employed to enhance the rate of aqueous biphasic cell separation and harvesting. The results help clarify the particle size, concentration, density and compressibility for which standing wave separation techniques can contribute either on a process engineering scale or on the scale of the manipulation of small particles for industrial and medical diagnostic procedures.

Bacteria↗
PubMedDate not supplied

Evaluation of cross-circulation through circle of Willis using an ultrasonic Doppler technique. Part II. Comparison between blood flow velocity by ultrasonic Doppler flowmetry and cerebrovascular resistance.

The correlation between the increase in velocity of blood flow in both the internal carotid and vertebral arteries during a carotid compression and the cerebrovascular resistance (CVR) was investigated in 11 patients with chronic ischemic cerebrovascular disease and 4 without organic brain lesions. The velocity of blood flow was measured by an ultrasonic Doppler flowmeter. CVR was calculated from cerebral blood flow and arterial blood pressure. There was no correlation between the increased velocity of blood flow in the internal carotid and vertebral arteries and CVR. The increased velocity of blood flow in patients with low CVR was, however, significantly higher than that of patients with high CVR. The investigation of cross-circulation by ultrasonic Doppler flowmetry is a useful non-invasive method for the detection of changes in cerebral vascular resistance.

Adolescent↗
PubMed1992

Ultrasonic prediction of carcass merit in beef cattle: evaluation of technician effects on ultrasonic estimates of carcass fat thickness and longissimus muscle area.

The objective of this study was to determine technician effects of live animal ultrasonic estimates of fat thickness (FTU) and longissimus muscle area (LMAU). Steers (n = 36) representing four breed-types (Brown Swiss, Average Zebu-cross Mexican, Corriente Mexican, and typical British crossbred) of commercial slaughter cattle were isonified to estimate accuracy and repeatability of fat thickness (FT) and longissimus muscle area (LMA) measurements by two experienced technicians. Repeated measures of FTU and LMAU were taken by technicians on two consecutive days with an Aloka 500V ultrasound unit equipped with a 3.5-MHz, 172-mm scanning width, linear-array transducer. Ultrasonic estimates of fat thickness and LMAU were taken at the 12th and 13th rib interface 48 h before slaughter; carcass fat thickness (FTC) and longissimus muscle area (LMAC) were measured 48 h postmortem. Means for FTU, FTC, LMAU, and LMAC were .91 +/- .36 cm, .82 +/- .40 cm, 70.7 +/- 9.43 cm2, and 72.4 +/- 8.9 cm2, respectively. Ultrasound and carcass measures of FT and LMA were different (P less than .01) among breed-types but were not different (P greater than .10) between technicians or for technician x breed-type interactions. Pooled simple correlation coefficients (P less than .01) were .87 and .86 between FTU and FTC and .76 and .82 between LMAU and LMAC for Technicians 1 and 2, respectively. Repeatabilities estimated by intraclass correlation methods were .91 +/- .03 and .81 +/- .06 for images repeated over 2 d and .95 +/- .02 and .83 +/- .05 for images repeated by two technicians for FT and LMA, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Adipose Tissue↗
PubMed1975

[Ultrasonic angiocardiography and ultrasonic cineangiography: comparison between two techniques (author's transl)].

In a comparison of the performances of ultrasonic tomography (UT) versus ultrasonic cineangiography (UC), a new technique of cross sectional imaging of the heart using a low resolution (40 lines per frame) real time multiscanner apparatus, was performed. Technical problems related to both techiques are reviewed and discussed. UT seems to deserve consideration when precise anatomical details are required while UC is particularly recommended when function studies are indicated, but mainly if computer facilities are available. Both systems represent a real technical advance on conventional echography.

Angiocardiography↗
PubMedDate not supplied

Comparative study of a 15-MHz focused ultrasonic transducer and a 15-MHz unfocused ultrasonic transducer for clinical in-vivo skin-thickness measurements in human subjects.

A commercial focused 15-MHz immersion ultrasonic transducer and a commercial unfocused 15-MHz thickness-gaging ultrasonic transducer were evaluated for invivo skin-thickness measurements in humans. The unfocused transducer produced thicker skin measurements than did the focused transducer but both measurements were generally within previously reported ranges. The differences in the determined thicknesses may have been a result of the uneven nature of the dermissubcutaneous tissue interface and the ability of the focused transducer to better follow this interface.

Arm↗
PubMed1984

Ultrasonic diagnosis of altered fetal growth by use of a normal ultrasonic fetal weight curve.

A previously developed normal ultrasonic fetal weight curve was used for antenatal diagnosis of altered fetal growth in 595 patients who had undergone real-time ultrasound examination within 72 hours before birth. Fetal weight was estimated using biparietal diameter and abdominal circumference and plotted on the normal curve. The diagnosis of small for gestational age (SGA) or large for gestational age (LGA) was based on whether the ultrasonic weight fell below or above the normal limits. After delivery, infants were classified as SGA, LGA, or average for gestational age (AGA) by birth weight, and the postnatal diagnosis was compared to the antenatal ultrasound diagnosis. The sensitivity of the technique for the diagnosis of SGA infants was 89.9%; for LGA it was 73.5%. The overall specificity of the technique was 79.8%.

Birth Weight↗
PubMed2005

Ultrasonic excitation of a bubble near a rigid or deformable sphere: implications for ultrasonically induced hemolysis.

A number of independent studies have reported increased ultrasound bioeffects, such as hemolysis and hemorrhage, when ultrasound contrast agents are present. To better understand the role of cavitation in these bioeffects, one- and two-dimensional models have been developed to investigate the interactions between ultrasonically excited bubbles and model "cells." First, a simple one-dimensional model based on the Rayleigh-Plesset equation was developed to estimate upper bounds for strain, strain rate, and areal expansion of a simulated red blood cell. Then, two-dimensional boundary element models were developed (with DynaFlow Inc.) to obtain simulations of asymmetric bubble dynamics in the presence of rigid and deformable spheres. The deformable spherical "cell" was modeled using Tait's equation of state for water, with a membrane approximated by surface tension that increases linearly with areal expansion. The presence of a rigid or deformable sphere had little effect on the bubble expansion, but caused an asymmetric collapse and jetting for the conditions considered. Predicted membrane areal expansions were found to be below critical values for hemolysis reported in the literature for the cases considered near the inertial cavitation threshold.

Animals↗
PubMed1975

[Influence of ultrasonic waves and enzymes on antigenic properties of human erythrocytes. I. Ultrasonic waves].

In order to desintegrate the membranes and to isolate Rh antigens erythrocytes with well defined Rh patterns are treated with ultrasonic waves. The results of investigation of the homogenous sonicates allow the following tentative conclusions: The Rh antignes (C and E) are combined obviously with certain functional membrane areas of a given size. After sonication the activity of the sonicate to neutralize specific antibodies is greater than the activity of the same amount of untreated cells. It is supposed that this effect is caused by making accessible hidden antigens that are inaccessible in the intact membrane. Immunization of rabbits with the sonicates does not stimulate Rh-specific antibodies.

Antigen-Antibody Reactions↗
PubMed1987

Methacholine responsiveness increases after ultrasonically nebulized water but not after ultrasonically nebulized hypertonic saline in patients with asthma.

Airway obstruction can be induced in patients with asthma by the inhalation of ultrasonically nebulized aerosols of nonisotonic solutions. It is the change in osmolarity of the periciliary fluid that is believed to be the stimulus for bronchoconstriction. However, it is not known whether hyperosmolar and hypo-osmolar aerosols induce asthma via the same mechanism. We have previously reported that patients with asthma have a reduction in the dose of provoking agent that induces a 20% fall in FEV1 (PD20) for methacholine after challenge with nebulized water. To determine whether hyperosmolar aerosols also increase sensitivity to methacholine, we studied 13 subjects with asthma on 3 days. On day 1, the PD20 to methacholine was determined. On day 2, a challenge with nebulized 4.5% saline was followed by a challenge with methacholine 40 to 60 minutes later. On day 3, a challenge with nebulized water was followed by a methacholine challenge. Sensitivity to methacholine was significantly increased after water (p less than 0.02) but not after 4.5% saline. Furthermore, there was no relationship between the PD20 to water and to 4.5% saline. When the Spearman's correlation coefficient was used to compare sensitivity to the challenges, there was a significant relationship between the PD20 to 4.5% saline and methacholine (p less than 0.01) but not between the PD20 to water and methacholine. These results suggest that the mechanism of asthma induced by hyperosmolar and hypo-osmolar solutions is different.

Adolescent↗
PubMed1988

[A study of ultrasonic scaler. The effect of the different frequencies of the ultrasonics in the experimental calculus removal and roughness of the metallic plate after scaling].

In an attempt to determine how the degree of the experimental calculus removal on the metallic plate and its roughness after scaling would be affected by ultrasonics under high or low frequency, quantitative measurement and morphological observation were made. The results obtained were as follows: 1. On the calculus removal, larger effect was obtained by high frequency unit than low frequency. 2. On the roughness of the metallic plate after scaling, larger defect was observed by high frequency unit than low frequency. 3. Scanning electron microscopically, strip like defects were observed under low frequency unit, while exfoliation of the metallic plate in addition to the strip like defects were observed under high frequency.

Dental Calculus↗
PubMed1984

Ultrasonic B-scanning of the human skin. An introduction of a new ultrasonic skin-scanner.

A high frequency, high resolution dynamic ultrasonic skin-scanner is described. The skin-scanner is shown to give a cross-sectional image of the skin and provides an accurate, simple and non-invasive method for measuring full-thickness human skin. In addition to the skin thickness it is demonstrated that the underlying subcutaneous fat and muscles can also be non-invasively explored with the possibility of identifying a variety of skin and underlying tissue lesions.

Humans↗
PubMed1984

[Fundamental studies of ultrasonic surgery. 5. Ultrasonically forced polymerization of Ligament-Fimomed in joining biological tissue].

About basis investigations to the mode of action, the energy transformation, and to the polymerization heat of Ligament-Fimomed adhesive is informed over the ultrasonic osteosynthesis. A prompt activation of the monomeric tissue adhesive is attained at the contact region with the osseous tissue by means of low frequency power ultrasound. The mechanism of the connecting formation and characteristic temperature-time course are shown.

Enbucrilate↗