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PubMed1975

An ultrasonic deflector for aspiration and biopsy.

A new ultrasonic deflector for aspiration and biopsy is described. It is made of a Plexiglas prism (45 degrees) with an oblique hole (27 degrees). The ultrasonic beam is bent in water by about 23 degrees. A puncture needle inserted through the prism hole passes through the ultrasonic beam in water with only minimal deviation from the beam axis. A fairly strong echo from the needle tip is a useful indicator for positioning the needle for aspiration. The resolution of the ultrasonic scan is not significantly affected by the deflector. This inexpensive ultrasonic deflector is capable of performing the functions offered by the expensive ultrasonic aspiration-biopsy transducer.

Biopsy, Needle↗
PubMedDate not supplied

Distortions of ultrasonic field introduced by the rib cage in echocardiography.

In ultrasonic examination of the heart, the anatomy and motion of heart structures can be observed by placing the ultrasonic transducer over an intercostal window adjacent to the sternum. The ultrasonic beam may be reflected, refracted, or scattered from its path by the ribs and soft tissues before reaching the target of interest. This interaction between the tissues and ultrasound beam, which introduces significant changes in ultrasonic beam characteristics, may result in considerable degradation of the lateral resolution of the ultrasonic system, determined largely by the beam width. In this paper, the effect of rib cage on the beam characteristics is examined. It is shown that the rib cage can produce severe distortions of the ultrasonic beam, namely, asymmetry in beam cross-section, alteration in beam diameter, and deflection of the beam from its central path. It is also demonstrated that this distortion is dependent upon transducer diameter, width of the intercostal window, and transducer angulation relative to the breast plate.

Echocardiography↗
PubMed1993

Ultrasonic DREZ-operations for treatment of pain due to brachial plexus avulsion.

One, if not the only effective way of treating pain due to preganglionic avulsion of the brachial plexus is the Dorsal Root Entry Zone (DREZ) lesion procedure. In 1985 the author began to use ultrasound as a lesion-maker for operations in the DREZ. Since then, 127 (3 patients were operated on twice) DREZ-Operations have been carried out on 124 patients suffering from chronic pain due to brachial plexus avulsion. Different technical lesioning modalities were employed: ultrasonic discontinuous DREZ lesions in 20 cases and a new modality: ultrasonic DREZ-sulcomyelotomy in 107 cases. Analysis of the results after ultrasonic DREZ-operations revealed that ultrasonic DREZ-sulcomyelotomy was the most effective technical modality. Immediately after operation good pain relief was obtained in 103 (96%) out of the 107 patients operated on with the ultrasonic DREZ-sulcomyelotomy method, and in 15 (75%) out of the 20 patients with ultrasonic discontinuous DREZ-lesions. The total follow-up study (47.5 months on average) revealed 87% good results overall.

Adult↗
PubMed2005

Improved ultrasonic extraction procedure for the determination of polycyclic aromatic hydrocarbons in sediments.

The aim of this work was to optimize an ultrasonic extraction procedure for the determination of polycyclic aromatic hydrocarbons (PAHs) in sediments and to compare it with the reflux procedure using methanolic potassium hydroxide. Sample extracts were purified with a miniaturized silica gel chromatographic column and analyzed by gas chromatography-mass spectrometry (GC-MS). Ultrasonication using n-hexane-acetone (1:1, v/v) solvent mixture on dried homogenized marine sediment gave better precision (smaller relative standard deviation (RSD) values) and comparable quantities of individual PAH's compared to the reflux procedure. Ultrasonication with the n-hexane-acetone (1:1, v/v) mixture, utilizing four 15 min extraction cycles, was found to be sufficient for extracting PAHs from wet sediments. The optimized ultrasonic extraction procedure extracted aliphatic and aromatic hydrocarbons from the National Institute of Standards and Technology SRM 1941a with recoveries greater than 90%. The major advantages of ultrasonication compared to the reflux method are the lower extraction times, simplicity of the apparatus and extraction procedure. The optimized ultrasonication procedure has been used in our laboratory to extract hydrocarbons from naturally wet sediments from rivers, and coastal and marine areas.

Acetone↗
PubMed2004

Endothelial integrity of ultrasonically skeletonized internal thoracic artery: morphological analysis with scanning electron microscopy.

OBJECTIVE: The skeletonized internal thoracic artery (ITA) has several advantages over a pedicled one in coronary artery bypass grafting (CABG). An ultrasonic scalpel makes ITA skeletonization easy and speedy, however, the ultrasonic energy that is transmitted to the artery itself can occasionally injure the endothelium. Therefore, the endothelial integrity of the ultrasonically skeletonized ITA is a major concern related to this technique. The purpose of this study is to assess the endothelial integrity of the ultrasonically skeletonized ITA. METHODS: We skeletonized the left ITA with an ultrasonic scalpel in nine patients who underwent CABG, and thereafter the terminal portion of this artery was subjected to a morphological study. The endothelial integrity of this artery was morphologically assessed using scanning electron microscopy, and the results were compared to that of the left ITA skeletonized with fine scissors. RESULTS: All ITA specimens showed a completely confluent endothelium, and no endothelial injury was observed by the scanning electron microscopic study. CONCLUSIONS: The skeletonization of the ITA with an ultrasonic scalpel had no deleterious effect on the endothelium. This morphological study confirmed the safety and the reliability of this technique, and we therefore recommend its clinical use in the skeletonization of the ITA for CABG.

Endothelium, Vascular↗
PubMed2005

Novel ultrasonic evaluation of tissue-engineered cartilage for large osteochondral defects--non-invasive judgment of tissue-engineered cartilage.

Although numerous methods for regenerating articular cartilage have been investigated, the regenerated tissue showed various histological findings from hyaline-like cartilage to fibrous tissue. Without biopsy, we are unable to know whether the cartilage regeneration method was histologically successful or not. We developed a new ultrasonic evaluation system for articular cartilage using the maximum magnitude (MM) from ultrasonic analysis. The purpose of this study was to investigate the usefulness of ultrasonic judgment of the cartilage regeneration procedure. Using our system we quantitatively evaluated tissue-engineered cartilage in rabbit cartilage defects. The specimens were retrospectively divided into two groups on the basis of histological findings and investigated whether significant differences in ultrasonic analysis could be found between the two (group H: hyaline-like cartilage group, successful; group F: fibrous tissue group, failure). In the ultrasonic findings, the MM was 1.11+/-0.32 in group H and 0.65+/-0.18 in group F and these differences were significant (P=0.00061). Our results suggest that the ultrasonic evaluation system used in the present study is capable of judging the success or failure of cartilage regeneration procedures, and therefore, it could be a valuable tool arthroscopic diagnosis of cartilage regeneration.

Animals↗
PubMed2005

Near infrared emission spectroscopy induced by ultrasonic irradiation.

Near infrared emission caused by ultrasonic excitation is demonstrated for the first time in this work. The instrument is constituted of an acousto-optical tunable filter-based spectrometer, an ultrasonic processor connected to a titanium alloy ultrasonic probe and a cylindrical borosilicate flask containing the sample to be excited. The radiation emitted by the sample is collected by a concave mirror and sent to the spectrometer. The effects of the position of the probe extremity in relation to a lateral entrance of the borosilicate flask and of the ultrasonic power on the emission signal were studied. The best results were obtained by positioning the probe extremity up to 2mm from the reflexive body (lateral entrance) using 30% of the full ultrasonic incident power and acquiring spectra after 5 min of sonication. The NIR emission spectra resulting from the ultrasonic excitation were in agreement with that obtained by thermal excitation. The proposed technique was utilized to study different poly(dimethylsiloxane) samples having different viscosities.

Acoustics↗
PubMed2000

Radial artery harvest: comparison of ultrasonic dissection with standard technique.

BACKGROUND: The radial artery (RA) is used increasingly for myocardial revascularization. Having an ultrasonic dissector available in our unit, we began to use it for RA harvest with the impression that harvest spasm might be less for the new technique. METHODS: We compared RA harvest using standard techniques (21 RA) with ultrasonic dissection (41 RA) in which all branches were divided between clips with scissors in the former and bleeding branches were clipped in the latter. RESULTS: Harvest times were not different. Conventional technique used 74+/-18 (mean +/- standard deviation) clips versus 3.2+/-4.3 clips (p<0.001). In situ free flow was 17.2+/-20.7 mL/min for conventional technique versus 52.5+/-48.1 for ultrasonic (p<0.001). Free flow after the proximal anastomosis to the left internal thoracic artery was 38.5+/-60.4 mL/min for conventional technique and 50.7+/-29.6 for ultrasonic (p = 0.008). Free flow 10 minutes after intraluminal papaverine was 78.5+/-45.9 mL/min for usual technique versus 102.8+/-51.7 for ultrasonic (p = 0.016). No patient required reoperation for bleeding. CONCLUSIONS: Ultrasonic dissection of the RA is associated with decreased RA spasm, good hemostasis, no additional harvest time, and has become our standard technique.

Anastomosis, Surgical↗
PubMed2000

Interactions between N-methyl-D-aspartate and nitric oxide in the modulation of ultrasonic vocalizations of infant rats.

The effects of interactions between N-methyl-D-aspartate (NMDA) and nitric oxide on ultrasonic vocalizations, motor activity and body temperature was investigated in 9-10-day-old rat pups. The competitive NMDA receptor antagonist, 3-((+/-)-2-carboxypiperazin-4-yl)-propyl-1-phosphonic acid (CPP), and the nitric oxide synthase inhibitor, nitro-L-arginine-methyl ester (L-NAME), decreased the emission of ultrasonic vocalizations while NMDA and the nitric oxide precursor, L-arginine, produced a trend toward increased emission of ultrasonic vocalizations. CCP also attenuated the geotaxic response. Co-administration of CPP with L-NAME virtually abolished the emission of ultrasonic vocalizations and the ability to show the geotaxic response while co-administration of NMDA with L-arginine increased the emission of ultrasonic vocalizations and decreased body temperature with no effect on the geotaxic response. NMDA and L-arginine reversed the effects of L-NAME, but not of CPP, on ultrasonic vocalizations. L-arginine but not NMDA antagonized the effect of CPP on the geotaxic response. Our results confirmed the functional coupling between NMDA receptor activation and nitric oxide in modulating anxiety-like behavior and motor coordination in infant rats.

Animals↗
PubMed2003

Thin-disc piezoceramic ultrasonic motor. Part II: system construction and control.

Design and performance evaluation of an ultrasonic motor was discussed in [Wen et al., Thin-disc piezoelectric ultrasonic motor. Part I: design and performance evaluation, Ultrasonics]. Higher precision position control of piezoceramic ultrasonic motor depends on mechanical design and servo control of a very precise and adequate metrology. This paper proposes the design of a driving circuit and controller to deal with non-linearities behavior in the model of piezoceramic-driving ultrasonic motor. The performance of the driver and the effectiveness of the proposed controller are demonstrated by command inputs of sinusoidal and step signals. For comparison purpose, the ultrasonic motor is controlled using two methods: i.e., proportional-integral-derivative (PID) and sliding-mode control (SMC). It was proven that SMC would compensate automatically for unmodeled behaviors such as piezoceramic non-linearities and mechanical stick-slip phenomena. Furthermore, SMC scheme has been successfully applied to position tracking to demonstrate the excellent robust performance in noise rejection.

Ceramics↗
PubMed2003

Ultrasonic absorption in polymer gel dosimeters.

Ultrasonic absorption in polymer gel dosimeters was investigated. An ultrasonic interferometer was used to study the frequency (f) dependence of the absorption coefficient (alpha) in a polyacrylamide gel dosimeter (PAG) in the frequency range 5-20 MHz. The frequency dependence of ultrasonic absorption deviated from that of an ideal viscous fluid. The presence of relaxation mechanisms was evidenced by the frequency dependence of alpha/f(2) and the dispersion in ultrasonic velocity. It was concluded that absorption in polymer gel dosimeters is due to a number of relaxation processes which may include polymer-solvent interactions as well as relaxation due to motion of polymer side groups. The dependence of ultrasonic absorption on absorbed dose and formulation was also investigated in polymer gel dosimeters as a function of pH and chemical composition. Changes in dosimeter pH and chemical composition resulted in a variation in ultrasonic dose response curves. The observed dependence on pH was considered to be due to pH induced modifications in the radiation yield while changes in chemical composition resulted in differences in polymerisation kinetics.

Acrylic Resins↗
PubMed2000

Determination of avocado and mango fruit properties by ultrasonic technique.

A nondestructive ultrasonic measurement system was developed for the assessment of some transmission parameters which might have quantitative relations with the maturity, firmness and other quality-related properties of avocado and mango fruits. The system utilizes a set of low-frequency probes arranged to measure the ultrasonic signal transmitted and received over a short distance across the peel. The attenuation of the ultrasonic waves, transmitted through the peel and the attached fruit tissue, changes as a result of the progressive ripening and softening of the fruit during the fruiting season and in the course of storage. The present study quantitatively addressed the linkage between the ultrasonic attenuation and the physiological parameters of the flesh of the fruits. Results were obtained in the time and frequency domain, and the data set was analyzed statistically to identify the relations between the major physiological indices and the ultrasonic parameters. Quantitative relations were developed to describe the linkage between ultrasonic parameters and the maturity, firmness and other quality-related properties in mango and avocado fruits.

Food Handling↗
PubMed1990

Ultrasonic condensation of gutta-percha: an in vitro dye penetration and scanning electron microscopic study.

Lateral condensation of gutta-percha with and without ultrasonic activation of the spreader was compared by use of dye penetration analysis and scanning electron photomicrographs of the gutta-percha fills in extracted human incisors and canines. The root canal fillings in three groups of 10 teeth each were laterally condensed using an ultrasonically activated spreader, a fine finger spreader, or a non-activated ultrasonic spreader. Significantly less apical dye penetration occurred when teeth were obturated using an ultrasonically activated spreader as compared with manual condensation with fine finger spreaders. The ultrasonically condensed gutta-percha mass was more homogeneous with fewer voids compared with gutta-percha masses from the two groups that were condensed without ultrasonic activation. A correlation between apical microleakage and the appearance of the gutta-percha mass was seen. All teeth with well-condensed, more homogeneous fillings had low dye penetration. All teeth with a high extent of dye penetration had poorly condensed, less homogeneous fillings. However, not all teeth that had poorly condensed fillings had high dye penetration.

Cuspid↗
PubMed1999

Comparison of the cleaning efficacy of passive sonic activation and passive ultrasonic activation after hand instrumentation in molar root canals.

The purpose of this study was to compare the cleaning efficacy of passive ultrasonic activation with that of passive sonic activation after hand instrumentation. Sixty curved molar canals were hand-instrumented to size 35 and divided into three groups. Group 1 received no further treatment. Group 2 received 3 min of passive sonic activation. Group 3 received 3 min of passive ultrasonic activation. The roots were split and photomicrographs (x20) were made of the apical 6 mm of canal. A transparent grid was placed over projected images, and the total number of squares covering the apical 6 mm of canal space and the number of squares containing debris were counted. A debris score was calculated for each specimen by dividing the number of squares with debris by the total number of squares. The mean debris scores were 31.6% for hand instrumentation only, 15.1% for the sonic group, and 16.7% for the ultrasonic group. The debris scores for the sonic and ultrasonic activation groups were significantly lower than that for the hand instrumentation only group (p < 0.01); however, there was no significant difference between the sonic and ultrasonic activation groups. Passive sonics after hand instrumentation produces a cleaner canal than hand instrumentation alone and is comparable with that of passive ultrasonics.

Analysis of Variance↗
PubMed1992

Revision arthroplasty facilitated by ultrasonic tool cement removal. An evaluation of whole bone strength in a canine model.

Ultrasonic driven tools have been developed to facilitate the removal of bone cement during revision arthroplasty. The effect on whole bone strength of cement removal by ultrasonic tools was examined in a canine femur model. Paired, fresh-frozen canine femora were divided into two groups. In group A, one femur from each pair was subjected to cement extraction with ultrasonic tools. In group B, one femur from each pair was subjected to manual cement extraction. Contralateral femora from each pair served as controls to determine the strength of intact femora. Torsional fractures were produced using a servocontrolled hydraulic testing machine (Minneapolis Testing System, Minneapolis, MN). Maximum torque, maximum angle, and energy capacity to failure were determined. Results were recorded as a reduction in percent value of the tested specimen versus the contralateral control. When comparing femora with cement removal by ultrasonic tools to the contralateral control femur, there were no statistical differences in ultimate torque (P = .83), maximum angle (P = .89), and energy capacity (P = .74) by analysis of variance. In addition, there were no significant differences between the group with ultrasonic tool cement removal and the group with manual tool removal. The authors conclude that in this canine model, removal of cement with ultrasonically driven tools has no adverse effects on whole bone strength.

Animals↗
PubMed1999

N-ethoxycarbonyl-2-ethoxy-1,2-dihydroquinoline studies on the role of 5-HT1A and 5-HT2 receptors in mediating foot-shock-induced ultrasonic vocalisation in adult rats.

The role of 5-HT1A and 5-HT2 receptors in mediating foot-shock-induced ultrasonic vocalisation has been studied in rats. Furthermore, behavioural effects were correlated to receptor reserves in the brain by means of receptor inactivation with N-ethoxycarbonyl-2-ethoxy-1,2-dihydroquinoline (EEDQ). The dose-dependent inhibition of ultrasonic vocalisation by the 5-HT precursor, L-5-hydroxy-L-tryptophan (110-450 micromol/kg), was abolished by pretreatment with the 5-HT1A/1B antagonist, (-)-penbutolol (27 micromol/kg), and the 5-HT2A/2C antagonist, ritanserin (10 micromol/kg). The inhibitory actions of the 5-HT1A receptor agonist 8-hydroxy-2-(di-n-propylamino)tetralin (8-OH-DPAT) and the 5-HT2A/5-HT2C. agonist, 1-(2,5-dimethoxy-4-iodophenyl)-2-aminopropane (DOI) were reversed by the 5-HT1A antagonist, (N-[2-[4-(2-methoxyphenyl)-1-piperazinyl]ethyl]-N-(2-pyridinyl) cyclohexanecarboxamide (WAY-100635), and the 5-HT2A antagonist, (+/-)alpha-(2,3-dimethoxyphenyl)-1-[2-(4-fluorphenyl)ethyl]-4-pipe ridine-methanol (MDL 100151), respectively. Pretreatment with EEDQ (24 h, subcutaneous [s.c.]) inhibited foot-shock-induced ultrasonic vocalisation (effective dose50=0.95 micromol/kg) and decreased [3H]-8-OH-DPAT and [3H]-ketanserin binding in the brain. Pretreatment with WAY-100635 (0.3-20 micromol/kg) 20 min prior to EEDQ administration (1.3 micromol/kg, s.c.) did not reverse the EEDQ-induced inhibition of ultrasonic vocalisation but protected the 5-HT1A receptors against EEDQ inactivation. Pretreatment with MDL 100151 (0.83-54 micromol/kg) 20 min prior to EEDQ administration both reversed the EEDQ-induced inhibition of ultrasonic vocalisation and protected the 5-HT2A receptors against EEDQ inactivation. These findings demonstrate that 5-HT1A and 5-HT2 receptors are involved in the regulation of ultrasonic vocalisation in rats. However, the function of 5-HT1A and 5-HT2 receptors in this model seems to differ as vocalisation was preserved after protection of 5-HT2 but not 5-HT1A receptors.

8-Hydroxy-2-(di-n-propylamino)tetralin↗
PubMed2002

Low-power transverse ultrasonic treatment of portal vein thrombosis in an animal model.

PURPOSE: The authors have recently developed a small-diameter, thin, flexible ultrasonic catheter device that permits the removal of thrombus by low-power transverse ultrasonic cavitation energy. In this study, the authors sought to determine whether this device could be used to eliminate portal vein thrombosis in an animal model. MATERIALS AND METHODS: In five anesthetized pigs, a total of six occlusions of the left portal vein were achieved with use of autologous clot with (n = 2) or without (n = 4) thrombin injection (250 U) introduced via a 7-F transhepatic catheter/sheath system. Angiographic examination documented complete occlusion of this vessel. The 75-cm-long, 21-gauge ultrasonic catheter (Resolution) was introduced into the clot under angiographic guidance via the transhepatic sheath. Transverse-wave ultrasonic energy was then delivered from the distal 5 cm of the probe at 3.5 W +/- 10% power for up to 6 minutes. Repeat angiographic studies were performed to document patency. After the procedure, gross and histopathologic examinations were performed. RESULTS: Restoration of patency of the main left portal vein was documented in all cases at angiography, with no evidence of residual clot fragments in the major branches. However, side branches demonstrated small thrombotic plugs on pathologic examination. No complications such as perforation of the vessel adjacent to the active ultrasonic tip were encountered. Virtually all thrombolysis was documented to occur within the first minute of energy application. At gross pathologic examination, there was no evidence of damage to the portal vein, and histopathologic examination demonstrated minimal intimal disruption without damage to the media. CONCLUSIONS: This preliminary animal study suggests the feasibility of a percutaneous transhepatic approach to the treatment of portal vein thrombosis with use of low-power ultrasonic cavitation energy. With further study, this method may have potential for the treatment of thrombotic disease, thereby offering novel therapy to patients with thrombotic vascular occlusions.

Animals↗
PubMed2000

Comparison of three commercial ultrasonic nebulizers.

BACKGROUND: The clinical acceptance of the initial ultrasonic nebulizers was impeded by their production of significant quantities of droplets larger than the respirable range that could have resulted in poor pulmonary deposition of nebulized medications. Subsequent modifications in the design of ultrasonic nebulizers have occurred. Overall nebulizer performance characteristics of the newer ultrasonic devices have not been evaluated. OBJECTIVE: Three commercially available ultrasonic nebulizers (DeVilbiss-Pulmosonic, Omron-Microair, Rhône Poulenc-Rorer-Fisoneb) were studied to compare the aerosol output characteristics. METHODS: The parameters studied were total volume output (TVO), time to nebulize total output (TTO), percent of droplets with volume diameters in the respirable range (PDVRR, 1 to 5 microm), albuterol concentration during nebulization, and the total drug delivered. All nebulizers were filled with 2.5 mL of saline and 0.5 mL of albuterol nebulizer solution. Three units from each manufacturer, each from a different lot, were evaluated in duplicate. RESULTS: The nebulizer with the largest volume output was the Omron (mean 2.94 mL), which also demonstrated the longest nebulization time (mean 10.3 min). The DeVilbiss and Rhône Poulenc-Rorer units delivered smaller volumes (mean 2.5 mL, 2.4 mL, respectively) but nebulized more rapidly (mean 2.21 min, 3.54 min, respectively). The Omron nebulizer generated the highest PDVRR with a mean of 38%. The DeVilbiss had a mean PDVRR of 16% and the Rhône Poulenc-Rorer a mean PDVRR of 21%. The majority of droplets from all three machines had a volume diameter smaller than the respirable range, ie, in the 0.5 to 1.0 microm range (Omron-60%, DeVilbiss-83%, Rhône Poulenc-Rorer-79%). For all three nebulizers there appeared to be no concentrating or diluting effect during nebulization implying that equal quantities of albuterol and diluent were delivered. The Rhône Poulenc-Rorer units demonstrated the greatest unit-to-unit variability with respect to TVO while the Omron units demonstrated the greatest unit to unit variability with respect to TTO. CONCLUSION: We conclude that several improvements in the design of ultrasonic nebulizers have resulted in the reduction of the size of the droplets generated. Our evaluation of the three commercially available ultrasonic nebulizers revealed that the majority of droplets generated were within or below the respirable range. There was no concentrating or diluting effect during nebulization for all three nebulizers. The output characteristics of the three devices differ and this will effect the delivery time as well as amount of drug delivered to the lungs.

Aerosols↗