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PubMed2005

Interlaboratory comparison of ultrasonic backscatter coefficient measurements from 2 to 9 MHz.

OBJECTIVE: As are the attenuation coefficient and sound speed, the backscatter coefficient is a fundamental ultrasonic property that has been used to characterize many tissues. Unfortunately, there is currently far less standardization for the ultrasonic backscatter measurement than for the other two, as evidenced by a previous American Institute of Ultrasound in Medicine (AIUM)-sponsored interlaboratory comparison of ultrasonic backscatter, attenuation, and speed measurements (J Ultrasound Med 1999; 18:615-631). To explore reasons for these disparities, the AIUM Endowment for Education and Research recently supported this second interlaboratory comparison, which extends the upper limit of the frequency range from 7 to 9 MHz. METHODS: Eleven laboratories were provided with standard test objects designed and manufactured at the University of Wisconsin (Madison, WI). Each laboratory was asked to perform ultrasonic measurements of sound speed, attenuation coefficients, and backscatter coefficients. Each laboratory was blinded to the values of the ultrasonic properties of the test objects at the time the measurements were performed. RESULTS: Eight of the 11 laboratories submitted results. The range of variation of absolute magnitude of backscatter coefficient measurements was about 2 orders of magnitude. If the results of 1 outlier laboratory are excluded, then the range is reduced to about 1 order of magnitude. Agreement regarding frequency dependence of backscatter was better than reported in the previous interlaboratory comparison. For example, when scatterers were small compared with the ultrasonic wavelength, experimental frequency-dependent backscatter coefficient data obtained by the participating laboratories were usually consistent with the expected Rayleigh scattering behavior (proportional to frequency to the fourth power). CONCLUSIONS: Greater standardization of backscatter measurement methods is needed. Measurements of frequency dependence of backscatter are more consistent than measurements of absolute magnitude.

1-Propanol↗
PubMed1997

Nondiseased dentinal root surface following citric acid or tetracycline hydrochloride conditioning: a scanning electron microscopic study on the effects of ultrasonic irrigation before and after root conditioning.

The scanning electron microscope was used to evaluate the effects of ultrasonic irrigation before and after root conditioning. Six groups of five specimens each received saline irrigation; ultrasonic irrigation; saline irrigation followed by root conditioning with either citric acid or tetracycline hydrochloride; or ultrasonic irrigation followed by root conditioning with either citric acid or tetracycline hydrochloride. After immersion in citric acid or tetracycline hydrochloride solutions, root dentin was rinsed again with saline or irrigated ultrasonically. Control specimens exhibited an amorphous, irregular surface smear layer. Ultrasonic irrigation, citric acid, and tetracycline hydrochloride were effective in removing the smear layer. Use of ultrasonic irrigation before and after acid application improved the exposure of dentinal fibrils.

Acid Etching, Dental↗
PubMed1998

[Ultrasonic tissue characterisation in cardiology].

Ultrasonic tissue characterization is a relatively new non-invasive examination method the application of which in cardiology is steadily increasing. It is therefore the objective of the present work to summarize hitherto assembled knowledge on the use of this method in clinical practice. Ultrasonic tissue characterization uses scattering of ultrasonic waves which penetrate into the heart muscle. This scatter is due to particles inside the heart muscle, their size being smaller than the wave length of the incident ultrasonic undulation. Evaluation of the intensity of the backscatter makes it possible to evaluate structural and functional changes of the examined cardiac tissue. Ultrasonic tissue characterization is so far used in cardiology for evidence of myocardial ischaemia, for evaluation of structural myocardial changes with hypertrophic cardiomyopathy, to detect rejection after transplantation of the heart and in the diagnosis of myocarditis. Other possibilities for application of this method is assessment of the viability of the heart muscle, quantification of the amount of fibrous tissue in the heart muscle and differentiation of acute from chronic vegetation in patients with infectious endocarditis. Due to some limitations ultrasonic tissue characterization is in the majority of the mentioned indications rather a subsidiary method which can supplement the diagnosis and make it more accurate. Its future position will obviously depend on further technical improvement and simplification.

Echocardiography↗
PubMed2001

[Ultrasonic removal of organic pollutants in tannery waste water].

The effect of ultrasonic treatment on flocculating settling of tannery effluent was studied, removal of COD in particular was did. The influences of irradiation method and duration of ultrasonic as well prescription of coagulants on the efficiency of minimizing organic chemicals in waste water were investigated. The results show that: 1. when waste water was treated only by ultrasonic for 60s, the removal rate of COD was 40.6%; 2. when total concentration of coagulants increased to 100 mg/L, the highest removal rate of COD was achieved; 3. when waste water was firstly treated with ultrasonic for 60s, then flocculated with coagulants, the removal rate of COD came to 73.2%, 10% higher than the control without ultrasonic. Thus the treatment of tannery waste water with flocculating settling technology can be effectively strengthened by ultrasonic.

Industrial Waste↗
PubMed2003

[Application of ultrasonic angioplasty in treating totally occluded peripheral arteries, a clinical study of 39 cases].

OBJECTIVE: To evaluate the efficacy and safety of intravascular ultrasonic angioplasty in treating atherosclerotic totally occluded peripheral arteries. METHODS: Percutaneous ultrasonic angioplasty was applied on 39 cases with peripheral atherosclerotic total occlusion under fluoroscopic guidance. The recanalization, clinical efficacy and complications were observed. RESULTS: 38 (97.4%) of the 39 cases achieved successful recanalization in (1157 +/- 376) seconds, with a mean residual stenosis of (32 +/- 11)%. The technical successful rate (residual stenosis < 50%) was 82.1% (32/39). Clinical improvement at different degrees was seen in 38 cases after ultrasonic angioplasty. The patency rates 24 hours, 30 days, 90 days and 180 days after the ultrasonic angioplasty were 100%, 94.7%, 89.5% and 81.6% respectively. The complications related to ultrasonic angioplasty included hemoglobinuria in 9 cases and distal embolization in 1 case. CONCLUSION: Ultrasonic angioplasty appears to be safe and effective for the treatment of atherosclerotic totally occluded peripheral arteries.

Adult↗
PubMed2004

Comparative study of manual and ultrasonic instrumentation of cementum surfaces: influence of lateral pressure.

The goal of periodontal treatments is to eliminate bacteria and their products without damaging cementum surfaces. Nonsurgical treatments are often limited by the inability of curettes to access the most apical zone of the pocket. While ultrasonic mini-inserts have been used for nearly 10 years now, their effect on dental tissues has not been tested. The purpose of the present study was to compare a new series of mini-inserts to Gracey curettes, which are the reference in nonsurgical treatments. Two experienced periodontists conducted root treatments on teeth destined for extraction using regular clinical criteria. One face of each root was instrumented using a Gracey curette, and the opposite face was instrumented using an ultrasonic mini-insert. After the instrumentation procedure, the teeth were prepared for examination by secondary electron (topographic features) and backscattered electron (organic and mineral composition) microscopy. Differences in surface composition between teeth treated by the two periodontists were noted and were related to the lateral pressure exerted. Calculus removal was less effective when strong lateral pressure was exerted using the ultrasonic mini-inserts, while more cementum was removed and more scratching occurred with both manual and ultrasonic instruments. In all cases, the ultrasonic mini-inserts allowed greater apical access. The new ultrasonic mini-inserts were as effective as manual curettes in eliminating plaque and calculus. The shape of the mini-inserts made them more effective in apical zones. The amount of damage to the cementum depended on the lateral pressure exerted by the periodontist.

Dental Calculus↗
PubMed2004

A comparison of sputum induction methods: ultrasonic vs compressed-air nebulizer and hypertonic vs isotonic saline inhalation.

Airway inflammation can be demonstrated by the modem method of sputum induction using ultrasonic nebulizer and hypertonic saline. We studied whether compressed-air nebulizer and isotonic saline which are commonly available and cost less, are as effective in inducing sputum in normal adult subjects as the above mentioned tools. Sixteen subjects underwent weekly sputum induction in the following manner: ultrasonic nebulizer (Medix Sonix 2000, Clement Clarke, UK) using hypertonic saline, ultrasonic nebulizer using isotonic saline, compressed-air nebulizer (BestNeb, Taiwan) using hypertonic saline, and compressed-air nebulizer using isotonic saline. Overall, the use of an ultrasonic nebulizer and hypertonic saline yielded significantly higher total sputum cell counts and a higher percentage of cell viability than compressed-air nebulizers and isotonic saline. With the latter, there was a trend towards squamous cell contaminations. The proportion of various sputum cell types was not significantly different between the groups, and the reproducibility in sputum macrophages and neutrophils was high (Intraclass correlation coefficient, r [95%CI]: 0.65 [0.30-0.91] and 0.58 [0.22-0.89], p < 0.001). Overall changes in median FEV, were small and comparable between all groups. Induction using ultrasonic nebulizers together with hypertonic saline was generally less well tolerated than compressed-air nebulizers and isotonic saline. We conclude that in normal subjects, although both nebulizers and saline types can induce sputum with reproducible cellular profile, ultrasonic nebulizers and hypertonic saline are more effective but less well tolerated.

Administration, Inhalation↗
PubMed2005

[Study on ultrasonic extraction technics of oleanolic acid in Akebia trifoliata].

OBJECTIVE: To optimize the ultrasonic extraction condition for oleanolic acid from Akebia trifoliata. METHOD: According to the orthogonal design L9 (3(4)), the optimum ultrasonic extraction technique was sought through experimental investigation, and was compared with the routine extraction technics. The contents of oleanclic acid were determined by UV-spectrophotometry. RESULT: The order of factors to affect the oleanolic acid extraction was extraction time > ethanol concentration > ultrasonic power > ration of interval time to ultrasonic time. The optimum ultrasonic extractions were A2B3C1D2. CONCLUSION: Compared with traditional extraction, ultrasonic method can save time, be easy to operate, improve extraction rates and need no heating.

Analysis of Variance↗
PubMedDate not supplied

Can a small ultrasonic dissector equipped for electrocautery improve the results of hepatic resection?

BACKGROUND/AIMS: In liver surgery, blood loss during hepatic transection is important. The use of an ultrasonic dissector was not always superior to conventional clamp crushing for performing hepatic parenchymal transections. The purpose of this study is to evaluate the effect of an ultrasonic dissector equipped with electrocautery in hepatic surgery. METHODOLOGY: A prospective study was conducted in 66 consecutive patients who underwent a partial hepatectomy using a new small ultrasonic dissector equipped for electrocautery. To evaluate the effectiveness of using the new instrument, the surgical outcomes were compared with those of historical control. RESULTS: The surgical outcomes of procedures using the new ultrasonic dissector were comparable to those of patients in the conventional ultrasonic dissector group; median blood loss, transection time, transection speed, percentage of tumor exposure at surgical margin, morbidity rate. The number of technical errors and the percentage of patients with an incomplete landmark appearance were lower in the new dissector group, but the differences were not significant. The distribution of hepatectomy grades also did not differ significantly. CONCLUSIONS: The surgical outcome of hepatectomies performed using an ultrasonic dissector cannot be significantly improved by the addition of an eletrocautery function to the dissector.

Adult↗
PubMed1989

[A case report of ultrasonic decalcification for calcified bicuspid aortic valve stenosis].

Calcified stenotic aortic valve are usually replaced by the artificial valve. Recently, we are trying to decalcify the calcification of the aortic valve by ultrasonic energy. This case report reviewed a small physique, 47 year old female, who had the calcified stenotic bicuspid aortic valve and the narrow aortic valve ring (18 mm diameter). The ultrasonic decalcification was performed by the ultrasonic surgical instrument, SUS-201D (ALOKA), ultrasonic energy output range from 25% to 45%. After the ultrasonic decalcification, the movability of the aortic cusps were improved and the aortic opening was enlarged. The systolic pressure gradient across the aortic valve was improved from 100 mmHg to 20 mmHg. This method "ultrasonic decalcification" is very useful technique for the repair of the calcified aortic valve stenosis.

Aortic Valve Stenosis↗
PubMed1985

Ultrasonic vocalizing by adult female mice (Mus musculus).

Though an extensive body of literature exists concerning the emission of 70-kHz ultrasonic vocalizations by adult male mice (Mus musculus), almost nothing is known about the ultrasonic vocalizing of adult females. A series of five experiments was conducted to examine adult female mouse ultrasound emission. Results indicated female ultrasonic vocalizing to be typically displayed among female mouse dyads and comparable to the ultrasonic vocalizing levels obtained among male-female pairs. Genotypically based variations in the production of ultrasounds by females were also noted. Like male mice, socially naive females readily ultrasonically vocalized to anesthetized female conspecifics and rarely vocalized to anesthetized males. Unlike males, socially experienced females emitted few ultrasounds to either female urine or female-soiled cage shavings. Although social experience served to increase the ultrasound emission of male mice to female sex cues, the production of ultrasounds by females to these cues was decreased by social experience. Implications with regard to the existence of a behavioral/functional sexual dimorphism in adult mouse ultrasonic vocalizing are discussed.

Animals↗
PubMed1995

Laparoscopic cholecystectomy in 200 consecutive patients using an ultrasonically activated scalpel.

Ultrasonic energy has not been previously used for surgical cutting and coagulating. Work in our laboratory has led to the development of an ultrasonically activated scalpel that safely and effectively cuts and coagulates tissue in animals. The purpose of this study was to determine if ultrasonic energy can replace monopolar electrosurgery in human laparoscopic surgery. Two hundred consecutive patients underwent laparoscopic cholecystectomy with the ultrasonically activated scalpel. The scalpel was the sole energy form in 98 of the first 100 patients, and in all of the last 100 patients. There were no common duct injuries, reoperations, or mortality. No patient had more than a 3-g drop in hemoglobin or transfusion. The ultrasonically activated scalpel is a safe and effective energy form for cutting and coagulating tissue during laparoscopic cholecystectomy in humans. The absence of need of monopolar electrosurgery combined with hemostatic effectiveness supports the concept that the ultrasonically activated scalpel can replace electrosurgery for laparoscopic cholecystectomy.

Case-Control Studies↗
PubMed2001

Randomized comparison of ultrasonic vs clamp transection of the liver.

HYPOTHESIS: Hepatic parenchymal transection is a technical priority in liver surgery. The use of an ultrasonic dissector for hepatectomy may result in less blood loss than conventional clamp crushing. DESIGN: Randomized controlled trial. SETTING: University teaching hospital. PATIENTS: The 132 patients scheduled to undergo partial hepatectomies were randomly assigned to receive hepatic transection by ultrasonic dissector or by clamp crushing (66 patients by each method). INTERVENTIONS: All resections were performed with inflow occlusion and were guided ultrasonographically. Hepatectomies were graded according to a predefined system based on 6 criteria (blood loss, transection time, technical error, surgical margin, landmark appearance, and postoperative morbidity), each with 3 scores (lower scores indicating higher quality). MAIN OUTCOME MEASURES: Blood loss and hepatectomy grade. RESULTS: No difference was found between the ultrasonic and clamp groups in median blood loss (515 mL [range, 15-2527 mL] vs 452 mL [range, 17-1912 mL]; P =.63), transection time (61 minutes [range, 16-177 minutes] vs 54 minutes [range, 7-205 minutes]; P =.58), or transection speed (1.1 cm(2)/min [range, 0.4-4.0 cm(2)/min] vs 1.0 cm(2)/min [range, 0.4-3.0 cm(2)/min]; P =.90). Ultrasonic dissection caused more frequent histologically proven tumor exposure at the surgical margin (9 vs 3 patients; P =.09), incomplete appearance of landmark hepatic veins on the cut surface after anatomical resection (12 vs 4 patients; P =.03), and postoperative morbidity (20 vs 14 patients; P =.32) than did clamp crushing. The hepatectomies with clamp crushing had significantly higher grades than those with ultrasonic dissection (P =.05), as indicated by the lower median sum score (4.0 [range, 0-12] vs 5.0 [range, 0-19]; 95% confidence interval for difference, -2.0 to 0; P =.03). The transection method independently influenced hepatectomy grade (adjusted odds ratio = 3.06; 95% confidence interval, 1.35-6.92; P =.01). CONCLUSIONS: Ultrasonic dissection offers no reduction in blood loss compared with clamp crushing for transection of the liver. Clamp crushing results in a higher quality of hepatectomy and is therefore the option of choice.

Adult↗
PubMed1998

Ultrasonic Spectroscopy Study of Flocculation and Shear-Induced Floc Disruption in Oil-in-Water Emulsions.

Ultrasonic attenuation spectroscopy was used to study flocculation and shear-induced disruption of flocs in oil-in-water emulsions. The ultrasonic attenuation spectra (1 to 150 MHz) of a series of 10 wt% corn oil-in-water emulsions (r32 = 0.2 µm) were measured. Depletion flocculation was induced in the emulsions by adding different concentrations (0 to 0.2 wt%) of a nonadsorbing biopolymer (xanthan) to the aqueous phase. At low frequencies, the attenuation coefficient of the emulsions decreased with increasing flocculation due to overlap of the thermal waves generated by the droplets. These observations were in good agreement with a theory recently developed to account for the influence of droplet flocculation on the ultrasonic properties of emulsions. The ultrasonic technique was also used to monitor the breakdown of flocs under shear flow. The dependence of the ultrasonic properties of emulsions on flocculation means that ultrasonic attenuation spectroscopy can be used to study droplet interactions in concentrated emulsions. Copyright 1998 Academic Press.

Journal Article↗
PubMed1996

Influence of marrow on ultrasonic velocity and attenuation in bovine trabecular bone.

Measurements of ultrasonic velocity and specific differential attenuation (SDA) were obtained on 24 bovine trabecular bone specimens from the femoral condyles. The measurements were obtained using two pairs of ultrasonic transducers, one with a low nominal center frequency (500 kHz) and the other pair with a high nominal center frequency (1 MHz). The ultrasonic velocity and specific differential attenuation associated with the bone samples were determined both with and without marrow, i.e., replacing the marrow with water in the pores of the trabecular bone. Significant increases (2.1% and 2.9%) in the velocity of ultrasound were observed after removal of the marrow, for the low and high frequency transducer pairs, respectively. In contrast, significant decreases (-6.5% and -8.8%) in SDA were observed after removal of the marrow, for the low and high frequency transducer pairs, respectively. The bone densities (BD) of the samples were also determined using single photon absorptiometry (SPA). Correlations between ultrasonic parameters and bone densities for samples both with and without marrow were found to be similar. For example, for the 1 MHz transducer pair, the correlation between BD and velocity was r = 0. 86 with marrow, and r = 0.89 without marrow. This study also compared the results obtained using a contact (no water bath) technique and an insertion (with a water bath) technique of ultrasonic measurements. For the high frequency transducer pair, the correlation coefficients between the two methods were r = 0.99 and r = 0.93, for the velocity and specific differential attenuation, respectively. Similar results were found for the low frequency transducer pair as well. In addition, approximately equal correlations between BD and ultrasonic velocity and SDA were also found, indicating that contact and insertion measurements provide essentially equivalent information.

Absorptiometry, Photon↗
PubMed2002

Effect of collagen and mineral content on the high-frequency ultrasonic properties of human cancellous bone.

The technology surrounding ultrasonic bone assessment is evolving rapidly as investigators explore the utility of new ultrasonic parameters and different ultrasonic frequencies. This study had three main goals. The first was to perform in vitro measurements of the speed of sound (SOS) and normalized broadband ultrasonic attenuation (nBUA) in specimens of normal human cancellous bone using a 2.25 MHz broadband measurement system. The second was to explore the utility of a backscatter-based parameter called apparent integrated backscatter (AIB). The third goal was to investigate the roles that collagen and mineral content play in affecting each of these three ultrasonic parameters. This was accomplished by chemically treating the specimens to remove one or the other of these two important constituents of bone. Our results showed that in most cases SOS and nBUA correlated well (p < 0.05) with bone mineral density (BMD) as measured by quantitative computed tomography (QCT). In contrast, AIB did not correlate strongly with BMD. When the specimens were demineralized, decreases were produced in SOS (19-39%) and nBUA (44-58%). Changes produced in AIB were not significant except along the superoinferior direction, in which a 12% decrease was measured. When the specimens were decollagenized, decreases were produced in SOS (10-12%). In contrast, increases were produced in both nBUA (35-77%) and AIB (14-15%). From this study we conclude that high-frequency ultrasonic measurements may yield useful information about the content and organization of both collagen and mineral in cancellous bone.

Bone Density↗
PubMed1991

Ultimate limits in ultrasonic imaging resolution.

According to elementary theory, the resolution of an ultrasonic imaging system increases with the ultrasonic frequency. However, frequency is limited by frequency-dependent attenuation. For imaging at any required depth, resolution improvement beyond the limit imposed by ultrasonic frequency can be obtained by increasing the ultrasonic intensity. This is itself, however, dependent on safety considerations and the effects of nonlinearity. In homogeneous media, image resolution increases with decreasing f-number. Particularly at low f-numbers, however, tissue inhomogeneity leads to a deterioration in image quality. Inhomogeneity may also be considered in terms of phase aberration. It has been found that for a given aperture, image degradation due to phase aberration is worse at higher frequencies. Schemes have been proposed for correction of this problem, but so far model systems do not lend themselves to clinical application. Deconvolution is unsatisfactory, speed correction is impracticable and synthetic aperture scanning and holography are virtually useless in biological tissues. Ultrasound-computed tomography has had only limited success. Speckle reduction can improve target detectability, but at the expense of resolution. Time-frequency control provides a useful partial solution to the problem of resolution reduction resulting from attenuation. It is clear that improved resolution would result in significant clinical benefits. An optimisation system for aperture size and ultrasonic frequency is proposed with signal averaging for resolution enhancement of a defined object area. This would have a compact ultrasonic beam and would allow frame rate to be traded for resolution, by means of signal averaging.

Humans↗
PubMed2006

Comparison of central corneal thickness measurements by rotating Scheimpflug camera, ultrasonic pachymetry, and scanning-slit corneal topography.

PURPOSE: To compare central corneal thickness measurements and their reproducibility when taken by a rotating Scheimpflug camera, ultrasonic pachymetry, and scanning-slit corneal topography/pachymetry. DESIGN: Experimental study. PARTICIPANTS: Seventy-four eyes of 64 subjects without ocular abnormalities other than cataract. METHODS: Corneal thickness measurements were compared among the 3 methods in 54 eyes of 54 subjects. Two sets of measurements were repeated by a single examiner for each pachymetry in another 10 eyes of 5 subjects, and the intraexaminer repeatability was assessed as the absolute difference of the first and second measurements. Two experienced examiners took one measurement for each pachymetry in another 10 eyes of 5 subjects, and the interexaminer reproducibility was assessed as the absolute difference of the 2 measurements of the first and second examiners. MAIN OUTCOME MEASURES: Central corneal thickness measurements by the 3 methods, absolute difference of the first and second measurements by a single examiner, absolute difference of the 2 measurements by 2 examiners, and relative amount of variation. RESULTS: The average measurements of central corneal thickness by a rotating Scheimpflug camera, scanning-slit topography, and ultrasonic pachymetry were 538+/-31.3 microm, 541+/-40.7 microm, and 545+/-31.3 microm, respectively. There were no statistically significant differences in the measurement results among the 3 methods (P = 0.569, repeated-measures analysis of variance). There was a significant linear correlation between the rotating Scheimpflug camera and ultrasonic pachymetry (r = 0.908, P<0.0001), rotating Scheimpflug camera and scanning-slit topography (r = 0.930, P<0.0001), and ultrasonic pachymetry and scanning-slit topography (r = 0.887, P<0.0001). Ultrasonic pachymetry had the smallest intraexaminer variability, and scanning-slit topography had the largest intraexaminer variability among the 3 methods. There were similar variations in interexaminer reproducibility among the 3 methods. CONCLUSIONS: Mean corneal thicknesses were comparable among rotating Scheimpflug camera, ultrasonic pachymetry, and scanning-slit topography with the acoustic equivalent correction factor. The measurements of the 3 instruments had significant linear correlations with one another, and all methods had highly satisfactory measurement repeatability.

Adult↗