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At least 919 records · Page 51Linked to original sources

PubMed1993

[The ultrasonic diagnosis of choledocholithiasis].

The results of examination and treatment of 162 patients with clinically suspected choledocholithiasis were analysed. The high significance of ultrasonic examination in the diagnosis of a calculous nature of the affection of the biliary tree with a record of its echosemeiotics is shown. The wide use of ultrasonic examination yields better information. Study of the results of complex examination of 110 patients with verified choledocholithiasis confirmed the high rarefying capacity of the ultrasonic method in the detection of stones in the extrahepatic biliary tree (85.8% accuracy of the examination) both when it is applied for the first time and when it is used during the treatment. Obligatory performance of ultrasonic examination in diseases of the extrahepatic biliary ducts is suggested.

Adult↗

PubMed1993

[Newly developed ultrasonic micro-probe (15MHz), basic and clinical study for gastrointestinal lesions].

The authors evaluated a new device the ultrasonic micro-probe (2.4mm in the outer diameter, radial scanning system, 15MHz, Toshiba Co.) from both its basic and clinical aspects using resected gastric specimens and clinical subjects. The ultrasonic resolution of this new ultrasound imaging catheter was demonstrated to be best the probe-object distance was 1.0-3.0mm and angle of inclination was 0-20. On clinical use of the probe, the above-mentioned basic evaluation is important to achieve high resolution ultrasonic image. For attenuation of ultrasound due to the high-frequency (15MHz), the main subjects of this probe for evaluation of gastrointestinal tract are small lesions of mucosal-submucosal layers. Because of its small caliber (2.4mm), the micro-probe can be passed through the biopsy channel of common used endoscope, and permits the intra-luminal ultrasound examination at routine endoscopy, if necessary. This new device the ultrasonic micro-probe will develop the ability of endoscopic ultrasound in diagnosing gastrointestinal disorders.

Carcinoma, Squamous Cell↗

PubMed1993

Reliability of B-mode ultrasonic measurements of subcutaneous adipose tissue and intra-abdominal depth: comparisons with skinfold thicknesses.

Adipose tissue deposits, particularly intra-abdominal adipose tissue, are associated with health risks such as diabetes mellitus and cardiovascular disease. Anthropometric techniques currently in use can measure subcutaneous adipose tissue (SAT) with skinfold calipers, but are limited to certain sites and cannot measure intra-abdominal adipose tissue (IAAT). Radiography, computerized tomography (CT) and magnetic resonance imaging (MRI) have been used, but they are expensive and some involve exposure to radiation. This study, which investigated the utility of B-mode ultrasound for measuring adipose tissue, found that ultrasonic measurements of SAT were as reliable as skinfold caliper measurements. Intra-observer and inter-observer coefficients of reliability for five of six ultrasonic measurements of SAT ranged from 91-98%, in comparison with coefficients of reliability ranging from 93-98% for three skinfold measurements. Coefficients of reliability for ultrasonic measurements of SAT at the paraspinal site were below 90%. Ultrasonic measurements of intra-abdominal depth (IAD), an index of IAAT, yielded an inter-observer coefficient of reliability of 64%. Ultrasound is recommended for measurement of subcutaneous adipose tissue but not for measurement of IAD.

Abdomen↗

PubMed1993

Whither ultrasonic prediction of fetal macrosomia?

During the past 15-20 years, ultrasonic estimation of fetal weight (EFW) has been used increasingly to make management decisions regarding the induction of labor or delivery route. The propriety of this approach depends on proof that its use improves newborn or maternal outcome without disproportionate increases in morbidity and mortality. A barrier to achieving this goal is the inaccuracy associated with ultrasonic EFW. The current ultrasonic EFW procedures are not accurate enough for detecting macrosomia defined by weight criteria. Even if clinicians could determine fetal weight accurately, the frequency of persistent fetal injuries associated with vaginal birth of the macrosomic fetus is so low that induction of labor or cesarean birth is not justified on that basis. Furthermore, the inaccurate ultrasonic determination of fetal weight leads to inappropriate obstetric interventions. Evidence-based decision-making should be an important goal for all obstetric care givers. Delivery decisions based on inaccurate EFW should be avoided.

Body Weight↗

PubMed1977

[Ultrasonics of ovarian changes under gonadotrophine stimulation (author's transl)].

It is known that there are difficulties in timing of ovulation induction under gonadotrophines. The reason is that investigation parameters used so far only permit indirect quantitative statements. Ultrasonics permit the direct presentation of ovaries, cystic structure-follicles, registration of their number and size as well as control of the further development. Using an typical case, possibilities with ultrasonics are demonstrated. Ovulation was induced when one follicle (0 23 mm) dominated over two others (0 17 mm), and a corpus-luteum-cyst and the pregnancy were observed. Two gestational-sacs perished during bleedings in the 9th week of pregnancy. The normal pregnancy was controlled with ultrasonics until delivery. Ultrasonic equipment was Vidoson 635 S by Siemens and Diasonograph NE 4102/B by Nuclear Enterprises.

Chorionic Gonadotropin↗

PubMed1995

[Ultrasonic assessment of cerebrovascular disease].

The aim of this paper of the symposium of the 36th Scientific Meeting of Japanese Society of Neurology is to clarify the general status of ultrasonic assessment in the imaging modality of cerebrovascular disease (CVD). Although there are many ultrasonic techniques, we want to address the carotid ultrasonography and transcranial ultrasonography. Cervical carotid atherosclerosis is known to be a major cause of brain infarction and Duplex ultrasonography is the best imaging tool. This method made it possible to visualize the living human arterial wall and to visualize the intraplaque characters. This was most advantage among several modalities. Few and really disadvantages of this method are examiner dependent results and narrow visual window. On the basis of these ultrasonic data, many investigations of nature of stroke have been performed. Transcranial ultrasonography have been accepted as a new method for non-invasive intracranial vascular imaging. There are the transcranial Doppler, transcranial tomography and the transcranial color flow imaging. Using these transcranial methods, we can evaluate the intracranial lesions. Transcranial color flow imaging made it possible to obtain real images of major arteries of circle of Willis. In conclusion, ultrasonic modality is a useful tool for assessing the risk of cerebrovascular disease or atherosclerosis, especially in chronic situations.

Aorta↗

PubMed1998

Hearing in mole crickets (Orthoptera: gryllotalpidae) at sonic and ultrasonic frequencies

We have studied auditory responses in two species of mole cricket (Scapteriscus borellii and S. abbreviatus) to determine (1) whether they show sensitivity to ultrasound, (2) whether their hearing (at both low and high frequencies) is based on the same neural circuitry as that of true crickets, and (3) whether ultrasound sensitivity in different mole cricket species varies with their ability to fly. S. borellii are sensitive to ultrasonic frequencies. There is evidence of a segregation of frequency bands in prothoracic auditory neurons. There are two pairs of &ohgr ; neurons (ONs) with similar morphology to ON1 of true crickets. The two pairs of ONs differ in tuning. One pair has two sensitivity peaks: at the frequency of the calling song of this species (3 kHz), and in the ultrasonic range (25 kHz). The other pair lacks the high-frequency sensitivity and responds exclusively to frequencies in the range of the species song. These two types are not morphologically distinguishable. In S. abbreviatus, only one class of ON was found. S. abbreviatus ONs are narrowly tuned to the frequency of the species' calls. A T-neuron had the best ultrasonic frequency sensitivity in S. borellii. This cell showed a broad tuning to ultrasonic frequencies and was inhibited by low-frequency stimuli. A morphologically similar neuron was also recorded in S. abbreviatus, but lacked the high-frequency sensitivity peak of that in S. borellii. We also assessed the responses of flying S. borellii to ultrasound using field playbacks to free-flying animals. The attractiveness of broadcast calling song was diminished by the addition of an ultrasound signal, indicating that S. borellii avoid high-frequency sound. The results indicate that mole crickets process low-frequency auditory stimuli using mechanisms similar to those of true crickets. They show a negative behavioural response to high-frequency stimuli, as do true crickets, but the organization of ultrasound-sensitive auditory circuitry in mole crickets differs from that of true crickets.

Journal Article↗

PubMed2002

Ultrasonic power measurements in the milliwatt region by the radiation force float method.

The radiation force float technique is extended in the present investigation, for the determination of the total radiated low ultrasonic power in the milliwatt region. It is elucidated, experimentally, using floats having a conical reflecting target comprising of new material (teflon insulated copper wire) stems with smaller diameters (0.55 and 1 mm). The sensitivity is improved with these two stems and the ultrasonic power levels are measured in the range from 1.4 to 140 mW and 4.6 to 460 mW respectively and the results are reproducible within +/- 5%. Limitations of float technique and factors influencing the uncertainties involved for the high quality ultrasonic power measurements are discussed. The proposed method is simple, versatile and inexpensive and can be used as an interim standard.

Calibration↗

PubMed1991

Sharpening of ultrasonic scalers.

Instruments suitable for removing calculus, plaque and necrotic cementum, which hinder normal periodontal reattachment, are extremely important for successful therapy. The test was carried out in order to see if a standard scaler used for ultrasonic tartar removal maintains its physical features when sharpened. 6 scalers, compatible with piezo-electric generators, were tested and 2 diameters, A and B, weights and resonance frequencies were measured. Scalers no. 2, 3, 4, 5, were sharpened and was used as control. All measurements were taken again at the end of the test. Statistical analysis reveals significant variations, after sharpening, of A diameter (t = 4.14 greater than 3.55, p less than 0.01), B diameter (t = 5.34 greater than 3.355, p less than 0.01) and resonance frequency (t = 2.82 greater than 2.306, p less than 0.05); in contrast, there is no significant change of weights (t = 1.17 less than 2.306, p greater than 0.05). These results suggest that sharpening slightly modifies the physical features of ultrasonic tips, so that sharpening ultrasonic scalers, from a physical point of view, can be carried out, paying attention not to damage the water cooling system.

Dental Scaling↗

PubMed1998

Focusing and steering through absorbing and aberrating layers: application to ultrasonic propagation through the skull.

The time-reversal process is applied to focus pulsed ultrasonic waves through the human skull bone. The aim here is to treat brain tumors, which are difficult to reach with classical surgery means. Such a surgical application requires precise control of the size and location of the therapeutic focal beam. The severe ultrasonic attenuation in the skull reduces the efficiency of the time reversal process. Nevertheless, an improvement of the time reversal process in absorbing media has been investigated and applied to the focusing through the skull [J.-L. Thomas and M. Fink, IEEE Trans. Ultrason. Ferroelectr. Freq. Control 43, 1122-1129 (1996)]. Here an extension of this technique is presented in order to focus on a set of points surrounding an initial artificial source implanted in the tissue volume to treat. From the knowledge of the Green's function matched to this initial source location a new Green's function matched to various points of interest is deduced in order to treat the whole volume. In a homogeneous medium, conventional steering consists of tilting the wave front focused on the acoustical source. In a heterogeneous medium, this process is only valid for small angles or when aberrations are located in a layer close to the array. It is shown here how to extend this method to aberrating and absorbing layers, like the skull bone, located at any distance from the array of transducers.

Brain Neoplasms↗

PubMed1958

Ultrasonic therapy: physiological basis and clinical application.

Ultrasound is a relatively new but fairly well accepted physical modality. Therapeutically, ultrasonic energy is employed empirically, but the present trend is to utilize low and medium intensities, 0.5 to 2.0 watts per square centimeter, rather than high intensities, over 2.0 watts per square centimeter, for medical purposes. The important physiological effects of ultrasonic energy on living tissue are thermal, mechanical, chemical and biological. Which one of these effects is dominant is not clearly understood. However, the intensity of the ultrasound field and the duration of application determines the extent to which the thermal or the mechanical effect prevails. From a clinical point of view ultrasonic energy has been most effective in the treatment of painful conditions involving the musculoskeletal and neuromuscular structures. More recently, studies have been directed toward the use of ultrasound as a neurosurgical tool.

Humans↗

PubMed2005

Ultrasonic bone removal with the Sonopet Omni: a new instrument for orbital and lacrimal surgery.

We used a new instrument that ultrasonically removes bone (Sonopet Omni, model UST-2001 Ultrasonic Surgical Aspirator) in 13 orbital decompressions and 6 dacryocystorhinostomies. We noted no surgical complications of ocular or soft tissue damage, infection, inflammation, or visual loss. Visualization, manipulation, ease of use, and speed were far superior with the Sonopet ultrasonic bone curette compared with drills or rongeurs. The Sonopet Omni is an outstanding innovation in technology for bone removal in surgery.

Aged↗

PubMed1985

Ultrasonic fragmentation. A new technique for mucosal proctectomy.

We report a new technique for mucosal proctectomy that does not require manual separation of the mucosa and submucosa from the underlying muscularis. Mucosal proctectomy using ultrasonic fragmentation of the rectal mucosa was performed in four patients. Three had severe ulcerative colitis, and one patient had radiation proctitis with a rectal stricture. In all cases an endorectal pullthrough with anastomosis to the area of the dentate line was performed. Healing after ultrasonic mucosal proctectomy occurred without infection or retraction. Ultrasonic fragmentation offers an alternative to the standard technique of mucosal proctectomy. This new method is useful in those patients in whom separation of the rectal mucosal layer is difficult to perform.

Adult↗

PubMed2001

Ultrasonic characterization of the curing process of hydroxyapatite-modified bone cement.

Ultrasonic parameters such as velocity of sound and broad-band ultrasonic attenuation (BUA) are sensitive to changes in the viscoelastic properties of a material. Bone cement undergoes changes is these properties as it cures. By monitoring the propagation of ultrasonic pulses through a sample of curing bone cement, the curing reaction of polymethylmethacrylate-based (PMMA) bone cement was investigated for hydroxyapatite (HA) concentrations of 0, 10, and 30% (by weight). As the material hardens, the velocity of sound increases by 70%. BUA shows a large peak at the midpoint of the velocity transition. These data are used to compare the cure time and cure duration for PMMA bone cement mixed with hydroxyapatite particles. Measurements of the final sound velocity and BUA were also performed to investigate the mechanical properties of the fully cured cement, and to compare to compression testing data. This is the first time the curing process of bone cement has been investigated as a function of hydroxyapatite concentration. Results indicate that the cure time is not significantly affected by the addition of HA particles, and that both velocity of sound and BUA are sensitive to the curing process.

Bone Cements↗

PubMed2002

Ultrasonic vocalizations and maternal-infant interactions in a rat model of fetal alcohol syndrome.

When isolated from their dams and littermates, rat pups emit ultrasonic vocalizations to elicit attention and retrieval from their dams. This study examined the effects of perinatal alcohol exposure on ultrasonic vocalizations and maternal-infant interactions. Alcohol was administered throughout gestation to the dams and during the early postnatal period to the pups. Control groups consisted of a nontreated control and an intubated, pair-fed control. Ultrasonic vocalizations were measured on postnatal day (PD) 5 under varying conditions of isolation. Maternal behaviors were examined on PD2, 4, 6, 8, and 10. Maternal behaviors were not significantly affected by prior alcohol administration to either the dams or the pups. However, ethanol-exposed rat pups vocalized more on PD5 than controls regardless of condition. The heightened vocalization response of the ethanol-exposed pups might be an underlying factor in the persistent effects of perinatal ethanol exposure on social behavior.

Animals↗

PubMed2001

Effects of chronic and acute methylphenidate hydrochloride (Ritalin) administration on locomotor activity, ultrasonic vocalizations, and neuromotor development in 3- to 11-day-old CD-1 mouse pups.

The present study examined the effects of chronic and acute treatment with methylphenidate hydrochloride (Ritalin) on isolation-induced ultrasonic vocalizations, spontaneous locomotor activity, and neuromotor coordination in 3- to 11-day-old CD-1 mouse pups. In Experiment 1, 3- to 11-day-old pups received daily injections of saline, 5 mg/kg or 20 mg/kg of methylphenidate hydrochloride, or no injection and were tested on postnatal Days 3, 5, 7, 9, and 11. Both doses of methylphenidate resulted in significant increases in locomotor activity at all ages, but had no significant effect on body weight, neuromotor development, or emission of ultrasonic vocalizations. In Experiment 2, pups were given a single dose of methylphenidate (5 or 20 mg/kg), saline, or no injection on one of postnatal Days 5, 7, 9, or 11. This acute methylphenidate treatment increased locomotor activity, but had no significant effects on ultrasonic vocalizations or neuromotor coordination. These results indicate that short-term, chronic methylphenidate treatment elevates locomotor responses, but has no immediate effects on anxietylike responses or on the development of neuromotor behavior of CD-1 mice in the first 11 days of life.

Animals↗

PubMed1975

A removable ultrasonic collimator for improving resolution.

A removable ultrasonic collimator is described. It could be easily attached to a general purpose transducer to improve resolution on ultrasound study of superficial small organs. The collimator is made of a small central focusing lens, 6 mm in diameter, surrounded by air. The air insulates the peripheral portion of the transducer surface. ONLY THE CENTRAL ULTRASONIC BEAM WOULD BE TRANSMITTED THROUGH THE LENS. As a result, the ultrasonic beam is narrowed and the resolution is improved. Draw-back of the collimator is a reduction in the ultrasound intensity. However, it can be compensated for by increasing either the transducer output or system gain.

Thyroid Gland↗

PubMed2001

Adhesion of composite resins to enamel irradiated by the Er:YAG laser: application of the ultrasonic scaler on irradiated surface.

BACKGROUND AND OBJECTIVE: The clinical use of the Er:YAG laser in cavity preparation has become widespread. With respect to cavities prepared with the Er:YAG laser, restorations using composite resins and glass ionomer cements are common. The bond strength of current resin bonding systems to ground enamel is 14-30 MPa, whereas the strength to Er:YAG laser-irradiated enamel, regardless of the use or non-use of phosphoric acid etching is less than 10 MPa. STUDY DESIGN/MATERIALS AND METHODS: In this investigation, an ultrasonic scaler was tested as a technique to increase the bond strength of composite resins to the Er:YAG irradiated enamel surface. RESULTS: The application of the ultrasonic scaler significantly increased bond strength. CONCLUSIONS: The tensile bond strength in the groups treated with the ultrasonic scaler exhibited approximately twice the strength observed in groups treated with laser irradiation alone.

Composite Resins↗