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BRL Abstracts Database |
Your search for ultrasound produced 3296 results. Page 230 out of 330
Title |
Skeletal muscle ultrasound: Correlation between fibrous tissue and echo intensity. |
Author |
Pillen S,Tak RO,Zwarts MJ,Lammens MMY,Verrijp KN,Arts IMP,van der Laak JA,Hoogerbrugge PM,van Engelen BGM,Verrips A. |
Journal |
Ultrasound Med Biol |
Volume |
|
Year |
2009 |
Abstract |
In this study, we examined the correlation between muscle ultrasound and muscle structure. Echo intensity (EI) of 14 muscles of two golden retriever muscular dystrophy dogs was correlated to the percentage interstitial fibrous tissue and fat in muscle biopsy. A significant correlation between interstitial fibrous tissue and EI was found (r = 0.87; p < 0.001). The separate influence of interstitial fat on muscle EI could not be established as only little fat was present. We conclude that fibrous tissue causes increased muscle EI. The high correlation between interstitial fibrous tissue and EI makes ultrasound a reliable method to determine severity of structural muscle changes. (E-mail: s.pillen@cukz.umcn.nl)©2009 World Federation for Ultrasound in Medicine and Biology
Key Words: Ultrasound; Echo intensity; Neuromuscular disorders; Duchenne muscular dystrophy; Dogs; Muscle
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Title |
Skeletal status in survivors of acute lymphoblastic leukemia assessed by quantitative ultrasound at the hand phalanges: A longitudinal study. |
Author |
Pluskiewicz W, Halaba Z, Chelmecka L, Drozdzowska B, Sonta-Jakimczyk D, Karasek D. |
Journal |
Ultrasound Med Biol |
Volume |
|
Year |
2004 |
Abstract |
The skeletal growth in a course of acute lymphoblastic leukemia (ALL) may be affected, and the aim of the longitudinal study was to assess the skeletal status in survivors of (ALL). The studied population consisted of 38 subjects (17 female and 21 male) measured at the age of 13.9 ? 3.8 years (5.7 ? 2.9 years after completion of the therapy, 11.0 ? 14.4 years after diagnosis) and 2 years earlier; compared with 1402 controls (628 female and 774 male). Patients and controls did not differ significantly in regard to age, height or weight. Skeletal status was assessed by quantitative ultrasound (US) measurements at the hand phalanges using the DBM Sonic 1200, which measures amplitude-dependent speed-of-sound, Ad-SoS (m/s). rms CV% was 0.43%. Mean baseline Ad-SoS value in patients was 1990 ? 76 m/s and, at second measurement, 2045 ? 86 m/s (p < 0.000001). In 31 patients, Ad-SoS increased and, in one patient, decreased more than the value of the least significant change. In controls, mean Ad-SoS values were 1973 ? 64 m/s (baseline) and 2016 ? 86 m/s (follow-up) and did not differ significantly vs. baseline values in patients. At second measurement, Ad-SoS in controls was significantly lower than in patients (p < 0.05). In five patients with low baseline Ad-SoS values, bone mineral density (BMD) at the spine using DPX-L was estimated; baseline mean BMD was 0.95 ? 0.11 g/cm2, Z-score was 1.25 ? 0.97 and, at second measurement, 1.16 ? 0.07 g/cm2, Z-score was 0.23 ? 0.43. A significant increase in BMD (p < 0.01) and Z-score (p < 0.05) was noted. In patients, Ad-SoS correlated significantly with age, period after completion of the therapy, body size and Tanner stages (r ranged from 0.43 to 0.83, p ranged from 0.0001 to 0.05). It can be concluded that skeletal status assessed by quantitative US at the hand phalanges in survivors of ALL improved significantly over the period of observation.
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Title |
Small cylindrical ultrasound sources for induction of hyperthermia via body cavities or interstitial implants. |
Author |
Hynynen K, Davis KL. |
Journal |
Int J Hyperthermia |
Volume |
|
Year |
1993 |
Abstract |
In this study, small (outside diameter 1 mm) cylindrical ultrasound sources were investigated for induction of hyperthermia in tumours. These ultrasound transducers could be placed in small-diameter body cavities, or they could be used interstitially in brachytherapy catheters. The ultrasound field measurements showed that the field is fairly uniform as a function of the length of the applicator except at the ends where sharp peaks were located. However, there were significant field variations as a function of rotation angle around the transducers. The degree of these non-uniformities varied from transducer to transducer, and also as a function of frequency. The temperature measurements in vitro perfused kidneys showed that therapeutic temperature elevations could be induced in perfused tissues. The radial extent of the therapeutic zone could be increased by circulating water around the applicators, thus avoiding high temperatures on the applicator surface. It was also shown that some control over the temperature distribution along the length of the applicator could be achieved by using a two-element applicator. An array of four applicators implanted in a square pattern with the spacing of 25 mm between the catheters, was able to heat the tissue volume inside of the implant. The results showed that these small ultrasound applicators may offer significant improvement over existing techniques by increasing the penetration depth and the control over the power deposition pattern. |
Title |
Small localized ultrasonic lesions in the white and gray matter of the cat brain. |
Author |
Barnard JW, Fry WJ, Fry FJ, Brennan JF. |
Journal |
AMA Arch Neurol Psychiat |
Volume |
|
Year |
1956 |
Abstract |
The work reported here is a continuation of the study in progress at this laboratory of the effects of accurately controlled doses of ultrasound on the tissue of the central nervous system. Previous publications were concerned with the production and study of ultrasonically produced lesions in white matter. It was reported that selective lesions of almost any desired shape can be produced at any depth in the brain without affecting any intervening tissue by positioning the focus of a beam of high-frequency sound in the region to be affected. The previous work was restricted to the study of relatively large white-matter lesions produced by irradiating the tissue in a number of positions in an appropriately chosen overlapping pattern of spots. This paper is concerned with the histological study of small lesions produced by irradiating the tissue in a single spot with focused beams. The dosage conditions necessary for producing selective small-size white and gray-matter lesions are reported. |
Title |
Soft tissue anatomy of the tongue and floor of the mouth: an ultrasound demonstration. |
Author |
Shawker TH, Sonies BC, Stone M. |
Journal |
Brain Lang |
Volume |
|
Year |
1984 |
Abstract |
Ultrasound technology has not been used extensively in the study of normal and abnormal oral physiology and speech. Features such as soft tissue detail, real-time motion display, and subject safety make ultrasound ideal for imaging the tongue and the floor of the mouth. This study demonstrates visualization of the muscles of the tongue and floor of the mouth for a normal subject using ultrasound imaging. By employing submandibular transducer placement of realtime sector scanners, tongue anatomy and motion were continuously visualized in sagittal or coronal planes. In addition to the entire tongue surface, much of the intrinsic anatomy was identified including: the genioglossus, geniohyoid, mylohyoid, and digastric muscles; fascial boundaries such as the median fibrous septum, floor intermuscular septum, and paramedian septums; and the hyoid bone. A tongue excised from a human cadaver was scanned using ultrasound and dissected to confirm the anatomy seen in the live tongue. Tongue surface shape and configuration of the intrinsic tissue structures were observed and compared for the phonemes /k/, /u/, and /i/. Anatomical landmarks in the resting and speaking tongue are discussed as well as applications in the fields of speech science and speech pathology. |
Title |
Soft tissue temperature rise caused by scanned, diagnostic ultrasound. |
Author |
Curley MG. |
Journal |
IEEE Trans UFFC |
Volume |
|
Year |
1993 |
Abstract |
An acoustic-thermal model was developed for scanned diagnostic ultrasound in soft tissue. An adiabatic surface between the transducer and the skin was justified, and the model accounted for attenuation and focusing. The temperature along the central plane of the temporally averaged acoustic field was calculated by integration of line sources of heat that result from the tissue's absorption of ultrasound. The temperature profiles were calculated for 1400 transducers. The results show that current diagnostic transducers heat more significantly at the transducer-tissue interface than at the focus. The temperature rise in the focal region is typically less than 25% of that at the surface. The acoustic power per scan length that results in a 1 ?C temperature rise at the surface is calculated as (210 mW-MHz/cm)/f. These results apply to both linear arrays and sector-like scan formats. The temperature rises for simultaneous multimode scanned beams are additive as the peak temperatures of each mode will occur on the surface. Consideration was given to the surface boundary condition for such models. This boundary is considered adiabatic for calculation of heating due to acoustic absorption alone. Additional heating or cooling resulting from the transducer can then be superimposed on this solution.. |
Title |
Solutions of the bio-heat transfer equation. |
Author |
Nyborg WL. |
Journal |
Phys Med Biol |
Volume |
|
Year |
1988 |
Abstract |
A solution of the bio-heat transfer equation for a 'step-function point source' is.presented and discussed. From this basic solution one can, in principle, obtain the.temperature field resulting from a general heat source distribution by superposition..As an example, the method is used to calculate the temperature on the body surface at.a point where therapeutic ultrasound is applied. Comparison is made with.experimental results recently published by Williams and co-workers. |
Title |
Some advances in acoustic imaging through skull. |
Author |
Smith SW, Phillips DJ, von Ramm OT, Thurstone FL. |
Journal |
Proc Second Int Symp Ultrason Tissue Character |
Volume |
|
Year |
1977 |
Abstract |
Previous attempts to image the adult brain through the skull using diagnostic ultrasound have resulted in images of poor lateral resolution and limited dynamic range. The skull can be modeled as an acoustic lens whose attenuation increases rapidly above 1 Mhz and whose thickness variations introduce phase aberrations on the order of several wavelengths across the transducer aperture. Statistical analysis of skull thickness data indicate that an electronic sector scanner using a 1 MHz linear array transducer is less sensitive to these effects of the skull than traditional pulse echo systems operating at higher frequencies. Representative ultrasound tomograms of the brain are shown. In addition, water tank experiments are described in which the skull phase aberration, phi (x), was measured on line and removed by incorporating a compensating phase variation, - phi (x), into the transmit and receive timing of a digitally controlled real time phased array imaging system. Preliminary results show that the lateral resolution of the imaging system is restored in both the transmit and receive modes. |
Title |
Some applications of ultrasonics. |
Author |
Brockelsby CF. |
Journal |
J Sci Instrum |
Volume |
|
Year |
1963 |
Abstract |
The history of ultrasonics is outlined, to provide a background for the discussion of present-day applications. These can be classified as processing, testing and communications. In processing applications, ultrasonic vibration at high power densities is used to produce a physical or chemical change in material. In liquids, the effective agent is often cavitation, which causes emulsification and dispersion, useful for cleaning and atomization. Focused ultrasound is used for surgery. Echo sounding techniques are used for testing materials as well as at sea. They have recently been applied in medical diagnosis. Ultrasonography by image-forming methods may be an alternative method. The high frequency elastic properties of a material can be measured with great precision and give information about its structure. The most important 'communications' application is in ultrasonic delay lines, which are useful in radar and data-handling systems. |
Title |
Some aspects of the present status of ultrasound in fundamental biological research and in medicine. |
Author |
Fry WJ, Dunn F. |
Journal |
J Acoust Soc Am |
Volume |
|
Year |
1957 |
Abstract |
No abstract available. |
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