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Diagnostic Ultrasound (diagnostic + ultrasound)

Distribution by Scientific Domains

Medical Sciences	50%

Selected Abstracts

First-trimester sonography: Is the fetus exposed to high levels of acoustic energy?,

JOURNAL OF CLINICAL ULTRASOUND, Issue 5 2007
Eyal Sheiner MD
Abstract Purpose. As a form of energy, diagnostic ultrasound has bioeffects on living tissues. The thermal index (TI), TIS (TI for soft tissue), TIB (TI for bone), TIC (TI for cranial bone) expresses the potential for rise in temperature at the ultrasound beam's focal point. The mechanical index (MI) indicates the potential for the ultrasound beam to induce inertial cavitation in tissues. The goal of this study was to characterize the acoustic output of clinical ultrasound instruments, as expressed by TI and MI, during routine first-trimester sonographic examinations. Methods. A prospective observational study was conducted. First-trimester patients were randomly selected from those scheduled for viability scans. An obstetrician collected data. Sonographers were blinded to the data being sought, which included gestational age, duration of the examination, and every variation in the MI and TI during each sonographic examination. Results. A total of 52 first-trimester examinations were evaluated. The mean gestational age was 8.9 ± 1.9 weeks. The mean duration of the sonographic examinations was 8.1± 1.4 minutes. During the examinations, there were 178 MI variations (mean ± SD, 0.9 ± 0.3) and 167 TI variations (mean ± SD, 0.2 ± 0.1). Conclusion. First-trimester sonographic examinations are associated with a negligible rise in TI. © 2007 Wiley Periodicals, Inc. J Clin Ultrasound, 2007 [source]

Diagnostic accuracy of shoulder ultrasound performed by a single operator

JOURNAL OF MEDICAL IMAGING AND RADIATION ONCOLOGY, Issue 3 2007
DM Cullen
Summary Both diagnostic ultrasound and magnetic resonance imaging (MRI) are used for investigation of the presence and severity of rotator cuff lesions. There is no consensus as to which is the more accurate and cost-effective study. We sought to examine the sensitivity of ultrasound, when used by one experienced radiologist with modern equipment. We compared the ultrasound and surgical results obtained from 68 patients. Ultrasound showed a sensitivity of 89% and specificity of 100% (Positive Predictive Value 100%) for full-thickness tears, and a sensitivity of 79% and specificity of 94% (Positive Predictive Value 87%) for partial-thickness tears. We found that shoulder ultrasound, in the hands of an experienced radiologist with the use of modern high-resolution equipment, is highly sensitive in differentiating complete tears and partial-thickness tears. Our results are similar to the best published results for MRI and given that ultrasound is significantly cheaper and more available, ultrasound by an experienced radiologist should be considered as a primary diagnostic tool for imaging the rotator cuff. [source]

Effect of molecular weight and end capping on poly(lactic- co -glycolic acid) ultrasound contrast agents

POLYMER ENGINEERING & SCIENCE, Issue 9 2008
J.R. Eisenbrey
Ultrasound contrast agents (CA) consist of stabilized gas bubbles that, when injected intravenously, provide an acoustic impedance mismatch, producing additional contrast to a diagnostic ultrasound scan. These agents must be smaller than 8 ,m in order to pass safely through the capillaries, contain gas for an impedance mismatch and should be stable enough to survive the duration of the imaging session. A double emulsion technique has previously been optimized within our laboratory to create CA with 50:50 poly (lactic- co -glycolic acid) (PLGA). Although a great deal of research has focused on the effects of molecular weight and end capping on solid PLGA particles, very little has been done to examine the effects of these parameters on hollow CAs formed in a double emulsion. Non-end capped PLGA was found to provide maximum enhancement at a molecular weight of 66.0 kDa, giving an ultrasound enhancement of roughly 18.5 dB. The enhancement demonstrated by CA formed using the end-capped PLGA rose to a maximum enhancement of 19 dB at the highest commercially available molecular weight of 82.4 kDa. A strong correlation was seen between ultrasound enhancement, stability under ultrasonic conditions, surface morphology and zeta potential. This study shows the influence of polymer characteristics on the resulting properties of CA and the ability to tailor CAs to particular applications by varying the polymer choice. POLYM. ENG. SCI., 2008. © 2008 Society of Plastics Engineers [source]

Gestational stage sensitivity to ultrasound effect on postnatal growth and development of mice

BIRTH DEFECTS RESEARCH, Issue 8 2006
Suresh Rao
Abstract BACKGROUND: An experiment was conducted to find out whether ultrasound exposure leads to changes in postnatal growth and development in the mouse. METHODS: A total of 15 pregnant Swiss albino mice were exposed to diagnostic levels of ultrasound (3.5 MHz, 65 mW/cm2, ISPTP = 1 mW/cm2 Intensity(Spatial Peak-Temporal Peak), ISATA = 240 mW/cm2 Intensity(Spatial Average-Temporal Average)) for 30 min for a single day between days 10 and 18 of gestation (GD 10,18). Virgin female mice were placed with same age group males for mating in the ratio 2 females : 1 male and examined the next morning for the presence of vaginal plug, a sign of successful copulation. The females with vaginal plugs were separated and labeled as 0-day pregnant. Maternal vaginal temperature was also measured. A sham exposed control group of 15 pregnant mice was maintained for comparison. All exposed as well as control animals were left to complete gestation and parturition. Their offspring were used in our further studies. They were monitored during early postnatal life for standard developmental markers, postnatal mortality, body weight, body length, head length, and head width, and growth restriction was recorded up to 6 weeks of age. RESULTS: An exposure to ultrasound induced nonsignificant deviations in the maternal vaginal temperature or developmental markers. Significant low birth weight was observed in the present study, after exposure at GD 11, 12, 14, and 16. However, 14 and 16 days postcoitus during the fetal period appears to be the most sensitive to the ultrasound effect, in view of the number of different effects as well as severity of most of the observed effects when exposed on these gestation days. CONCLUSIONS: The results indicate that diagnostic ultrasound can induce harmful effects on mouse growth and development when given at certain critical periods of gestation. Birth Defects Research (Part A) 76:602,608, 2006. © 2006 Wiley-Liss, Inc. [source]