Belinda Breyer

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A CATHETER, whether cardiac or otherwise, can be imaged ultrasonically when inserted into the body owing to its different acoustic impedance. However, a major problem stands in the way of positive catheter tip identification. As illustrated in Fig. 1, and in a waterbath experiment in Fig. 2, any section of the catheter (or puncture needle) will appear as(More)
We have developed an ultrasonic marking system for pacing leads and the electrophysiological study of catheters. The aim of this study was to evaluate the accuracy of our system, its usability in the measurement of performance of implanted leads, and to investigate the potential of electrical shock and ultrasonic hazard. The measurements have shown that(More)
Ultrasound catheters offer the possibility of various non-imaging applications. Some of these applications, now in different stages of development, have been studied and will be described here in some detail. Ultrasonically marked catheters have different applications. The catheter has a miniature marker transducer mounted at the tip or some other place of(More)
Blood flow characteristics were measured in patients with histologically proved cervical cancer and compared to normal values. Flow parameters were derived by color and pulsed Doppler ultrasound. The results showed a significant difference in the mean values of resistance index and pulsatility index among the diseased patients and healthy controls. However,(More)
In many developing countries ultrasound services are either nonexistent or inadequate, although the diagnostic problems for which ultrasound is particularly suited are common in such countries. In view of this, the World Health Organization (WHO) has outlined the indications for diagnostic ultrasound together with the technical specifications for equipment.(More)
Changes in glycoprotein and ganglioside composition in human trophoblasts (eighth week of gestation) after in vitro exposure to pulsed Doppler ultrasound (pulse duration 1.22 microseconds; repetition frequency 11.1 kHz; center frequency 4 MHz; ISPPA = 175.5 W/cm2; ISPTA = 0.59 W/cm2) were investigated. Evacuated trophoblasts were divided in two halves and(More)
Ultrasound of time average acoustic intensities between 0.5 and 3 W cm-2 is widely used in physiotherapy. A simple device for semiquantitative checking of output power and beam shape has been designed. The beam tester consists of an absorbing plate and a sheath liquid crystal thermometer for temperature distribution display. The ultrasonic beam is fed to(More)