We describe here a method for generating relative pressure maps from magnetic resonance velocity data in three spatial and one temporal dimension (4D). The relative pressure map calculated for pulsatile flow in a compliant phantom was shown to be consistent with independent pressure transducer measurements. The feasibility of performing 4D pressure mapping in vivo is also demonstrated.

PURPOSE The purpose of this study was to evaluate the Tono-Pen 2 tonometer for measuring intraocular pressure (IOP) in the living rat eye. METHODS One eye from each of 20 adult, anesthetized brown Norway rats (group 1) was cannulated and simultaneously connected to a syringe and a pressure transducer with a chart recorder. We increased IOP from 15 to 45 mmHg in 5-mmHg increments and obtained ...

A comparison was made in 7 dogs of the results obtained by 6 different apex cardiographic transducers applied before, during, and after controlled infusion of angiotensin and isoprenaline. The electrocardiogram, internal phonocardiogram, aortic and left ventricular pressure using a Telco micromanometer, and apex cardiogram were recorded simultaneously on magnetic tape and paper. Digital compute...

Neonatal ultrasonography entails potential procedural hazards to the newborn infant. When performing ultrasound studies, the examiner may inadvertently move the endotracheal tube or may facilitate the spread of infection from one baby to another. The examiner should also be aware that the pressure of applying the transducer to the scalp is transmitted to the central nervous system and that the ...

In this article the calculation, along with practical examples of near and far fields of acoustic antennas are presented. Knowing the near and far fields is important because the radiation patterns and physical measurements of the antennas depend on them. These antennas designed for measurements in air consist of transducers in flexural vibration, which give the best possibility to match acoust...

Pulse ultrasound technique has been applied to measure the reflected echo signals from vapor bubbles in boiling two-phase flow. In this study, an ultrasonic transducer was developed for the ultrasonic measurement in boiling two-phase flow under the atmospheric pressure. Since the Curie point of piezoelements of the transducer is above 250 ̊C, it has an allowable temperature limit of 120 ̊C. The b...

An inhomogeneous wave equation is derived describing propagation and scattering of ultrasound in an inhomogeneous medium. The scattering term is a function of density and propagation velocity perturbations. The integral solution to the wave equation is combined with a general description of the field from typical transducers used in clinical ultrasound to yield a model for the received pulse-ec...

The use of different optical-fiber sensors for weighing measurements is Abstract described. By using three different mechanical stressing mechanisms, the operation of the fiber-to-fiber transducer systems are tested and the results are presented. Parameters such as sensitivity, hysteresis, resolution, and dynamic range are measured. A comparison of the results has shown that the sensor system m...