OBJECTIVE To determine whether pulsed Doppler examination of the ductus venosus in rat fetuses could damage exposed tissue. METHODS On gestational day 18, the livers of a mean of approximately five fetuses per mother (n = 5.14, SD = 1.6), in a cohort of 35 pregnant female rats, were exposed individually to pulsed Doppler and these were considered the 'exposed group'. The remaining fetuses in ...

The linear Doppler shift is familiar as the rise and fall in pitch of a siren as it passes by. Less well known is the rotational Doppler shift, proportional to the rotation rate between source and receiver, multiplied by the angular momentum carried by the beam. In extreme cases the Doppler shift can be larger than the rest-frame frequency and for a red shift, the observed frequency then become...

The longitudinal Doppler shift is a measure of hyperbolic distance. Transformations of uniform motion are determined by the Doppler shift, while its square root transforms to a uniformly accelerated frame. A time-velocity space metric is derived, by magnifying the Beltrami coordinates with the geometric time, which is similar to the one obtained by Friedmann using Einstein’s equations in which ...

t a fi d T t p n r r l fi w N of Diagnostic and Interventional Imaging, to an emerging technique: ultrasound elastography. This issue provides the readers with information necessary to understand this new modality on the eve of its clinical expansion. Analogies with the development of pulsed wave and color Doppler modes are important, especially for techniques providing two-dimensional color-co...

Wind speed is a most important weather parameter to record and monitor for many applications like meteorology, shipping, aviation etc. Wind observations are very important for general (operational) aviation meteorology, and weather prediction. Wind profilers are vertically directed pulsed Doppler radars which can analyze the back scattered signals and determine the velocity of air along the bea...

Two cases with rib injuries are reported where intercostal nerve block without rib palpation was safely and successfully performed on six separate occasions using a Doppler blood-flow detector ultrasound stethoscope. A third case studied by a radiologist using a pulsed Doppler flowmeter, determined the source of the Doppler signals as originating from the intercostal artery. The significance of...

Myocardial ischemia results in altered left ventricular (LV) diastolic compliance, reflected by an abnormal mitral inflow pattern on Doppler echocardiography. To investigate the relationship of Doppler echocardiography and regional myocardial systolic function during dipyridamole infusion, we evaluated transmitral flow changes detected by pulsed Doppler technique during a high-dose dipyridamole...

Pulsed Doppler echocardiography was used to determine prospectively the prevalence of mitral, aortic, tricuspid and pulmonary regurgitation in 80 consecutive patients with mitral valve prolapse and 85 normal subjects with similar age and sex distribution. Mitral valve prolapse was defined by posterior systolic displacement of the mitral valve on M-mode echocardiography of 3 mm or more (40 patie...

RATIONALE Vein of Galen aneurysmal malformation (VGAM) is a rare complex malformation of the cerebral vascular system consisting of arteriovenous shunts between the vein of Galen and the cerebral arteries. PATIENT CONCERNS We present the case of a 31-year-old pregnant woman, para 1, gravida 1. DIAGNOSES At 26 weeks' gestation who was examined for an anechoic mass on the cerebral median midl...

Pulsed Doppler mapping of the flow disturbance of mitral insufficiency is commonly employed to estimate the severity of regurgitation. We re-examined the customary pulsed Doppler criterion of relative depth of jet penetration (MR ratio) in 50 patients undergoing left ventriculography and found a modest correlation (r = 0.70) between Doppler and angiographic estimates of regurgitant grade. The M...