| carotid doppler | <investigation> A noninvasive test which uses high-frequency sounds waves to determine extent of blood flow through the carotid arteries in the neck. Used in the evaluation of stoke and TIA symptoms. (08 Jan 1998) |
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| doppler | The use of an augmented listening device for the purpose of detecting the pulse in an extremity. Use in the evaluation of peripheral (occlusive) vascular disease. (27 Sep 1997) |
| doppler broadening | <radiobiology> Frequency spreading which causes broadening of single-frequency radiation (for example, spectral lines) when the radiating bodies (atoms, molecules, etc.) have different velocities. Radiation from each individual radiating body has a different Doppler shift, and the collection of radiations at different frequencies broadens the peak of the line in an intensity-vs-frequency plot. (09 Oct 1997) |
| Doppler, Christian | <person> Austrian mathematician and physicist in U.S., 1803-1853. See: Doppler echocardiography, Doppler effect, Doppler phenomenon, Doppler shift, Doppler ultrasonography. (05 Mar 2000) |
| Doppler colour flow | A computer-generated colour image produced by Doppler ultrasonography in which different directions of flow are represented by different hues. This technique is typically used to examine blood flow when evaluating heart disease. Where obstructions (for instance, arterial plaques) exist, blood flow will alter according to the principles of fluid mechanics. Eddies and reversals are readily apparent on the colour image. See: Doppler ultrasonography. (05 Mar 2000) |
| Doppler echocardiography | Use of Doppler ultrasonography techniques to augment two-dimensional echocardiography by allowing velocities to be registered within the echocardiographic image. See: duplex ultrasonography, Doppler ultrasonography. Synonym: duplex echocardiography. (05 Mar 2000) |
| doppler effect | <radiobiology> Variation in the frequency of a wave (as measured by an observer) due to relative motion between the observer and the source of the wave. (The observed frequency increases if the source is moving towards the observer and vice versa.) The equation can be found in most optics texts and many introductory physics texts. (09 Oct 1997) |
| Doppler phenomenon | <radiobiology> Variation in the frequency of a wave (as measured by an observer) due to relative motion between the observer and the source of the wave. (The observed frequency increases if the source is moving towards the observer and vice versa.) The equation can be found in most optics texts and many introductory physics texts. (09 Oct 1997) |
| doppler shift | <radiobiology> The amount of change in the observed frequency of a wave due to the Doppler effect, sometimes called the Doppler frequency. (09 Oct 1997) |
| duplex Doppler scan | A method of visualizing and selectively assessing the flow patterns of peripheral arteries and veins using ultrasound imaging and pulsed Doppler. (05 Mar 2000) |
| echocardiography, doppler | Measurement of intracardiac blood flow using an m-mode and/or two-dimensional (2-d) echocardiogram while simultaneously recording the spectrum of the audible doppler signal (e.g., velocity, direction, amplitude, intensity, timing) reflected from the moving column of red blood cells. (12 Dec 1998) |
| echocardiography, doppler, colour | Echocardiography applying the doppler effect, with the superposition of flow information as colours on a gray scale in a real-time image. (12 Dec 1998) |
| echocardiography, doppler, pulsed | Echocardiography applying the doppler effect, with velocity detection combined with range discrimination. Short bursts of ultrasound are transmitted at regular intervals and the echoes are demodulated as they return. (12 Dec 1998) |
| foetal doppler study | <radiology> Non-stress test (NST), external monitoring for 20 minutes; poor specificity, greater than4 foetal heart accelerations (greater than15 bpm over baseline for 15 seconds) following foetal movement in foetus greater than34 weeks, no heart accelerations in immaturity, sleep, maternal sedation contraction stress test (CST), external monitoring after oxytocin or maternal breast stimulation, greater than 3 uterine contraction in 10 minutes; 50% specificity uterine and umbilical artery waveform, elevated systolic:diastolic ratio = increased vascular resistance foetal aortic flow volume, 185-246 ml/kg/min see also: biophysical profile, intrauterine growth retardation (IUGR) (12 Dec 1998) |
| laser-doppler flowmetry | A method of non-invasive, continuous measurement of microcirculation. The technique is based on the values of the doppler effect of low-power laser light scattered randomly by static structures and moving tissue particulates. (12 Dec 1998) |