1. A reverberating sound sometimes heard during auscultation of the chest. 2. In ultrasonography, the acoustic signal received from scattering or reflecting structures or the corresponding pattern of light on a CRT or ultrasonogram. 3. In magnetic resonance imaging, the signal detected following an inverting pulse. [G.]
- atrial e. electrical reactivation of the atrium by a retrograde impulse returning from the A-V node while the antegrade impulse continues to the ventricle; characterized electrocardiographically, by a pair of P waves enclosing a QRS complex, the second P wave being opposite in polarity (usually inverted in lead II), indicating that it is the reverse (the retrograde pathway) of the pathway of the first P wave (the antegrade pathway).
- navigator e. a method of respiratory gating q.v., used in magnetic resonance imaging to limit respiratory motion artifact; a signal is derived from the top of the diaphragm, and image data are collected only when it is in a selected range.
- nodus sinuatrialis e., NS e. a postectopic sinus beat occurring earlier than would be expected from the preceding sinus node discharge interval; i.e., the interval following a premature beat of supraventricular origin is less than the ordinary cycle length between sinus beats, whereas ordinarily the interval would be expected to exceed cycle length.
- e. planar a method of magnetic resonance imaging that allows rapid image acquisition during free induction decay, using technically demanding rapidly oscillating radiofrequency gradients.
- spin e. a commonly used technique to recover T1 and T2 relaxation signals in magnetic resonance imaging, by using a 180° inverting pulse in the pulse sequence to compensate for loss of transverse magnetization caused by magnetic field inhomogeneities.
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echocardiography; enteric cytopathic human orphan [virus]; Etoposide, cyclophosphamide, Adriamycin, and vincristine

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echo 'ek-(.)ō n, pl ech·oes also echos
1) the repetition of a sound that is caused by reflection of sound waves
2) the sound that is due to reflection of sound waves
echo vb, ech·oed; echo·ing 'ek-(.)ō-iŋ, 'ek-ə-wiŋ

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(ekґo) [Gr. ēchō a returned sound] 1. repetition of a sound as a result of reverberation of sound waves. 2. the reflection of ultrasonic, radio, or radar waves. sometimes used in reference to any kind of repetition.

Medical dictionary. 2011.


Look at other dictionaries:

  • écho — écho …   Dictionnaire des rimes

  • Echo — Echo …   Deutsch Wörterbuch

  • écho — [ eko ] n. m. • XIIIe; lat. echo, gr. êkhô 1 ♦ Phénomène de réflexion du son par un obstacle qui le répercute; le son ainsi répété. Effet d écho. Il y a de l écho dans cette église. ⇒ réverbération. Écho simple, qui ne reproduit les sons qu une… …   Encyclopédie Universelle

  • Echo — Écho Cette page d’homonymie répertorie les différents sujets et articles partageant un même nom.  Pour les articles homophones, voir écot et eco …   Wikipédia en Français

  • Echo 1 — (eigentlich Echo 1A) ist der Name eines großen Ballonsatelliten der USA, der am 12. August 1960 als erster Nachrichten und geodätischer Satellit gestartet wurde. Seine internationale COSPAR Nummer war 60 009 01 (9. Start des Jahres …   Deutsch Wikipedia

  • Echo 1A — Echo 1 Echo 1 (eigentlich Echo 1A) ist der Name eines großen Ballonsatelliten der USA, der am 12. August 1960 als erster Nachrichten und geodätischer Satellit gestartet wurde. Seine internationale COSPAR Nummer war 60 009 01 (9. Start des Jahres… …   Deutsch Wikipedia

  • echo — (от англ. echo эхо) команда Unix, предназначенная для отображения строки текста. Команда echo выводит текст (выводит текст на стандартное устройство вывода). Синтаксис echo [ПАРАМЕТР]... [СТРОКА]... Параметры n не выводить в конце символ… …   Википедия

  • Echo — Ech o ([e^]k [ o]), n.; pl. {Echoes} ([e^]k [=o]z). [L. echo, Gr. hchw echo, sound, akin to hchh , h^chos, sound, noise; cf. Skr. v[=a][,c] to sound, bellow; perh. akin to E. voice: cf. F. [ e]cho.] 1. A sound reflected from an opposing surface… …   The Collaborative International Dictionary of English

  • Echo — Saltar a navegación, búsqueda Echo puede referirse a: Echo (computación), un concepto informático. Toyota Echo, un modelo de automóvil de la marca Toyota. ECHO (premio), un premio musical. Echo and the Bunnymen, un grupo musical británico. Echo… …   Wikipedia Español

  • ECHO — ECHO  хеш функция, выдвинутая как кандидат на конкурс SHA 3, проводимый Национальным институтом стандартов и технологий (США). Алгоритм разработан в Orange Labs, его авторы: Ryad Benadjila Olivier Billet Henri Gilbert Gilles Macario Rat… …   Википедия

  • écho — ÉCHO. s. m. (Prononcez Éco.) Les Poëtes ont feint une Nymphe de ce nom, fille de l Air, qui étant devenue amoureuse de Narcisse, dont elle ne put se faire aimer, fut métamorphosée en rocher, et ne conserva que la voix. Ce mot est féminin en ce… …   Dictionnaire de l'Académie Française 1798

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