心脏超声基础.pptx

心脏超声基础。1、Basics of Ultrasound；2、M‐mode；3、2D imaging；4、Continuous；5、doppler；6、Pulse wave doppler；7、Colour flow doppler；8、Tissue doppler imaging；9、Artefact；10、Bubble, contrast and stress echo。

Frequency: number of cycles per unit time，Propagation speed: speed of ultrasound through tissue，Period: time required for one cycle in microseconds，Power: rate of energy transfer determined by the ultrasound source ‐ decreases as the beam is propagated。Propagation speed of ultrasound depends on the density and stiffness/ compressibility of the media.Air – 330m/s; Water – 1570m/s; Tissue – 1540m/s; Bone – 4080s/s，Given that the velocity is fixed at 1540m/s we can calculate the wavelength of cardiac ultrasound。 Electric energy causes vibration of the piezoelectric crystals within the transducer which creates ultrasound waves，Waves are sent from the transducer and reflected off structures in the heart，Piezoelectric effect，Send waves: Convert electricity to ultrasound waves，Receive waves: Convert ultrasound waves into electricity，The crystals act as a ‘speaker’ and ‘microphone’。本课件是针对生物健康行业所编写的，旨在为生物健康行业提供关于心脏超声方向更为专业的指导和建议。