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Ultrasound has been used by radiologists and sonographers to image the human body for at least 50 years and has become a widely used diagnostic tool. [36] The technology is relatively inexpensive and portable, especially when compared with other techniques, such as magnetic resonance imaging (MRI) and computed tomography (CT).
uses ultrasound to produce images from within the body; video link: X-ray: uses X-rays to produce images of structures within the body; video link: Contrast media for X-rays: to provide a high contrast image of the details of the viscera under study; e.g. salts of heavy metals, gas like air, radio-opaque dyes, organic iodides, etc ...
Medical ultrasound includes diagnostic techniques (mainly imaging techniques) using ultrasound, as well as therapeutic applications of ultrasound. In diagnosis, it is used to create an image of internal body structures such as tendons, muscles, joints, blood vessels, and internal organs, to measure some characteristics (e.g., distances and velocities) or to generate an informative audible sound.
A contrast agent (or contrast medium) is a substance used to increase the contrast of structures or fluids within the body in medical imaging. [1] Contrast agents absorb or alter external electromagnetism or ultrasound, which is different from radiopharmaceuticals, which emit radiation themselves.
Absence of the portal system in a first trimester case associated with hygroma and aorto-umbilical fistula. (A): Transverse plane of the upper abdomen with color Doppler applied, showing umbilical cord insertion, stomach, the prominent hepatic artery and no afferent liver venous perfusion; (B): midsagittal plane reconstructed from a three-dimensional volume acquisition were the crown-rump ...
Unlike X-ray or other physical properties which provide typically only one information, ultrasound provides multiple information of the object for imaging: the attenuation the wave's sound pressure experiences indicate on the object's attenuation coefficient, the time-of-flight of the wave gives speed of sound information, and the scattered ...
Essentially, ultrasound is considered safe. While other imaging modalities use radioactive dye or ionizing radiation, for example, ultrasound transducers send pulses of high frequency sound into the body and then listen for the echo. In summary, the primary risks associated with ultrasound would be the potential heating of tissue or cavitation ...
The body is 73% water, and therefore, acoustically homogeneous. Blood and surrounding tissues have similar echogenicities, so it is also difficult to clearly discern the degree of blood flow, perfusion, or the interface between the tissue and blood using traditional ultrasound. [4] Ultrasound imaging allows real-time evaluation of blood flow. [29]