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Echogenicity (sometimes as echogenecity) or echogeneity is the ability to bounce an echo, e.g. return the signal in
Echogenicity (sometimes as echogenecity) or echogeneity is the ability to bounce an echo, e.g. return the signal in medical ultrasound
Medical ultrasound includes Medical diagnosis, diagnostic techniques (mainly medical imaging, imaging) using ultrasound, as well as therapeutic ultrasound, therapeutic applications of ultrasound. In diagnosis, it is used to create an image of ...
examinations. In other words, echogenicity is higher when the surface bouncing the sound echo reflects increased sound waves. Tissues that have higher echogenicity are called "hyperechoic" and are usually represented with lighter colors on images in medical ultrasonography
Medical ultrasound includes Medical diagnosis, diagnostic techniques (mainly medical imaging, imaging) using ultrasound, as well as therapeutic ultrasound, therapeutic applications of ultrasound. In diagnosis, it is used to create an image of ...
. In contrast, tissues with lower echogenicity are called "hypoechoic" and are usually represented with darker colors. Areas that lack echogenicity are called "anechoic" and are usually displayed as completely dark.
Microbubbles
Echogenicity can be increased by intravenously administering gas-filled microbubble contrast agent to the systemic circulation, with the procedure being called contrast-enhanced ultrasound. This is because microbubbles have a high degree of echogenicity. When gas bubbles are caught in an ultrasonicfrequency
Frequency is the number of occurrences of a repeating event per unit of time. Frequency is an important parameter used in science and engineering to specify the rate of oscillatory and vibratory phenomena, such as mechanical vibrations, audio ...
field, they compress, oscillate
Oscillation is the repetitive or periodic variation, typically in time, of some measure about a central value (often a point of equilibrium) or between two or more different states. Familiar examples of oscillation include a swinging pendulu ...
, and reflect a characteristic echo- this generates the strong and unique sonogram in contrast-enhanced ultrasound. Gas cores can be composed of air
An atmosphere () is a layer of gases that envelop an astronomical object, held in place by the gravity of the object. A planet retains an atmosphere when the gravity is great and the temperature of the atmosphere is low. A stellar atmosph ...
, or heavy gases like perfluorocarbon, or nitrogen
Nitrogen is a chemical element; it has Symbol (chemistry), symbol N and atomic number 7. Nitrogen is a Nonmetal (chemistry), nonmetal and the lightest member of pnictogen, group 15 of the periodic table, often called the Pnictogen, pnictogens. ...
. Heavy gases are less water-soluble so they are less likely to leak out from the microbubble to impair echogenicity (McCulloch ''et al.'', 2000). Therefore, microbubbles with heavy gas cores are likely to last longer in circulation.
Reasons for higher echogenicity
During ultrasound examinations, sometimes echogenicity is higher in certain parts of body. Fatty liver could cause increased echogenicity in the liver, especially if the liver transaminases are elevated. Women withpolycystic ovary syndrome
Polycystic ovary syndrome, or polycystic ovarian syndrome, (PCOS) is the most common endocrine disorder in women of reproductive age. The name is a misnomer, as not all women with this condition develop cysts on their ovaries. The name origin ...
may also show an increase in stromal echogenicity.
See also
* Contrast-enhanced ultrasound * Echogenic intracardiac focus *Medical ultrasound
Medical ultrasound includes Medical diagnosis, diagnostic techniques (mainly medical imaging, imaging) using ultrasound, as well as therapeutic ultrasound, therapeutic applications of ultrasound. In diagnosis, it is used to create an image of ...
References
{{Reflist Acoustics Hearing Medical physics Medical ultrasonography Ultrasound