ultrasonography

ultrasonography /ul·tra·so·nog·ra·phy/ (-sŏ-nog´rah-fe) the imaging of deep structures of the body by recording the echoes of pulses of ultrasonic waves directed into the tissues and reflected by tissue planes where there is a change in density. Diagnostic ultrasonography uses 1–10 megahertz waves.ultrasonograph´ic

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Doppler ultrasonography  that in which the shifts in frequency between emitted ultrasonic waves and their echoes are used to measure the velocities of moving objects, based on the principle of the Doppler effect. The waves may be continuous or pulsed; the technique is frequently used to examine cardiovascular blood flow (Doppler echocardiography).

gray-scale ultrasonography  a B-scan technique in which the strength of echoes is indicated by a proportional brightness of the displayed dots.

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ul·tra·so·nog·ra·phy (ltr-s-ngr-f)

n.

Diagnostic imaging in which ultrasound is used to visualize an internal body structure or a developing fetus. Also called echography, sonography.

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ultra·so·nogra·pher n.

ultra·sono·graphic (-sn-grfk, -sn-) adj.

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Ultrasonography

A process that uses the reflection of high-frequency sound waves to make an image of structures deep within the body. Ultrasonography is routinely used to detect fetal abnormalities.

Mentioned in: Ascites, Cholestasis, Eye Examination, Mental Retardation, Pelvic Ultrasound, Pyloric Stenosis, Splenic Trauma, Transient Ischemic Attack

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ultrasonography

[-sənog′rəfē]

Etymology: L, ultra + sonus, sound; Gk, graphein, to record

the process of imaging deep structures of the body by measuring and recording the reflection of pulsed or continuous high-frequency sound waves. It is valuable in many medical situations, including the diagnosis of fetal abnormalities, gallstones, heart defects, and tumors. Also called sonography.

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ultrasonography,

n the process of imaging deep structures of the body by measuring and recording the reflection of pulsed or continuous high-frequency sound waves. It is valuable in many medical situations, including the diagnosis of fetal abnormalities, gallstones, heart defects, and tumors. Also called
sonography.

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ultrasonography

an imaging technique in which deep structures of the body are visualized by recording the reflections (echoes) of ultrasonic waves directed into the tissues.

Frequencies in the range of 1 million to 10 million hertz are used in diagnostic ultrasonography. The lower frequencies provide a greater depth of penetration and are used to examine abdominal organs; those in the upper range provide less penetration and are used predominantly to examine more superficial structures such as the eye.

The basic principle of ultrasonography is the same as that of depth-sounding in oceanographic studies of the ocean floor. The ultrasonic waves are confined to a narrow beam that may be transmitted through, refracted, absorbed, or reflected by the medium toward which they are directed, depending on the nature of the surface they strike.

In diagnostic ultrasonography the ultrasonic waves are produced by electrically stimulating a piezoelectric crystal called a transducer. As the beam strikes an interface or boundary between tissues of varying acoustic impedance (e.g. muscle and blood) some of the sound waves are reflected back to the transducer as echoes. The echoes are then converted into electrical impulses that are displayed on an oscilloscope, presenting a 'picture' of the tissues under examination.

Ultrasonography can be utilized in examination of the heart (echocardiography) and in identifying size and structural changes in organs in the abdominopelvic cavity. It is, therefore, of value in identifying and distinguishing cancers and benign cysts. The technique also may be used to evaluate tumors and foreign bodies of the eye, and to demonstrate retinal detachment. Ultrasonography is not, however, of much value in examination of the lungs because ultrasound waves do not pass through structures that contain air.

A particularly important use of ultrasonography is in the field of obstetrics and gynecology. It is a fast, relatively safe, and reliable technique for diagnosing pregnancy, and for detecting some typical fetal anomalies.

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A-mode ultrasonography

(amplitude modulation) that in which on the cathode-ray tube (CRT) display one axis represents the time required for the return of the echo and the other corresponds to the strength of the echo, as in echoencephalography.

B-mode ultrasonography

(brightness modulation) that in which the position of a spot on the CRT display corresponds to the time elapsed (and thus to the position of the echogenic surface) and the brightness of the spot to the strength of the echo; movement of the transducer produces a sweep of the ultrasound beam and a tomographic scan of a cross-section of the body.

Doppler ultrasonography

see doppler ultrasound.

endoscopic ultrasonography

a high resolution ultrasound transducer, mounted on a flexible endoscope, can be used to gain images from within a hollow organ, such as the gastrointestinal tract. This overcomes some of the problems ingesta and fecal material cause in other methods of ultrasound examination.

gray-scale ultrasonography

B-mode ultrasonography in which the strength of echoes is indicated by a proportional brightness of the displayed dots.

M-mode ultrasonography

(motion mode) a type of B-mode ultrasonography in which spots on the CRT display produce a tracing of the motion of echogenic objects. Used in echocardiography.

real-time ultrasonography

B-mode ultrasonography using an array of detectors so that scans can be made electronically at a rate of 30 frames a second, thus giving a true display of motion, such as that of the heart.

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ultrasonography 

A technique utilizing high frequency ultrasound waves (greater than 18 000 Hz) emitted by a transducer placed near the eye. The silicone probe, which rests on the eye, is separated from the transducer by a water column to segregate the noise from the transducer. The technique is used to make biometric measurements such as the axial length of the eye, the depth of the anterior chamber, the thickness of the lens, the distance between the back of the lens and the retina, the thickness of the cornea and detect ocular pathology. The ultrasound wave is reflected back when it encounters a change in density (or elasticity) of the medium through which it is passing. The reflected vibration is called an echo. Echoes from the interfaces between the various media of the eye are converted into an electrical potential by a piezoelectrical crystal and can be displayed as deflections or spikes on a cathode-ray oscilloscope.There are two basic techniques used for examination: a contact system (often referred to as applanation) described above in which the probe is in contact with cornea and an immersion system in which the transducer and the cornea are separated by a water bath. This latter method eliminates the risk of indentation of the cornea and underestimation of the anterior chamber depth and axial length. Two types of ultrasonographic measurements are used: (1) The time-amplitude or A-scan which measures the time or distance from the transducer to the interface and back. Thus echoes from surfaces deeper within the eye take longer to return to the transducer for conversion into electrical potential and so they appear further along the time base on the oscilloscope display. The A-scan is useful for the study of the biometric measurements, as well as measurements of intraocular tumour size (e.g. choroidal melanoma) (Fig. U1). (2) The intensity-modulated or B-scan in which various scans are taken through the pupillary area and any change in acoustic impedance is shown as a dot on the oscilloscope screen, and these join up as the transducer moves across a meridian. The B-scan is useful to indicate the position of a retinal or vitreous detachment, or of an intraocular foreign body or a tumour, and for the examination of the orbit. The B-scan is especially useful in the examination of the posterior structures of the eye when opacities prevent ophthalmoscopic examination (e.g. cataract, corneal oedema). Syn. echography. See biometry of the eye; axial length of the eye.

Fig. U1 Histogram of ultrasound reflections (or echoes) in the eye. Echoes from the various boundaries are given against total time, i.e. the time interval from the cornea to the boundary and back to the cornea. The velocity of the ultrasound waves in the eye is approximately 1550 m/s (it is 1641 m/s in the lens and 1532 m/s in the humours). In the above diagram the total time between the cornea and the retina is 32 μs. The length is then equal to 32/2 ✕ 10⁻⁶ ✕ 1550 ✕ 10³ = 24

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ultrasonography

Ultrasound Imaging The generation of diagnostic images–sonograms–based on differences in the acoustic impedance of tissues. See Aortic ultrasonography–US, Breast US, Carotid US, Doppler US, Duplex Doppler US, Endoscopic US, Hydrocolonic US, HIFU, Ocular US, Pancreatic US, Pelvic US, Prostate US, Transcranial US Obstetrics A noninvasive technique for visualizing the gestational sac or fetus in utero.

Ultrasonography types

A-mode ultrasonography An ultrasonographic modality that provides simple displays that are plotted as a series of peaks, the height of which represents the depth of the echoing structure from the transducer

B-mode ultrasonography Brightness-modulated display Ultrasonography with a wide range of applications including imaging of a fetus, kidneys, liver, gallbladder, uterus, cardiovascular structures, breast, prostate, early ovarian CA, liver transplant recipients preoperatively–a narrow or thrombosed portal vein precludes transplant, and postoperatively to assess various complications–rejection, infection, thrombosis and patency of biliary tracts and identifying gallbladder calculi; the most common clinical use of BMU is to evaluate fetal status, providing real-time 2-D evaluation of the fetus, presenting the images in rapid succession on a monitor, and likened to a motion picture; the 'biophysical profile' has a B-mode display, and measures the head–cephalometry, thorax, abdomen, estimates fetal maturation and identifies growth retardation and major congenital anomalies, including anencephaly, hydrocephaly, meningocele, congenital heart disease, dextrocardia, fetal tumors, diaphragmatic hernia, gastroschisis, omphalocele, polycystic kidneys, hydrops fetalis, GI obstruction and death; BMU helps localize the amniocentesis needle and is of use in identifying placental anomalies including hydatidiform mole or anomalous implantation, eg placenta previa. Side effects Minimal–the energy levels for diagnostic imaging are too low to produce tissue destruction; WBCs subjected to ultrasound may mutate, ? significance

Duplex ultrasonography Ultrasonography that combines the standard real-time B-mode display with pulsed Doppler signals, allowing analysis of frequency shifts in an ultrasonographic signal, reflecting motion within a tissue, eg blood flow; DU is thus useful in evaluating ASHD of the carotid arteries, AV malformations and circulatory disturbances in the neonatal brain

M-mode ultrasonography Time-motion display A modality in which the echo signal is recorded on a continuously moving strip of paper, with the transducer is held in a fixed position over the aortic or mitral valves; each dot corresponding to a moving structure has a sinewy path, while stationary structures are represented as straight lines; M-mode was the first display used and continues to be useful for precise timing of cardiac valve opening and correlating valve motion with EKG, phonocardiography and Doppler echocardiography

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Patient discussion about ultrasonography.

Q. Do doctors normally do ultrasounds to prove you have mis carried?? 2 weeks ago i found out i was pregnant, i started spottion so we went to the hospital where they toldl me i miscarried, but they did not do any alternative tests to prove it not even check my Hcg levels. Im wandering if i should get a second opinion to make sure.

A. Congratulations on the new pregnancy - that's wonderful news!

Q. what kind of uses the medicine do with computers related to ultra sound? how does the computer helps the doctors in the ultra sound? what do the compuers use for?

A. the computers help the doctors (in ultrasound cases) to interpret/convert the ultrasound waves into a specific imaging showed in the monitor. by that a doctor can find what is normal or not inside the patient's body.
for pregnancy purposes, it really helps patient in antenatal screening to find some abnormalities (if there's any) and to monitor the fetus' development along the 9-months pregnancy.

yesterday I wrote a short article about ultrasound update : http://doctoradhi.com/blog/?p=388

Q. Can anyone suggest a treatment for plantar fasciitis, apart from ultrasound, physio, anti-inflammatory agents? My friend has had Plantar Fasciitis for more than 1 year and has persevered with all the ususal treatments above plus lots of rest from weight-bearing and elevation.

A. Padded foot splints, silicone heels insert and special shoes (e.g. arch-supporting shoes) may also help. These are usually sold and fitted by a professional. Exercise is another important measure. Some patients benefit from avoiding walking barefoot or in sleepers but rather using shoes from the first step.

More advanced treatments include steroid-local anesthetics injections, botulinum toxin (similar to botox) injections and surgery.

The prognosis is usually favorable, and most patients achieve relief of the pain.

However, all of the above is just for general knowledge - if you have any specific question, you may want to consult a doctor.

You may read more here:
www.nlm.nih.gov/medlineplus/ency/article/007021.htm