Diagnostic ultrasound (sonography) is a noninvasive diagnostic imaging technique that uses high-frequency sound waves to produce images of structures within the body. The sound waves are sent through the body tissues with a device called a transducer. Objects inside the body reflect a part of the sound waves back to a sensor, where the waves are recorded, analyzed, and displayed for viewing on a screen. Modern sonographic equipment can display live images of moving tissues (real-time viewing) and can also provide 3-dimensional reconstruction information about different structures. The area covered by the ultrasound beam depends on equipment design.
Doppler sonography (duplex Doppler sonography) enables the visualization of blood flow in both arteries and veins (vascular systems), as well as in organs. It measures changes in the pitch of the sound waves (Doppler effect) as they bounce off circulating blood cells. When combined with advanced data processing technology, color Doppler sonography can acquire data rapidly enough to study complex blood flow in the heart and other organs. A computer image that represents the speed and direction of blood flow is then generated from the data. Power Doppler sonography is a new technique that is about 5 times more sensitive than color Doppler. It is most useful in measuring the blood flow in blood vessels traversing solid organs.
Diagnostic ultrasound is painless and safe. Studies have not revealed any negative side effects of this procedure. The capability of ultrasound to visualize internal organs can be enhanced by combining it with endoscopy, an invasive procedure in which the transducer is introduced into a body cavity for better viewing. |
Source: Medical Disability Advisor
Diagnostic ultrasound has a wide variety of uses in general medical practice.
Sonography has become the most frequently used diagnostic technique in the branch of medicine specializing in pregnancy and delivery (obstetrics), since there do not appear to be any adverse biological effects from this procedure. Sonography can be used to visualize a developing baby (fetus), monitor developmental progress, and detect abnormalities in the developing fetus or its environment (placenta).
In gynecology, sonography is most commonly used for the evaluation of pelvic masses and infertility problems. Evaluation of uterine and ovarian disorders is accomplished with a small transducer that is inserted into the vagina (transvaginal sonography). Breast ultrasound assesses whether masses seen on mammography are solid or liquid in nature and may help detect breast cysts in women with dense breasts and normal mammograms.
In general, ultrasonography can be used in the initial evaluation of many abdominal disorders, especially diseases of the gallbladder and biliary tract, as well as blunt abdominal trauma. Real-time sonography allows more consistent and detailed images of the kidneys than do static imaging techniques; for example, Doppler capabilities allow assessment of renal artery stenosis and other blood flow abnormalities. The major vessels in the abdomen can also be studied. Lower frequency ultrasound instruments can study the deeper structures in the abdomen and pelvis and can help diagnose deep vein blood clots (thrombosis).
3D-ultrasound determination of large organ volume is precise within a small margin of error. Endoscopic ultrasound is reliable in the diagnosis of chronic pancreatitis, with good agreement among different experienced endosonographers reviewing the same test
Ultrasound can be used to guide the physician during other procedures, such as needle biopsy or removal of fluid (aspiration). Endoscopic ultrasound is a minimally invasive method helpful in the diagnosis of chronic pancreatitis and in guiding fine-needle aspiration of masses deep within the chest (mediastinal masses). Regular ultrasound assists the physician performing liver biopsy by visualizing structures in the path of the biopsy needle. Small ultrasound probes can be inserted into the rectum during prostate biopsy to guide the physician and to increase the accuracy of the procedure.
For the evaluation of dynamic effects such as those associated with blood flow, heart function, vascular disorders, or organ perfusion, ultrasound is often superior to other techniques. Echocardiography and 3D-echocardiography help visualize heart structure, function, and volume. A number of superficial organs (less than 2 inches from the surface of the skin) can be imaged in real time, including the thyroid, testes, breast, carotid arteries, and eye. 3D-sonography can determine volumes of organs and other structures, allowing physicians to determine if organs are enlarged or if a tumor is changing size in response to treatment.
Sonography provides imaging whenever other methods are considered riskier or are even contraindicated because of the individual's condition. It is relatively inexpensive compared to MRI and CT scan. It uses no ionizing radiation, as do CT and plain x-rays. It does not involve the hazards of strong magnetic fields as in MRI. Ultrasonography is much more comfortable for individuals compared to the other imaging methods. Although it is thought to be safe and without adverse effects, either to the individual or to the developing baby in the case of obstetrical ultrasound, it should always be done only for valid diagnostic indications. Obstetrical ultrasound merely to determine the sex of the fetus or to "see how the baby is doing" is not recommended. |
Source: Medical Disability Advisor
Ultrasound may be performed in the doctor's office, in a designated unit in a hospital, or at the bedside if necessary, using a portable device. Depending on the area of the body being examined, the doctor may require that the individual take certain steps to prepare for the procedure. These steps may include not eating for a designated period of time (for example, in gallbladder evaluation) or drinking several glasses of water if the pelvis is to be examined.
During the procedure, the individual generally sits or lies down. The area being examined is exposed, and a technician applies a gel to the skin in that area, which improves the transmission of the sound waves. The technician or doctor moves the transducer back and forth over the area being examined. As the sound waves echo off the internal structures, they create an image seen on a video monitor. The individual may be asked to hold his or her breath or change position. There may be several pauses while the images are examined and/or recorded for later examination. In obstetrical ultrasound, the images may be printed out and copies may be given to the individual. The gel is then wiped off, and the procedure is over.
In transvaginal ultrasound, the transducer is inserted into the vagina. To help guide the physician performing prostate biopsy, the transducer is inserted into the rectum. In endoscopic ultrasound, the transducer is inserted into the upper gastrointestinal tract. |
Source: Medical Disability Advisor
| Diagnostic ultrasound is effective for visualizing internal structures without producing undesirable side effects. It is more effective for visualizing soft tissues or those filled with fluid and less effective for visualizing bone or air-filled organs. |
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- Gynecologist
- Obstetrician/Gynecologist
- Radiologist
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Source: Medical Disability Advisor
| Ultrasound is not associated with any complications. In late pregnancy, lying flat on the back on the hard ultrasound table may cause the uterus to compress the large vein (inferior vena cava) in the mother, leading blood back to the heart. This may cause her to feel faint or dizzy, which is corrected rapidly by allowing her to sit up or change position. |
Source: Medical Disability Advisor
| Ultrasound does not result in any disability. |
Source: Medical Disability Advisor
| No work restrictions and accommodations are associated with this procedure. |
Source: Medical Disability Advisor
| GeneralSpengler, Renée. "Doppler Ultrasound." WebMD.com. WebMD, LLC. 22 May 2005 <http://my.webmd.com/hw/health_guide_atoz/hw4477.asp?lastselectedguid={5FE84E90-BC77-4056-A91C-9531713CA348}>. |
Source: Medical Disability Advisor