Ultrasonography, also known as ultrasound or sonography, is a procedure in which body tissues and organs are examined using high-energy sound waves. Ultrasound is a non-invasive and painless procedure. It uses high-frequency sound waves, called ultrasound, to create images of organs, soft tissues, blood vessels, and blood flow from inside the body. These images are used for medical analysis. A device called transducer converts electrical current into sound waves that are sent to the body tissue. The sound waves reflect body structures and are reflected on the transducer, which converts them into electrical signals. A computer converts the pattern of electrical signals into an image displayed on a monitor and recorded on a film, video tape, or digital image. The idea of ultrasound comes from sonar technology, which uses sound waves to detect underwater objects.
Ultrasound is used to create images of soft tissue structures such as
- Gall bladder,
- Female reproductive organs and
- even babies still in the womb.
- Blockages in the blood vessels.
Ultrasound can not be used for bone imaging because they are too tight for entry. In addition, the intestinal tract and normal lung tissue are not easily identified by ultrasound because air or gases interfere with the generation of ultrasound images.
Benefits of Ultrasonography
Ultrasounds offer many advantages:
- Ultrasound is painless, relatively inexpensive and is also considered very safe during pregnancy.
- Ultrasound acquires images of soft tissues that are not clearly visible on X-rays.
- Patients are not exposed to ionizing radiation, making the procedure safer than diagnostic techniques such as X-rays and CT scans.
- In fact, no harmful effects are known if used by the doctor.
- Ultrasound is more common and less expensive than other methods.
How does the Ultrasonography Work?
It works by transmitting sound waves of 1 to 10 million Hertz to a transducer by placing it on body structures. The sound waves are absorbed or collide with crystals in the head of the transducer. For example, sound waves pass through areas that are empty or filled with fluid, such as the bladder and blood vessels. These areas appear black on the screen. The areas filled with cloth provide some penetration and refraction of the tone and produce a grayish image. Very hard structures, such as bones, create a bright, white image because the sound waves bounce off completely from the transducer. Normally, the patient is asked to lie on the table with the appropriate part of the body. A transducer or probe is used to project and receive sound waves and their echoes. The examiner applies a thick gel on the skin to ensure good sound transmission. A palmar transducer is placed on the skin and moved to the area to be examined. To evaluate parts of the body, the examiner inserts the transducer into the body, for example, into the vagina, for example, to better show the uterus and the ovaries.
Types of Ultrasonography
Most ultrasounds are done with a transducer on the skin surface. However, sometimes doctors and technicians can get a better diagnosis image by inserting a special transducer into one of the natural openings of the body:
- During transvaginal ultrasound, a transducer rod is inserted into a woman’s vagina to get better pictures of Uterus and ovaries.
- Transrectal ultrasound is sometimes used to diagnose prostate problems.
- In a transesophageal echocardiogram, the transducer probe is used in the esophagus to allow the ultrasound to obtain clearer images of the heart.
Other variations in ultrasound include:
- Doppler ultrasound can be used to measure and visualize blood flow in the heart and blood vessels.
- Elastography is used to differentiate tumors from healthy tissue.
- Therapeutic ultrasound is used to heat or break tissue.
- High Intensity Focused Ultrasound (HIFU) focused ultrasound is used to destroy or alter abnormal body tissue without opening the skin.
Ultrasound is commonly used for diagnosis, treatment and orientation in procedures such as biopsies. It can be used to examine internal organs such as the liver and kidneys, pancreas, thyroid, testicles and ovaries and others. This can help diagnose problems with soft tissues, muscles, blood vessels, tendons and joints. It is used to examine frozen shoulder, tennis elbow, carpal tunnel syndrome, etc. An ultrasound can show if a mass is a tumor. This could be cancerous or a cyst filled with liquid.
Ultrasonography is commonly used to evaluate the following:
1. Heart: ultrasound of the heart, called echocardiography. It is used for the detection of cardiac arrhythmias, structural abnormalities such as defective heart valves and abnormal enlargement of the cavities or walls of the heart.
2. Blood vessels: Ultrasound can be used to screen for blood vessel diseases. By measuring blood flow and blockage in carotid arteries, the test can predict the potential risk of future stroke.
3. Biliary and bile ducts: Ultrasonography is used for the detection of gallstones and obstructions in the bile duct .
4. Pregnancy: Ultrasonography is used to assess the growth and development of the fetus and to detect placental anomalies (eg placenta previa)
5. Liver, spleen and pancreas: Ultrasonography is also used for the detection of tumors and other diseases.
6. Urinary tract: Ultrasound is used to distinguish benign cysts from solid masses (which may be carcinogenic) in the kidneys or to detect blockages such as stones or other structural abnormalities in the kidneys, ureters or bladders.
7. Female reproductive organs: For example, to detect tumors and inflammation in the ovaries, fallopian tubes or uterus
8. Knee: Ultrasound can be used to detect swelling of the knee joint on the back of the knee, the so-called Baker’s cyst.
8. Therapeutic Applications of Ultrasound: Ultrasound can and is used to help doctors guide needles through the body If an intravenous route is required, but it is difficult to find a vein, The ultrasound guide can be used to identify larger veins in the neck, chest wall, or groin.
There are no known risks to Ultrasonography and, as the technology has improved, the devices are smaller, portable and available for use at the bedside. Inserting the transducer into the body can cause discomfort. In rare cases, when a transducer is used, the tissue is damaged, causing bleeding or infection. Bones or gases can block ultrasound Thus, using it to obtain images of certain structures (those behind bone or gas) is difficult.