An ultrasound scan, or sonogram, is a procedure that uses high frequency sound waves to create an image of part of the inside of the body, such as the heart.
As sound waves are used rather than radiation, the procedure is safe. Ultrasound scans are commonly used during pregnancy to produce images of the baby in the womb.
Ultrasound scans can also be used to:
- detect heart problems
- examine other parts of the body such as the liver, kidneys and abdomen
- help guide a surgeon performing some types of biopsy
An ultrasound scan (which is also known as a sonogram or a diagnostic medical sonography) is a procedure that uses high frequency oscillating sound waves and other types of vibrations in order to create a medical image of specific areas of the body, such as the heart. The images are used for providing vital information in diagnosing and treating a variety of diseases and conditions.
The science of sound can be traced as far back as the 6th century BC with Pythagoras writing about the mathematical properties of stringed instruments, though the first technical application of ultrasound occurred in 1917.
Ultrasounds use low-power sound waves, as opposed to radiation, which makes the procedure safer for patients, as there are no known risks. Sonar devices are placed outside of the patient’s body, though in some cases, devices are placed within the body for examination. There are many different types of ultrasounds. For example, 3D imaging is one such technique that can be utilized, and 4D ultrasounds, show 3D images in motion. Three types of an internal exam include: Transesophageal echocardiogram, transrectal ultrasound, and transvaginal ultrasound. Due to insertion inside of the body, these procedures may cause mild discomfort.
Ultrasounds are used for a number of reasons, such as:
- The detection of heart problems via echocardiograms
- Diagnose some types of cancers
- Diagnose gallbladder disease
- Reveal abnormalities within the genitals and prostate
- Assist in the measurement of elastic properties of tissue
- Examination and targeting of issues in various organs and tissues of the body, such as the abdomen, bladder, eyes, gall bladder, kidneys, liver, ovaries, pancreas, spleen, testicles, thyroid, and uterus
- Evaluate the flow in blood vessels via imagery (called a Doppler)
- Help to guide a surgeon perform some types of biopsies, where doctors can remove tissue from specific areas of the body for lab testing
- Guide a needle for biopsy or tumor treatment purposes
- During pregnancy the view the uterus and ovaries of a woman during pregnancy, and produce scanned images of her fetus while in the womb (this is one of the most common usages of ultrasounds, as they can detect due dates, reveal twins, or determine birth defects or other related issues)
- Detect osteoporosis via a bone sonography
- Check a thyroid gland
- Break up stony deposits or tissue
- Accelerate the effect of drugs in a targeted area
- Therapy to detect and treat soft-tissue injuries
Being a simple procedure, ultrasounds require little to no preparation, with only a few exceptions:
- For gallbladder exams, a doctor may require the patient not to ingest food or drink before the procedure
- For pelvic exams, a full bladder may be required for testing, so a doctor may ask the patient to drink up to six full glasses of water two hours before the exam, and not urinate
Jewelry, watches, glasses, and even clothing may need to be removed before the exam, requiring the patient to changes into a hospital dressing gown.
Patients will be asked to lie on an examination table, where a special type of gel will be applied to keep sound-blocking air pockets from forming.
Once prepared, a trained technician called a sonographer will press a device called a transducer against the skin where the test is being performed to capture the image. The transducer emits a high-frequency sounds (one that is inaudible to human ears) to send sound waves into the body that collect the information (by determining the size, shape, and consistency of organs and soft tissues), and sends it back to a computer that processes and forms the images. On average, ultrasounds can take anywhere from 30 minutes to up to an hour.
The radiologist and doctor will interpret the images in order to help the patient diagnose and treat potential conditions. Once complete, normal activity can be resumed.
Ultrasounds, while useful, do have some limitations. For example, being a sound based procedure, the effects do not pass well through air or bone, making it ineffective to image parts of the body that are filled with gas or are hidden by bone. In these instances, doctors may have to order other types of imaging scan tests, such as a CT or MRI scans, or traditional X-rays.