Ultrasound also connoted as sonography is a medical diagnostic procedure which uses sounds waves to produced images of the organs of the human body. Ultrasound is a non-invasive and painless procedure and yields accurate results. The procedure is also called as sonography or Doppler ultrasound. Ultrasound imaging is one of the simple diagnostic procedures which does not require much preparation and yields very good quality two dimensional (2D) images of the organs with the help of a probe or a device which is either moved on to the external body surface or the internal organ which needs to be imaged.
What is the principle of ultrasound imaging ?
An ultrasound works on the principle of how sound travels in an object and then reverts back in the form of an echo. These echoes/echo waves are then used to create images of the organ, and also determine its distance from the device, its size, shape and whether it is liquid or solid. The reverted echo signals are monitored by a computer which creates the images of organ depending upon the echo waves.
Doppler ultrasound is a more advanced application of a general ultrasound which is used to measure the speed and direction of red blood cells as they pass through the blood vessels, which are later captured by a computer in the form of images and graphs.
How does an ultrasound device look like ?
An ultrasound scanning device usually consists of two components, a probe to send sound waves and receive the echo waves which are reverted, and a computer which captures the sound waves and converts them into 2D images. The probe or the transducer is placed on the body with the help of a gel so that any air does not interfere with a scanning and the probe moves on the surface smoothly.
When is an ultrasound advised ?
An ultrasound is advised to detect both normal and abnormal structures in the human body. If the patient presents with symptoms of pain, swelling and infection at a particular site, then an ultrasound scan can be used to make the diagnosis. Almost all of the internal organs, thyroid, heart, liver, kidney, gall bladder, spleen, pancreas, uterus and testicles. It can also be used to determine the brain in infants.
Ultrasound scans are one of the most routinely performed diagnostic tests during pregnancy to determine the size, position, weight and sex of the baby. (Some countries prohibit the determination of sex of the fetus and is considered illegal).
An ultrasound is also used to guide certain procedures like needle biopsies, endoscopy (identifying the problem in the gut), echocardiography (analysis of the heart muscles) and breast biopsy.
A Doppler ultrasound is performed to identify any blood clots, narrowing of the blood vessels, any cancer or growth, vascular malformations and to determine the blood flow to the organs.
Therapeutic effects of an ultrasound include treatment of tumors, gall stones and treatment of musculoskeletal injuries.
When is an ultrasound not advised ?
An ultrasound scan is not advised in obese individuals as excess fat can make visualizing of the internal organs difficult. It is also not advised in cases of air as sound waves are effected by air or gas, so in case of any entrapped air or air filled organs like lungs an ultrasound is not recommended. Patients who have a barium swallow or some enema are also not advised to get an ultrasound done as it may interfere with the scan results. An ultrasound scans are usually not used to study or identify bones.
What are the types of an ultrasound ?
Depending on the organ or a part of the body that needs to be scanned such as an abdominal scan mostly covers all the organs in the abdominal area like the stomach, liver, kidney, pancreas and the intestines. Usually an ultrasound scan is performed externally over the desired organ to be imaged.
Certain ultrasound scans are performed by inserting the transducer or the probe inside the organ to be imaged such as transvaginal ultrasound (internal imaging of the female reproductive organs), transrectal ultrasound (to diagnose prostate conditions), a transesophageal ultrasound to image the esophagus and the heart.
Doppler ultrasound is used to study the blood vessels and the blood flow.
Echocardiogram are nothing but ultrasound examinations of the heart.
Recent advances include 3D and 4D imaging of organs.
How do you prepare for an ultrasound ?
Not much preparation is required for an ultrasound examination. The technician or the sonographer will advise you to remove any piece of jewelry and wear comfortable clothing which could ease the scan procedure. Depending upon the type of scan advised your doctor might advise you to abstain from eat few hours before the procedure or drink lots of water and not urinate especially during examination of the uterus and kidney as drinking water separates the intestines and the organs are clearly visible and pictured.
What happens during an ultrasound sound scanning ?
Once you are prepared for the scan and dressed in comfortable clothing, the technician or sonographer will ask you to lie down and be comfortable. The probe will be gently moved on the surface of the organ to be imaged after application of a gel like substance on the skin. The sound echo waves received by the transducer are converted into images by the computer and then a scanning report is printed with the scanned images. The procedure of an ultrasound scan usually takes about 30 minutes to an hour.
In case of internal scans, a local anesthetic agent might be sprayed or applied on to the probe to facilitate the insertion into the organ before imaging.
Who reports an ultrasound scan ?
An ultrasound scanning is done by a technician or a radiologist or a gynecologist who specialize in ultrasound scans. The report is referred as a sonogram and is signed off by a radiologist or head of the department of imaging.
Are there any risks associated with an ultrasound scan ?
No, an ultrasound is a rather safe procedure which is painless, non-invasive and does not contain any ionizing radiation, and is easy to perform. Some patients might feel a little discomfort during scanning of internal organs, but it is not painful.
What are the limitations of an ultrasound ?
Apart from certain situations mentioned above where an ultrasound is not advised, it is also not indicated in cases of medical emergencies where a CT scan or an MRI could be of much help in accurate diagnosis.
Disclaimer: The content provided here is meant for general informational purposes only and hence SHOULD NOT be relied upon as a substitute for sound professional medical advice, care or evaluation by a qualified doctor/physician or other relevantly qualified healthcare provider.
