Ultrasound imaging produces detailed images of the internal structures and organs of the body. A handheld device called a transducer transmits a series of sound waves through the body. Sound waves that are reflected by internal structures and organs are also received by the transducer, transmitting them to a computer, which converts the data into an image displayed on a monitor.
Ultrasound images are captured in real-time, showing the structure of organs as well as blood flow through the vessels. It produces detailed images of soft tissues that are not well shown on X-rays. No ionizing radiation is used to produce the image therefore ultrasound is a safe procedure.
Depending on the nature of the clinical query, ultrasound imaging can be used to assess various organs and structures in the body. Ultrasound can also be used as a guide to direct biopsy procedures and needle placements for cyst aspirations.
Ultrasound includes sound waves in the frequency range of Twenty Thousand hertz or cycles per second, which cannot be heard by the human ear. Ultrasound in medical imaging uses frequencies in the 2-12 million hertz range.
How Is The Examination Done?
You will be asked to undress and wear a gown or your clothing will be moved away from the region to be examined.
You will lie on an exam table, the warm gel will be applied to the area of examination.
A sonographer presses the transducer against your skin and moves it back and forth to obtain the necessary images.
The radiologist may obtain more images after the sonographer has completed the examination.
Interpretation of Images and Results
A radiologist who specializes in ultrasound will review the images and issue a report to your referring doctor. The radiologist may discuss early findings with you when your exam is over.
The organs most often examined include the liver, gallbladder, biliary system, spleen, pancreas, kidneys, aorta and urinary bladder.
For ultrasounds of the abdomen you must fast for at least 8 hours before the exam.
For evaluation of the urinary bladder, a full bladder is required and you will be asked to drink 4-6 glasses of water at least 30 minutes prior to the examination.
Pelvic ultrasound in women is used to examine the uterus, ovaries, fallopian tubes, and nearby structures such as blood vessels and lymph nodes.
In men, the pelvic ultrasound is used to examine the bladder and the prostate gland. A full bladder is required for all pelvic ultrasounds.
With advances in technology and image quality the use of ultrasound to assess the musculoskeletal system has increased considerably.
Muscles, tendons, ligaments and soft tissues lining the joints can be evaluated. It is a painless, non invasive method to assess joint problems due to injury, degeneration or arthritis.
It is a useful investigation to help diagnose conditions such as:
Detecting blood clots (thrombosis) in the veins.
Determining the location and severity of varicose veins, by locating poorly functioning valves
Identify and characterise blockages (stenosis) in the arteries of the neck and legs causing decreased circulation
Determine if there is enlargement of an artery (aneurysm)
Evaluate the success of procedures such as bypass grafts.
Evaluate the circulation in tumours.
No special preparation is necessary
Depending on the region to be examined you may be asked to undress and wear a gown during the procedure.
For non emergency examinations booking an appointment is essential as some examinations are time consuming
Vascular ultrasound is a useful method to examine the arteries and veins in the body. Not only are the structures of blood vessels assessed, but using a special technique called Doppler, measurements can be done to determine the direction, speed and pressure of blood flow in the vessels. speed and pressure of blood flow in the vessels.
Obstetric Ultrasound is the use of ultrasound imaging in pregnancy. It is a safe, non-invasive, accurate and cost-effective investigation of the foetus. It has proven to be a useful diagnostic tool in obstetrics, playing an important role in the management of every pregnant woman.
With effect from 1 October 2013, antenatal obstetric scans will no longer be offered beyond 13 weeks gestation i.e. beyond the 1st trimester. First trimester scans will continue to be done for diagnosis of pregnancy, location and gestational age only. See circular below for further explanation:
Small Parts Ultrasound
Ultrasound imaging is a useful way of evaluating many superficial organs of the body such as the thyroid gland, the salivary glands, the eye, breast, scrotum and testes.
Is used for diagnosing suspected thyroid disease. The ultrasound can establish if the thyroid gland is enlarged, has solid or fluid filled nodules as well as determine its vascularity.