Medical Ultrasonography is a medical
diagnostic technique used to visualize inner body structures like muscles and other soft
tissues as well as organs like the
liver, gallbladder and various other
structures. It helps to
identify any pathology in the
tissues and record any lesion.
The Ultrasound Machine
The word ‘ultrasound’ refers to sound
waves with a frequency too high for
human ears to hear. In medical ultrasound, sound waves in frequencies ranging from 1.6 to 10
megahertz are employed. Superficial structures like muscles, tendons, thyroid
etc are at a higher frequency (7–18 MHz)
while deeper structures such as the liver and kidney are imaged at a lower
frequency 1–6 MHz.
Ultrasonography utilizes sound waves which are sent into the body in pulsatile waves with
the help of a transducer or probe. The sound waves bounce off the structures
and the echo is received by the probe
and displayed on screen on a monitor.
Ultrasonography used during pregnancy to
monitor the growth and health of the fetus
and other pregnancy tissues like the placenta and amniotic fluid is
known as Obstetrical ultrasound and is widely used. Nowadays, it is a routine
procedure performed in all pregnancies in the first trimester to help identify any anatomical defects in the
fetus.
Ultrasonography is also used as an aid in
treatment procedures – for example,
draining of fluid or pus or in ultrasound guided biopsies. This
procedure is known as interventional ultrasonography.
Other types of ultrasonography include
cardiac ultrasonography (echocardiography), dental ultrasonography, Doppler
ultrasonography to study blood flow and muscle motion as well as high intensity
focused ultrasonography. Lithotripsy , a procedure used to break up kidney
stones is a type of high intensity focused ultrasonography.
Compared to other medical devices,
ultrasound has many advantages – it is safe because it does not use any
ionizing radiation, the device is portable and can be easily carried to the
patient’s bedside, it is not very
expensive and the results are obtained in real time, meaning that the result is
available instantly at the time of the test and the patient does not need to
wait for a long time for the report to be available.
The main disadvantage of ultrasound is that
it requires a skilled operator for an
accurate report. Another disadvantage is that structures behind bones may not be
readily seen.
Ultrasonography is one of the most widely used diagnostic aids in medical care today.