CT Scan, Ultrasound And MRI – Understanding The Difference
Our bodies are like icebergs floating in the sea. Only a tip can be seen on the surface but a lot of things are happening beneath the surface that go unnoticed. Many a times, infections, growths, bleeding and other medical complications exist but we are not aware of them. And, yet, they make their presence felt in some really uncomfortable ways. It is very normal then, for medical practitioners in such situations to recommend a scan of the body.
There are various technologies in the market that provide insights into the human body. The three most common ones are CT or CAT scan, Ultrasound scan and MRI. Let’s look at each of them to better understand how they work and under which circumstances are they used.
CT scan or CAT scan
CT/CAT stands for Computed Tomography/Computed Axial Tomography. A CT scan is sometimes called a CAT scan for the ease of saying it. It is a very painless and rapid scan that lasts anywhere from 5 to 20 minutes. It uses X-rays (a small amount of radiation that quickly passes through the body to capture a single image), along with computers. Together, they produce a 360 degree, cross-sectional view of the body. The radiologist, who oversees the scan, is able to see the details of bony structures and injuries, and can diagnose lung and chest problems as well as detect cancers. CAT scans can produce images of the bones, soft tissue and blood vessels. The best part is that they are able to do this all at the same time, thereby reducing the time taken for the process. CAT scans are not recommended for pregnant women or children, unless it is absolutely necessary. People with claustrophobia or anxiety might not like getting into the tube during the procedure.
MRI stands for Magnetic Resonance Imaging. It combines three things to create very detailed images of the internal body structures. These are:
- Radio waves
- A powerful magnetic field, and
- An advanced computer system
Together, they constitute the MRI machine, which is a tube scanner (also referred to as a bore scanner) in which the patient has to lie down flat and stay still till the scanning process is finished. Usually, patients with tattoos, pacemakers and metal implants are not allowed near MRI machines.
MRI scans are typically used for showing the tissue differences between abnormal and normal tissues, performing spinal scans, imaging soft tissues and any body organ, in general. A typical MRI scan lasts from 30 minutes to an hour. There are further distinctions used in the machine such as high-field MRI and open upright MRI, but the basic idea remains the same.
An ultrasound scan uses high-frequency sound waves to capture images from inside the body and, hence, it is also known as sonography. Interestingly, the technology that is used in ultrasound scans is similar to the technologies commonly used by militaries, namely sonar and radar. In military applications, sonar and radar help the operator detect enemy planes and ships well ahead of their reaching. Similarly, an ultrasound scan lets doctors see problems inside the patient’s body, especially with organs, vessels and tissues. All this is done without the need to make an incision and physically look inside.
The difference between ultrasound and MRI/CT scans is that ultrasound does not use any radiation. Due to this fact, it is the most commonly used method for pregnancy related medical check-ups, especially when there are any complications. In addition, ultrasound scans are used for recreating images of various body parts, such as the pancreas, spleen, thyroid, gallbladder, kidneys, liver, ovaries, blood vessels, uterus, eyes, bladder, etc. It is a simple and cost effective technology that saves both the doctor and patient lots of time, money and hassle in understanding the complications inside the patient’s body.