Computed Axial Tomography (CAT scan) is a process of using computers to generate three dimensional images from a flat two dimensional X rays pictures through the 'slice' technique. Aided by computer, cross-sectional views are generated and if needed three dimensional images of the internal organs and structures of the body. In CAT scan the body is seen in 'slices' from the skin to the central part of the body. When all the levels (slices) are added together, a three dimensional picture of an organ is obtained. Together the cross sections give a very accurate picture of where the tumor is and how big or small it is. They also show how close the major body organs are to the area that needs to be treated or operated upon. A CAT scan can be used to define both the normal and abnormal structures the body. It also helps as an accurate guide in placement of instruments and treatments for undergoing procedures.
Many of the procedures in CAT scan are minimally invasive. CAT scan is very low risk procedure. The amount of radiation in CAT scan is very minimal. Unlike MRI, CT scans can be done even if the patient has a pace maker or an internal cardioverter defibrillator devices implanted into the chest to help regulate the heart beat. CAT scan may pose a potential risk to the fetus during the first trimester of pregnancy. Sometimes in contrast studies using iodine-based, there may be itching, a rash, hives or a feeling of warmth throughout the body. But these reactions tend to go away quickly. Very rarely does a more serious reaction occur during intravenous contrast studies. This anaphylactic reaction results in severe hives and/or difficulty in breathing.
Benefits of CAT Scan
A CAT scan or a CT scanner machine is a large machine in the shape of a doughnut. The patient is made to lie on a couch. The couch can slide backwards and forwards. The couch slips into the center of the doughnut shaped machine which takes the x-ray images around the body. The actual procedure takes anywhere from half an hour to one and half hours. During the CAT scan procedure, the patient's bodily movement has to be minimal and should remain as still and quiet as possible. This significantly helps to increase the clarity of the x ray images.
Some CAT scans need special preparations before hand. The preparation may vary according to the type of scan taken.
Spiral CT Scan
CAT scan technology continues to evolve and promises better quality pictures and patients safety. Newer type of CT scans is known as Spiral or helical CT scan. It is called Spiral scan because the X-ray beam rotates around the patient during the scan in a spiral shape. This helps to give a continuous picture with no possible gaps between the 'slices' of the scan. The 'spiral' or 'helical' CAT scans provide more rapid and accurate visualization of the internal organs. They give more detailed pictures of the organs and tissues including blood vessels. The Spiral CT scans are faster than a normal CT scan. Many trauma centers have started using such scans for more rapid diagnose of internal injuries after serious body trauma.
Bibliography / Reference
Collection of Pages - Last revised Date: January 16, 2019