A computed tomography (CT) scan can create cross-sectional images of any part of your body using special X-rays and a computer. This type of radiology study is an important part of diagnosing medical diseases like strokes, cancers, and infections in the abdomen like appendicitis. You can learn to read a CT scan if you understand the normal anatomy and what the shades of white, grey, and black on the films mean.
Preparing to Read the CT Scan
1. Read the information on the CT scan. Check to see what is printed on the films to determine they are yours and what part of the body is represented in the films.
2. Read up on your anatomy. The CT scan images are sharp with good definition, but they are still X-rays. The structures inside of you are shown in shades of white, gray, and black. You must have an idea of what you are looking at and what is normal.
3. Find a good light source. If you have a printed CT scans, the films will be a little smaller than an opened New York Times newspaper. The best light source will be flat and around that size or a little larger. If your CT scan is on a computer disk, the computer screen is the “light source”.
4. Do not get disoriented. You need to know if the CT scan images are presented in the transverse, coronal, or sagittal plane. You must have this information when you use the anatomy atlas as a reference.
Reading the CT Scan
1. Hold the film in the proper orientation. The words on the film will let you know which side of the film should be facing towards you and where the top is. This should not be an issue if the CT films are on a disk, but you still should check.
2. Put the films in the correct order. Numbers will be printed on the CT films. The CT scan cuts your body into cross-sections which are like very thin slices of bread. As you look at the images in order, you will notice a normal and natural flow. Any sudden breaks can suggest disease or an abnormality.
3. Take note of the shades of white, gray, and black. The soft tissues, fat, air, and bone inside of you are represented in these different shades. An unexpected color in a part of your body could be a sign of an abnormality.
4. Compare the two sides to help you see abnormalities. Bilateral organs should be hard to tell apart like identical twins. The CT anatomy atlas is a good reference, but the best point of reference is the normal organ on the other side.
5. Talk to your doctor. A radiologist is a doctor who specializes in interpreting all types of X-rays, including CT scans, has read your films. She sent a report to your doctor with a detailed description of what she saw on your films.