Computerized tomography (CT) scans are special types of x-rays that create high definition images of body parts using contrast dyes. They are typically read by radiologists or other qualified medical doctors. Reading a CT scan requires training and an in-depth knowledge of human anatomy, but there are some tricks to analyzing the images produced. Using an effective light source, knowing the details of the anatomical area being analyzed, noting differences in color, and looking for asymmetrical areas are all helpful tools for reading a CT scan.
An appropriate light source is necessary to interpret any scan correctly. The best tool is a bright light box that highlights contrast, but any bright light will be sufficient. Light should be placed directly behind the scan images for maximum clarity. While it may seem obvious, correctly identifying the right and left sides of the body is imperative to accurately interpreting a scan, but may not be as simple as it sounds.
Knowledge of the area being assessed, even at a basic level, is essential to understanding a CT scan. Before the images are analyzed, the reader should familiarize himself or herself with the anatomy of the area in question. This should include prominent structures, major points of reference, areas of fluid, and structural cavities. Abnormalities will be much easier to identify if normal anatomy is understood.
Since contrast dye is used to produce tomographic images, noting colors is particularly important when reading a CT scan. Certain body structures will absorb dye, while others will repel it, resulting in color contrasts when the image is created. Black is indicative of fluid, while white areas suggest tissue buildup. Abnormal objects, including surgical hardware or unidentified matter, will appear silver in color. Masses that may be cancerous will appear as bright white areas, while lesions in the brain or other organs caused by excessive fluid will appear dark black.
Much of the body's anatomy is organized symmetrically to improve function and efficiency. Noting areas that are not symmetrical may help to identify problems, such as organ displacement or swelling in the brain. Often, comparing one side of the body to another when reading a CT scan can be very helpful in identifying issues, as differences will become more obvious.
Definitive diagnoses based on the images obtained from a CT scan can only be made by qualified medical professionals. Any questions about the images or results of scans should be directed to a radiologist or medical professional. These doctors should be able to explain the pictures in simple terms to help their patients fully understand the results.