Why is CT Performed?

CT is one of the best tools for studying the lungs and abdomen. CT is an invaluable tool in the cancer diagnosis process and is often the preferred method for diagnosing lung, liver and pancreas cancer. CT imaging and CT angiography are finding a greater role in the detection, diagnosis and treatment of heart disease, acute stroke and vascular diseases which can lead to stroke, gangrene or kidney failure. Additionally, CT can be used to measure bone mineral density for the detection of osteoporosis. CT has excellent application in trauma cases and other emergencies. All dedicated shock-trauma centers have a CT scanner in the trauma department so patients can be immediately scanned to scout for major internal injuries such as aortic aneurysm (see image below) or other internal bleeding.

Sagittal multiplanar reconstructed CT image of the thorax and abdomen showing an aortic aneurysm. The aorta (short arrow) looks like a white "candy-cane" in the middle of this image. The aneurysm (long arrow) is thethin line running through the candy cane.

CT is used extensively for diagnosing problems of the inner ears and sinuses because of its ability to generate very high resolution images. The anatomy of the inner ear and sinuses is made up of delicate soft tissue structure and very fine bones. CT is excellent for imaging tumors or polyps in the sinuses and disease that cause degeneration of the small bones in the inner ear.

High resolution axial CT image of the inner ears and sinuses. A large polyp in the right sinus (arrow) can be seen

CT can provide detailed cross sectional images and diagnostic information for nearly every part of the body including:

• the brain, vessels of the brain, eyes, inner ear, sinuses
• the neck, shoulders, cervical spine and blood vessels of the neck
• the chest, heart, aorta, lungs, mediastinum
• the thoracic and lumbar spine
• the upper abdomen, liver, kidney, spleen, pancreas and other abdominal vessels
• the pelvis and hips, male and female reproductive system, bladder, and GI tract
• the skeletal system including bones of the hands, feet, ankles, legs and arms, and jaws