How are CT scans used to diagnose hip and knee problems?

Scott D. Martin, MD
Orthopedic Surgery

When you have knee and hip problems, sometimes a physical exam and your symptoms provide sufficient information for your doctor to make a diagnosis. But when that's not enough, a variety of imaging techniques and laboratory tests can clarify the situation.

Doctors sometimes order a computed tomography (CT) scan to look for hidden fractures, bone lesions, and other structural abnormalities. A CT scan uses a rotating x-ray tube housed in a doughnut-shaped machine to take many cross-sectional x-rays of your anatomy. A computer assembles these "slices" into a three-dimensional picture. During the scan, which takes less than an hour, you lie on your back on a movable table that is raised, lowered, and moved in and out of the scanner. The equipment doesn't touch you, and the test isn't uncomfortable. CT is expensive, but it provides an enhanced view of bone, allowing your doctor to better evaluate bone shape and diagnose some defects hidden on standard x-rays. CT does not show soft tissue as well as an MRI does.

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Important: This content reflects information from various individuals and organizations and may offer alternative or opposing points of view. It should not be used for medical advice, diagnosis or treatment. As always, you should consult with your healthcare provider about your specific health needs.