Orbit CT scan

Definition

An orbital CT scan is a procedure that uses computed tomography to examine the orbits (the eye sockets) and the globes (the eyes).

How the test is performed

A contrast dye may be injected into a vein before the test.

You lie on a table that can be moved by the technician operating the scanner. Only your head is positioned inside the CT scanner. The exam usually lasts no more than a few minutes.

You may be allowed to rest your head on a pillow, but this must be done before the scan begins.

How to prepare for the test

You must sign an informed consent form. Remove dentures, any jewelry, and anything metal.

How the test will feel

The most discomfort arises from the need to lie still on the table during the scan. The scan itself is painless.

Why the test is performed

This test is helpful in diagnosing a lesion or other disease which affects the tissues around the eyes, sinuses, optic nerves (nerves supplying the eyes), or eye muscles and vessels. Subtle fractures of the orbits may also be detected.

What abnormal results mean

• Graves' disease
• Lesions
• Tumor
• Hemorrhage

What the risks are

The amount of radiation in a CT scan is minimal. There may be some concern for nursing or pregnant women. However, the benefits of the scan generally outweigh any risk to the fetus or newborn.

Special considerations

The contrast dye may cause adverse reactions in some patients. These reactions may include headache, nausea, and vomiting.

Illustrations

CT scan

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CT scan - orbital