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Transillumination

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Illustrations

Infant brain test
Infant brain test

Definition    Return to top

Transillumination is the shining of a light through a body cavity or organ.

How the Test is Performed    Return to top

The room lights are dimmed or turned off so that the appropriate part of the body may be seen more easily. A bright light is then pointed at a location on the body, typically the head, scrotum, chest of a premature or newborn infant, or breast of an adult female.

Transillumination is also sometimes used to find blood vessels.

How to Prepare for the Test    Return to top

No preparation is necessary for this test.

How the Test Will Feel    Return to top

There is no discomfort associated with this test.

Why the Test is Performed    Return to top

This test may be done along with other tests to diagnose:

In newborns, a bright halogen light may be used to transilluminate the chest cavity if there are signs of a collapsed lung. (Transillumination through the chest is only possible on small newborns.)

Normal Results    Return to top

Normal findings depend on the area being evaluated, and the normal tissue of that region.

What Abnormal Results Mean    Return to top

Areas filled with abnormal air or fluid will light up when they should not. For example, in a darkened room, the head of a newborn with possible hydrocephalus will light up when this procedure is done.

When done on the breast:

Risks    Return to top

There are no risks associated with this test.

Considerations    Return to top

In general, transillumination is not a particularly good test for any of these above-mentioned disorders, and further tests, such as an x-ray or ultrasound, are needed to confirm the diagnosis.

Update Date: 11/14/2007

Updated by: Deirdre O’Reilly, M.D., M.P.H., Neonatologist, Division of Newborn Medicine, Children’s Hospital Boston and Instructor in Pediatrics, Harvard Medical School, Boston, Massachusetts.

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