How Performed: The room lights are dimmed or turned off for better visualization. Then a bright light is shined through a cavity or organ, typically the head, scrotum, or chest in the premature or newborn infant or the breast in an adult female.

How To Prepare: No preparation is necessary for this test.

How It Feels: There is no discomfort associated with this test.

Risks: There are no risks associated with this test.

Why Performed: This test is most commonly performed on newborns or infants with hydrocephalus, or males suspected of having a hydrocele. But the test may also be performed on breast tissue to detect lesions and/or cysts. In newborns, a bright halogen light may be used to transilluminate the chest cavity if it is suspected they have a pneumothorax. Transillumination through the chest is only possible on small newborns. Diagnosis of pneumothorax is always confirmed by chest X-ray.

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

Abnormal Results:

Areas filled with air or fluid that is not native to that location have increased light transmission and transilluminate when they should not. For example, in a darkened room, a newborn infant’s head can be seen to light up brightly when transilluminated if there is excess fluid present (suggesting hydrocephalus).

Results specific to the breasts include:

• If there is a lesion and bleeding has occurred, those internal areas will be dark to black, because blood does not transilluminate.
• Benign tumors tend to appear red.
• Malignant tumors are brown to black.

Cost:

Special Considerations: Not applicable.