Transillumination

How the Test is 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 , breast, or chest in the premature newborn infant.

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 this Test is 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.
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:
Information not available.

Special Considerations:
Not applicable.


An abnormal accumulation of fluid within the brain (hydrocephalus) causes excessive pressure and compresses the brain tissue. Light passes readily through the fluid (transillumination).



Hydrocephalus is a condition in which the head is full of cerebrospinal fluid (CSF) and the brain tissue has been compressed to only a thin layer. Light passes readily through the fluid. Transillumination is used to detect the presence of fluid within the skull.