Encephalogram and Roentgenogram

Encephalogram noun - An X ray of the brain made by replacing spinal fluid with a gas (usually oxygen) to improve contrast.

Roentgenogram and encephalogram are semantically related. In some cases you can use "Roentgenogram" instead a noun "Encephalogram".

Roentgenogram noun - A radiogram made by exposing photographic film to X rays; used in medical diagnosis.

Encephalogram and roentgenogram are semantically related. Sometimes you can replace term "Encephalogram" with "Roentgenogram", this nouns are similar.