Infiltrate

Build-up of substances or cells within a tissue that are either not normally found in it or are usually present only in smaller amounts. Infiltrate may refer to a drug (such as a local anaesthetic) that has been injected into a tissue, or to the build-up of a substance within an organ (for example, fat in the liver caused by excessive alcohol consumption). Radiologists use the term to refer to the presence of abnormalities, most commonly on a chest X-ray, due to conditions such as infection.