in computed tomography, when a bright circle appears on an image made after injection of contrast medium, characteristic of localization of the contrast in the wall of an abscess.
Farlex Partner Medical Dictionary © Farlex 2012
DiffDx Infections—pyogenic abscess, toxoplasmosis, cysticercosis, necrotising fungal lesions; neoplasms—brain tumours—e.g., aggressive glial tumours, cystic astrocytoma, primary brain lymphoma, metastases with central necrosis; demyelinating disease; vascular lesions—resolving infarction, hematoma, thrombosed giant aneurysm; radiation therapy; postoperative changes; IV contrast material may be used to enhance faint radiodense ‘rings’
Segen's Medical Dictionary. © 2012 Farlex, Inc. All rights reserved.
ring enhancementImaging A CT finding in the brain consisting of a radiolucent zone surrounded by a faint radiodense rim, in turn is surrounded by a 2nd radiolucent zone outside of the rim, where the rings correspond to regional edema, hypervascularity and hypercellularity with early ingrowth of fibroblasts; RE is a nonspecific finding typically linked to early cerebral abscesses DIffDx Brain tumors–eg, cystic astrocytoma, or metastases with central necrosis; IV contrast material may be used to enhance faint radiodense 'rings'
McGraw-Hill Concise Dictionary of Modern Medicine. © 2002 by The McGraw-Hill Companies, Inc.