Ring-enhancing lesion

Ring-enhancing lesion is a radiographic finding defined as an abnormal lesion with central hypodensity (computed tomography) or hypointensity (magnetic resonance imaging) and a peripheral rim of contrast enhancement. These lesions are frequently encountered in the setting of neuroradiology and can resemble a wide range of pathologies. Clinical presentation of the pathologies that can cause a ring-enhancing lesion are oftentimes non-specific, making clinical diagnosis difficult. As a result, it is vital that radiologists not only recognize these lesions, but characterize them based on their appearance, location, and other associated imaging findings in order to make a precise diagnosis. Although the differentials are numerous, the presence of a ring-enhancing lesion is fundamentally abnormal. When brain tissue takes up radiocontrast, this implies disruption of the blood-brain barrier. Therefore, presence of a ring-enhancing lesion requires careful workup and investigation by the radiologist as many of the causes may lead to neurological sequelae and possible death.