ring enhancement

ring en·hance·ment

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.
A CT finding in the brain consisting of a radiolucent zone surrounded by a faint radiodense rim, in turn surrounded by a 2nd radiolucent zone outside of the rim, where the rings correspond to regional oedema, hypervascularity and hypercellularity with early ingrowth of fibroblasts. Ring enhancement is a nonspecific finding typically linked to early cerebral abscesses
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’

ring enhancement

Imaging 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'
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Fist-like or lumpy enhancement is frequently seen in people with normal immunity; whereas patients with immunodeficiency usually shows ring enhancement.
CT scan sometimes shows large cysts with ring enhancement causing compression of the adjacent structures and simultaneously the patient is symptomatic.
Gadolinium enhanced T1 images shows ring enhancement.
Ring enhancement is not specific for pyogenic abscess and may be seen in other conditions such as nonpyogenic abscess, high grade neoplasm, primary central nervous system lymphoma, metastasis, infarct, hematoma, thrombosed giant aneurysm, radiation necrosis, demyelinating disease, and Toxoplasmosis gondii infection.
7-cm, oval-shaped fatty mass with peripheral ring enhancement projecting anteriorly from the descending colon (Figure 1).
Those with liquid centre are hypointense on T1W1, the centre is hyperintense on T2W1 but the periphery is hypointense and shows ring enhancement (1).
Caseating granulomas appear hypo- or isointense on T1 & T2 weighted images and show ring enhancement after gadolinium contrast with variable degree of perilesional oedema.
white matter lesions with little mass-like effect or vasogenic edema, and post-gadolinium magnetic resonance imaging (MRI) typically showing an incomplete ring enhancement (2,4).
1) However, MS can present with atypical imaging features consisting of solitary, large (>2 cm)demyelinating plaques with edema, associated mass effect, and/or ring enhancement.
Enhancing cryptococcomas often do not show restricted diffusion on diffusion-weighted imaging (DWI), (9) low signal intensity on T1-weighted imaging, and low (9) or high intensity (12) on T2 imaging, with uniform or ring enhancement.
The lesions may show nodular homogeneous enhancement or ring enhancement, unless the patient has a very low cellular immunity in which case there may be no enhancement (CD4 cell count <50 cells/[mm.
The radiological classical pictures of TE are multiple parenchymal lesions, with ring enhancement, which are generally localized at the corticomedullar junction, in the white matter, or the basal ganglia [3].