Concentric target sign (cerebral toxoplasmosis)

Last revised by Mostafa Elfeky on 12 Aug 2023

Citation, DOI, disclosures and article data

Citation:

Voss Y, Elfeky M, Yap J, et al. Concentric target sign (cerebral toxoplasmosis). Reference article, Radiopaedia.org (Accessed on 19 Apr 2024) https://doi.org/10.53347/rID-70680

DOI:

https://doi.org/10.53347/rID-70680

Permalink:

https://radiopaedia.org/articles/70680

rID:

70680

Article created:

30 Aug 2019, Yves Leonard Voss

Disclosures:

At the time the article was created Yves Leonard Voss had no recorded disclosures.

View Yves Leonard Voss's current disclosures

Last revised:

12 Aug 2023, Mostafa Elfeky ◉

Disclosures:

At the time the article was last revised Mostafa Elfeky had no financial relationships to ineligible companies to disclose.

View Mostafa Elfeky's current disclosures

Revisions:

6 times, by 5 contributors - see full revision history and disclosures

Systems:

Central Nervous System, Haematology

Sections:

Signs

Tags:

cerebral toxoplasmosis, neurotoxoplasmosis

The concentric target sign is a typical sign of cerebral toxoplasmosis. It is seen on T2 weighted MR imaging as a deep parenchymal lesion showing a series of concentric rings with hyperintense and hypointense/isointense signals alternatingly. Strong perifocal edema is usually visible on T2/FLAIR images.

Pathology

Microscopic appearance

Histopathologically there are zones of fresh hemorrhage and/or compact coagulative necrosis (hypo/isointense) alternating with zones of edema, fibrin-rich necrosis or foamy histiocytic infiltration (hyperintense).