Dual rim sign (brain abscess)

Case contributed by Ayaz Hidayatov
Diagnosis certain

Presentation

Severe headache and seizures since 2 weeks. No past medical history.

Patient Data

Age: 25 years
Gender: Male
mri

MR demonstrates a well defined T1WI hypointense and T2WI hyperintense lesion in the left frontal subcortical white matter with extension to centrum semiovale. The lesion has a thick wall with dual rim sign best seen on T2WI and is intensely enhancing on post contrast T1WI (ring enhancement). The lesion shows true restricted diffusion on DW images. There is marked perilesional edema.

The MRI findings are most suggestive of a brain abscess. A craniotomy was performed and the lesion was resected.

Histopathology report: 

Granulation tissue with fibroblasts, macrophages with surrounding inflammatory necrotic tissue. No malignant cells were observed.

Diagnosis: Pyogenic abscess

Case Discussion

The imaging appearance of some cystic or necrotic glial tumors is similar to that of brain abscesses. DWI is very useful for the differential diagnosis between brain abscesses and cystic or necrotic brain tumors with the former typically demonstrating central diffusion restriction. The dual rim sign is the most specific imaging feature that is typically seen in pyogenic brain abscesses.

How to use cases

You can use Radiopaedia cases in a variety of ways to help you learn and teach.

Creating your own cases is easy.

Updating… Please wait.

 Unable to process the form. Check for errors and try again.

 Thank you for updating your details.