QUIZ: No. 37, 23/11/2025

MR

CT

ANS – Chronic encapsulated intracerebral hematoma (CEIH)

Findings: Well-defined, round intra-axial lesion in the left parietal lobe beneath the prior craniotomy site, demonstrating a central T1-hyperintense and mildly T2-hypointense cavity, consistent with proteinaceous and hemorrhagic breakdown products. DWI shows high signal with corresponding low ADC values rather than true restriction. GRE/SWI reveals a complete hypointense hemosiderin rim, and post-contrast imaging shows a smooth, thin, enhancing capsule without any solid enhancing components. CT shows a hypodense core with a hyperdense enhancing capsule. Note – Recurrent parafalcine meningioma with SSS invasion noted in coronal PC images.

CEIH is a rare condition occurring in young to middle-aged adults, most commonly associated with prior hemorrhage, trauma, vascular malformations, or postoperative surgical sites.

It develops when an intracerebral bleed becomes walled off by a vascularized fibrous capsule; repeated microbleeds and accumulation of protein-rich fluid lead to gradual enlargement.

Imaging typically shows a T1-hyperintense, mildly T2-hypointense center, a hemosiderin rim, smooth rim enhancement, and pseudorestriction on DWI/ADC due to the T2 blackout effect.

Surgical excision with capsule removal is the treatment of choice and offers an excellent prognosis.

Take-home Points:

Ø  Consider CEIH when a postoperative or prior hemorrhage site shows a T1-bright, T2-dark cystic lesion with a hemosiderin rim and smooth rim enhancement.

Ø  Bright DWI with dark ADC in CEIH usually reflects mixed shine-through + blackout artifacts, not true diffusion restriction—helpful in differentiating it from abscess.