Cavernoma

Axial CT image shows a small well-defined hyperdense lesion (arrow) in the gray-white matter junction of the left posterior parietal lobe without evidence of mass effect or surrounding edema.

Axial T2W MR image shows the lesion predominantly high signal intensity with a complete ring of dark T2 signal, suggesting the presence of hemosiderin.

Facts: Cavernoma

• Low-flow vascular anomaly of the brain
• Endothelium-lined blood cavities without muscular or adventitial layers. No brain tissues present between these blood cavities
• May be sporadic, related to prior radiation, or hereditary
• Patients commonly present with seizures due to internal bleeding
• Annual bleeding rate between 0.25 to 0.7% per year
• On follow up, most cavernomas increase in size due to osmotic changes
• 80% are supratentorium, and size between 1-2 cm

Imaging

• Appearance depends on amount of internal thrombosis, hemorrhage and calcification
• MRI is the modality of choice because it can show various stages of bleeding in the lesion, which is characteristic for cavernoma
• If presents with acute hemorrhage, CT appearance will be similar to intracerebral hemorrhage of other causes. MRI in acute phase may provide a clue to the diagnosis of cavernoma if it shows various stages of bleeding in particular the presence of hemosiderin
• If presents incidentally, cavernoma appears as a hyperdense mass without causing mass effect on CT. If calcified, it will be only partially calcified. On MRI, it shows a complete ring of dark T2 signal due to the presence of hemosiderin (this effect is best seen on GRE T2* sequence)

Reference:

Kuker W and Forsting M. Cavernomas and Capillary Telangiectasias. In: Baert AL, Knauth M, Sartor K. Intracranial Vascular Malformations and Aneurysms, 2nd revised edition, 2008