In cerebral angiography, the dye is injected through –: (A) Femoral artery, (B) Brachial artery, (C) Axillary artery, (D) Radial artery
Answer is A. On MRI, diagnostic confusion occasionally arises between arachnoid cysts and epidermoid cysts. The two masses may have similar characteristics on T1-weighted and T2-weighted images, and neither shows enhancement with gadolinium.
However, arachnoid cysts follow CSF signals on all sequences, in particular on FLAIR sequence, in contradistinction to epidermoid cyst.
Diffusion-weighted images (DWIs) allow easier differentiation of the two masses.