Blister aneurysm of the hypophyseal segment — these are the subtle ones. The days of angio-negative SAH, with subsequent discovery of an occult saccular aneurysm may be waning (though certainly not history). The blister kind is one where follow-up catheter angiography is key. For us, anything other than classic perimesencephalic pattern means two catheter angios — baseline and follow up.
On day presentation, there is impressive SAH. Day 1 angio shows very subtle spasm on the hypophyseal segment. Day 5 angio demonstrates much more spasm in the hypophyseal segment and proximal MCA/ACA (not shown). An oblique view of the hypophyseal segment uncovers the nasty, crater-like blister aneurysm.
The patient was loaded with plavix and aspirin and Pipeline Embolized on the following day. The ancient Bellevue machine (since then replaced) does well, with external measurement devices (dimes). Three months later, the aneurysm is cured.
See companion case of Tiny Aneurysm Coil Embolization