MR angiography of peripheral posterior inferior cerebellar artery aneurysms.

OBJECTIVE

A small subset of posterior inferior cerebellar artery (PICA) aneurysms arise distal to the vertebral artery origin of the PICA. We present two such cases seen on conventional angiography and MR angiography (MRA).

MATERIALS AND METHODS

The findings in two patients are presented. In one the aneurysm presented with subarachnoid hemorrhage. The second was found incidentally but later ruptured.

RESULTS

There was good agreement between the appearance of the aneurysms on MRA and conventional angiography.

CONCLUSION

Awareness of the possibility of peripheral PICA aneurysms and their features is important. The positioning of the volume of excitation for MRA may have to be adjusted to include a very low PICA caudal loop.