|T1 post-gad||T1 post-gad||R vert angio Towne projection|
If the angiogram were not available, the differential diagnosis of this lesion would also include hemangioma, meningioma, ependymoma and schwannoma. Although the lesion does lack a dural tail, which would suggest meningioma and it seems somewhat removed from the internal auditory canal which goes heavily against schwannoma. Other remote considerations may include a metastasis or an exophytic astrocytoma. This lesion has a bright rim on T1 pre gad which suggests subacute thrombus in the periphery. This is born out by the angiogram which showed a small lesion measuring approximately 3 mm in diameter. The MRA is somewhat misleading since it was performed after the administration of gadolinium. Most of the subtle signal which is seen on the MRA in the vicinity of the lesion is probably due to the presence of the thrombus whose T1 has been additionally shortened by the administration of gadolinium. The surgical report states that the aneurysm was either a focal fusiform type or a broad based saccular type which was approximately 1 cm in diameter. The aneurysm was seen to be compressing the 7th and 8th cranial nerve complex inferiorly. Related Cases
Uede T, Matsumura S, Ohtaki M, et al. Aneurysm of the anterior inferior cerebellar artery at the internal auditory meatus: report of two cases. No Shinkei Geka, Spe 1986; 14(10): p1263-8.
Dalley RW, Robertson WD, Nugent RA, et al. Computed tomography of anterior inferior cerebellar artery aneurysm mimicking an acoustic neuroma. J Comput Assist Tomogr, Sep-Oct 1986; 10(5):p881-4.
Fukuya T, Kishikawa T, Ikeda J, et al. Aneurysms of the peripheral portion of the anterior inferior cerebellar artery; report of two cases. Neuroradiology, 1987; 29(5):p493-6.
Rinehart R, Harre RG, Roski RA, et al. Aneurysm of the anterior inferior cerebellar artery producing hearing loss. Ann Otol Rhinol Laryngol, Aug 1992; 101(8):p705-6.
|Acoustic schwannoma||AICA aneurysm|