Neurosurgery Service, Alicante University General Hospital, Alicante Institute for Health and Biomedical Research (ISABIAL - FISABIO Foundation), Alicante, Spain.
Those that arise from the superomedial aspect of the internal carotid artery just distal to the ophthalmic artery origin and projects superiorly or dorsomedially towards the lateral portion of the optic nerve.
It is the most common type of paraclinoid aneurysm.
Try oblique 25º away from injection side, center beam 3-4 cm above lateral aspect of ipsilateral orbital rim, orient x-ray tube in Towne view. Try submentovertex view.
Peschillo S, Biraschi F, Diana F, Colonnese C, Marenco M, Delfini R. Aneurysms of the Intracranial Segment of the Ophthalmic Artery Trunk: Case Report and Systematic Literature Review. J Neurol Surg A Cent Eur Neurosurg. 2017 Jul 25. doi: 10.1055/s-0037-1604268. [Epub ahead of print] PubMed PMID: 28743134 8).