title: A pneumatized anterior clinoid mimicking an aneurysm on MR imaging. Report of two cases.
abstract: The advent of magnetic resonance (MR) imaging has marked a new era in neuroimaging--particularly in terms of diminishing the need for more invasive diagnostic procedures. A cautionary note should be sounded, however, about an important limitation of standard spin-echo MR studies. Two patients were referred for angiography because MR imaging indicated the presence of a "paraclinoid aneurysm." In retrospect, these findings were due instead to a pneumatized anterior clinoid. Angiography could have been avoided had this pitfall been recognized, and had a gradient-echo flow-imaging protocol been utilized. This latter approach (which does not replace spin-echo imaging) is more sensitive to flowing blood and thus allows differentiation of an air space from a nonthrombosed aneurysm.
authors.affiliation: Department of Neuroradiology, Massachusetts General Hospital, Boston.
authors.forename: A D
authors.initials: AD
authors.lastname: Gean
authors.forename: J
authors.initials: J
authors.lastname: Pile-Spellman
authors.forename: R C
authors.initials: RC
authors.lastname: Heros
mesh_terms: D000328:Adult; D002533:Cerebral Angiography; D003937:Diagnosis, Differential; D006801:Humans; D002532:Intracranial Aneurysm / Q000175:diagnosis*; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D013100:Sphenoid Bone / Q000033:anatomy & histology* / Q000000981:diagnostic imaging; D014057:Tomography, X-Ray Computed