title: Cervical Carotid Pseudo-Occlusions and False Dissections: Intracranial Occlusions Masquerading as Extracranial Occlusions.
abstract: Pseudo-occlusion (PO) of the cervical internal carotid artery (ICA) refers to an isolated occlusion of the intracranial ICA that appears as an extracranial ICA occlusion on computed tomography angiography (CTA) or digital subtraction angiography because of blockage of distal contrast penetration by a stagnant column of unopacified blood. We aim to better characterize this poorly recognized entity.
  
  
  
  Retrospective review of an endovascular database (2010-2015; n=898). Only patients with isolated intracranial ICA occlusions as confirmed by angiographic exploration were included. CTA and digital subtraction angiography images were categorized according to their apparent site of occlusion as (1) extracranial ICA PO or (2) discernible intracranial ICA occlusion.
  
  
  
  Cervical ICA PO occurred in 21/46 (46%) patients on CTA (17 proximal cervical; 4 midcervical). Fifteen (71%) of these patients also had PO on digital subtraction angiography. A flame-shaped PO mimicking a carotid dissection was seen in 7 (33%) patients on CTA and in 6 (29%) patients on digital subtraction angiography. Patients with and without CTA PO had similar age (64.8±17.1 versus 60.2±15.7 years;P=0.35), sex (male, 47% versus 52%;P=1.00), and intravenous tissue-type plasminogen activator use (38% versus 40%;P=1.00). The rates of modified Treatment In Cerebral Ischemia 2b-3 reperfusion were 71.4% in the PO versus 100% in the non-PO cohorts (P<0.01). The rates of parenchymal hematoma, 90-day modified Rankin Scale score 0-2, and 90-day mortality were 4.8% versus 8% (P=0.66), 40% versus 66.7% (P=0.12), and 25% versus 21% (P=0.77) in PO versus non-PO patients, respectively. Multivariate analysis indicated that PO patients had lower chances of modified Treatment In Cerebral Ischemia 3 reperfusion (odds ratio 0.14; 95% confidence interval 0.02-0.70;P=0.01).
  
  
  
  Cervical ICA PO is a relatively common entity and may be associated with decreased reperfusion rates.
authors.affiliation: From the Department of Neurosurgery (J.A.G), and Department of Neurology (D.C.H., L.C.R., M.B., A.M.A., M.R.K., R.G.N.), Emory University/Grady Memorial Hospital, Atlanta, GA; and Department of Neurology, Universidade Estadual de Campinas, SP, Brasil (F.B.C).
authors.forename: Jonathan A
authors.initials: JA
authors.lastname: Grossberg
authors.affiliation: From the Department of Neurosurgery (J.A.G), and Department of Neurology (D.C.H., L.C.R., M.B., A.M.A., M.R.K., R.G.N.), Emory University/Grady Memorial Hospital, Atlanta, GA; and Department of Neurology, Universidade Estadual de Campinas, SP, Brasil (F.B.C).
authors.forename: Diogo C
authors.initials: DC
authors.lastname: Haussen
authors.affiliation: From the Department of Neurosurgery (J.A.G), and Department of Neurology (D.C.H., L.C.R., M.B., A.M.A., M.R.K., R.G.N.), Emory University/Grady Memorial Hospital, Atlanta, GA; and Department of Neurology, Universidade Estadual de Campinas, SP, Brasil (F.B.C).
authors.forename: Fabricio B
authors.initials: FB
authors.lastname: Cardoso
authors.affiliation: From the Department of Neurosurgery (J.A.G), and Department of Neurology (D.C.H., L.C.R., M.B., A.M.A., M.R.K., R.G.N.), Emory University/Grady Memorial Hospital, Atlanta, GA; and Department of Neurology, Universidade Estadual de Campinas, SP, Brasil (F.B.C).
authors.forename: Leticia C
authors.initials: LC
authors.lastname: Rebello
authors.affiliation: From the Department of Neurosurgery (J.A.G), and Department of Neurology (D.C.H., L.C.R., M.B., A.M.A., M.R.K., R.G.N.), Emory University/Grady Memorial Hospital, Atlanta, GA; and Department of Neurology, Universidade Estadual de Campinas, SP, Brasil (F.B.C).
authors.forename: Mehdi
authors.initials: M
authors.lastname: Bouslama
authors.affiliation: From the Department of Neurosurgery (J.A.G), and Department of Neurology (D.C.H., L.C.R., M.B., A.M.A., M.R.K., R.G.N.), Emory University/Grady Memorial Hospital, Atlanta, GA; and Department of Neurology, Universidade Estadual de Campinas, SP, Brasil (F.B.C).
authors.forename: Aaron M
authors.initials: AM
authors.lastname: Anderson
authors.affiliation: From the Department of Neurosurgery (J.A.G), and Department of Neurology (D.C.H., L.C.R., M.B., A.M.A., M.R.K., R.G.N.), Emory University/Grady Memorial Hospital, Atlanta, GA; and Department of Neurology, Universidade Estadual de Campinas, SP, Brasil (F.B.C).
authors.forename: Michael R
authors.initials: MR
authors.lastname: Frankel
authors.affiliation: From the Department of Neurosurgery (J.A.G), and Department of Neurology (D.C.H., L.C.R., M.B., A.M.A., M.R.K., R.G.N.), Emory University/Grady Memorial Hospital, Atlanta, GA; and Department of Neurology, Universidade Estadual de Campinas, SP, Brasil (F.B.C). raul.g.nogueira@emory.edu.
authors.forename: Raul G
authors.initials: RG
authors.lastname: Nogueira
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015901:Angiography, Digital Subtraction / Q000009:adverse effects* / Q000379:methods; D001157:Arterial Occlusive Diseases / Q000150:complications / Q000175:diagnosis; D002545:Brain Ischemia / Q000175:diagnosis* / Q000188:drug therapy; D002343:Carotid Artery, Internal / Q000002:abnormalities / Q000000981:diagnostic imaging*; D002533:Cerebral Angiography / Q000009:adverse effects* / Q000379:methods; D002544:Cerebral Infarction / Q000150:complications / Q000175:diagnosis; D057510:Endovascular Procedures / Q000379:methods; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D010959:Tissue Plasminogen Activator / Q000627:therapeutic use*
chemical_list: D010959:Tissue Plasminogen Activator
keywords: CT angiography; brain ischemia; carotid artery; cerebral infarction; pseudo-occlusion