title: Anatomical variations in the posterior part of the circle of willis and vascular pathology in bilateral thalamic infarction.
abstract: OBJECTIVE
  Bilateral paramedian thalamic infarction is a rare subtype of stroke the etiology of which still remains undetermined in many patients.
  
  
  METHODS
  From a computed tomography (CT)/magnetic resonance imaging report database, we identified and analyzed 48 patients with bilateral paramedian thalamic infarction on diffusion-weighted imaging. Vascular pathologies were noted on CT angiography (CTA)/magnetic resonance angiography (MRA) and the P1 segments of the posterior cerebral artery (PCA) described as normal, hypoplastic, or absent.
  
  
  RESULTS
  Vascular imaging revealed top of the basilar artery (BA) occlusion in 6 (12.5%), BA occlusion in 4 (8.3%), BA stenosis in 1 (2.1%), and BA hypoplasia in 3 (6.3%), PCA occlusion in 4 (8.3%), and PCA stenosis in 4 (8.3%) patients. In 18 (37.5%) patients, one or both P1 segments of the PCA were hypoplastic or absent. Patients with hypoplastic/absent P1 segments were more likely to have exclusively bilateral paramedian thalamic lesions (P < .001). An embolic source could be identified in 25 (55.6%) patients; there were no significant differences between both groups.
  
  
  CONCLUSIONS
  Vascular imaging is useful to determine underlying vascular pathologies and may support the diagnosis of small vessel disease in those patients with isolated bilateral paramedian thalamic infarction, hypoplastic/absent P1 segment of the PCA, and lack of vascular pathology.
authors.affiliation: Department of Neuroradiology, Universitätsmedizin Mannheim, University of Heidelberg, Mannheim, Germany.
authors.forename: Alex
authors.initials: A
authors.lastname: Förster
authors.forename: Ingo
authors.initials: I
authors.lastname: Nölte
authors.forename: Holger
authors.initials: H
authors.lastname: Wenz
authors.forename: Mansour
authors.initials: M
authors.lastname: Al-Zghloul
authors.forename: Hans U
authors.initials: HU
authors.lastname: Kerl
authors.forename: Marc A
authors.initials: MA
authors.lastname: Brockmann
authors.forename: Christoph
authors.initials: C
authors.lastname: Groden
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002533:Cerebral Angiography / Q000379:methods*; D002539:Cerebral Arterial Diseases / Q000150:complications / Q000175:diagnosis*; D002544:Cerebral Infarction / Q000175:diagnosis* / Q000209:etiology; D002941:Circle of Willis / Q000002:abnormalities / Q000000981:diagnostic imaging* / Q000473:pathology*; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013788:Thalamus / Q000098:blood supply* / Q000000981:diagnostic imaging / Q000473:pathology; D014057:Tomography, X-Ray Computed / Q000379:methods
keywords: Bilateral thalamic stroke; PCA; etiology