title: Prevalence of superficial siderosis in patients with cerebral amyloid angiopathy.
abstract: BACKGROUND
  Cerebral amyloid angiopathy (CAA) typically presents with lobar intracerebral macrohemorrhages (ICH) or microbleeds (MBs). Several case reports also found superficial siderosis (SS) in patients with CAA. We aimed to assess the value of SS for the in vivo diagnosis of CAA, and tested whether the inclusion of SS as a criterion alters the sensitivity and specificity of the Boston criteria for CAA-related hemorrhage.
  
  
  METHODS
  We retrospectively analyzed the T2*-weighted MRIs of 38 patients with histopathologically proven CAA and of 22 control patients with histopathologically proven non-CAA ICHs regarding the presence of ICHs, MBs, and SS. We compared the sensitivity and specificity of the classic Boston criteria to that of modified criteria, which included SS as a criterion.
  
  
  RESULTS
  ICHs were present in 71% of the patients with CAA, and in all control patients. MBs were found in 47.4% of patients with CAA and in 22.7% of controls. SS was detected in 60.5% of patients with CAA, but in none of the controls. The classic criteria had a sensitivity of 89.5% for CAA-related hemorrhage, while inclusion of SS increased their sensitivity to 94.7% (not significant). On the contrary, the specificity of the Boston criteria was 81.2% both for the classic and for the modified criteria.
  
  
  CONCLUSIONS
  Superficial siderosis (SS) occurs with high prevalence in cerebral amyloid angiopathy (CAA) and is rare in non-CAA forms of intracerebral hemorrhages. Thus, we propose that inclusion of SS in the Boston criteria might enhance their sensitivity for CAA-related hemorrhage without loss of specificity.
authors.affiliation: Department of Neuroradiology, University Hospital Munich, Marchioninistrasse 15, 81377 Munich, Germany. linn@nrad.de
authors.forename: J
authors.initials: J
authors.lastname: Linn
authors.forename: A
authors.initials: A
authors.lastname: Halpin
authors.forename: P
authors.initials: P
authors.lastname: Demaerel
authors.forename: J
authors.initials: J
authors.lastname: Ruhland
authors.forename: A D
authors.initials: AD
authors.lastname: Giese
authors.forename: M
authors.initials: M
authors.lastname: Dichgans
authors.forename: M A
authors.initials: MA
authors.lastname: van Buchem
authors.forename: H
authors.initials: H
authors.lastname: Bruckmann
authors.forename: S M
authors.initials: SM
authors.lastname: Greenberg
mesh_terms: D000368:Aged; D001921:Brain / Q000473:pathology; D016657:Cerebral Amyloid Angiopathy / Q000150:complications* / Q000453:epidemiology* / Q000473:pathology; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D015995:Prevalence; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D012806:Siderosis / Q000150:complications* / Q000453:epidemiology* / Q000473:pathology