title: Prevalence and mechanisms of cortical superficial siderosis in cerebral amyloid angiopathy.
abstract: OBJECTIVE
  We investigated the prevalence and clinical-radiologic associations of cortical superficial siderosis (cSS) in patients with probable cerebral amyloid angiopathy (CAA) compared to those with intracerebral hemorrhage (ICH) not attributed to CAA.
  
  
  METHODS
  We conducted a retrospective multicenter cohort study of 120 patients with probable CAA and 2 comparison groups: 67 patients with either single lobar ICH or mixed (deep and lobar) hemorrhages; and 22 patients with strictly deep hemorrhages. We rated cSS, ICH, white matter changes, and cerebral microbleeds.
  
  
  RESULTS
  cSS was detected in 48 of 120 (40%; 95% confidence interval [CI]: 31.2%-49.3%) patients with probable CAA, 10 of 67 (14.9%; 95% CI: 7.4%-25.7%) with single lobar ICH or mixed hemorrhages, and 1 of 22 (4.6%; 95% CI: 0.1%-22.8%) patients with strictly deep hemorrhages (p < 0.001 for trend). Disseminated cSS was present in 29 of 120 (24%; 95% CI: 16.8%-32.8%) patients with probable CAA, but none of the other patients with ICH (p < 0.001). In probable CAA, age (odds ratio [OR]: 1.09; 95% CI: 1.03-1.15; p = 0.002), chronic lobar ICH (OR: 3.94; 95% CI: 1.54-10.08; p = 0.004), and a history of transient focal neurologic episodes (OR: 11.08; 95% CI: 3.49-35.19; p < 0.001) were independently associated with cSS. However, cSS occurred in 17 of 48 patients with probable CAA (35.4%; 95% CI: 22.2%-50.5%) without chronic lobar ICH.
  
  
  CONCLUSIONS
  cSS (particularly if disseminated) is a common and characteristic feature of CAA. Chronic lobar ICH is an independent risk factor for cSS, but the causal direction and mechanism of association are uncertain. Hemorrhage into the subarachnoid space, independent of previous (chronic) lobar ICH, must also contribute to cSS in CAA. Transient focal neurologic episodes are the strongest clinical marker of cSS.
authors.affiliation: Stroke Research Group, Department of Brain Repair and Rehabilitation, UCL Institute of Neurology and The National Hospital for Neurology and Neurosurgery, London, UK.
authors.forename: Andreas
authors.initials: A
authors.lastname: Charidimou
authors.forename: Rolf Hans
authors.initials: RH
authors.lastname: Jäger
authors.forename: Zoe
authors.initials: Z
authors.lastname: Fox
authors.forename: Andre
authors.initials: A
authors.lastname: Peeters
authors.forename: Yves
authors.initials: Y
authors.lastname: Vandermeeren
authors.forename: Patrice
authors.initials: P
authors.lastname: Laloux
authors.forename: Jean-Claude
authors.initials: JC
authors.lastname: Baron
authors.forename: David John
authors.initials: DJ
authors.lastname: Werring
mesh_terms: D000368:Aged; D016657:Cerebral Amyloid Angiopathy / Q000150:complications* / Q000473:pathology; D002543:Cerebral Hemorrhage / Q000150:complications / Q000473:pathology; D015331:Cohort Studies; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D012189:Retrospective Studies; D012806:Siderosis / Q000150:complications* / Q000453:epidemiology* / Q000473:pathology