Background: Convexity subarachnoid hemorrhage (cSAH) or subdural Hematoma (SDH) are occasionally described on CT or MRI in the area of acute lobar intracerebral hematoma (ICH). The prevalence and the etiologic significance of this association are not well known.
Hypothesis: We hypothesized that cSAH and SDH were more frequent in Cerebral Amyloid Angiopathy (CCA)-related lobar ICH.
Methods: Using our electronic database, we retrospectively reviewed the clinical and MRI characteristics of 165 consecutive patients (mean age 70 ± 13 years) admitted for acute lobar ICH. The presence of cSAH and SDH was assessed by 2 reviewers on a brain MRI performed within 10 days after ICH onset.
Results: SDH and cSAH were present in respectively 28.5 and 54.5 % of all patients. Among patients with acute lobar ICH meeting the modified Boston criteria for probable CAA, the frequency was 37.5 % (27/72) for SDH and 73 % (53/72) for cSAH, which is significantly higher than among patients with hematoma of other causes ( 21.5 and 39.8 %; p=0.03 and p<0.001 respectively). The association remained significant considering patients meeting the modified Boston criteria for probable or possible CAA versus others causes.
Conclusions: Using MRI for evaluation of acute lobar ICH, cSAH and SDH were very frequent and associated with CCA. This is consistent with the involvement of leptomeningeal arteries in this disease. The presence of subarachnoid or subdural hemorrhage should be systematically assessed and could be added to diagnostic criteria for CAA.