Distribution of subclinical DWI lesions in patients with intracranial hemorrhage.

Abstract

Background and Rationale: Subclinical ischemic lesions on diffusion weighted MR imaging (DWI) were recently described in patients with spontaneous intracerebral hemorrhage (ICH) and convexity subarachnoid hemorrhage (cSAH), possibly related to amyloid angiopathy. The topography of these lesions may provide clue regarding their pathogenesis with investigators suggesting preference of these lesions in watershed infarct location. The aim is to study the topography of these lesions. Method(s): Patients presenting to Monash Medical Centre between 2011-2014 with ICH and cSAH were included in the absence of aneurysm, arteriovenous malformation, hemorrhagic infarction, or contra-indication for Magnetic Resonance Imaging (MRI). Diffusion weighted imaging (DWI) lesions were segmented and registered to stereotactic coordinates. Their locations were compared to digital maps of arterial territory and watershed areas. Result(s): There were 114 eligible patients; mean age was 69.6 +/- 12.3 years (male 53.9%). The distribution of patients were cSAH 16 (14.0%), lobar ICH 48 (42.1%) and deep ICH 50 (43.9%). Among 30 patients (26%) who had DWI positive lesions, 16 (53.3%) occurred within 7 days and 29 (96.7%) by 6 months. The predominant locations were frontal 15/30 (50.0%), parietal 10/30 (33.3%) and subcortical 7/30 (23.3%). These locations and the haemorrhage types are displayed [convexity subarachnoid hemorrhage (red), lobar hemorrhage (blue) and deep hemorrhage (yellow)]. There were no statistical association between the DWI lesion locations and the type of intracranial haemorrhage. Conclusion(s): Subclinical ischemic lesions have random distribution and are not easily explained by current hypotheses.