Anatomic pattern of intracerebral hemorrhage expansion: relation to CT angiography spot sign and hematoma center.

BACKGROUND AND PURPOSE We sought to identify baseline determinants of the anatomic pattern of hematoma expansion in patients with intracerebral hemorrhage and spot sign. METHODS We coregistered baseline and follow-up CT scans from 15 intracerebral hemorrhage patients and measured growth at each surface node from baseline to follow-up hematoma. We analyzed the effects of proximity to the spot sign or hematoma center on distance of expansion, controlling for covariates. RESULTS There was substantial node-to-node variation in the extent of expansion around each hematoma surface (mean coefficient of variation for expansion distance, 0.43; 95% confidence interval, 0.39-0.48), indicating nonuniform expansion. Closer proximity to the hematoma center was independently associated with increased expansion (0.185 mm greater expansion for each 1 mm closer to the center; P<0.0001). Closer proximity to the spot sign was not independently associated with increased expansion in models including both terms. CONCLUSIONS Hemorrhages expand nonuniformly around their surface with a tendency for greater expansion closer to their center. These findings provide a novel framework for analyzing mechanisms underlying hemorrhage growth and response to treatment.