Cytotoxic Lesions of the Corpus Callosum after Aneurysmal Subarachnoid Hemorrhage and Risk of Shunt-Dependent Chronic Hydrocephalus.

Cytotoxic lesions of the corpus callosum are increasingly recognized after aneurysmal subarachnoid hemorrhage, but their prognostic value for shunt-dependent chronic hydrocephalus remains uncertain. We conducted a two-center retrospective cohort study of consecutive patients with aneurysmal subarachnoid hemorrhage who underwent brain magnetic resonance imaging within 7 days of onset. Cytotoxic lesions of the corpus callosum were defined as diffusion restriction with corresponding apparent diffusion coefficient reduction and were classified as none, small-type, or large-type using prespecified morphological criteria. The primary outcome was shunt-dependent chronic hydrocephalus, and the secondary outcome was unfavorable functional outcome (modified Rankin Scale score 3-6 at discharge or at approximately day 60). Associations were evaluated using prespecified multivariable logistic regression. As a sensitivity analysis, binary intraventricular hemorrhage was replaced by the Graeb score to account for quantitative intraventricular hemorrhage burden. Among 230 patients, 68 (29.6%) had cytotoxic lesions of the corpus callosum (small-type, 44 [19.1%]; large-type, 24 [10.4%]), and 62 (27.0%) developed shunt-dependent chronic hydrocephalus. After adjustment, small-type cytotoxic lesions of the corpus callosum (vs none) were associated with shunt-dependent chronic hydrocephalus (adjusted odds ratio 2.99, 95% confidence interval 1.31-6.83; p = 0.009) and unfavorable functional outcome (adjusted odds ratio 4.85, 95% confidence interval 1.79-13.93; p = 0.002). For large-type cytotoxic lesions of the corpus callosum, point estimates for both outcomes were elevated, but the 95% confidence interval included 1.0. Modified Fisher grade and Graeb score differed significantly across cytotoxic lesion of the corpus callosum subtypes (both p < 0.001). Early cytotoxic lesion of the corpus callosum assessment, particularly identification of small-type lesions, was associated with shunt-dependent chronic hydrocephalus and unfavorable outcome after aneurysmal subarachnoid hemorrhage.