Abstract 71: Diffusion Imaging Of Cerebral Diaschisis In Neonatal Arterial Ischemic Stroke

Objectives: Diffusion MRI (DWI) corticospinal changes remote from neonatal arterial ischemic stroke (NAIS) correlate with physiology and outcome. We hypothesized that DWI can quantify acute alterations in other remote connected structures (“diaschisis”). Methods: Children from Calgary and SickKids Stroke Programs were studied with unilateral NAIS, DWI <10 days from term birth and follow up (Pediatric Stroke Outcome Measure). Image J thresholding quantified DWI diaschisis in connected structures according to validated methods (figure). Subsequent atrophy was measured volumetrically on MRI >12 mos (OsiriX). Primary outcome was total diaschisis signal (TD) which was then corrected for stroke volume (% brain infarcted). Scores were regionalized by cerebral structure. Associations with MRI timing and outcome were sought (nonparametric statistics). Method reliability was confirmed. Results: Twenty neonates met criteria (55% male). Median age at MRI was 72 hours. Diaschisis was common, observed in 16 (80%). Thalamic diaschisis was most common (100%), followed by callosal (50%) and striatal (15%). Perilesional diaschisis estimates were highly variable. Structures manifesting acute diaschisis atrophied on follow-up imaging. TD correlated with stroke volume (p=0.001). TD correlation to poor outcome (p=0.01) did not persist with correction for infarct volume. TD did not correlate with age at MRI. Method reliability was good (ρ >0.80). Conclusion: DWI diaschisis is common and measureable in NAIS. As a possible early imaging marker of network injury, larger studies are required to determine clinical relevance.