Hypoperfusion ratio predicts infarct growth during transfer for thrombectomy

We hypothesized that automated assessment of collaterals on computed tomography perfusion can predict the rate of infarct growth during transfer from a primary to a comprehensive stroke center for endovascular stroke treatment. We identified consecutive patients (N=28) and assessed their collaterals based on the hypoperfusion intensity ratio (HIR) prior to transfer. Infarct growth rate was strongly correlated with HIR (r=0.78, p<0.001). Receiver operating characteristic analysis identified HIR0.5 as optimal for predicting infarct growth. Patients with HIR0.5 had a median infarct growth rate of 10.1ml/h (interquartile range [IQR]=6.4-18.4) compared with 0.9ml/h (IQR=0-2.8; p<0.001) in patients with HIR<0.5. Patients with HIR0.5 had an 83% probability of significant core growth, whereas patients with HIR<0.5 had an 88% probability of core stability. These preliminary data have the potential to guide decision making regarding whether repeat brain imaging should be performed after transfer to a comprehensive stroke center. Ann Neurol 2018;84:616-620