Abstract TP241: Correlation of Smartphone Pupillometry Parameters With NIH Stroke Scale and CT Perfusion Core to Penumbra Volume Ratio

Abstract

Introduction: Objective pupillometry involves the quantitative measurement of the pupillary light reflex (PLR). We investigated changes in the PLR, National Institutes of Health Stroke Scale (NIHSS), and core infarct to penumbra volume ratio in acute large vessel occlusion (LVO). Methods: A smartphone pupillometry application was used. Subjects with LVO were enrolled prior to intervention. PLR parameters obtained included: maximum diameter (MAX), minimum diameter (MIN), percent change (CHANGE), latency (LAT), mean constriction velocity (MCV), maximum constriction velocity (MAXCV), and mean dilation velocity (MDV). Computed Tomography Perfusion (CTP) and NIHSS values were also obtained prior to intervention. Pearson correlation was performed between the PLR parameters, NIHSS, and CTP core infarct to penumbra volume ratio. This ratio was used instead of the traditional mismatch ratio due to the presence of 0 mL core infarcts and a desire to bound these at a ratio of zero instead of leaving them unbounded at an infinite ratio value for analysis. Results: N=22 subjects were enrolled with mean age 69 years. A significant negative correlation between NIHSS and CHANGE (p=0.04) as well as MCV (p=0.005), was observed (Table 1). A significant negative correlation between the core infarct to penumbra volume ratio on CTP and MAX (p=0.04), CHANGE (p<0.001), and MCV (p=0.04) was observed (Table 2). Conclusions: This study illustrates the potential value of smartphone pupillometry as a bedside test in the early workup of LVO. Larger trials are needed.