CT based Water Uptake Quantification per Time predicts Malignant Middle Cerebral Artery Infarctions

Purpose: Early selection of patients with acute McA infarctions at risk for malignant edema has a high clinical relevance in order to initiate timely decompressive surgery, which improves outcome. It was shown that water uptake per volume contributing to space-occupying ischemic edema can be quantitatively measured in ct by relative density changes. We hypothesize that net water uptake (NWU) per time interval from onset to imaging can predict malignant edema. Methods: 151 stroke patients with M1-MCA infarctions and complete admission multimodal ct protocol were included in the retrospective analysis. 29/151 patients developed a malignant edema as defined endpoint in follow-up imaging targeted at 48 hours including decompressive surgery and/or death as a direct implication of stroke. NWU was quantified based on relative ct density decrease in the admission ct (Minnerup et al. 2016). Results: the mean%-NWU for non-malignant infarctions was 7.1% ([+ or -] 5.2) and 18.0% ([+ or -] 5.7) in malignant infarctions. The area under the curve (AUc) for distinguishing these patient groups according to %-NWU was 0.93 (95% CI, 0,87-0,97). A logistic regression model adjusted for sex, age and NIHSS achieved a Sensitivity of 100% and Specificity of 82,8% using NWU in a non-linear time relationship. Conclusion: Water uptake per hour is a suitable early surrogate marker for malignant edema and could help to predict malignant infarctions. This imaging biomarker might help to identify patients with fast progressing edema.