Association between Edema and Contrast Extravasation on Immediate Post-Endovascular Treatment Dual-Energy CT and Final Brain Infarction

BACKGROUND AND PURPOSE: The evaluation of hypodense ischemic areas on early post-endovascular treatment (EVT) CT imaging may be hindered by contrast extravasation (CE). On the other hand, it has been suggested that regions with CE often progress to infarction. Dual-energy CT can provide multiple reconstructions, including iodine overlay maps (IOM) and virtual non-contrast (VNC), which may aid in the evaluation of CE and hypodensities. This study aims to assess whether CE on IOM, or hypodensities on VNC reconstructions correlate better with infarction on follow-up imaging compared to hypodensities on mixed-energy reconstructions (comparable to NCCT). MATERIALS AND METHODS: EVT records in our centre from 2010-2019 were screened. The main inclusion criteria were anterior circulation stroke, DECT within three hours post-EVT, and follow-up imaging performed after DECT. On DECT IOM, hyperdense CE was scored according to the ASPECTS (CE-ASPECTS). Likewise, hypodensities were scored on VNC (VNC-ASPECTS) and mixed-energy reconstructions (NCCT-ASPECTS) of DECT, as well as on the last follow-up scan performed during hospitalisation (FU-ASPECTS). Kendall's tau correlation was used to assess the relationship between the various DECT ASPECTS measures and the FU-ASPECTS. Sensitivity, specificity, positive and negative predictive value, and accuracy were assessed. For the VNC-ASPECTS, the average sensitivity, specificity, positive- and negative predictive value, and accuracy were 67%, 85%, 86%, 74%, and 81%, respectively. CONCLUSIONS: On immediate post-EVT imaging, hypodensities on VNC-reconstructions correlate best to infarction on follow-up imaging. CE is only weakly correlated to follow-up infarction. These results may provide an additional argument for using DECT imaging in the evaluation of the early post-EVT brain parenchyma.