The Potential of Microvessel Density in Prediction of Infarct Growth: A Two-Month Experimental Study in Vessel Size Imaging

OBJECTIVES: Vessel size imaging is a novel technique to evaluate pathological changes of the microvessel density quantity Q and the mean vessel size index (VSI). As a follow-up study, we assessed these parameters for microscopic description of ischemic penumbra and their potentials in predicting lesion growth. METHODS: Seventy-five patients with a perfusion-diffusion mismatch were examined within 24 h from symptom onset. We defined three regions of interest: the initial infarct (INF), the ischemic penumbra (IPE), and the healthy region (HEA) symmetric to the IPE. For 23 patients with a 6th-day follow-up, IPE regions were divided into areas of infarct growth and areas of oligemia. RESULT: The median values of Q and VSI were: for INF 0.29 s(-1/3) and 15.8 μm, for IPE 0.33 s(-1/3) and 20.6 μm and for HEA 0.36 s(-1/3) and 17.4 μm. The Q in the IPE was significantly smaller than in HEA, and VSI was significantly larger. The Q with a threshold of 0.32 s(-1/3) predicted the final infarction with a sensitivity of 69% and a specificity of 64%. CONCLUSIONS: The reduced Q and increased VSI in the IPE confirmed our previous pilot results. Although Q showed a trend to identify the severity of ischemia in an overall voxel population, its potential in predicting infarct growth needs to be further tested in a larger cohort including a clear status of reperfusion and recanalization.