Ultrasound biomicroscopy in the quantification of brain perfusion parameters of a rat stroke model: Analysis of contrast agent bolus kinetic dynamics

Background: Ischemic stroke represents a significant global health concern, necessitating thorough investigations and the utilization of stroke animal models to explore novel treatment modalities and diagnostic imaging techniques. New method: Ultrasound biomicroscopy (BMU), operating at a center frequency of 21 MHz, along with ultrasound contrast agents (UCAs), was used to quantify microcirculation cerebral blood flow in a rat model of ischemic stroke. The microcirculation parameters were derived from time intensity curve (TIC) plots obtained based on UCA-bolus kinetics. Results: Semiquantitative perfusion-related parameters were assessed. The TIC curves showed differences in amplitude when compared intra-animal between the left and right sides, and three situations were observed: normal perfusion, hypoperfusion, and nonperfusion. ROC analysis of delays between the left and right time intensity peak (TIP) for regions of interest (ROIs) in the control and stroke-hypoperfusion groups revealed an optimal cutpoint of 0.39 s to indicate when hypoperfusion is occurring in rats, with a sensitivity of 93.33 % and a specificity of 80 %. Comparison with existing method(s): Ultrasound perfusion imaging through the temporal bone window has been clinically applied to stroke patients using a UCA bolus for TIC analysis. TIC parameters were correlated with MRIand CT-based measurements. Conclusions: This investigation quantified cerebral blood flow in a rat model of ischemic stroke by measuring microcirculation parameters. The study demonstrated the efficacy of this approach as a valuable tool for conducting preclinical studies.

Automated summary

This study quantified microcirculation cerebral blood flow in a rat model of ischemic stroke using ultrasound biomicroscopy and ultrasound contrast agents. The results showed high sensitivity and specificity of this method, making it a valuable tool for preclinical studies.