Perivascular Space Detection by Using Contrast-enhanced Ultrafast Power Doppler Imaging: A Feasibility Study

Studies have shown that the perivascular space (PVS) plays an important role in regulation of cerebrospinal fluid (CSF) flow and elimination of endogenous metabolites, and the fluid dynamics of the PVS is related to certain physiological and pathological conditions. Benefiting from high-frame-rate plane wave imaging and advanced clutter filters, ultrafast power Doppler imaging (uPDI) has been developed to visualize microvessels which are invisible using conventional power Doppler imaging. In this study, we explore the feasibility of uPDI in the detection of PVS by injecting microbubbles (MBs) into the cisterna magna of rats and acquiring the ultrasound data in the sections of cerebral ventricle and common carotid artery. Results showed that aggregation of MBs was observed in the cerebral ventricle, which proved that there is a pathway for the CSF flow between the cisterna magna and the cerebral ventricle. After unilateral ligation of the common carotid artery, region of the PVS became larger than before MBs injection and ligation. It suggests that unilateral ligation of the common carotid artery causes unilateral cerebral ischemia, which leads to influx of CSF with MBs into the PVS and further causes expansion of PVS. In conclusion, this study demonstrates that uPDI can be used in the detection of PVS and has the potential to monitor the hemodynamic of PVS in the pathological conditions.