Quantification of cerebral blood flow with contrast enhanced ultrasound

In patients with acute brain injury, optimal cerebral perfusion and oxygenation is necessary. Therefore, adequate cerebral blood flow (CBF) is essential. Contrast enhanced ultrasound (CEUS) is a promising technique for bedside quantification of CBF. However, previous research showed that intra- and inter individual variability in the measurements was high. The clinical potential and repeatability of CEUS was assessed in a systematic review. Data on repeatability was scarce and the results heterogeneous. The aim of this study is to reduce variability. One possible cause of variation is the distance travelled after injection of the ultrasound contrast agent (UCA) to the brain. A reference closer to the brain might improve repeatability. Repeatability of CEUS quantification of CBF in the microcirculation by using the middle cerebral artery(MCA) as reference for arrival of ultrasound contrast agents (UCA) was studied. For both the macro- and microcirculation the internal carotid artery (ICA) might serve as a reference point. Simultaneous measurements with two probes can be performed by a Verasonics Vantage 256. In vitro measurements in a flow phantom were performed to investigate repeatability of perfusion.