Brain PERfusion Evaluation by Contrast-Enhanced UltraSound

Contrast-enhanced ultrasound perfusion imaging (PerCEUS) will be performed by a dedicated study team. The transcranial color duplex sonography will be performed with a 1-5 MHz dynamic sector array (S5-1) from a Philips Epiq 7 ultrasound machine (Philips Healthcare, Andover, MA). The field-of-view will be set to an imaging depth of 150 mm in a sector angle of 90°. The imaging plane will be then tilted to the diencephalic, in which the frontal horns of the side ventricles and the third ventricle serve as landmarks and where the anterior and posterior middle cerebral artery (MCA) territory and the basal ganglia (BG) as region of interest could be identified without artefacts from major vessels. High mechanical index bolus imaging will be performed from the sanest side of the head. Data acquisition of 45 seconds will be recorded immediately after the beginning of the contrast ultrasound imaging, using a mechanical index (MI) setting of 1.1 and a frame rate of 33 Hz.