Brain Perfusion Analysis in Rat Stroke Using Micro-ultrasound and Contrast Agent Bolus-Tracking

Ischemic stroke is a worldwilde health problem that justifies the need for investigations and for stroke animal models in determining new treatment and diagnostic imaging strategies Brain perfusion of a rat model for stroke was analyzed using a functional micro-ultrasound (fMUS) imaging technique associated with ultrasound contrast agent (UCA) bolus-tracking imaging sequence to quantify the hemodynamic parameters. Stroke was previously induced occluding the left middle cerebral artery and then the rats (n = 3) had a cranial window opened in on both sides of the Bregma and contrast-enhanced ultrasound perfusion imaging were acquired from both sides. The non-affected contralateral ROIs served as reference. The measured perfusion parameters AUC (area under the curve) and Pi (perfusion index) were significantly lower in the stroke side when compared with control. This technique provided an effective tool to quantify the microcirculation of the rat cerebral cortex, using UCAs for an improved visualization of capillary tissue blood flow in real time, which facilitated discrimination of viable from necrotic tissue.