The narnar app for contrast-enhanced ultrasound (CEUS) allows researchers to process and quantify perfusion studies of various organs (e.g., heart, kidney, liver, skeletal muscle), acquired across a range of research protocols, including cardiac realtime, cardiac triggered and generic realtime studies. Key features include: • Automatic and manual image alignment • Color-coding of digitally-subtracted images • Averaged and maximum intensity projection (MIP) imaging • Quantification and modeling of microvascular blood flow from time-videointensity curves, calculated in real-time. • Parametric imaging of blood flow and velocity