Influence of injection speed of contrast agent on perfusion analysis using fast bolus method

Dynamic contrast enhanced ultrasound (DCE-US) imaging is a promising modality for noninvasive assessment of various tissue kinetic parameters (e.g. time-to-peak, mean transit time (MTT), blood flow etc.). These parameters can be used for diagnosis of pathological tissue functions caused by different diseases. Fast bolus method is based on the fast injection of bolus of contrast agent and repeated imaging with low MI to track contrast agent in tissue of interest (TOI) in time. Mathematical model fitting is an important part of this analysis, which usually presumes that injected bolus is infinitely short, but in practice this is impossible. The main aim of this paper is an analysis of influence of bolus injection rate on MTT estimated by different fitting model. We discover that using a finite-width bolus causes systematic error in MTT estimation.