New reference-free, simultaneous motion-correction and quantification in dynamic contrast-enhanced ultrasound

Dynamic contrast-enhanced ultrasound (DCE-US) sequences are subject to motion which can disturb functional flow quantification. Methods that compensate for motion are therefore desirable and one possible strategy is to use motion correction.A reference-free registration methods is proposed that uses the flow information to improve the registration. This method is based on a realistic multiplicative model of the DCE-US noise. By maximizing likelihood in this model, motion and flow parameters are both estimated. First, the maximization is accomplished by iteratively estimating functional flow and motion. Then, a final registration based on a non-parametric temporal smoothing of the sequence is performed. This method is compared to a registration method where all the images of the sequence are registered with respect to a reference image chosen by an expert. The two methods are compared on simulated sequences with known motion added. The new method demonstrates significantly (p <; 0.05) lower Dice coefficients on the simulated data set. On the in vivo data set, it performs better in terms of mean Dice criteria for 80% of the sequences.