A Doppler ultrasound system, comprising: an ultrasound probe configured to transmit an ultrasound beam through a bodily vessel for generating imaging data illustrative of an ultrasound image of a fluid flow through the bodily vessel; a vessel Fiber-Optic RealShape sensor configured to be introduced into the bodily vessel for generating sensing data informative of a reconstructed shape of the vessel Fiber-Optic RealShape sensor within the bodily vessel, relative to the ultrasound probe ; a Fiber-Optic RealShape sensor controller configured to control a generation of the reconstructed shape of vessel Fiber-Optic RealShape sensor , an ultrasound probe controller configured to generate imaging data , from received ultrasound wave, illustrative of the ultrasound image of bodily vessel ; characterized by a Doppler ultrasound controller being configured, in response to the generation o: the imaging data by the ultrasound probe controller and in response to the generation of the sensing data by the vessel Fiber-Optic RealShape sensor , to estimate a parametric relationship between the fluid flow through the bodily vessel and a transmission of the ultrasound beam through the bodily vessel by the ultrasound probe, based on a registration between the ultrasound probe and the vessel Fiber-Optic RealShape sensor , wherein the Doppler ultrasound controller is configured to estimate the parametric relationship from a shape of the bodily vessel as well as a position and an orientation of the bodily vessel within the ultrasound image from said sensing data and imaging data , and in that the Doppler ultrasound controller is further arranged to derive a Doppler measurement of the fluid flow through the bodily vessel from said estimation of the parametric relationship. an ultrasound probe configured to transmit an ultrasound beam through a bodily vessel for generating imaging data illustrative of an ultrasound image of a fluid flow through the bodily vessel; a vessel Fiber-Optic RealShape sensor configured to be introduced into the bodily vessel for generating sensing data informative of a reconstructed shape of the vessel Fiber-Optic RealShape sensor within the bodily vessel, relative to the ultrasound probe ; a Fiber-Optic RealShape sensor controller configured to control a generation of the reconstructed shape of vessel Fiber-Optic RealShape sensor , an ultrasound probe controller configured to generate imaging data , from received ultrasound wave, illustrative of the ultrasound image of bodily vessel ; characterized by a Doppler ultrasound controller being configured, in response to the generation o: the imaging data by the ultrasound probe controller and in response to the generation of the sensing data by the vessel Fiber-Optic RealShape sensor , to estimate a parametric relationship between the fluid flow through the bodily vessel and a transmission of the ultrasound beam through the bodily vessel by the ultrasound probe, based on a registration between the ultrasound probe and the vessel Fiber-Optic RealShape sensor , wherein the Doppler ultrasound controller is configured to estimate the parametric relationship from a shape of the bodily vessel as well as a position and an orientation of the bodily vessel within the ultrasound image from said sensing data and imaging data , and in that the Doppler ultrasound controller is further arranged to derive a Doppler measurement of the fluid flow through the bodily vessel from said estimation of the parametric relationship. <EOS>