Analysis of Doppler ultrasound time frequency images using deformable models

Doppler ultrasound is a widely used technique to study the blood flow velocity and evaluate the severity of an arterial stenosis. The envelope of maximal frequencies in the power spectrum of the signal represents important information for the characterisation of the blood flow. Classical signal processing techniques usually rely on local observations (i.e. computed at a given time instant). Therefore, they are quite unreliable in the presence of low-level signals and/or in noisy environments. In this article, we propose a new automatic method to estimate the maximal frequency profile. It is derived from image processing techniques and based on deformable models. The application of this more global method to real noisy signals gives very promising results, according to a clinical expert and in comparison with the results that we obtain with other classical methods