Quantification of mitral regurgitation using PW Doppler and parallel beamforming

Delayed decision to replace or repair a defective mitral valve may lead to worsening ventricular function. A correct diagnosis of the severity of the regurgitation that results from a defective mitral valve is therefore important. This work takes advantage of the latest developments of ultrasound matrix probes and modern acquisition with many parallel beams to develop a Doppler-based method for a semi quantitative evaluation of mitral regurgitation. Parallel beamforming makes it possible to acquire several beams from closely-spaced regions simultaneously. Velocity spectra from all these regions can then be generated. The idea behind the proposed method is to combine velocity spectra from all the beams into one composite velocity spectrum and add information about the size of a potential regurgitant jet to the spectrum. This is achieved by color coding the composite velocity spectrum with colors representing the number of beams intersecting with the jet. Ultrasound data produced from simulations of flow in straight tubes were used to evaluate the method. The colored spectra were successful in giving information about the approximate size of the tubes. A colored spectrum generated from an in vivo ultrasound recording of a regurgitant jet is also presented, showing that the method is applicable for clinical use.