Evaluation of 3-D colour Doppler ultrasound for the measurement of proximal isovelocity surface area

Three-dimensional (3-D) colour Doppler ultrasound (US) enables flow rate es timation across a diseased valve without the need for a priori geometric as sumptions. This study quantitatively evaluates the accuracy of 3-D colour D oppler US for measuring the flow rate (8.3-75 mL/s) through a valve using t he proximal how convergence field, Flow rate measurements by this 3-D techn ique underestimate how through finite circular orifices due to two major so urces of error: 1. surface area slicing technique (18.3% +/- 3.8%) and 2. D oppler angle effect(41.0% +/- 1.5%). Combined total underestimation is 51% +/- 3.3%. To utilize 3-D US, the development of an improved proximal isovel ocity surface area (PISA) measurement technique and a correction factor for the Doppler angle effect is required. (C) 2000 World Federation for Ultras ound in Medicine & Biology.