Simplified Bernoulli's method significantly underestimates XXXX drop.

@entity1 @entity3886 @entity120 @entity195
PURPOSE: To determine whether neglecting the flow unsteadiness in simplified Bernoulli's equation significantly affects the @entity120 drop estimation. MATERIALS AND METHODS: 3.0T magnetic resonance imaging (MRI) 4D velocity mapping was performed on four healthy volunteers, seven @entity1 with repaired tetralogy of Fallot, and thirteen @entity1 with @entity3886 repaired by arterial switch. Pulmonary transvalvular pressure drop was estimated based on two methods: General Bernoulli's Equation (GBE), ie, the most complete form; and @entity195 ( @entity195 ), known as 4V(2) . More than 2300 individual pressure drop measurements were used to compare the simplified and the general Bernoulli's methods. A linear mixed-effects model was employed for statistical analyses, fully accounting for clustering of observations among the methods and systolic phases. RESULTS: The simplified Bernoulli's method systematically underestimated the pressure drop compared to general Bernoulli's method during the entire systolic phase (P < 0.05), including the peak systole, where on average   pSBE/  pGBE=78%. CONCLUSION: The simplified Bernoulli method underestimated the pressure drop during all systolic phases in all the studied subjects. Therefore, it is necessary to take into account the flow unsteadiness for more accurate estimation of the pressure drop. J. Magn. Reson. Imaging 2015.
