ABSTRACT
Flow convergence is a new method of color Doppler flow quantification.The effect of instrumental settings on flow convergence was investigated in an in-vitro model.The result showed that the flow convergence volume increased from 1.67±1.01 l/min to 2.20±1.35～2.30±1.43 l/min(P< 0.0001)when aliasing limit(same concept as Nyquist frequency)was changed from 23 cm/s to 12cm/s. There was no significant effect on flow convergence volume with the change of other instrumental settings,including Color gain,frame frequency,paket size,transmit power,transducer frequency,etc. Color Doppler flow convergence is influenced by aliasing limit.mainly because that the isovelocity surfaces in acceleration region developed by different aliasing limits are not always in the shape of hemisphere.The result suggested that besides the selection of aliasing limit fits to a hemispherical isovelocity surface,flow convergence is rarely affected by the other instrumental settings,and therefore is a relatively stable parameter of flow quantification.
ABSTRACT
Mitral effective regurgitant orifice area was measured by using color Doppler flow convergenee method,and its value on quantilarian of mitral insufficiency Was evaluated.The results showed that the parameter was correlated well with regurgitant volume,regurgitant fraction,color Doppler jet beginning width and jet area(r=0.89、0.84、0.82 and 0.67 respectively,P<0.001～0,0001).The accurate rate in differentiating mild and moderate from severe mitral regurgitation was 95.7% with the effective regurgitant orifice area≥30mm2.The effective regurgitant orifie area is a good parameter in quantification of naitral insufficiency.
ABSTRACT
The value of flow convergence and jet parameters in quantification of mitral regurgitation was estimated.The resultS showed that there were excellent correlations between mitral regurgitant flow convergence volume and mitral regurgitant volume,regurgitant fraction(r=0.87～0.93,P<0.0001).The correlations between jet parameters and regurgtant volume,regurgitant fraction were different,jet beginning width:r=0.88 and 0.81(P<0.0001),jet area : r=0.72 and O.50 and 0.61(P<0.05)and the ratio of jet area to left atrial area:r=0.27 and 0.29(P>0.05).The accurate rates of regurgitant flow convergence volume and jet beginning width in differentiating the grades of mitral regurgitation were 91.3～95.7%and 82.6～95.7%respectively.Mitrai regurgitant flow convergence volume is an accurate and reliable parameter in the quantification of mitral regurgitation.Jet parameters are of relative value in semiquantitation of mitral regurgitation,especially the jet beginning width.