Two Dimensional And Real-time Three-dimensional Echocardiography For Assessment Of Right Ventricular Volume: Accuracy Validated By Magnetic Resonance Imaging

Objective1、 To evaluate the accuracy of real-time three-dimensionalechocardiography(RT-3DE) for assessment of right ventricular(RV) volume.2、Todiscuss the method of two-dimensional echocardiography(2-DE) for measuring RVvolume and its accuracy.Methods A total of27healthy volunteers were examined by2-DE,RT-3DE andcardiac magnetic resonance imaging (cMRI) within24hours.2-DE adopts threemethods to measure RV volume, the first is Simpson, the second is the half ellipsoidmethod, and the last is biplane area-length method. RV volume by the half ellipsoidmethod was defined as π×X×Y×Z/8.X is the basement diameter of right ventricle.Y is the max distance from intersection of tricuspid valve and right ventricular freewall to RVOT, that is the distance from pulmonary valve to tricuspid valve. Z isright ventricle long diameter, that is the distance from right ventricular apex totricuspid valve. RV volume by biplane area-length method was defined as2/3×(theproduct of RV area from apical four-chamber view and the distance from pulmonaryvalve to tricuspid valve). In RT-3DE, RV volume were calculated respectively byTri-plane method and Tom-Tec4D RV-function CAP software. In cMRI, RV volumewas calculated by Argus software. Right ventricular end-diastolic and end-systolicvolume (RVEDV and RVESV) were measured respectively. Then the measurementof2-DE and RT-3DE were compared to cMRI.(The results of RT-3DE analyzed byTri-plane method is recorded as RT-3DEV1,while analyzed by Tom-Tec4DRV-Function CAP is recorded as RT-3DEV2)Results As compared to cMRI, Simpson, the half ellipsoid method and RT-3DEV1underestimated RVEDV and RVESV (p<0.05, each),with statistical significance.Biplane area-length method underestimated RVEDV and RVESV (p>0.05, each), with no statistical significance. RT-3DEV2underestimated RVEDV andoverestimated RVESV (p>0.05, each); but there had no significant statisticaldifference. The result of correlation analysis was as follows: RV volumes fromSimpson and RT-3DEV1had bad correlation with those from cMRI （P>0.05）.RVvolumes from RT-3DEV2,half ellipsoid method and biplane area-length methodcorrelated highly with those from cMRI(P<0.001),and the measurements byRT-3DEV2had better correlations than the others(RVEDV, r=0.85; RVESV, r=0.80).The three methods which correlated highly with cMRI were comparing with thecMRI results by Bland-Altman analysis. The results showed that each measurementby RT-3DEV2and biplane area-length method had a smaller limit of the agreementand a smaller difference average.Conclusion1、RT-3DE evaluated by Tom-Tec4D RV-Function CAP can quantifyRV volumes accurately.2、Among various methods of2-DE measurement, biplanearea-length method can quantify RV volumes accurately.