Quantitative vs Semi-Quantitative Methods
The strong correlation between MR and prognosis underscores that the
assessment of MR severity is an important part for the decision making
in patients with IMR[14,15]. The recently updated
guidelines of the American Society of Echocardiography (ASE) recommended
an comprehensive method involving quantitative, semi-quantitative and
qualitative methods to confirm the degree of secondary MR, which was
divided into mild, moderate and severe[15-17]. The
color Doppler is the most commonly used method for quantifying MR. The
effective regurgitant orifice area (EROA), regurgitant volume and
fraction can be obtained by evaluating the distal MR jet area/left
atrium area ratio, vena contracta width and the proximal isovolumetric
surface area (PISA)[16]. Hoverer, there are some
limitations in using color Doppler to evaluate MR, such as eccentric or
multiple or non-holosystolic MR jet, non-circular regurgitant orifice,
non-hemispherical PISA, and the influence of load conditions[16].
Three dimensional (3D) imaging can provide supplementary information,
which is an adjunct to a comprehensive examination of 2D transesophageal
echocardiography (TEE). Specifically, it enhances the spatial
orientation and accuracy of linear measurements,
allows synchronous visualization of
orthogonal views, and allows the volumetric analysis of cardiac chambers
without geometric assumptions. 2D imaging can provide a wide range of
methods for the identification of cardiac anatomy, physiology and
structures of interest, while 3D TEE is used to obtain specific
supplementary quantitative and qualitative information from the
interested structures at present[18]. It is
recommended to use 3D echocardiography to overcome some of the pitfalls
encountered in 2D examination: the 3D image acquisition of MR enables
the direct planimetry of the vena contracta (i.e., regurgitant orifice
area) and thus optimizes the MR assessment in the case of
non-hemispherical PISA and multiple
jets[16,19,20].