Abstract 17011: Mitral Annulus Sweep Volume Velocity Measured with Cine MRI Correlates Strongly with Mitral Annulus Velocity Measured Using Tissue Doppler Echocardiography

Abstract

Introduction: Tissue doppler imaging (TDI)-based measures of early diastolic mitral annulus velocity (E') is often used to assess diastolic function. Cardiac MRI has higher spatial resolution with potential for more accurate characterization of mitral annulus motion. In this study, cine MRI was used to calculate early diastolic sweep volume velocity (V'), a three-dimensional variable analogous to E'. We hypothesized that this MRI-based V' measurement would correlate with TDI-based E'.

Methods: We retrospectively obtained routine cardiac cine MR and TDI studies of 23 patients with known hypertrophic cardiomyopathy (HCM) (57.5 +/- 5.5 years; 3T Tim Trio, Siemens). Standard TDI was used to measure the mitral annulus velocity (E') at the septum . To calculate V', MR images were obtained in 2-, 3-, and 4-chamber longitudinal views. The two focal locations of the MA were identified on each longitudinal view, creating six spatial points. A 3D representation of the MA was reconstructed from these points. The volume swept by the annulus as it moved throughout the cardiac cycle was tracked to obtain the 'Sweep Volume Profile' (Figure 1a). This profile measured a combination of radial and longitudinal distance traversed by the MA over time, so its slope was analogous to velocity of MA motion. Early diastolic sweep volume velocity (V') was measured as the maximum slope during early diastole. Mean and standard deviation E' and V' were calculated, and a Spearman rank test was performed to correlate the two variables.

Results: Mean E' was 9.7 +/- 4.0 cm/s, and mean V' was 63.7 +/- 27.4 cm3/s. There was significant positive correlation between the TDI E' and CMR V' measurements (r= 0.715, p < 0.001). (figure 1b)

Conclusions: Cine MRI-based sweep volume velocity correlated very well with TDI-based mitral annulus velocity during early diastole. In conclusion, cine MRI provides an alternative approach to assess mitral annulus motion with potential for more accurate and detailed characterization.