Non-Invasive Intraventricular Diastolic Pressure Mapping Estimated with 4D-Flow Cardiac MRI

The intraventricular pressure difference (IVPD) created between the base and the apex of the left ventricle (LV) is one of the main determinants of diastolic filling. It can be estimated non-invasively using Color Doppler M-mode echocardiography to assess the diastolic function. However, as this method has limitations in terms of velocity sampling along a line within the LV, in recent years some attempts have been made to estimate IVPD with 4D-Flow cardiac magnetic resonance imaging that considers the temporal blood flow velocity in the three spatial directions (3D + t). In this work, a method has been proposed to estimate and visualize an IVPD mapping in 3D with 4D-Flow using the Navier Stokes equations. To evaluate the method, 8 young and 8 elderly healthy volunteers (age 23 ± 3 vs 72 ± 4 years) were analyzed retrospectively and IVPD in the peak of E-wave was compared between them. In the elderly group, lower E-IVPD values were found compared to young volunteers (0.9 ± 0.3 mmHg vs 1.5 ± 0.4 mmHg, p < 0.01). Furthermore, E-wave and A-wave peak velocity were calculated. The first was lower in elderly people than in the young (43 cm/s vs 70 cm/s, p < 0.001), while the second was greater in the elderly (45 cm/s vs 29 cm/s, p < 0.001). Accordingly, E/A ratio was lower in the elderly group (2.5 ± 0.7 vs 1.0 ± 0.3). This study explored a non-invasive method to visualize a LV IVPD map using 4D-Flow studies and showed that the gradients between the mitral valve and the apex significantly decreased with aging.