Work

Quantification and comparison of 4D‐flow MRI‐derived wall shear stress and MRE‐derived wall stiffness of the abdominal aorta

Year: 2016

Type: article

Abstract: Purpose Aortic wall shear stress (WSSFlow) alters endothelial function, which in‐turn changes aortic wall stiffness leading to remodeling in different disease states. Therefore, the aims of this study are to determine normal physiologic correlations between: (1) Magnetic Resonance Elastography (MRE)‐derived aortic wall stiffness (WSMRE) and WSSFlow; (2) WSMRE and mean velocity; (3) WSMRE and pulse wave velocity (PWV);( 4) WSMRE and mean peak flow; and (5) WSMRE, WSSFlow and age using MRE and 4D‐flow MRI in the abdominal aorta in healthy human subjects. Materials and Methods Cardiac‐gated aortic MRE and 4D‐flow MRI data were acquired in 24 healthy volunteers using a 3 Tesla scanner. For MRE, 70 Hz external motion was applied to obtain wave images in all spatial directions in a separate breathhold. Whereas, 4D‐flow data was acquired under free‐breathing. Wave images in all the directions were processed to obtain three‐dimensional‐weighted stiffness map at end‐systole (ES). WSSFlow, mean velocity, PWV and mean peak flow were obtained using 4D‐flow data. Pearson correlation was performed to determine association between all variables. Results A significant negative correlation was observed between: (1) ES WSMRE and WSSFlow in both axial (r = ‐0.62; P = 0.006) and circumferential (r = ‐0.52; P = 0.016) directions; (2) ES WSMRE and mean velocity (r = ‐0.58; P = 0.012); and (3) age and WSSFlow in both axial (r = ‐0.71; P < 0.0001) and circumferential (r = ‐0.58; P = 0.0012) directions. A significant positive correlation was observed between: (1) ES WSMRE and PWV (r = 0.69; P < 0.0001); (2) ES WSMRE and mean peak flow (r = 0.53; P = 0.016); and (3) ES WSMRE and age (r = 0.63;P = 0.006). Conclusion The negative significant correlation between aortic WSSFlow and WSMRE in normal volunteers demonstrates a relationship between WSMRE and WSSFlow. Level of Evidence: 2 J. Magn. Reson. Imaging 2017;45:771–778.

Source: Journal of Magnetic Resonance Imaging

DOI: 10.1002/jmri.25445