Quantification and comparison of 4D-flow MRI-derived wall shear stress and MRE-derived wall stiffness of the abdominal aorta.
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) WSMREand mean velocity; (3) WSMREand pulse wave velocity (PWV);( 4) WSMREand mean peak flow; and (5) WSMRE, WSSFlowand age using MRE and 4D-flow MRI in the abdominal aorta in healthy human subjects.



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.



A significant negative correlation was observed between: (1) ES WSMREand WSSFlowin both axial (r = -0.62; P = 0.006) and circumferential (r = -0.52; P = 0.016) directions; (2) ES WSMREand mean velocity (r = -0.58; P = 0.012); and (3) age and WSSFlowin 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 WSMREand PWV (r = 0.69; P < 0.0001); (2) ES WSMREand mean peak flow (r = 0.53; P = 0.016); and (3) ES WSMREand age (r = 0.63;P = 0.006).



The negative significant correlation between aortic WSSFlowand WSMREin normal volunteers demonstrates a relationship between WSMREand WSSFlow.



2 J. Magn. Reson. Imaging 2017;45:771-778.
Department of Radiology, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA.|Department of Internal Medicine-Division of Cardiology, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA.
Arunark
A
Kolipaka
Department of Radiology, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA.|Department of Biomedical Engineering, The Ohio State University, Columbus, Ohio, USA.
Venkata Sita Priyanka
VS
Illapani
Department of Radiology, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA.
Prateek
P
Kalra
Department of Radiology, Feinberg School of Medicine Northwestern University, Chicago, Illinois, USA.
Julio
0000-0001-9528-8155
J
Garcia
Center for Biostatistics, Department of Biomedical Informatics, Columbus, Ohio, USA.
Xiaokui
X
Mo
Department of Radiology, Feinberg School of Medicine Northwestern University, Chicago, Illinois, USA.|Biomedical Engineering, McCormick School of Engineering, Northwestern University, Chicago, Illinois, USA.
Michael
M
Markl
Department of Radiology, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA.|Department of Internal Medicine-Division of Cardiology, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA.
Richard D
RD
White
D000328:Adult; D000368:Aged; D001012:Aorta, Abdominal / Q000000981:diagnostic imaging* / Q000502:physiology*; D055424:Cardiac-Gated Imaging Techniques / Q000379:methods*; D055119:Elastic Modulus / Q000502:physiology; D054459:Elasticity Imaging Techniques / Q000379:methods*; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D007090:Image Interpretation, Computer-Assisted / Q000379:methods; D021621:Imaging, Three-Dimensional / Q000379:methods*; D018810:Magnetic Resonance Angiography / Q000379:methods*; D008875:Middle Aged; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D033081:Shear Strength / Q000502:physiology; D013314:Stress, Mechanical; D059289:Vascular Stiffness / Q000502:physiology*; D055815:Young Adult
4D-flow MRI; MR elastography; aortic wall stiffness; wall shear stress