TRADITIONAL POSTER - ismrm

Poster Sessions
1354. MRI Measurements of Wall Shear Stress in the Descending Aorta Downstream of an Ascending Aortic
Aneurysm
Andrew L. Wentland 1,2 , Erik T. Bieging 2 , Alex Frydrychowicz 2 , Thomas M. Grist 1,2 , Oliver Wieben 1 , Chris
J. Francois 2
1 Medical Physics, University of Wisconsin School of Medicine & Public Health, Madison, WI, United States; 2 Radiology, University
of Wisconsin School of Medicine & Public Health, Madison, WI, United States
While studies have shown that high wall shear stress (WSS) creates aneurysms and low WSS contributes to aneurysmal growth, the downstream effects of
an aneurysm on WSS remain unknown. In this study we compared measurements of peak WSS in the descending aorta of volunteers and in patients with an
ascending aortic aneurysm. Measurements of peak WSS were lower in patients than in normal volunteers; the percent increase in WSS from diastolic
baseline to peak systole was greater in volunteers than in patients. The long-term effects of lower WSS in the patients require further investigation.
1355. MRI Measurements of Wall Shear Stress in the Infrarenal Aorta in the Young and Old
Andrew L. Wentland 1 , Erik T. Bieging 2 , Alex Frydrychowicz 2 , Mark L. Schiebler 2 , Thomas M. Grist 1 , Oliver
Wieben 1 , Chris J. Francois 2
1 Medical Physics, University of Wisconsin School of Medicine & Public Health, Madison, WI, United States; 2 Radiology, University
of Wisconsin School of Medicine & Public Health, Madison, WI, United States
While studies have shown that low wall shear stress (WSS) contributes to the formation of atherosclerotic plaques and that low WSS correlates with high
atherosclerotic indices, WSS in the elderly, who have a greater incidence of atherosclerosis, remains unknown. In this study, we compared measurements of
peak WSS in the infrarenal aorta in young and old subjects. Measurements of peak WSS tended to be lower in the old than the young, although this trend
was not statistically significant. The percent increase in WSS from diastolic baseline to peak systole was not significantly different between young and old
subjects.
1356. Evaluation of the Coherence of Local Indices of Aortic Stiffness Calculated from Magnetic Resonance
Data Using a Theoretical Model Derived from the Moens-Korteweg Equation
Anas Dogui 1 , Nadjia Kachenoura 2 , Alain De Cesare 2 , Muriel Lefort 1 , Mourad Bensalah 1,3 , Alain Herment 1 ,
Boutouyrie Pierre 4,5 , Elie Mousseaux 1,6
1 INSERM U678 ,UPMC, Paris, France; 2 INSERM U678,UPMC, Paris, France; 3 Radiology department, APHP, European Hospital
Georges Pompidou,, Paris, France; 4 INSERM U970, Paris, France; 5 Pharmacology department, APHP, European Hospital Georges
Pompidou, Paris, France; 6 Radiology department, APHP, European Hospital Georges Pompidou, Paris, France
Aortic stiffness indices such as the local aortic deformability (AD) and the regional aortic pulse wave velocity (PWV) were assessed directly and noninvasively
from morphological and hemodynamic magnetic resonance data on 40 subjects. The consistency of these indices was well described by a
theoretical model derived from the Moens-Korteweg equation. A global aortic deformability (ADe) was estimated from PWV and carotid pulse pressure
using the theoretical model and gave a similar description of stiffness of the ascending aorta as the local AD.
1357. Wall Shear Stress Analysis in Ascending Aortic Aneurysms Using PC VIPR
Erik Tierney Bieging 1 , Benjamin R. Landgraf 1 , Alex Frydrychowicz 1 , Kevin M. Johnson 2 , Oliver Wieben, 12 ,
Christopher J. Francois 1
1 Radiology, University of Wisconsin - Madison, Madison, WI, United States; 2 Medical Physics, University of Wisconsin - Madison,
Madison, WI, United States
Wall shear stress (WSS) was analyzed in patients with ascending aortic aneurysms (AscAA) using phase-contrast MRI with 3D radial undersampling (PC
VIPR), a 4D flow technique. Time resolved WSS was compared between patients with AscAA and healthy volunteers with normal aortic anatomy. Patients
with AscAA were shown to have increased diastolic WSS, decreased WSS change over the cardiac cycle, and slower onset of systolic WSS. Additionally,
spatial changes in WSS in AscAA were demonstrated.
1358. Quantification of Left and Right Ventricular Kinetic Energy Using Four Dimensional Intracardiac
Magnetic Resonance Imaging Flow Measurements
Marcus Carlsson 1 , Einar Heiberg 1 , Johannes Töger 1 , Karin Markenroth 2 , Freddy Ståhlberg 3 , Håkan
Arheden 1
1 Clinical Physiology, Lund University Hospital, Lund, Skane, Sweden; 2 Philips Medical Systems, Lund University Hospital, Lund,
Skane, Sweden; 3 Radiation Physics, Lund University Hospital, Lund, Skane, Sweden
This study has demonstrated the feasibility of a new method for non-invasive quantification of biventricular kinetic energy using 4D phase contrast velocity
encoded CMR. Three energy peaks of the LV and RV were seen in healthy subjects. Interestingly, the systolic energy was higher in the RV compared to the
LV and in contrast the energy during early diastole was higher in the LV compared to the RV.
1359. A Novel MRI Framework for the Quantification of Any Moment of Arbitrary Velocity Distributions
Petter Dyverfeldt 1 , Andreas Sigfridsson 1 , Hans Knutsson 1 , Tino Ebbers 1
1 Linköping University and Center for Medical Image Science and Visualization (CMIV), Linköping, Sweden
Under the assumption that the intravoxel velocity distribution is symmetric about its mean, the well-known MRI phase-difference method permits an
estimation of the mean velocity of a voxel. The mean velocity corresponds to the first moment of the velocity distribution. Here, a novel framework for the
quantification of any moment of arbitrary spin velocity distributions is presented. Simulations on realistic velocity distributions demonstrate its application.
The presented moment framework may assist in improving the understanding of existing MRI methods for the quantification of flow and motion and serve
as a basis for the development of new methods.