TRADITIONAL POSTER - ismrm

Poster Sessions
Flow Quantification: Vessel Function
Hall B Wednesday 13:30-15:30
1331. T 2 -Weighted Fourier Velocity Encoding: MR Oximetry in Small Vessels
Christopher Marek Wernik 1 , Venkat Ramanan 2 , Graham A. Wright 1,2 , Christopher K. Macgowan 1,3
1 Dept. of Medical Biophysics, University of Toronto, Toronto, ON, Canada; 2 Imaging Research, Sunnybrook Health Sciences Centre,
Toronto, ON, Canada; 3 Dept. of Diagnostic Imaging, Hospital for Sick Children, Toronto, ON, Canada
MR oximetry based on quantitative T2 measurement is a noninvasive technique for measuring blood oxygen saturation. However, partial volume effects
limit T2 accuracy in narrow vessels or impose long scan times at reduced SNR. In this study, we propose an improved technique which uses Fourier velocity
encoding to control for partial volume effects and test its feasibility using an apparatus that mimics constant blood flow in a vessel. The results show that the
proposed technique is more accurate than conventional MR oximetry in the presence of partial volume effects. Considerations for in vivo application are
discussed.
1332. Evaluation of Different Techniques for Measuring Pulse Wave Velocity Using 3 Tesla MRI
Elsayed H. Ibrahim 1 , Kevin R. Johnson 1 , Jean M. Shaffer 1 , Richard D. White 1
1 University of Florida, College of Medicine, Jacksonville, FL, United States
Arterial stiffness can be noninvasively estimated by measuring pulse wave velocity(PWV) from velocity-encoded MR images using different methods:
transit-time(TT), flow-area(QA), and cross-correlation(XC). However, the reproducibility and comparison of these different techniques have not yet been
studied in a large diverse group of patients for relative durability and reproducibility, especially at 3T field. In this work, the aortic PWV is measured in 50
patients, representing a wide range of cardiovascular conditions, to assess inter-observer, intra-observer, inter-scan, and inter-method variabilities using 3T
MRI. The TT method resulted in the most-reproducible measurements and required the shortest processing-time, followed by XC and QA.
1333. Accelerated Dual Velocity Encoded Phase Contrast VIPR
Elizabeth Janus Nett 1 , Kevin M. Johnson 1 , Christopher J. Francois 2 , Darren Lum 2 , Oliver Wieben, 2,3
1 Medical Physics, University of Wisconsin , Madison, WI, United States; 2 Radiology, University of Wisconsin, Madison, WI, United
States; 3 Medical Physics, University of Wisconsin, Madison, WI, United States
We present a method for improving the VNR in 3D radial undersampled phase contrast exams using an accelerated dual Venc acquisition. This method will
allow for more accurate velocity measurements and advanced hemodynamic analysis, particularly in vascular areas that have wide ranges of velocities of
interest such as arterial and venous systems .
1334. Probabilistic Flow Connectivity Mapping
Ola Friman 1 , Anja Hennemuth 1 , Andreas Harloff 2 , Jelena Bock 3 , Michael Markl 3 , Heinz-Otto Peitgen 1
1 Fraunhofer MEVIS, Bremen, Germany; 2 Neurology and Clinical Neurophysiology, Albert-Ludwigs Universität, Freiburg, Germany;
3 Diagnostic Radiology, Medical Physics, Albert-Ludwigs Universität, Freiburg, Germany
Standard techniques for visualizing and quantifying flow data obtained with phase contrast (PC) MRI treat the measurements as if they were free of noise.
This practice may lend the results a false sense of precision. This work contributes a flow connectivity mapping algorithm that models the noise in PC MRI
velocity measurements and visualizes the flow uncertainty as a probabilistic flow distribution. New probabilistic measures such as the assignment of
likelihoods to flow pathways to evaluate mixing of blood, or to quantify embolization probabilities in stroke and infarction, are also envisaged.
1335. Age-Related Changes of Regional Pulse Wave Velocity in the Descending Aorta Using Fourier Velocity
Encoded MR M-Mode
Valentina Taviani 1 , Stacey S. Hickson 2 , Christopher J. Hardy 3 , Andrew James Patterson 1 , Carmel M.
McEniery 2 , Ian B. Wilkinson 2 , Jonathan Harvey Gillard 1 , Martin J. Graves 1
1 Department of Radiology, University of Cambridge, Addenbrooke's Hospital, Cambridge, United Kingdom; 2 Clinical Pharmacology
Unit, University of Cambridge, Addenbrooke's Hospital, Cambridge, United Kingdom; 3 GE Global Research, Niskayuna, NY, United
States
Age-related changes of regional aortic compliance play a crucial role in the pathophysiology of cardiovascular disease. Fourier velocity encoded (FVE) M-
mode can produce Doppler-like time-velocity traces with high temporal and spatial resolution along relatively straight arterial segments. In this work, FVE
M-mode was used to measure global and regional pulse wave velocity (PWV) in the descending aorta of 56 healthy subjects. A significant nonlinear
relationship between overall PWV and age was found (r2=0.73, p