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BioMed Research International
Volume 2017, Article ID 7087086, 8 pages
Research Article

Direct Assessment of Wall Shear Stress by Signal Intensity Gradient from Time-of-Flight Magnetic Resonance Angiography

1Research Institute of Clinical Medicine, Chonbuk National University, Biomedical Research Institute of Chonbuk National University Hospital, Jeonju, Jeonbuk 54907, Republic of Korea
2Equipment Qualification Center for Nuclear Power Plants, Korea Institute of Machinery and Materials, Daejeon 34103, Republic of Korea
3Department of Neurology, Chonbuk National University Medical School and Hospital, Jeonju, Jeonbuk 54907, Republic of Korea
4Pixoneer Geomatics, Inc., Daejeon 34126, Republic of Korea
5Department of Radiology, Chonbuk National University Medical School and Hospital, Jeonju, Jeonbuk 54907, Republic of Korea
6Department of Mechanical Engineering and Mechanics, Drexel University, Philadelphia, PA 19104, USA

Correspondence should be addressed to Seul-Ki Jeong;

Received 8 March 2017; Revised 30 June 2017; Accepted 12 July 2017; Published 16 August 2017

Academic Editor: Dobrin Vassilev

Copyright © 2017 Kap-Soo Han et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


The aim of the study was to calculate the arterial wall signal intensity gradient (SIG) from time-of-flight MR angiography (TOF-MRA) and represent arterial wall shear stress. We developed a new algorithm that uses signal intensity (SI) of a TOF-MRA to directly calculate the signal intensity gradient (SIG). The results from our phantom study showed that the TOF-MRA SIG could be used to distinguish the magnitude of blood flow rate as high (mean SIG ± SD, 2.2 ± 0.4 SI/mm for 12.5 ± 2.3 L/min) and low (0.9 ± 0.3 SI/mm for 8.5 ± 2.6 L/min) in vessels (). Additionally, we found that the TOF-MRA SIG values were highly correlated with various flow rates (, ). Remarkably, the correlation coefficient between the WSS obtained from the computational fluid dynamics (CFD) analysis and the TOF-MRA SIG was greater than 0.8 in each section at the carotid artery ( for all β values). This new technique using TOF-MRA could enable the rapid calculation of the TOF-MRA SIG and thereby the WSS. Thus, the TOF-MRA SIG can provide clinicians with an accurate and efficient screening method for making rapid decisions on the risk of vascular disease for a patient in clinical practice.