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Proceedings Paper

Dynamic three-dimensional phase-contrast technique in MRI: application to complex flow analysis around the artificial heart valve
Author(s): Soo Jeong Kim; Dong Hyuk Lee; Inchang Song; Nam Gook Kim; Jae-Hyeung Park; JongHyo Kim; Man Chung Han; Byong Goo Min
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Paper Abstract

Phase-contrast (PC) method of magnetic resonance imaging (MRI) has bee used for quantitative measurements of flow velocity and volume flow rate. It is a noninvasive technique which provides an accurate two-dimensional velocity image. Moreover, Phase Contrast Cine magnetic resonance imaging combines the flow dependent contrast of PC-MRI with the ability of cardiac cine imaging to produce images throughout the cardiac cycle. However, the accuracy of the data acquired from the single through-plane velocity encoding can be reduced by the effect of flow direction, because in many practical cases flow directions are not uniform throughout the whole region of interest. In this study, we present dynamic three-dimensional velocity vector mapping method using PC-MRI which can visualize the complex flow pattern through 3D volume rendered images displayed dynamically. The direction of velocity mapping can be selected along any three orthogonal axes. By vector summation, the three maps can be combined to form a velocity vector map that determines the velocity regardless of the flow direction. At the same time, Cine method is used to observe the dynamic change of flow. We performed a phantom study to evaluate the accuracy of the suggested PC-MRI in continuous and pulsatile flow measurement. Pulsatile flow wave form is generated by the ventricular assistant device (VAD), HEMO-PULSA (Biomedlab, Seoul, Korea). We varied flow velocity, pulsatile flow wave form, and pulsing rate. The PC-MRI-derived velocities were compared with Doppler-derived results. The velocities of the two measurements showed a significant linear correlation. Dynamic three-dimensional velocity vector mapping was carried out for two cases. First, we applied to the flow analysis around the artificial heart valve in a flat phantom. We could observe the flow pattern around the valve through the 3-dimensional cine image. Next, it is applied to the complex flow inside the polymer sac that is used as ventricle in totally implantable artificial heart (TAH). As a result we could observe the flow pattern around the valves of the sac, though complex flow can not be detected correctly in the conventional phase contrast method. In addition, we could calculate the cardiac output from TAH sac by quantitative measurement of the volume of flow across the outlet valve.

Paper Details

Date Published: 3 July 1998
PDF: 8 pages
Proc. SPIE 3337, Medical Imaging 1998: Physiology and Function from Multidimensional Images, (3 July 1998); doi: 10.1117/12.312580
Show Author Affiliations
Soo Jeong Kim, Seoul National Univ. (South Korea)
Dong Hyuk Lee, Seoul National Univ. (South Korea)
Inchang Song, Seoul National Univ. College of Medicine (South Korea)
Nam Gook Kim, BIT Computer Co., Ltd. (South Korea)
Jae-Hyeung Park, Seoul National Univ. College of Medicine (South Korea)
JongHyo Kim, Seoul National Univ. College of Medicine (United States)
Man Chung Han, Seoul National Univ. College of Medicine (South Korea)
Byong Goo Min, Seoul National Univ. (South Korea)


Published in SPIE Proceedings Vol. 3337:
Medical Imaging 1998: Physiology and Function from Multidimensional Images
Eric A. Hoffman, Editor(s)

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