Guk Bae Kim1, Hojin Ha2, Jihoon Kweon1, Sang Joon Lee3, Young-Hak Kim4, Dong Hyun Yang5, Namkug Kim6. 1. Biomedical Engineering Research Center, Asan Institute of Life Science, Asan Medical Center, Seoul, Republic of Korea. 2. POSTECH Biotech Center, Pohang University of Science and Technology, Pohang, Republic of Korea. 3. Department of Mechanical Engineering, Pohang University of Science and Technology, Pohang, Republic of Korea. 4. Department of Cardiology, University of Ulsan College of Medicine, Asan Medical Center, Seoul, Republic of Korea. 5. Department of Radiology, University of Ulsan College of Medicine, Asan Medical Center, Seoul, Republic of Korea. Electronic address: donghyun.yang@gmail.com. 6. Department of Radiology, University of Ulsan College of Medicine, Asan Medical Center, Seoul, Republic of Korea; Department of Convergence Medicine, University of Ulsan College of Medicine, Asan Medical Center, Seoul, Republic of Korea. Electronic address: namkugkim@gmail.com.
Abstract
PURPOSE: To investigate the details of the flow structure of a plug-like jet that had a vortex ring in pulsatile stenotic phantoms using 4D flow MRI. METHOD: Pulsatile Newtonian flows in two stenotic phantoms with 50% and 75% reductions in area were scanned by 4D flow MRI. Blood analog working fluid was circulated via the stenotic phantom using a pulsatile pump at a constant pulsating frequency of 1Hz. The velocity and vorticity fields of the plug-like jet with a vortex ring were quantitatively analyzed in the spatial and temporal domains. RESULTS: Pulsatile stenotic flow showed a plug-like jet at the specific stenotic degree of 50% in our pulsatile waveform design. This plug-like jet was found at the decelerating period in the post-stenotic region of 26.4mm (1.2 D). It revealed a vortex ring structure with vorticity strength in the range of ±100s(-1). CONCLUSION: We observed a plug-like jet with a vortex ring in pulsatile stenotic flow by in vitro visualization using 4D flow MRI. In this plug-like jet, the local fastest flow region occurred at the post-systole phase in the post-stenotic region, which was distinguishable from a typical stenotic jet flow at systole phase.
PURPOSE: To investigate the details of the flow structure of a plug-like jet that had a vortex ring in pulsatile stenotic phantoms using 4D flow MRI. METHOD: Pulsatile Newtonian flows in two stenotic phantoms with 50% and 75% reductions in area were scanned by 4D flow MRI. Blood analog working fluid was circulated via the stenotic phantom using a pulsatile pump at a constant pulsating frequency of 1Hz. The velocity and vorticity fields of the plug-like jet with a vortex ring were quantitatively analyzed in the spatial and temporal domains. RESULTS: Pulsatile stenotic flow showed a plug-like jet at the specific stenotic degree of 50% in our pulsatile waveform design. This plug-like jet was found at the decelerating period in the post-stenotic region of 26.4mm (1.2 D). It revealed a vortex ring structure with vorticity strength in the range of ±100s(-1). CONCLUSION: We observed a plug-like jet with a vortex ring in pulsatile stenotic flow by in vitro visualization using 4D flow MRI. In this plug-like jet, the local fastest flow region occurred at the post-systole phase in the post-stenotic region, which was distinguishable from a typical stenotic jet flow at systole phase.