Myung-Kyun Woo1, Suk-Min Hong2, Jongho Lee1, Chang-Ki Kang3, Sung-Yeon Park4, Young-Don Son5, Young-Bo Kim4, Zang-Hee Cho6. 1. Department of Electrical and Computer Engineering, Seoul National University, Seoul, Republic of Korea. 2. Institute of Neuroscience and Medicine-4, Forschungszentrum Jülich, Jülich, Germany. 3. Neuroscience Research Institute, Gachon University, Incheon, Republic of Korea; Department of Radiological Science, College of Health Science, Gachon University, Incheon, Republic of Korea. 4. Neuroscience Research Institute, Gachon University, Incheon, Republic of Korea. 5. Neuroscience Research Institute, Gachon University, Incheon, Republic of Korea; Department of Biomedical Engineering, College of Health Science, Gachon University, Incheon, Republic of Korea. 6. Graduate School of Convergence Science and Technology, Seoul National University, Suwon, Republic of Korea.
Abstract
PURPOSE: To propose a new Extended Monopole antenna Array with individual Shields (EMAS) coil that improves the B1 field coverage and uniformity along the z-direction. METHODS: To increase the spatial coverage of Monopole antenna Array (MA) coil, each monopole antenna was shielded and extended in length. Performance of this new coil, which is referred to as EMAS coil, was compared with the original MA coil and an Extended Monopole antenna Array coil with no shield (EMA). For comparison, flip angle, signal-to-noise ratio (SNR), and receive sensitivity maps were measured at multiple regions of interest (ROIs) in the brain. RESULTS: The EMAS coil demonstrated substantially larger flip angle and receive sensitivity than the MA and EMA coils in the inferior aspect of the brain. In the brainstem ROI, for example, the flip angle in the EMAS coil was increased by 45.5% (or 60.0%) and the receive sensitivity was increased by 26.9% (or 14.9%), resulting in an SNR gain of 84.8% (or 76.3%) when compared with the MA coil (or EMA). CONCLUSION: The EMAS coil provided 25.7% (or 24.4%) more uniform B1+ field distribution compared with the MA (or EMA) coil in sagittal. The EMAS coil successfully extended the imaging volume in lower part of the brain. Magn Reson Med 75:2566-2572, 2016.
PURPOSE: To propose a new Extended Monopole antenna Array with individual Shields (EMAS) coil that improves the B1 field coverage and uniformity along the z-direction. METHODS: To increase the spatial coverage of Monopole antenna Array (MA) coil, each monopole antenna was shielded and extended in length. Performance of this new coil, which is referred to as EMAS coil, was compared with the original MA coil and an Extended Monopole antenna Array coil with no shield (EMA). For comparison, flip angle, signal-to-noise ratio (SNR), and receive sensitivity maps were measured at multiple regions of interest (ROIs) in the brain. RESULTS: The EMAS coil demonstrated substantially larger flip angle and receive sensitivity than the MA and EMA coils in the inferior aspect of the brain. In the brainstem ROI, for example, the flip angle in the EMAS coil was increased by 45.5% (or 60.0%) and the receive sensitivity was increased by 26.9% (or 14.9%), resulting in an SNR gain of 84.8% (or 76.3%) when compared with the MA coil (or EMA). CONCLUSION: The EMAS coil provided 25.7% (or 24.4%) more uniform B1+ field distribution compared with the MA (or EMA) coil in sagittal. The EMAS coil successfully extended the imaging volume in lower part of the brain. Magn Reson Med 75:2566-2572, 2016.
Authors: Myung Kyun Woo; Lance Delabarre; Matt Waks; Jingu Lee; Russell Luke Lagore; Steve Jungst; Andrea Grant; Yigitcan Eryaman; Kamil Ugurbil; Gregor Adriany Journal: IEEE Trans Med Imaging Date: 2021-04-01 Impact factor: 10.048
Authors: Myung Kyun Woo; Lance DelaBarre; Matt Thomas Waks; Young Woo Park; Russell Luke Lagore; Steve Jungst; Yigitcan Eryaman; Se-Hong Oh; Kamil Ugurbil; Gregor Adriany Journal: Sensors (Basel) Date: 2021-09-08 Impact factor: 3.576