Junghwan Kim, PhD

 IMG_2187Principle Engineer at GE Research and Development

email: mrfkim@gmail.com

 

 

BioE PhD Dissertation: “Advances in Ultra-High Field 7 Tesla (T) Human MRI: Design and Methodology of Trasmit (TX) and Receive (RX) Radio Frequency (RF) Coil” 

Magnetic Resonance Imaging (MRI) is known as non-invasive imaging modality that provides superb anatomical soft tissue details. Over a decade, studies in ultrahigh field (UHF) MRI have been widely carried out in order to further improve the technology as well as understand the diseases. RF coil design and performance studies have been widely conducted to fully utilize the advantages that are given by UHF MRI. The aim of the design is typically producing uniform electromagnetic (EM) field distribution within the volume of interest while lowering the specific absorption rate (SAR) for Tx array and preserving/enhancing high signal to noise ratio (SNR) with Rx array.

Clinically available MRI such as 1.5 Tesla (T) and 3T, uses a whole body RF coil that is embedded in the scanner as the field exciter/transmitter, and separate receivers for different parts of the body. This body coil is not available in UHF MRI due to shorter wavelength resulting in inhomogeneous EM field distributions and the large size of the body coil challenges to tune and match the coil at resonant frequency of the UHF MRI, ~300MHz as well as the size of the UHF MRI market is too small that the vendors are not actively investing in the body coil development. Due to the inexistence of the body coil at UHF MRI, it is critical to develop a RF transmit coil systems that produce a uniform B1+ field (clockwise rotating circularly polarized transverse magnetic field that is responsible for excitation) and low specific absorption rate (SAR).

Aim of this thesis is to develop and evaluate new design of transmit (Tx) arrays and receive (Rx) arrays for breast and extremity (knee and ankle/foot) MR imaging at 7T. This thesis consists of several articles associated with breast and extremity MR imaging, namely:

1) Experimental and numerical analysis of B1+ field and SAR with a new transmit array design for 7T breast MRI (published as a first author),

2) Development of a 7T RF coil system for breast imaging (published as a first author),

3) Two way – split RF array development for knee MRI at 7T (under preparation as a main author), 4) A new RF Transmit Coil for Foot and Ankle Imaging at 7T MRI (published as a second author), and

Overall, the work of this thesis contributes toward the understanding RF coil design and evaluation for UHF MRI human imaging.

Research activities

INTERNATIONAL JOURNALS

  1. Dual-Echo Arteriovenography imaging with 7T MRI. Kyongtae Ty Bae, Sung-Hong Park, Chan-Hong Moon, Junghwan Kim, Diana Kaya, and Tiejun Zhao. J. Magn. Reson. Imaging 2010;31:255–261.
  2. Quantitative evaluation of k-space reordering schemes for compatible dual-echo arteriovenography (CODEA). Park SH, Shim H, Moon CH, Junghwan Kim , Bae KT. Magn Reson Med. 2010 May;63(5):1404-10.
  3. Suppression of effects of gradient imperfections on imaging with alternate ascending/descending directional navigation. Park SH, Zhao T, Junghwan Kim, Boada FE, Bae KT. Magn Reson Med. 2012 Jan 27.
  4. Part 1: Dual-tuned Proton/sodium Magnetic Resonance Imaging of the Lumbar Spine in a Rabbit Model. Moon CH, Junghwan Kim, Jacobs L, Zhao T, Sowa G, Vo N, Kang J, Bae KT. Spine (Phila Pa 1976) 2012 Apr 24.
  5. Part 2: Quantitative Proton T2 and Sodium MR Imaging to Assess Intervertebral Disc Degeneration in a Rabbit Model. Moon CH, Jacobs L, Junghwan Kim, Sowa G, Vo N, Kang J, Bae KT. Spine (Phila Pa 1976). 2012 Apr 14.
  6. Multichannel transceiver dual-tuned RF coil for proton/sodium MR imaging of knee cartilage at 3 T. Junghwan Kim, Moon CH, Park BW, Furlan A, Zhao T, Bae KT. Magn Reson Imaging. 2012 May;30(4):562-71.
  7. Suppression of effects of gradient imperfections on imaging with alternate ascending/descending directional navigation. Park SH, Zhao T, Kim JH, Boada FE, Bae KT. Magn Reson Med. 2012 Jan 27.
  8. Quantitative 23Na MRI of human knee cartilage using dual-tuned 1H/23Na transceiver array RF coil at 7T. CH Moon, Junghwan Kim, T. Zhao, and K. T. Bae. JMRI. 2013 in press

 

INTERNATIONAL CONFERENCE PROCEEDINGS

  1. High-Resolution in Vivo MR imaging of the Human Spinal Cord at 7T, Kyongtae Ty Bae, Chan-Hong Moon, Junghwan Kim, Sung-Hong Park. 2009 ISMRM
  2. Compatible Dual-Echo Arteriovenography (CODEA) Imaging at 7T Versus 3T, Kyongtae Ty Bae, Sung-Hong Park, Chan-Hong Moon, Junghwan Kim. 2009 ISMRM
  3. Proton and Sodium MR Imaging of Prostate Using a Dual-Tuned Endorectal Coil at 3T, Kyongtae Ty Bae, Chan-Hong Moon, George J. Misic, Junghwan Kim, Sung-Hong Park, Tiejun Zhao. 2009 ISMRM
  4. Signal Intensity Profile Comparison of Two Different QD Surface Coils, Suk-min Hong, Kyoung-Nam Kim, Jae-Yong Han, Junghwan Kim, Zang-Hee Cho. 2009 ISMRM
  5. Experiments and Quatification of Lumped Elements Volume Coil for B1+ Excitation at 7T, Kyoung-Nam Kim, Suk-Min Hong, Jae-Yong Han, Hyo Woon Yoon, Jun-Young Chung, Junghwan Kim, Zang-Hee Cho. 2009 ISMRM
  6. Sodium MR imaging of kidney and other abdominal organs using a dual-tuned body RF coil at 7T, K, T. Bae, Junghwan Kim, C. Moon, A. Furlan, B. Park, T. Zhao. 2010 ISMRM
  7. 1H/23Na dual-tuned RF unicoil for human body MR imaging at 3T, Junghwan Kim, K-N. Kim, C. Moon, S-M. Hong, B-W. Park, H. J. Park and K. T. Bae. 2010 ISMRM
  8. High-Resolution 1H/23Na MR imaging of knee articular cartilage using dual-tuned knee coil at 7T, Junghwan Kim, C. Moon, A. Furlan, B. Park, T. Zhao, and K. T. Bae. 2010 ISMRM
  9. 23Na/1H MR imaging of female pelvis at 7T using a dual-tuned multi-channel body coil, K, T. Bae, Junghwan Kim, C. Moon, A. Furlan, B. Park, J. Wang. 2010 ISMRM
  10. Proton and sodium MR imaging of in vivo human prostate using dual-tuned body and endorectal coils at 7T, K, T. Bae, Junghwan Kim, A. Furlan, C. Moon, B. Park, T. Zhao. 2010 ISMRM
  11. Development of Multi-Tranceiver Dual-Tuned Knee Coil at 3T, Junghwan Kim, C. Moon, B. Park, A. Furlan, A. Defranco, T. Zhao, and K. T. Bae. 2011 ISMRM
  12. Development of dual-tuned knee coil at 7T: a feasibility study of high-resolution sodium MR imaging and T2 mapping in knee cartilage in vivo, Junghwan Kim, B. Park, A. Furlan, C. Moon, S-H. Park, T. Zhao, and K. T. Bae. 2011 ISMRM
  13. In Vivo Sodium and Proton T1rho MR Imaging of Human Knee Cartilage at 3T, C. Moon, Junghwan Kim, T. Zhao, X. He, B-W. Park, and K. T. Bae. 2011 ISMRM
  14. In Vivo Sodium and Proton T1rho MR Imaging of Human Spine Disc at 3T, C. Moon, Junghwan Kim, X. He, T. Zhao, and K. T. Bae. 2011 ISMRM
  15. In Vivo Sodium MR Imaging of Rabbit Kidney using Dual-tuned RF Coil at 3T, C. Moon, A. Furlan, Junghwan Kim, L. Jacobs, T. Zhao, and K. T. Bae 2011 ISMRM
  16. In Vivo Sodium MR Imaging of Rabbit Lumbar Disc using Dual-tuned coil at 3T, C. Moon, L. Jacobs, Junghwan Kim, B. Bechara, T. Zhao, J. Kang, and K. T. Bae 2011 ISMRM
  17. in vivo T1ρ Study on Human Kidney, X. He, C. Moon, Junghwan Kim, and K. T. Bae 2011 ISMRM
  18. In Vivo T2 and T1rho Mapping of Rabbit Disc using Spin-Lock sequence at 3T, C. Moon, L. Jacobs, Junghwan Kim, X. He, J. Kang, and K. T. Bae 2011 ISMRM
  19. Sodium MR Imaging of Human Kidney Using a Dual-Tuned (23Na/1H) Body RF Coil at 3T: Quantitative Assessment of Sodium Concentration and Corticomedullary Gradient in Healthy Subjects, A. Furlan, C. Moon, Junghwan Kim, X. He, B-W. Park, T. Zhao, and K. T. Bae. 2011 ISMRM
  20. Mapping of Cerebral Blood Flow Directionality with Alternate Ascending/Descending Directional Navigation (ALADDIN). Sung-Hong Park, Bumwoo Park, Junghwan Kim, Tiejun Zhao, and Kyongtae Ty Bae. 2012 ISMRM.
  21. Eddy Currents in MT Asymmetry Imaging with Alternate Ascending/Descending Directional Navigation (ALADDIN). Sung-Hong Park, Tiejun Zhao, Junghwan Kim, Fernando Boada, kyongtae Bae. 2012 ISMRM
  22. Development of cross-pole RF Tx array for breast imaging at 7T. Junghwan Kim, Narayan Krishnamurthy, Yujuan Zhao, Tiejun Zhao, Kyongtae Ty Bae, and Tamer S. Ibrahim. 2013 ISMRM
  23. High temporal and spatial resolution breast MR imaging at 7T; Feasibility study using 8-to-1 channel Tx-only array combined with 8 channel Rx-only insert. Junghwan Kim, Yujuan Zhao, Narayan Krishnamurthy, Tiejun Zhao, Kyongtae Ty Bae, and Tamer S. Ibrahim. 2013 ISMRM
  24. 20-To-8 Channel Tx Array with 32-Channel Adjustable Receive-Only Insert for 7T Head Imaging. Ibrahim Tamer, Zhao Yujuan, Krishnamurthy Narayanan, Raval Shailesh, Zhao Tiejun, Wood Sossena, Kim Junghwan. 2013 ISMRM
  25. Assessment of Skeletal Muscle Oxygen Kinetics Using Quantitative BOLD (QBOLD). He Xiang, Gumus Serter, Kim Junghwan, Huppert Ted, Goodpaster Bret, Yablonskiy Dmitriy A., Bae Kyongtae Ty. 2013 ISMRM
  26. Quantitative 23Na MRI of Human Knee Cartilage Using Dual-Tuned 1H/23Na Transceiver Array RF Coil at 7T. Moon, Chan Hong; Kim, Junghwan; Zhao, Tiejun; Bae, Kyongtae Ty. 2013 ISMRM

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