Wonje Lee

All Publications

• A 60-channel high-density flexible receive array for pediatric abdominal MRI. Magnetic resonance in medicine Lee, W., Stickle, Y., Follante, C., Grafendorfer, T., Yang, T., Robb, F., Zhang, F., Pauly, J., Scott, G., Vasanawala, S., Syed, A. 2025

  Abstract

  Conventional MRI coils offer suboptimal parallel imaging performance for young children. Our goal was to enhance imaging acceleration by dedicated, flexible high-density coil design for pediatric patients at 3T.We design, construct, and evaluate a highly flexible small loop array. Key design notes include full-wave simulation and analysis of the dual-turn loop, miniature feedboard allocation at the loop center, and cable management. Phantom experiments and adult and pediatric volunteer case studies were conducted to evaluate the small loop array imaging performance compared to commercial reference coils.Dual-turn loop configuration forms higher preamp decoupling impedance than the same size single-turn, supporting a flexible form factor that requires a wide range of critical overlap. Both phantom and in-vivo studies demonstrate superior parallel imaging performance or high spatial resolution imaging using the small loop, compared to commercial reference coils.A dedicated high-density coil array with a minimum inter-component interference layout design allows a flexible form factor and higher imaging accelerations. Phantom and in-vivo volunteer case studies demonstrate promising results in improving efficiency for pediatric patients in routine clinical imaging procedures.

  View details for DOI 10.1002/mrm.30456

  View details for PubMedID 39902561

• MRI Retrospective Respiratory Gating and Cardiac Sensing by CW Doppler Radar: A Feasibility Study IEEE TRANSACTIONS ON BIOMEDICAL ENGINEERING Lee, W., Ryu, K., Li, Z., Oscanoa, J., Wu, Y., Robb, F., Vasanawala, S., Pauly, J., Scott, G. 2025; 72 (1): 112-122

  Abstract

  This study investigates the feasibility of non-contact retrospective respiratory gating and cardiac sensing using continuous wave Doppler radar deployed in an MRI system. The proposed technique can complement existing sensors which are difficult to apply for certain patient populations.We leverage a software-defined radio for continuous wave radar at 2.4 GHz to detect in-vivo respiratory and cardiac timescrolled signals. In-bore radar signal demodulation is verified with full electromagnetic simulations, and its functionality is validated on a test bench and within the MR bore with four normal subjects. Radar sensing was compared against well-known references: electrocardiography on a test bench, system bellows, and pulsed plethysmography sensors with in the MRI bore.The feasibility of noncontact cardiac rate sensing, dynamic breathing sequence synchronization, and in-bore motion correction for retrospective respiratory gating applications was demonstrated. Optimal radar front-end system arrangement, along with spectral isolation and narrow bandwidth of operation, enable MRI-compatible and interference-free motion sensing. The signal-to-noise-ratio degradation by the radar integration was within 4.5% on phantom images.We confirmed that in-bore retrospective motion correction using CW Doppler radar is feasible without MRI system constraints.Non-contact motion correction sensing in MRI may provide better patient handling and through put by complementing existing system sensors and motion correction algorithms.

  View details for DOI 10.1109/TBME.2024.3440317

  View details for Web of Science ID 001398974700003

  View details for PubMedID 39115989