Abstract #0640

Distortion Correction in TSE Near Metal Implants at 0.55T Using Model-Based Iterative Reconstruction and Opposite Readout Acquisitions

Bochao Li¹, Nam G. Lee¹, Kübra Keskin², Daehyun Yoon³, Alexander R. Toews⁴, Jay Acharya⁵, Jordan S. Gross⁵, Brian A. Hargreaves^4,6, and Krishna S. Nayak^1,2

¹Biomedical Engineering, University of Southern California, Los Angeles, CA, United States, ²Electrical and Computer Engineering, University of Southern California, Los Angeles, CA, United States, ³Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, CA, United States, ⁴Electrical Engineering, Stanford University, Stanford, CA, United States, ⁵Diagnostic Radiology, University of California, Los Angeles, Los Angeles, CA, United States, ⁶Bioengineering, Stanford University, Stanford, CA, United States

Synopsis

Keywords: Artifacts, Low-Field MRI

Motivation: View angle tilting for reducing signal displacement artifacts near metal is difficult to adopt at 0.55T due to blurring and decreased SNR due to high readout bandwidth.

Goal(s): To develop a method that corrects in-plane displacement artifacts near metal implants at 0.55T, achieving higher SNR without sacrificing image sharpness.

Approach: TSE acquisitions with opposite frequency-encoding directions were performed. Gradient nonlinearity-corrected images were first generated. Displacement maps were estimated by TOPUP from the GNL-corrected images. Final images were reconstructed using Type-1 NUFFT-based CG-SENSE by incorporating both GNL and TOPUP-derived displacement fields.

Results: The proposed method, performed without VAT, eliminated blurring and achieved superior SNR.

Impact: This method enhances SNR without blurring for MRI near metal implants at 0.55T, benefiting low-SNR regions such as the spine and disc, while avoiding the prolonged scan times associated with VAT methods that require multiple averages for SNR improvement.

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