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“Minimum Field Strength Requirements for Proton Density Weighted MRI”
by Ziyue Wu, Weiyi Chen, and Krishna S. Nayak
May 2015
Objectives: To provide a framework for simulating low-field proton-density weighted MRI acquisitions, which can be used to predict the minimum B0 field strength requirements for MRI techniques. This framework may be particularly useful in the evaluation of de-noising and constrained reconstruction techniques, and the possibility of translating them to less expensive low-field MRI scanners.
Materials and Methods: Given MRI raw data, lower field MRI acquisitions can be simulated based on the signal and noise scaling with field strength. Certain assumptions were imposed for the simulation and their validity was discussed. A validation experiment was performed using a standard resolution phantoms imaged at 1.5 T, 3 T, and 7 T. This framework was then applied to two sample proton-density weighted MRI applications that demonstrated estimation of minimum field strength requirements: real-time airway imaging and liver fat fraction measurement.
Results: The phantom experiment showed good match between the SNR of the simulated and measured images, within 8% in all cases. The predicted minimum field strength requirements for the two sample applications were 0.2 T and 0.3 T, respectively.
Conclusions: Under certain assumptions, low-field MRI acquisitions can be simulated from high-field MRI data. This enables prediction of the minimum field strength requirements for a broad range of MRI techniques.