Quantitative Conductivity Estimation Error due to Statistical Noise in Complex B1 + Map

다국어 초록 (Multilingual Abstract)

In-vivo conductivity reconstruction using transmit field (B1+) information of MRI was proposed. We assessed theaccuracy of conductivity reconstruction in the presence of statistical noise in complex B1+ map and provided a parametricmodel of the conductivity-to-noise ratio value.
Materials and Methods: The B1+ distribution was simulated for a cylindrical phantom model. By adding complex Gaussiannoise to the simulated B1+ map, quantitative conductivity estimation error was evaluated. The quantitative evaluationprocess was repeated over several different parameters such as Larmor frequency, object radius and SNR of B1+ map. Aparametric model for the conductivity-to-noise ratio was developed according to these various parameters.
Results: According to the simulation results, conductivity estimation is more sensitive to statistical noise in B1+ phase thanto noise in B1+ magnitude. The conductivity estimate of the object of interest does not depend on the external object surroundingit. The conductivity-to-noise ratio is proportional to the signal-to-noise ratio of the B1+ map, Larmor frequency,the conductivity value itself and the number of averaged pixels. To estimate accurate conductivity value of the targetedtissue, SNR of B1+ map and adequate filtering size have to be taken into account for conductivity reconstruction process.
In addition, the simulation result was verified at 3T conventional MRI scanner.
Conclusion: Through all these relationships, quantitative conductivity estimation error due to statistical noise in B1+ map ismodeled. By using this model, further issues regarding filtering and reconstruction algorithms can be investigated for MREPT.

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