The Experiment Research on the Influence of Some MR Parameters on Signal-to-Noise Ratio / 实用放射学杂志

ABSTRACT

Objective To research some parameters' influence on signal-to-noise ratio (SNR) of MR. Methods Magphan phantom was used to do experiments on 1.5T, 0.5T and 0.23T MRI. Scan parameters such as NEX, scan matrix and slice thickness were altered.Evaluate whether the change of SNR varied with parameter to be in accordance with the SNR law.Results (1) When spin echo pulse applied and NEX changed, the results of high field device A and B weren't in accordance with SNR theory, and high filed device C and low field device F were in accordance with SNR theory. When fast spin echo pulse applied and NEX changed, the result of device B was in accordance with SNR theory. (2) When scan matrix changed, measured value was lower than ideal value for little matrix, and vice versa. (3) The measured value was very closely to ideal value for little slice thickness. When slice thickness exceed 5 mm, the difference between the measured value and ideal value was significance.Conclusion Based on the SNR theory, the user of MRI should consider the running characteristic of MR system to select scan parameters.