关于MRI质量控制中ROI对信噪比检测影响的研究

摘要

Objective To research the effect of the change of region of interest (ROI) on the signal to noise ratio (SNR) detection based on the regulation of metrological verification implemented in some areas of China, so as to proposed a suitable proportion of ROI to improve the objectivity and accuracy of the image SNR's evaluation. Methods Automatic evaluation module was developed based on phantom SMR170 and combined with SNR detection principle. SNR with different ROI was evaluated by this module, and SNR trend changing with ROI was discussed. Results The change of ROI had a significant effect on the SNR Results . The value of image noise increased with the enlargement of ROI, while SNR of the image reduced accordingly.Conclusion It is suggested that the selection ratio of ROI is between 0.60 and 0.75, which effectively reduce the artificial measurement error and ensure the evaluation result objectively reflected the performance of the imaging system.%目的 针对我国部分地方计量检定规程所规定的MRI图像信噪比(SNR)检测方法 ,研究感兴趣区域(ROI)比例的变化对信噪比检测结果 的影响,旨在提出合适比例的ROI,以提高图像信噪比检测程序的客观性与准确性.方法 基于SMR170体模,结合信噪比检测原理,自行研制信噪比自动检测模块;利用该模块准确检测不同ROI下的图像信噪比值,讨论信噪比随ROI的变化趋势.结果 ROI的比例变化对信噪比检测结果 有显著影响,ROI越大,图像噪声值越大,相应的图像信噪比值越小.其中ROI比例为0~0.15时,信噪比呈迅速的变化趋势;ROI比例为0.60~0.75时,信噪比呈平缓变化趋势.结论 建议ROI的选取比例为0.60~0.75之间,有效减小检测者带来的人工测量误差,保证信噪比检测程序的科学性,使检测结果 客观反映成像系统性能.