Calculating potential error in sodium MRI with respect to the analysis of small objects
Calculating potential error in sodium MRI with respect to the analysis of small objects
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DOI：
10.1002/mrm.26962
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发表时间：
2018-06-01
影响因子：
3.3
通讯作者：
Beaulieu, Christian
中科院分区：
文献类型：
--
作者：
Stobbe, Robert W.;Beaulieu, Christian
目的为了便于正确解释钠MRI测量结果，引入了关于快速信号衰减的误差计算，并将其与空间相关噪声的误差计算相结合，以评估感兴趣体积（VOI）Na-23信号测量的不准确性，特别是对于小物体。方法噪声和信号衰减-使用扭曲投影成像和具有恒定升高钠浓度的不同尺寸球体的专门设计的体模来验证相关误差计算。作为一个示范，病变信号测量变化（5多发性硬化症参与者）进行了比较，预测从calculation.ResultsBoth理论和幻影实验表明，VOI信号测量在一个大的10-mL，314体素球体是20%小于预期的点扩散函数涂抹时，VOI绘制，包括完整的球体。感兴趣的体积收缩减少了这个错误，但增加了噪声相关的错误。对于较小的球体，误差甚至更大（比0.35 mL，11体素球体的预期误差小40-60%）。图像强度VOI测量值随多发性硬化病变大小的变化而增加，其方式与理论预测相似。相关性表明大低估的Na-23信号在小lesions. ConclusionsAcquisition特定的测量误差计算辅助Na-23 MRI数据分析，并强调了目前的低分辨率方法的局限性。Magn Reson Med 79：2968-2977，2018。(c)2017年国际医学磁共振学会。
PurposeTo facilitate correct interpretation of sodium MRI measurements, calculation of error with respect to rapid signal decay is introduced and combined with that of spatially correlated noise to assess volume-of-interest (VOI) Na-23 signal measurement inaccuracies, particularly for small objects.MethodsNoise and signal decay-related error calculations were verified using twisted projection imaging and a specially designed phantom with different sized spheres of constant elevated sodium concentration. As a demonstration, lesion signal measurement variation (5 multiple sclerosis participants) was compared with that predicted from calculation.ResultsBoth theory and phantom experiment showed that VOI signal measurement in a large 10-mL, 314-voxel sphere was 20% less than expected on account of point-spread-function smearing when the VOI was drawn to include the full sphere. Volume-of-interest contraction reduced this error but increased noise-related error. Errors were even greater for smaller spheres (40-60% less than expected for a 0.35-mL, 11-voxel sphere). Image-intensity VOI measurements varied and increased with multiple sclerosis lesion size in a manner similar to that predicted from theory. Correlation suggests large underestimation of Na-23 signal in small lesions.ConclusionsAcquisition-specific measurement error calculation aids Na-23 MRI data analysis and highlights the limitations of current low-resolution methodologies. Magn Reson Med 79:2968-2977, 2018. (c) 2017 International Society for Magnetic Resonance in Medicine.