磁敏感加权成像脑铁含量感兴趣区选择及测量研究

目的探讨苍白球区异常矿物质沉积时,选取不同感兴趣区(region of interest,ROI)(整个苍白球或局部矿物质沉积区域)对铁含量测值的影响,从而为脑组织铁含量测定感兴趣区选择及其测量的便捷性提供依据。材料与方法采用常规磁共振成像和磁敏感加权成像扫描94例健康志愿者,其中苍白球区存在明显矿物质沉积10例,分别选取苍白球整体(A1组)及局部矿物质沉积区域(A2组)为ROI测量灰度值。另外选取性别和年龄相匹配的苍白球区无异常铁含量沉积10例作为对照组(B组)。通过Pearson线性相关分析比较苍白球区有无异常铁含量沉积时的信号值对苍白球区铁含量测量的影响。结果 A1组和A2组灰度值测量相关系数r=0.827(P0.05),整个苍白球区灰度值测量与局部区域灰度值测量具有显著一致性;A1组和B组相关系数r=0.183(P0.05),A2组和B组间相关系数r=0.344(P0.05),说明苍白球区内有无矿物质沉积对灰度值测量影响具有统计学意义。结论通过SWI技术分析含有异常矿物质沉积的苍白球区,选取整个苍白球区作为ROI与只将异常的矿物质沉积区作为ROI反映矿物质沉积趋势具有一致性,对脑铁测量影响不大,因此可以直接选取苍白球整体区域作为ROI测量脑铁含量,方法便捷,值得临床推广应用。

Study of region-of-interest choosing in measuring brain iron content by susceptibility weighted imaging

AbstractObjective: To explore the influence of selecting different region of interest (the whole globus pallidus or a local mineral deposition area) on evaluating the iron content when mineral deposited abnormally in the globus pallidus. The present study might provide a convenient approach to choose the appropriate ROI and to measure the brain iron.Materials and Methods:There were 94 healthy volunteers underwent the routine MRI and SWI scan, and group A had 10 cases with abnormal mineral deposit in the region of globus pallidus, while another 10 cases with normal mineral deposition were group B. Group A was then sub-divided into group A1 or group A2 based on defining the region of the whole globus pallidus (A1) or the region of the only abnormal mineral deposition area as ROI, respectively. Pearson correlation analysis was applied to analyze the relationship between the different ROI on iron measurement and the abnormal mineral depositing content in the region of globus pallidus.Results:The correlationr value between the group A1 and group A2 was 0.827 (P<0.05), which showed that the value of mineral depositing content was remarkably consistent between the two different ROIs measurement (ROI with whole globus pallidusor the local abnormal mineral deposition area). The correlation ofr value between group B and group A1, or between group A2 was 0.183 (P>0.05) and 0.344 (P>0.05), respectively. The difference of the signal intensity in globus pallidus was signiifcant between the cases with and without abnormal mineral deposition.Conclusion:We both choose the whole globus pallidus and the local abnormal mineral depositing area as ROI in analyzing the mineral deposition by SWI. Our results showed that these two different ROIs we selected had little inlfuence on brain iron measurements. Therefore we conclude that taking the whole globus pallidus as ROI to measure brain iron content in the globus pallidus by SWI is reliable and much more convenient in comparison with the ROI drawn around the local abnormal mineral depositing area.