Equating quantitative emphysema measurements on different CT image reconstructions.
Equating quantitative emphysema measurements on different CT image reconstructions.
复制标题
等同于不同 CT 图像重建的定量肺气肿测量。
DOI：
10.1118/1.3615624
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发表时间：
2011
期刊：
影响因子：
3.8
通讯作者：
Gierada,DavidS
中科院分区：
文献类型：
--
作者：
Bartel,SethT;Bierhals,AndrewJ;Pilgram,ThomasK;Hong,Cheng;Schechtman,KennethB;Conradi,SusanH;Gierada,DavidS
目的建立肺气肿CT测量值之间的数学模型，并评价将测量结果转换为参考重建值的模型的准确性。方法对138例重度吸烟者的肺癌筛查CT原始数据进行15种不同的切片厚度和核素组合重建。肺气肿指数被量化为密度低于−950HU(EI950)的肺的百分比。使用线性、二次和幂函数对参考1 mm的EI950值、中等平滑核重建和来自其他14个重建的值之间的关系进行建模。采用修正后的阿凯克信息准则、决定系数(R2)和残差(换算误差)选择优选模型，并采用留一法进行交叉验证。结果优选模型为幂函数，模型R2值在0.949~0.998之间。在留一法检验中，将其他重建的EI950测量值转换为1 mm、中等平滑的核重建时，所有重建的误差均小于3.0个指数百分点，5个重建的误差小于1.0个百分点。转换误差部分与图像噪声、肺气肿分布和衰减直方图参数有关。随着切片厚度的增加，与核锐度增加相关的转换不精确度趋于减小。结论图像重建相关的肺气肿定量测量差异可以用幂函数成功地建模。
PurposeTo mathematically model the relationship between CT measurements of emphysema obtained from images reconstructed using different section thicknesses and kernels and to evaluate the accuracy of the models for converting measurements to those of a reference reconstruction.MethodsCT raw data from the lung cancer screening examinations of 138 heavy smokers were reconstructed at 15 different combinations of section thickness and kernel. An emphysema index was quantified as the percentage of the lung with attenuation below −950 HU (EI950). Linear, quadratic, and power functions were used to model the relationship between EI950values obtained with a reference 1 mm, medium smooth kernel reconstruction and values from each of the other 14 reconstructions. Preferred models were selected using the corrected Akaike information criterion (AICc), coefficients of determination (R2), and residuals (conversion errors), and cross‐validated by a jackknife approach using the leave‐one‐out method.ResultsThe preferred models were power functions, with modelR2values ranging from 0.949 to 0.998. The errors in converting EI950measurements from other reconstructions to the 1 mm, medium smooth kernel reconstruction in leave‐one‐out testing were less than 3.0 index percentage points for all reconstructions, and less than 1.0 index percentage point for five reconstructions. Conversion errors were related in part to image noise, emphysema distribution, and attenuation histogram parameters. Conversion inaccuracy related to increased kernel sharpness tended to be reduced by increased section thickness.ConclusionsImage reconstruction‐related differences in quantitative emphysema measurements were successfully modeled using power functions.