■研究切片厚度对实性肺结节中放射组学特征(RF)值的影响,并评估线性插值方法在校正影响中的作用。
■前瞻性选择了28例患者的30个肺结节,CT上的厚切片为5mm,薄切片为1.25mm。采用重采样方法,通过线性插值将厚切片和薄切片CT图像的体素尺寸归一化为1×1×1mm3。手动分割肺结节。从厚切片和薄切片图像中总共提取了396个放射学特征(RFs),以及从厚(厚r)和薄(薄r)切片重新采样的图像。使用配对t检验评估RF值之间的差异。使用卡方检验进行组间比较。
■在396个RFs中,305个RFs在测试-重测分析后显示出类内相关系数≥0.75(包括22个直方图特征,20个几何特征,和263个纹理特征)。在非重采样数据中,239个射频值(78.4%,239/305)显示厚切片和薄切片CT图像之间存在显着差异。厚图像重采样显示202个RF值(66.2%,202/305)显示厚-r和薄层CT图像之间存在显著差异,与非重采样数据相比,显示不同RF值的数量显着减少(P<0.01)。对于RF子组,只有纹理特征显示重采样后不同RF值的数量显着减少(P<0.01)。当厚切片和薄切片图像都被重新采样时,厚r和薄r图像之间显著不同的RF值的数量增加到247(81.0%,247/305),与非重采样数据相比没有显着差异(P=0.421)。
■切片厚度对实性肺结节的RF值具有相当大的影响,当使用不同切片厚度的CT图像时,会产生错误的结果。由于校正效果相对较小,因此重采样方法的线性插值受到限制。
UNASSIGNED: To investigate the influence of slice thickness on radiomic feature (RF) values in solid pulmonary nodules and evaluate the effect of a linear interpolation method in correcting the influence.
UNASSIGNED: Thirty pulmonary nodules from 28 patients were selected prospectively with a thick-slice of 5 mm and a thin-slice of 1.25 mm on CT. A resampling method was used to normalize the voxel size of thick and thin slices CT images to 1×1×1 mm3 by linear interpolation. Lung nodules were segmented manually. A total of 396 radiomic features (RFs) were extracted from thick-slice and thin-slice images, together with the images resampled from thick (thick-r) and thin (thin-r) slices. The differences between the RF values were evaluated using a paired t-test. A comparison between groups was made using the Chi-squared test.
UNASSIGNED: Among the 396 RFs, 305 RFs showed an intraclass correlation coefficient ≥0.75 after test-retest analysis (including 22 histogram features, 20 geometry features, and 263 texture features). In the non-resampled data, 239 RF values (78.4%, 239/305) showed significant differences between thick and thin slice CT images. Resampling of thick images revealed that 202 RF values (66.2%, 202/305) showed significant differences between thick-r and thin slice CT images, showing a significant decrease in the number of different RF values when compared to non-resampled data (P<0.01). For the RF subgroups, only texture features showed a significant reduction in the number of different RF values after resampling (P<0.01). When both thick and thin slice images were resampled, the number of significantly different RF values between thick-r and thin-r images was increased to 247 (81.0%, 247/305), showing no significant difference when compared to non-resampled data (P=0.421).
UNASSIGNED: Slice thickness demonstrated a considerable influence on RF values in solid pulmonary nodules, producing false results when CT images with different slice thicknesses were used. Linear interpolation of the resampling method was limited because of the relatively small correction effect.