摘要目的:构建一种基于深度学习的肺结节分类以及分割算法，探究其在不同CT重建算法下的诊断效能。方法:回顾性收集2019年6至9月天津医科大学朱宪彝纪念医院放射科363例胸部CT平扫影像学资料，每例患者的胸部CT平扫均包含三种CT重建算法（肺重建、纵隔重建、骨重建）生成的图像，这些数据构成了模型的测试集；模型的训练集由公开数据集（LIDC-IDRI）和私有数据集共4 185例患者胸部CT图像组成。模型的构建采用3D深度卷积神经网络和递归神经网络结合的方式，在多任务联合学习下训练肺结节密度类型分类和分割，最后将训练好的模型在天津医科大学朱宪彝纪念医院放射科363例测试病例上进行效果测试，得到三种CT图像重建算法下结节分类准确率和分割Dice系数指标。采用方差分析对三种CT重建算法下的结节分类准确率和分割Dice系数进行比较以分析差异是否有统计学意义。结果:在三种CT重建算法下，模型对肺结节密度类型的分类准确率分别为98.67%±5.70%、98.38%±6.61% 和97.89%±7.32%，其中实性结节的分类准确率分别为98.79%±5.58%、98.49%±6.89%和97.90%±7.41%，亚实性结节的分类准确率分别为97.57%±10.19%、98.52%±7.77%和98.52%±7.77%，三种不同重建算法下的肺结节的分类准确率差异无统计学意义（均 P>0.05）。三种重建算法下，所有结节分割的Dice系数分别为79.87%±5.78%、79.02%±6.04%和79.31%±5.95%，三组间结节分割的Dice系数差异无统计学意义（均 P>0.05）。 结论:结合了3D卷积神经网络和递归神经网络的深度学习算法，对不同CT重建算法图像中肺结节的分类和分割均有较为稳定的效果。

abstractsObjective:To evaluate the diagnostic value of the lung nodule classification and segmentation algorithm based on deep learning among different CT reconstruction algorithms.Methods:Chest CT of 363 patients from June 2019 to September 2019 in Radiology Department of Tianjin Medical University Chu Hsien-I Memorial Hospital were retrospectively collected in this study, each of which consisted of images by three different reconstruction methods (lung reconstruction, mediastinal reconstruction, bone reconstruction).These collected data were used as testing set and a total of 4 185 Chest CTs including the public data set and the constructed private data set were used as the training set. A model combines 3D deep convolutional neural network and recurrent neural network under a multi-task joint learning algorithm for lung nodule classification and segmentation were constructed. The well-trained method was tested on 363 test cases using two metrics, i.e., the accuracy of the density classification and the Dice coefficient of nodule segmentation. The performances under three reconstruction methods were statistically analyzed according to the variance analysis among three different reconstruction methods.Results:The average classification accuracies of the nodule under three reconstruction methods were 98.67%±5.70%, 98.38%±6.61% and 97.89%±7.32%. Specifically, the accuracies of the solid nodules under three reconstruction methods were 98.79%±5.58%, 98.49%±6.89% and 97.90%±7.41% and the accuracies of the sub-solid nodules were 97.57%±10.19%, 98.52%±7.77% and 98.52%±7.77%. There was no significant difference in the classification accuracy of pulmonary nodules under three different reconstruction algorithms (all P>0.05). The average Dice coefficients of nodule segmentation was 79.87%±5.78%, 79.02%±6.04% and 79.31%±5.95%. There was no significant difference in the average Dice coefficients of nodule segmentation under three different reconstruction algorithms (all P>0.05). Conclusion:Deep learning algorithm which combined with 3D convolutional neural network and recurrent neural network has demonstrated relatively stable in classification and segmentation of lung nodules under different CT reconstruction method.