[论文解读] Reliability of PET/CT shape and heterogeneity features in functional and morphological components of Non-Small Cell Lung Cancer tumors: a repeatability analysis in a prospective multi-center cohort

Marie-Charlotte Desseroit, Florent Tixier+5 more|arXiv (Cornell University)|Oct 5, 2016

Radiomics and Machine Learning in Medical Imaging参考文献 22被引用 6

一句话总结

本研究评估了在多个中心进行的非小细胞肺癌（NSCLC）患者PET和低剂量CT图像中形状与异质性特征的可重复性。基于74名患者的重复扫描PET/CT数据，研究发现特征可靠性因指标和量化方法而异，其中量化B方法可提高PET的可靠性，而量化W方法可增强CT的可靠性，凸显了在放射组学模型开发中需重点关注的关键因素。

ABSTRACT

Purpose: The main purpose of this study was to assess the reliability of shape and heterogeneity features in both Positron Emission Tomography (PET) and low-dose Computed Tomography (CT) components of PET/CT. A secondary objective was to investigate the impact of image quantization.Material and methods: A Health Insurance Portability and Accountability Act -compliant secondary analysis of deidentified prospectively acquired PET/CT test-retest datasets of 74 patients from multi-center Merck and ACRIN trials was performed. Metabolically active volumes were automatically delineated on PET with Fuzzy Locally Adaptive Bayesian algorithm. 3DSlicerTM was used to semi-automatically delineate the anatomical volumes on low-dose CT components. Two quantization methods were considered: a quantization into a set number of bins (quantizationB) and an alternative quantization with bins of fixed width (quantizationW). Four shape descriptors, ten first-order metrics and 26 textural features were computed. Bland-Altman analysis was used to quantify repeatability. Features were subsequently categorized as very reliable, reliable, moderately reliable and poorly reliable with respect to the corresponding volume variability. Results: Repeatability was highly variable amongst features. Numerous metrics were identified as poorly or moderately reliable. Others were (very) reliable in both modalities, and in all categories (shape, 1st-, 2nd- and 3rd-order metrics). Image quantization played a major role in the features repeatability. Features were more reliable in PET with quantizationB, whereas quantizationW showed better results in CT.Conclusion: The test-retest repeatability of shape and heterogeneity features in PET and low-dose CT varied greatly amongst metrics. The level of repeatability also depended strongly on the quantization step, with different optimal choices for each modality. The repeatability of PET and low-dose CT features should be carefully taken into account when selecting metrics to build multiparametric models.

研究动机与目标

• 评估多中心NSCLC肿瘤的PET和低剂量CT影像中放射组学特征的测试-重测可重复性。
• 确定图像量化方法对功能型（PET）和解剖型（CT）影像组件中特征可靠性的影响。
• 基于可重复性度量，将形状和异质性特征分类为极可靠、可靠、中等可靠或不可靠。
• 通过识别模态和量化方法特定的最优特征，指导NSCLC多参数建模中稳健放射组学特征的选择。

提出的方法

• 对74名NSCLC患者在多中心临床试验（默克和ACRIN）中获取的去标识化重复扫描PET/CT数据集进行符合HIPAA要求的二次分析。
• 使用模糊局部自适应贝叶斯（FLAB）算法自动勾画PET图像中代谢活跃的肿瘤体积。
• 使用3DSlicer™半自动勾画低剂量CT图像中的解剖肿瘤体积。
• 应用两种量化方法：固定分箱数量（量化B）和固定分箱宽度（量化W）以计算特征。
• 在两种模态中分别计算4种形状描述符、10种一阶指标和26种纹理特征。
• 采用Bland-Altman分析量化测试-重测可重复性，并按可靠性水平对特征进行分类。

实验结果

研究问题

• RQ1 在NSCLC肿瘤的重复扫描中，从PET和低剂量CT提取的形状与异质性特征的可靠性如何？
• RQ2 图像量化方法的选择（固定分箱数量 vs. 固定分箱宽度）如何影响放射组学特征的可重复性？
• RQ3 哪些放射组学特征在PET与低剂量CT中表现出高可重复性，且在不同特征类别中表现如何？
• RQ4 影像模态（功能型PET vs. 解剖型CT）在多大程度上影响放射组学特征的可靠性？

主要发现

• 放射组学特征的可重复性差异显著，许多特征在PET和CT中均被归类为不可靠或中等可靠。
• 一小部分特征——尤其是形状、一阶和纹理类特征——在PET和CT模态中均表现出（极高）可靠性。
• 量化B显著提高了PET图像中特征的可靠性，而量化W在低剂量CT图像中表现更优。
• 量化方法的选择对特征可重复性有重大影响，表明方法学选择对特征稳健性具有关键影响。
• 本研究识别出应在NSCLC多参数放射组学模型中优先考虑的特定特征类别和量化策略。