Impact of Tumor Size and Tracer Uptake Heterogeneity in 18F-FDG PET and CT Non-Small Cell Lung Cancer Tumor Delineation
Impact of Tumor Size and Tracer Uptake Heterogeneity in 18F-FDG PET and CT Non-Small Cell Lung Cancer Tumor Delineation
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DOI：
10.2967/jnumed.111.092767
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发表时间：
2011-11-01
影响因子：
9.3
通讯作者：
Visvikis, Dimitris
中科院分区：
文献类型：
--
作者：
Hatt, Mathieu;Cheze-le Rest, Catherine;Visvikis, Dimitris
本研究的目的是研究基于CT和F-18-FDG PET的非小细胞肺癌（NSCLC）肿瘤体积之间的关系，以及肿瘤大小和摄取异质性对PET图像上描绘摄取的各种方法的影响。方法：对25例非小细胞肺癌患者进行F-18-FDG PET/CT检查。17例接受了肿瘤手术切除，并测量了最大直径。两名观察员手动描绘CT图像上的肿瘤和相应PET图像上的肿瘤摄取，使用最大值（T-50）的50%的固定阈值、自适应阈值方法和模糊局部自适应贝叶斯（FLAB）算法。当可用时，将描绘体积的最大直径与组织病理学参考进行比较。比较肿瘤的体积，并研究解剖体积和PET摄取异质性之间的相关性以及轮廓之间的差异。结果：PET和CT测量的最大径与病理对照值均呈显著相关（r > 0.89，P < 0.0001）。在这些方法之间观察到显著差异：CT描绘导致大幅高估（132% +/- 37%），而PET图像上的所有描绘均导致低估（从T-50的215% +/- 17%到FLAB的24% +/- 8%），手动描绘除外（18% +/- 17%）。总体而言，CT体积显著大于PET体积（CT为55 +/- 74 cm（3），PET为18 +/- 25至47 +/- 76 cm（3））。解剖肿瘤大小和异质性之间存在显著相关性（较大的病变更异质）。最后，肿瘤摄取越不均匀，基于阈值的技术对PET体积的低估就越大。结论：CT图像上的病灶大于PET图像上的病灶。肿瘤大小和示踪剂摄取异质性对基于阈值的方法有影响，不应用于描述大型异质性NSCLC病例，因为这些方法往往在很大程度上低估了此类病例中功能性肿瘤的空间范围。为了准确描绘NSCLC中的PET体积，应首选能够处理示踪剂摄取异质性的高级图像分割算法。
The objectives of this study were to investigate the relationship between CT-and F-18-FDG PET-based tumor volumes in non-small cell lung cancer (NSCLC) and the impact of tumor size and uptake heterogeneity on various approaches to delineating uptake on PET images. Methods: Twenty-five NSCLC cancer patients with F-18-FDG PET/CT were considered. Seventeen underwent surgical resection of their tumor, and the maximum diameter was measured. Two observers manually delineated the tumors on the CT images and the tumor uptake on the corresponding PET images, using a fixed threshold at 50% of the maximum (T-50), an adaptive threshold methodology, and the fuzzy locally adaptive Bayesian (FLAB) algorithm. Maximum diameters of the delineated volumes were compared with the histopathology reference when available. The volumes of the tumors were compared, and correlations between the anatomic volume and PET uptake heterogeneity and the differences between delineations were investigated. Results: All maximum diameters measured on PET and CT images significantly correlated with the histopathology reference (r > 0.89, P < 0.0001). Significant differences were observed among the approaches: CT delineation resulted in large overestimation (132% +/- 37%), whereas all delineations on PET images resulted in underestimation (from 215% +/- 17% for T-50 to 24% +/- 8% for FLAB) except manual delineation (18% +/- 17%). Overall, CT volumes were significantly larger than PET volumes (55 +/- 74 cm(3) for CT vs. from 18 +/- 25 to 47 +/- 76 cm(3) for PET). A significant correlation was found between anatomic tumor size and heterogeneity (larger lesions were more heterogeneous). Finally, the more heterogeneous the tumor uptake, the larger was the underestimation of PET volumes by threshold-based techniques. Conclusion: Volumes based on CT images were larger than those based on PET images. Tumor size and tracer uptake heterogeneity have an impact on threshold-based methods, which should not be used for the delineation of cases of large heterogeneous NSCLC, as these methods tend to largely underestimate the spatial extent of the functional tumor in such cases. For an accurate delineation of PET volumes in NSCLC, advanced image segmentation algorithms able to deal with tracer uptake heterogeneity should be preferred.