（18）F-FDG PET 和 CT 用于非小细胞肺癌肿瘤勾画中肿瘤大小和示踪剂摄取异质性的影响。
Impact of tumor size and tracer uptake heterogeneity in (18)F-FDG PET and CT non-small cell lung cancer tumor delineation.
机构信息
INSERM, U650 LaTIM, CHRU Morvan, Brest, France.
出版信息
J Nucl Med. 2011 Nov;52(11):1690-7. doi: 10.2967/jnumed.111.092767. Epub 2011 Oct 11.
UNLABELLED
The objectives of this study were to investigate the relationship between CT- and (18)F-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 (18)F-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 (+32% ± 37%), whereas all delineations on PET images resulted in underestimation (from -15% ± 17% for T(50) to -4% ± 8% for FLAB) except manual delineation (+8% ± 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.
目的
本研究旨在探讨非小细胞肺癌（NSCLC）患者 CT 和（18）F-FDG PET 肿瘤体积之间的关系，以及肿瘤大小和摄取异质性对各种方法勾画 PET 图像摄取的影响。
方法
25 例 NSCLC 患者行（18）F-FDG PET/CT 检查，17 例行肿瘤切除术，测量最大直径。2 位观察者分别在 CT 图像上手动勾画肿瘤和相应的 PET 图像上的肿瘤摄取，采用固定阈值（50%最大摄取，T（50））、自适应阈值方法和模糊局部自适应贝叶斯（FLAB）算法。在有组织病理学参考的情况下，将勾画的肿瘤体积最大直径与病理参考进行比较。比较肿瘤体积，研究肿瘤的解剖体积与 PET 摄取异质性之间的相关性以及勾画之间的差异。
结果
PET 和 CT 图像上测量的所有最大直径均与组织病理学参考显著相关（r > 0.89，P < 0.0001）。不同方法之间存在显著差异：CT 勾画导致明显的高估（+32% ± 37%），而所有 PET 图像上的勾画均导致低估（从 T（50）的-15% ± 17%到 FLAB 的-4% ± 8%），只有手动勾画是例外（+8% ± 17%）。总体而言，CT 体积明显大于 PET 体积（CT 为 55 ± 74 cm3，而 PET 为 18 ± 25 至 47 ± 76 cm3）。肿瘤的解剖大小与异质性之间存在显著相关性（较大的病变更具异质性）。最后，肿瘤摄取的异质性越大，基于阈值的技术对 PET 体积的低估就越大。
结论
基于 CT 图像的体积大于基于 PET 图像的体积。肿瘤大小和示踪剂摄取异质性对基于阈值的方法有影响，因此不应将其用于勾画大的异质性 NSCLC 病例，因为这些方法往往会大大低估此类病例中功能性肿瘤的空间范围。为了准确勾画 NSCLC 的 PET 体积，应优先选择能够处理示踪剂摄取异质性的先进图像分割算法。
Zotero 插件