South West Sydney Cancer Services, Liverpool, Australia; Ingham Institute for Applied Medical Research, Liverpool, Australia; South Western Sydney Clinical School, University of New South Australia, Sydney, Australia.
South West Sydney Cancer Services, Liverpool, Australia; Ingham Institute for Applied Medical Research, Liverpool, Australia; South Western Sydney Clinical School, University of New South Australia, Sydney, Australia; Institute of Medical Physics, School of Physics, University of Sydney, Sydney, Australia; School of Mathematical and Physical Sciences, University of Newcastle, Newcastle, Australia; Centre for Medical Radiation Physics, University of Wollongong, Wollongong, Australia.
Radiother Oncol. 2022 Feb;167:292-299. doi: 10.1016/j.radonc.2021.11.036. Epub 2021 Dec 8.
To compare gross tumour volume (GTV) delineation of lung cancer on magnetic resonance imaging (MRI) and positron emission tomography (PET) versus computed tomography (CT) and PET.
Three experienced thoracic radiation oncologists delineated GTVs on twenty-six patients with lung cancer, based on CT registered to PET, T2-weighted MRI registered to PET and T1-weighted MRI registered with PET. All observers underwent education on reviewing T1 and T2 images along with guidance on window and level setup. Interobserver and intermodality variation was performed based on dice similarity coefficient (DSC), Hausdorff distance (HD), and average Hausdorff distance (AvgHD) metrics. To compute interobserver variability (IOV) a simultaneous truth and performance level estimation (STAPLE) volume for each image modality was used as reference volume. For intermodality analysis, each observers CT based primary and nodal GTV was used as reference volume.
A mean DSC of 0.9 across all observers for primary GTV (GTVp) and a DSC of >0.7 for nodal GTV (GTVn) was demonstrated for IOV. Mean T2 and T1 GTVp and GTVn were smaller than CT GTVp and GTVn but the difference in volume between modalities was not statistically significant. Significant difference (p < 0.01) for GTVp and GTVn was found between T2 and T1 GTVp and GTVn compared to CT GTVp and GTVn based on DSC metrics. Large variation in volume similarity was noted based on HD of up-to 5.4 cm for observer volumes compared to STAPLE volume.
Interobserver variability in GTV delineation was similar for MRI and PET versus CT and PET. The significant difference between MRI compared to CT delineated volumes needs to be further explored.
比较磁共振成像（MRI）和正电子发射断层扫描（PET）与计算机断层扫描（CT）和 PET 相比，肺癌的大体肿瘤体积（GTV）勾画。
三位经验丰富的胸部放射肿瘤学家根据 CT 与 PET 配准、T2 加权 MRI 与 PET 配准以及 T1 加权 MRI 与 PET 配准，对 26 例肺癌患者的 GTV 进行勾画。所有观察者都接受了 T1 和 T2 图像复习以及窗口和水平设置指导方面的教育。基于骰子相似系数（DSC）、Hausdorff 距离（HD）和平均 Hausdorff 距离（AvgHD）指标，进行了观察者间和模式间的变异性分析。为了计算观察者间变异性（IOV），使用每个图像模式的同时真实和性能水平估计（STAPLE）体积作为参考体积。对于模式间分析，每个观察者基于 CT 的原发性和淋巴结 GTV 被用作参考体积。
在 IOV 中，所有观察者的原发性 GTV（GTVp）的平均 DSC 为 0.9，淋巴结 GTV（GTVn）的 DSC 大于 0.7。T2 和 T1 GTVp 和 GTVn 的平均体积小于 CT GTVp 和 GTVn，但各模式之间的体积差异无统计学意义。基于 DSC 指标，T2 和 T1 GTVp 和 GTVn 与 CT GTVp 和 GTVn 相比，GTVp 和 GTVn 的差异有统计学意义（p<0.01）。基于 HD，观察者体积与 STAPLE 体积相比，体积相似性的变化较大，高达 5.4cm。
与 CT 和 PET 相比，MRI 和 PET 中 GTV 勾画的观察者间变异性相似。MRI 与 CT 勾画体积之间的显著差异需要进一步探讨。
