Klaassen Lisa, Ferreira Teresa A, Luyten Gregorius, Beenakker Jan-Willem M
Department of Ophthalmology, Leiden University Medical Center, Leiden, the Netherlands.
Department of Radiology, Leiden University Medical Center, Leiden, the Netherlands.
Acta Ophthalmol. 2025 Sep;103(6):691-698. doi: 10.1111/aos.17492. Epub 2025 Apr 3.
Ellipsoid tumour models are used to approximate the tumour volume of uveal melanomas, as the conventionally used ultrasound does not provide a three-dimensional visualization of the tumour. However, these models are a simplification of the actual tumour geometry. The aim of this study was to determine to what extent several of these frequently used ellipsoid tumour models accurately describe uveal melanoma volume.
Tumours were delineated on contrast-enhanced T1-weighted MRI for 70 uveal melanoma patients. The MRI-delineated volume was compared with three ellipsoid models, which used two-dimensional measurements such as thickness and basal diameters as input: half ellipsoids with round (V) or oval base (V) and a paraboloid consisting of two parts, also incorporating the curvature of the eye wall (V).
Statistically significant relative differences between MRI-delineated and model volume of 53 ± 32% (V), 26 ± 24% (V) and 15 ± 24% (V) were observed (p < 0.001). Tumour volume and shape did not influence the difference between the model volumes and MRI-delineated tumour volume.
All tumour models result in considerable systematic overestimations of tumour volume, with large variations in overestimation between patients. Adding the perpendicular basal diameter to the model decreases this variation. Although ellipsoid tumour models have been shown to be valuable on a group level, they should be used with caution for individual patients.
椭球体肿瘤模型用于估算葡萄膜黑色素瘤的肿瘤体积，因为传统使用的超声无法提供肿瘤的三维可视化图像。然而，这些模型是对实际肿瘤几何形状的简化。本研究的目的是确定这些常用的椭球体肿瘤模型在多大程度上能够准确描述葡萄膜黑色素瘤的体积。
对70例葡萄膜黑色素瘤患者的增强T1加权MRI图像上的肿瘤进行勾画。将MRI勾画的体积与三种椭球体模型进行比较，这三种模型使用厚度和基底直径等二维测量值作为输入：具有圆形（V）或椭圆形基底（V）的半椭球体以及由两部分组成的抛物面，该抛物面还纳入了眼壁的曲率（V）。
观察到MRI勾画的体积与模型体积之间的统计学显著相对差异分别为53±32%（V）、26±24%（V）和15±24%（V）（p<0.001）。肿瘤体积和形状并未影响模型体积与MRI勾画的肿瘤体积之间的差异。
所有肿瘤模型均导致对肿瘤体积的系统性高估，且患者之间的高估差异很大。在模型中加入垂直基底直径可减少这种差异。尽管椭球体肿瘤模型在群体水平上已被证明是有价值的，但对于个体患者应谨慎使用。
