Three-dimensional model of lesion geometry for evaluation of MR-guided thermal ablation therapy
Three-dimensional model of lesion geometry for evaluation of MR-guided thermal ablation therapy
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DOI：
10.1016/s1076-6332(03)80514-7
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发表时间：
2002-10-01
影响因子：
4.8
通讯作者：
Wilson, DL
中科院分区：
文献类型：
--
作者：
Lazebnik, RS;Weinberg, BD;Wilson, DL
理由和目标。高射频能量在临床上用于通过介入磁共振（MR）成像消融病理组织。对于许多组织，所产生的病变在对比增强的T1和T2加权MR图像上具有特征性的外观，具有两个边界，包括内部低信号区域和外部高信号边缘。动物实验和患者治疗中三维热损伤的几何建模将改善分析和可视化。作者创建了一个具有两个二次曲面和12个参数的模型来描述两个病变表面。通过迭代优化来估计参数，以最小化从分割点到模型表面的最短距离的平方和。作者使用模拟不同程度分割错误和缺失表面信息的数字病变体模验证了估计过程。他们还将他们的方法应用于兔子模型中病变的体内图像。对于模拟体模病变，尽管存在手动分割错误和表面数据不完整，但病变几何形状是准确的。即使当50%的表面缺失时，中位误差也小于0.5 mm。对于所有体内病变，从模型表面到数据的中位距离对于内表面和外表面均不超过0.58 mm，小于体素宽度（0.7 mm）。所有数据的四分位距为0.89 mm或更小。作者的模型提供了一个很好的近似实际病变的几何形状，是高度抵抗丢失的分割信息。它应该被证明是有用的三维病变可视化，体积估计，自动分割和体积配准。
Rationale and Objectives. High-radiofrequency energy is used clinically to ablate pathologic tissue with interventional magnetic resonance (MR) imaging. For many tissues, resulting lesions have a characteristic appearance on contrast-enhanced T1- and T2-weighted MR images, with two boundaries enclosing an inner hypointense region and an outer hyperintense margin. Geometric modeling of three-dimensional thermal lesions in animal experiments and patient treatments would improve analyses and visualization.Materials and Methods. The authors created a model with two quadric surfaces and 12 parameters to describe both lesion surfaces. Parameters were estimated with iterative optimization to minimize the sum of the squared shortest distances from segmented points to the model surface. The authors validated the estimation process with digital lesion phantoms that simulated varying levels of segmentation error and missing surface information. They also applied their method to in vivo images of lesions in a rabbit model.Results. For simulated phantom lesions, the lesion geometry was accurate despite manual segmentation error and incomplete surface data. Even when 50% of the surface was missing, the median error was less than 0.5 mm. For all in vivo lesions, the median distance from the model surface to data was no more than 0.58 mm for both inner and outer surfaces, less than a voxel width (0.7 mm). The interquartile range was 0.89 mm or less for all data.Conclusion. The authors' model provides a good approximation of actual lesion geometry and is highly resistant to missing segmentation information. It should prove useful for three-dimensional lesion visualization, volume estimation, automated segmentation, and volume registration.