Chen Lih-Shyang, Hsu Ta-Wen, Chen Shao-Jer, Chang Shu-Han, Lin Chih-Wen, Chen Yu-Ruei, Hsieh Chin-Chiang, Han Shu-Chen, Chang Ku-Yaw, Hou Chun-Ju
Department of Electric Engineering, National Cheng Kung University, Tainan, Taiwan, ROC.
Department of General Surgery, Dalin Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation, Chiayi, Taiwan, ROC.
J Med Biol Eng. 2020;40(6):868-879. doi: 10.1007/s40846-020-00565-0. Epub 2020 Sep 26.
To improve the three dimensional (3D) and two dimensional (2D) image correlation and differentiation of 3D endoluminal lesions in the traditional surface rendering (SR) computed tomographic endoscopy (CTE), a target gray level mapping (TGM) technique is developed and applied to computed tomographic colonography (CTC) in this study.
A study of sixty-two various endoluminal lesions from thirty patients (13 males, 17 females; age range 31-90 years) was approved by our institutional review board and evaluated retrospectively. The endoluminal lesions were segmented using gray level threshold. The marching cubes algorithm was used to detect isosurfaces in the segmented volumetric data sets. TGM allows users to interactively apply grey level mapping (GM) to region of interest (ROI) in the 3D CTC. Radiologists conducted the clinical evaluation and the resulting data were analyzed.
TGM and GM are significantly superior to SR in terms of surface texture, 3D shape, the confidence of 3D to 2D, 2D to 3D image correlation, and clinical classification of endoluminal lesions (P < 0.01). The specificity and diagnostic accuracy of GM and TGM methods are significantly better than those of SR (P < 0.01). Moreover, TGM performs better than GM (specificity: 75.0-85.7% vs. 53.6-64.3%; accuracy: 88.7-93.5% vs. 77.4-83.9%). TGM is a preferable display mode for further localization and differentiation of a lesion in CTC navigation.
Compared with only the spatial shape information in traditional SR of CTC images, the 3D shapes and gray level information of endoluminal lesions can be provided by TGM simultaneously. 3D to 2D image correlations are also increased and facilitated at the same time. TGM is less affected by adjacent colon surfaces than GM. TGM serves as a better way to improve the image correlation and differentiation of endoluminal lesions.
为了改善传统表面渲染（SR）计算机断层扫描内镜检查（CTE）中三维（3D）腔内病变的三维（3D）和二维（2D）图像相关性及区分度，本研究开发了一种目标灰度映射（TGM）技术并将其应用于计算机断层扫描结肠成像（CTC）。
本研究经机构审查委员会批准，对30例患者（13例男性，17例女性；年龄范围31 - 90岁）的62种不同腔内病变进行回顾性评估。使用灰度阈值对腔内病变进行分割。利用移动立方体算法在分割后的体数据集里检测等值面。TGM允许用户在三维CTC中对感兴趣区域（ROI）交互式地应用灰度映射（GM）。放射科医生进行临床评估并对所得数据进行分析。
在表面纹理、三维形状、三维到二维、二维到三维图像相关性以及腔内病变的临床分类方面，TGM和GM显著优于SR（P < 0.01）。GM和TGM方法的特异性和诊断准确性显著优于SR（P < 0.01）。此外，TGM的表现优于GM（特异性：75.0 - 85.7%对53.6 - 64.3%；准确性：88.7 - 93.5%对77.4 - 83.9%）。TGM是在CTC导航中对病变进行进一步定位和区分的更优显示模式。
与传统CTC图像SR中仅有的空间形状信息相比，TGM能同时提供腔内病变的三维形状和灰度信息。同时，三维到二维的图像相关性也得到增强和促进。与GM相比，TGM受相邻结肠表面的影响更小。TGM是改善腔内病变图像相关性和区分度的更好方法。
