Department of Obstetrics and Gynecology, National Cheng Kung University Medical College and Hospital, Tainan, Taiwan.
Ultrasound Obstet Gynecol. 2012 Jun;39(6):642-7. doi: 10.1002/uog.10104. Epub 2012 May 22.
Three-dimensional (3D) ultrasound is useful in the prenatal evaluation of fetal craniofacial structures, particularly as it provides a multiplanar view. However, an expert must designate the area of interest and the appropriate view, making measurement of fetal structures using 3D ultrasound both time-consuming and subjective. In this study we propose an image analysis system that measures automatically and precisely the fetal craniofacial structures and evaluate its performance in the second trimester of pregnancy using a new 3D volume analysis algorithm.
A universal facial surface template model containing the geometric shape information of a fetal craniofacial structure was constructed from a fetal phantom. Using the proposed image analysis system we fitted this stored template model using a model deformation approach to individual fetal 3D facial volumes from 11 mid-trimester fetuses, and extracted automatically the following standard measurements: biparietal diameter (BPD), occipitofrontal diameter (OFD), interorbital diameter (IOD), bilateral orbital diameter (BOD) and distance between vertex and nasion (VN). The same five parameters were measured manually by an expert and the results compared.
Comparison of the algorithm-based automatic measurements with manual measurements made by an expert gave correlation coefficients of 0.99 for BPD, 0.98 for OFD, 0.80 for BOD, 0.83 for IOD and 0.99 for VN. There were no significant differences between automatic and manual measurements.
Our proposed system measures precisely the fetal craniofacial structures using 3D ultrasound, making it potentially useful for clinical service. This system could also be applied to other clinical fields in future testing.
三维（3D）超声在胎儿颅面结构的产前评估中很有用，尤其是它提供了多平面视图。然而，专家必须指定感兴趣的区域和适当的视图，这使得使用 3D 超声测量胎儿结构既耗时又主观。在这项研究中，我们提出了一种图像分析系统，可以自动精确地测量胎儿颅面结构，并使用新的 3D 体积分析算法在妊娠中期评估其性能。
从胎儿模型中构建了一个包含胎儿颅面结构几何形状信息的通用面部表面模板模型。使用提出的图像分析系统，我们使用模型变形方法将该存储的模板模型拟合到 11 个中期胎儿的个体 3D 面部体积中，并自动提取以下标准测量值：双顶径（BPD）、枕额径（OFD）、眶间径（IOD）、双侧眶径（BOD）和顶点到鼻根的距离（VN）。由专家手动测量相同的五个参数，并进行比较。
算法自动测量与专家手动测量的比较给出了 BPD 的相关系数为 0.99，OFD 为 0.98，BOD 为 0.80，IOD 为 0.83，VN 为 0.99。自动测量与手动测量之间没有显著差异。
我们提出的系统使用 3D 超声精确测量胎儿颅面结构，这使其在临床服务中具有潜在的应用价值。该系统在未来的测试中也可应用于其他临床领域。
