Division of Plastic Surgery, Children's Hospital of Philadelphia, University of Pennsylvania, Buerger Center, 3500 Civic Center Boulevard, Philadelphia, PA 19104.
Department of Radiology, University of Pennsylvania, Philadelphia, PA.
Acad Radiol. 2020 Nov;27(11):1515-1522. doi: 10.1016/j.acra.2020.03.001. Epub 2020 Apr 13.
Computed tomography (CT) is the clinical gold-standard for high-resolution 3D visualization of cortical bone structures. However, ionizing radiation is of concern, particularly for pediatric patients. This study evaluates the feasibility of producing 3D human skull renderings using a novel bone-selective magnetic resonance imaging technique.
A dual-radiofrequency pulse, dual-echo, 3D ultrashort echo time sequence was applied for scanning of a cadaver skull and five healthy adult subjects. Scans were each completed within 6 minutes. Semiautomatic segmentation of bone voxels was performed using ITK-SNAP software, leading to 3D renderings of the skulls. For comparison, thin-slice head CT scans were performed. Mimics software was used to measure eight anatomic distances from 3D renderings. Lin's Concordance Correlation test was applied to assess agreement between measurements from MR-based and CT-based 3D skull renderings.
The 3D rendered MR images depict most craniofacial features (e.g., zygomatic arch), although some voxels were erroneously included or excluded in the renderings. MR-based measurements differed from CT-based measurements by mean percent difference ranging from 2.3%-5.0%. Lin's Concordance Correlation Coefficients for MR-based vs CT-based measurements ranged from 0.998-1.000.
The proposed dual-radiofrequency dual-echo 3D ultrashort echo time imaging technique produces high-resolution bone-specific images within a clinically feasible imaging time, leading to clear visualization of craniofacial skeletal structures. Concordance coefficients suggest good reliability of the method compared to CT. The method is currently limited by time and manual input necessary for segmentation correction. Further investigation is needed for more accurate 3D renderings and for scanning of pediatric patients.
计算机断层扫描（CT）是用于高分辨率三维皮质骨结构可视化的临床金标准。然而，电离辐射是一个关注点，尤其是对于儿科患者。本研究评估了一种新型的骨选择性磁共振成像技术生成 3D 人类颅骨渲染的可行性。
对一个尸体颅骨和五个健康成年人进行了双射频脉冲、双回波、3D 超短回波时间序列的扫描。每次扫描均在 6 分钟内完成。使用 ITK-SNAP 软件对骨体素进行半自动分割，从而生成颅骨的 3D 渲染。为了比较，进行了薄层头部 CT 扫描。使用 Mimics 软件测量了 3D 渲染图中的八个解剖距离。应用 Lin's 一致性相关系数评估基于 MR 和基于 CT 的 3D 颅骨渲染的测量值之间的一致性。
3D 渲染的 MR 图像描绘了大多数颅面特征（例如，颧骨弓），尽管在渲染中有些体素被错误地包括或排除。基于 MR 的测量值与基于 CT 的测量值之间的平均百分比差异范围为 2.3%-5.0%。基于 MR 与基于 CT 的测量值之间的 Lin's 一致性相关系数范围为 0.998-1.000。
所提出的双射频双回波 3D 超短回波时间成像技术在临床可行的成像时间内产生高分辨率的骨特异性图像，可清晰显示颅面骨骼结构。一致性系数表明，与 CT 相比，该方法具有良好的可靠性。该方法目前受到时间和分割校正所需的手动输入的限制。需要进一步研究以获得更准确的 3D 渲染和对儿科患者的扫描。
