颈丛及周围结构三维模型的构建与可视化研究

Three-dimensional construction and visualization of cervical plexus and its surrounding structures

目的寻求建立颈丛及周围结构数字模型及三维可视化的方法。方法取健康志愿者头顶至第3胸椎下缘连续CT血管成像(CTA)动脉造影及MR脊髓造影(MRM)断面图像,经内插值处理达到亚体素精度,调整窗位、窗宽及对比度使其达到最佳视度。在CTA血管造影断层数据集中,基于骨骼CT阈值,采用Mimics软件,以Thresholding和Region Growing工具进行半自动分割,重建骨骼结构的三维数字模型,基于动脉、静脉、甲状腺、喉软骨在血管造影不同时期CT阈值的差异,以Thresholding和Dynamic Region Growing工具进行分割,重建升主动脉、主动脉弓、锁骨下动脉、颈总动脉、椎动脉、颈外静脉、颈内静脉、锁骨下静脉、胸锁乳突肌、甲状腺、舌骨和喉软骨(甲状软骨)的三维数字模型。以医学计算机辅助设计(MedCAD)模块对肌肉、颈丛等细小解剖结构重建,三维化显示颈丛及周围相关解剖结构。结果建立了颈丛及周围结构的三维可视化模型,可清晰显示骨性结构、主动脉、上腔静脉、胸锁乳突肌、中斜角肌、肩胛提肌、脊髓、颈丛皮支(枕小神经、耳大神经、颈横神经、锁骨上神经)和膈神经等解剖结构的位置关系。结论颈丛及周围结构三维可视化模型可以为骨科和颈丛麻醉提供解剖形态学参考。

Objective To find a method of establishing digital model and three-dimensional visualization for cervical plexus and its surrounding structures. Methods Cross-sectional images of continuous CT angiography （CTA） and magnetic resonance myelography （MRM） from the vertex to inferior border of the 3rd thoracic vertebrae of a healthy volunteer were obtained, and treated to sub-voxel accuracy by interpolation, then the window level, window width and contrast were adjusted to achieve the best visual degree. In the CTA data set, 3-D digital model of bone structure was reconstructed by semi-automatic segmentation with Thresholding and Region Growing tools of Mimics software based on the CT threshold of skeleton, and 3-D digital models of ascending aorta, aortic arch, subclavian artery, common carotid artery, vertebral artery, external jugular vein, internal jugular vein, subclavian vein, sternocleidomastoid muscle, thyroid, hyoid bone and laryngeal cartilage （thyroid cartilage） were reconstructed by segmentation with Thresholding and Dynamic Region Growing tools of Mimics software based on the threshold differences of arteries, veins, thyroid, larynx cartilage in different periods of CTA. Small anatomic structures such as muscles and cervical plexus were reconstructed with the MedCAD module, and the 3-D model of cervical plexus and its surrounding structures were successfully displayed. Results A 3-D digital model of cervical plexus and its surrounding structures was established, and the positional relationship of anatomic structures was successfully displayed including skeletal structures, aorta, superior vena cava, sternocleidomastoid, mediscalenus, levator scapulae, spinal cord, cervical plexus cutaneous branch （lesser occipital nerve, great auricular nerve, transverse nerve of neck, supraclavicular nerve） and phrenic nerve. Conclusion The 3-D visualization of cervical plexus and its surrounding structures may provide morphologic data for orthopedics surgical procedures and cervical plexus block.