三维重建CTA对脊柱节段动脉解剖及微创术前评估的价值

The value of 3D reconstructions of spinal segmental arteries using CTA in anatomy and minimally invasive spinal procedures

目的：评估CTA结合三维后处理重建对脊柱节段动脉的显示能力，以及对于脊柱微创手术术前评估的价值。方法收集2011年～2013年间于我院因行脊柱血管CTA检查患者共61例，两位放射科医生利用三维后处理技术对全部节段动脉进行独立分析。将节段动脉走形路径按其与邻近椎体的关系分为A-D四种类型进行统计分析。将全部节段动脉分为T8～L1段、L2～L4段上下两组，对两组分布特点进行对比分析。结果61例病例的SSA在CTA上均得到良好显示，三维重建图像能很好显示SSA走形路径以及与邻近椎体结构的毗邻关系。绝大部分SSA（982／1098，89.4％）沿B、C区域走形；但也有少部分SSA（75／1098，6．8％）走形于A、D区域，其中45支（12．6％）出现于L2～L4段SSA中，30支（4．3％），下组L2～L4段比例明显上组T8～L1段（ P ＜0．05）。另外，还发现SSA存在缺失和双供血两种变异。结论多排螺旋CTA结合三维后处理图像可以准确、直观地显示SSA位置走形及其与相邻椎体结构的解剖关系，结合本文提出的4分区法为外科行椎弓旁椎体成形术提供了一种既准确又简单的确定安全穿刺部位的方法，从而最大限度的降低SSA损伤的发生率。

Objective Injury to spinal segmental arteries may potentially occur during spinal surgery , particularly during ante-rior or minimally invasive approaches .By use of a noninvasive radiologic tool to evaluate these arteries before surgery may reduce this risk.Methods We performed spinal CT angiography and reconstructed 3D images of segmental arteries in 61 patients.We classified the pathways and locations of the segmental arteriesinto 4 zones （A, B, C, and D） according to pedicle and vertebral endplates .We designated segmental arteries from T 8 to L1 as “high-level segmental arteries” and those from L 2 to L4 , as “low-level segmental arteries .” We compared the distribution of segmental arteries between these 2 groups.We also investigated ana-tomic variations of segmental arteries .Results In all patients, 3D reconstruction images from spinal CT angiography clearly showed the pathways of segmental arteries on the vertebral bodies .Most of the segmental arteries passed the zones B and C .How-ever, 75 of 1098 segmental arteries （6.8%） passed zones A and D.Segmental arteries from L2 to L4 had a higher incidence of uncommon pathways than higher level vertebrae （ P 〈.05）.We also observed 2 types of anatomic variation：agenesis and dual supply.Conclusion We suggest that spinal CTA can help to precisely visualize the spinal segmental arteries and surrounding bony structures and can aid clinicians in deciding on optimal approaches for spinal surgery .