Accuracy of image-guided percutaneous injection into a phantom spinal cord utilizing flat panel detector CT with MR fusion and integrated navigational software

Accuracy of image-guided percutaneous injection into a phantom spinal cord utilizing flat panel detector CT with MR fusion and integrated navigational software

Purpose To evaluate the accuracy of percutaneous fluoroscopic injection into the spinal cord of a spine phantom utilizing integrated navigational guidance from fused flat panel detector CT (FDCT) and MR datasets. Conventional and convection-enhanced delivery (CED) techniques were evaluated. Materials and methods FDCT and MR datasets of a swine thoracic spine phantom were co-registered using an integrated guidance system and surface to spinal cord target trajectory planning was performed on the fused images. Under real-time fluoroscopic guidance with pre-planned trajectory overlay, spinal cord targets were accessed via a coaxial technique. Final needle tip position was compared with a pre-determined target on 10 independent passes. In a subset of cases, contrast was injected into the central spinal cord with a 25G spinal needle or customized 200 µm inner diameter step design cannula for CED. Results Average needle tip deviation from target measured 0.92±0.5 mm in the transverse, 0.47±0.4 mm in the anterior-posterior, and 1.67±1.2 mm in the craniocaudal dimension for an absolute distance error of 2.12±1.12 mm. CED resulted in elliptical intramedullary diffusion of contrast compared with primary reflux observed with standard needle injection. Conclusions These phantom feasibility data demonstrate a minimally invasive percutaneous approach for targeted injection into the spinal cord utilizing real-time fluoroscopy aided by overlay trajectories derived from fused MRI and FDCT data sets with a target error of 2.1 mm. Intramedullary diffusion of injectate in the spinal cord is facilitated with CED compared with standard injection technique. Pre-clinical studies in large animal models are warranted.

目的：利用融合平板探测器CT（FDCT）和磁共振（MR）数据集的集成导航引导，评估对脊柱体模脊髓进行经皮透视注射的准确性。对常规和对流增强递送（CED）技术进行了评估。 材料和方法：使用集成引导系统对猪胸椎体模的FDCT和MR数据集进行配准，并在融合图像上进行从体表到脊髓目标轨迹的规划。在带有预先规划轨迹叠加的实时透视引导下，通过同轴技术到达脊髓目标。在10次独立进针过程中，将最终针尖位置与预先确定的目标进行比较。在部分病例中，使用25G脊髓针或定制的内径为200μm的阶梯设计套管将造影剂注入脊髓中央以进行CED。 结果：针尖与目标的平均偏差在横向上为0.92±0.5mm，在前后方向上为0.47±0.4mm，在头尾方向上为1.67±1.2mm，绝对距离误差为2.12±1.12mm。与标准针注射时观察到的主要反流相比，CED导致造影剂在髓内呈椭圆形扩散。 结论：这些体模可行性数据表明，利用从融合的MRI和FDCT数据集得出的叠加轨迹辅助的实时透视，可采用一种微创经皮方法对脊髓进行靶向注射，目标误差为2.1mm。与标准注射技术相比，CED有助于脊髓内注射物的髓内扩散。有必要在大型动物模型中进行临床前研究。