Purpose

Using 4D magnetic particle imaging (MPI), intravascular optical coherence tomography (IVOCT) catheters are tracked in real time in order to compensate for image artifacts related to relative motion. Our approach demonstrates the feasibility for bimodal IVOCT and MPI in-vitro experiments.

Material and methods

During IVOCT imaging of a stenosis phantom the catheter is tracked using MPI. A 4D trajectory of the catheter tip is determined from the MPI data using center of mass sub-voxel strategies. A custom built IVOCT imaging adapter is used to perform different catheter motion profiles: no motion artifacts, motion artifacts due to catheter bending, and heart beat motion artifacts. Two IVOCT volume reconstruction methods are compared qualitatively and quantitatively using the DICE metric and the known stenosis length.

Results

The MPI-tracked trajectory of the IVOCT catheter is validated in multiple repeated measurements calculating the absolute mean error and standard deviation. Both volume reconstruction methods are compared and analyzed whether they are capable of compensating the motion artifacts. The novel approach of MPI-guided catheter tracking corrects motion artifacts leading to a DICE coefficient with a minimum of 86% in comparison to 58% for a standard reconstruction approach.

Conclusions

IVOCT catheter tracking with MPI in real time is an auspicious method for radiation free MPI-guided IVOCT interventions. The combination of MPI and IVOCT can help to reduce motion artifacts due to catheter bending and heart beat for optimized IVOCT volume reconstructions.

中文翻译：

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体外MPI引导的IVOCT导管实时跟踪，用于运动伪影补偿。

目的

使用4D磁性粒子成像（MPI），可以实时跟踪血管内光学相干断层扫描（IVOCT）导管，以补偿与相对运动有关的图像伪影。我们的方法证明了双峰IVOCT和MPI体外实验的可行性。

材料与方法

在狭窄体模的IVOCT成像期间，使用MPI跟踪导管。使用质心次体素策略从MPI数据确定导管尖端的4D轨迹。定制的IVOCT成像适配器用于执行不同的导管运动曲线：无运动伪影，由于导管弯曲引起的运动伪影和心跳运动伪影。使用DICE指标和已知的狭窄长度，定性和定量比较了两种IVOCT体积重建方法。

结果

IVOCT导管的MPI跟踪轨迹在多次重复测量中得到了验证，计算出绝对平均误差和标准偏差。比较并分析了两种体积重建方法是否能够补偿运动伪影。MPI引导导管跟踪的新颖方法纠正了导致DICE系数最小的运动伪影，而DICE系数则为86％，而标准重建方法为58％。

结论

采用MPI实时进行IVOCT导管跟踪是用于无放射MPI指导的IVOCT干预的一种吉祥方法。MPI和IVOCT的组合可帮助减少由于导管弯曲和心跳引起的运动伪影，从而优化了IVOCT体积重建。