Department of Internal Medicine I, Cardiology, University Hospital Wuerzburg, Oberduerbacher Strasse 6a, 97080, Wuerzburg, Germany.
German Heart Center Munich, Electrophysiology, Munich, Germany.
Sci Rep. 2024 May 15;14(1):11130. doi: 10.1038/s41598-024-61283-0.
CMR at 3.0T in the presence of active cardiac implants remains a challenge due to susceptibility artifacts. Beyond a signal void that cancels image information, magnetic field inhomogeneities may cause distorted appearances of anatomical structures. Understanding influencing factors and the extent of distortion are a first step towards optimizing the image quality of CMR with active implants at 3.0T. All measurements were obtained at a clinical 3.0T scanner. An in-house designed phantom with a 3D cartesian grid of water filled spheres was used to analyze the distortion caused by four representative active cardiac devices (cardiac loop recorder, pacemaker, 2 ICDs). For imaging a gradient echo (3D-TFE) sequence and a turbo spin echo (2D-TSE) sequence were used. The work defines metrics to quantify the different features of distortion such as changes in size, location and signal intensity. It introduces a specialized segmentation technique based on a reaction-diffusion-equation. The distortion features are dependent on the amount of magnetic material in the active implants and showed a significant increase when measured with the 3D TFE compared to the 2D TSE. This work presents a quantitative approach for the evaluation of image distortion at 3.0T caused by active cardiac implants and serves as foundation for both further optimization of sequences and devices but also for planning of imaging procedures.
在存在心脏活性植入物的情况下，由于磁化率伪影，3.0T 的心脏磁共振成像仍然是一个挑战。除了信号缺失导致图像信息丢失之外，磁场不均匀性可能会导致解剖结构的外观失真。了解影响因素和失真程度是优化 3.0T 心脏活性植入物磁共振图像质量的第一步。所有测量均在临床 3.0T 扫描仪上进行。使用内部设计的带有三维笛卡尔网格充满水的球体的体模来分析四个代表性的心脏活性设备（心脏环记录仪、起搏器、2 个 ICD）引起的失真。对于成像，使用梯度回波（3D-TFE）序列和涡轮自旋回波（2D-TSE）序列。该工作定义了用于量化失真的不同特征的指标，例如大小、位置和信号强度的变化。它介绍了一种基于反应扩散方程的专门分割技术。失真特征取决于心脏活性植入物中的磁性材料的量，并且与 2D-TSE 相比，使用 3D-TFE 测量时会显著增加。该工作提出了一种用于评估 3.0T 心脏活性植入物引起的图像失真的定量方法，既可以为序列和设备的进一步优化提供基础，也可以为成像程序的规划提供基础。
