Influence of geometric and material properties on artifacts generated by interventional MRI devices: Relevance to PRF-shift thermometry.
Influence of geometric and material properties on artifacts generated by interventional MRI devices: Relevance to PRF-shift thermometry.
复制标题
几何和材料特性对介入 MRI 设备产生的伪影的影响：与 PRF 位移测温的相关性。
DOI：
10.1118/1.4938099
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发表时间：
2016
期刊：
影响因子：
3.8
通讯作者：
Chopra,Rajiv
中科院分区：
文献类型：
--
作者：
Tatebe,Ken;Ramsay,Elizabeth;Mougenot,Charles;Kazem,Mohammad;Peikari,Hamed;Bronskill,Michael;Chopra,Rajiv
目的磁共振成像(MRI)能够在医疗过程中提供有价值的实时反馈，部分原因是良好的软组织对比度。由于大多数传统设备与这种成像方式不兼容，医疗设备与MRI的无缝集成仍然存在几个技术障碍。在这项研究中，使用有限元分析模型研究了医疗器械磁化引起的局部磁场扰动的影响。以经尿道高强度超声辐射器为例，研究了其几何和材料特性对质子共振频移测温法测温的影响。方法采用有限元分析模型，研究了医疗器械部件磁化引起的局部磁场扰动的影响。模拟了经尿道超声敷贴器产生的测温伪影，并与分析模型和体模中敷贴器的扫描结果进行了验证。然后改变几个参数来确定哪个参数对模拟测温伪影的水平影响最大，在消融高强度超声治疗过程中，随着敷贴器的移动而变化。结果被确定为对测温伪影大小有强烈影响的关键设计参数包括材料的敏感性和其体积。部件的位置也很重要，特别是当定位为最大限度地实现设备的对称性时。最后，元件边缘的位置和器件相对于磁场的倾斜度也是重要的因素。结论验证了以前的最小化测温伪影的设计策略，并确定了新的设计策略，大大减少了不同器件取向下的PRF-Shift测温伪影。这些新战略正在被纳入下一代施肥器。这项研究中描述的一般策略可以应用于其他旨在与MRI一起使用的介入设备的设计。
PurposeMagnetic resonance imaging (MRI) is capable of providing valuable real‐time feedback during medical procedures, partly due to the excellent soft‐tissue contrast available. Several technical hurdles still exist to seamless integration of medical devices with MRI due to incompatibility of most conventional devices with this imaging modality. In this study, the effect of local perturbations in the magnetic field caused by the magnetization of medical devices was examined using finite element analysis modeling. As an example, the influence of the geometric and material characteristics of a transurethral high‐intensity ultrasound applicator on temperature measurements using proton resonance frequency (PRF)‐shift thermometry was investigated.MethodsThe effect of local perturbations in the magnetic field, caused by the magnetization of medical device components, was examined using finite element analysis modeling. The thermometry artifact generated by a transurethral ultrasound applicator was simulated, and these results were validated against analytic models and scans of an applicator in a phantom. Several parameters were then varied to identify which most strongly impacted the level of simulated thermometry artifact, which varies as the applicator moves over the course of an ablative high‐intensity ultrasound treatment.ResultsKey design parameters identified as having a strong influence on the magnitude of thermometry artifact included the susceptibility of materials and their volume. The location of components was also important, particularly when positioned to maximize symmetry of the device. Finally, the location of component edges and the inclination of the device relative to the magnetic field were also found to be important factors.ConclusionsPrevious design strategies to minimize thermometry artifact were validated, and novel design strategies were identified that substantially reduce PRF‐shift thermometry artifacts for a variety of device orientations. These new strategies are being incorporated into the next generation of applicators. The general strategy described in this study can be applied to the design of other interventional devices intended for use with MRI.