Department of Diagnostic and Interventional Radiology, University Hospital Würzburg, Würzburg, Germany.
Department of Diagnostic and Interventional Radiology, University Hospital Würzburg, Würzburg, Germany; Department of Experimental Physics V, University of Würzburg, Würzburg, Germany.
Phys Med. 2021 Jan;81:210-214. doi: 10.1016/j.ejmp.2020.12.020. Epub 2021 Jan 19.
This study aimed to investigate the potential of magnetic particle imaging (MPI) to quantify artificial stenoses in vessel phantoms in near real-time.
Custom-made stenosis phantoms with different degrees of stenosis (0%, 25%, 50%, 75%, and 100%; length 40 mm, inner diameter 8 mm, Polyoxymethylene) were filled with diluted Ferucarbotran (superparamagnetic iron-oxide nanoparticle (SPION) tracer agent, 500 mmol (Fe)/l). A traveling wave MPI scanner (spatial resolution ~ 2 mm, gradient strength ~ 1.5 T/m, field of view: 65 mm length and 29 mm diameter, frequencies f = 1050 Hz and f = 12150 Hz) was used to acquire images of the phantoms (200 ms total acquisition time per image, 10 averages). Standardized grey scaling was used for comparability. All measured stenoses (n = 80) were graded manually using a dedicated software tool.
MPI allowed for accurate visualization of stenoses at a frame rate of 5frames per second. Less severe stenoses were detected more precisely than higher-grade stenoses and came with smaller standard deviations. In particular, the 0%, 25%, 50%, 75%, and 100% stenosis phantom were measured as 3.7 ± 2.7% (mean ± standarddeviation), 18.6 ± 1.8%, 52.8 ± 3.7%, 77.8 ± 14.8% and 100 ± 0%. Geometrical distortions occurred around the center of the high-grade stenosis and led to higher standard deviations compared to lower grade stenoses. In the frame of this study the MPI signal depended linearly on the SPION concentration down to 0.05 mmol (Fe)/l.
Near real-time MPI accurately visualized and quantified different stenosis grades in vascular phantoms.
本研究旨在探究磁共振粒子成像（MPI）实时定量评估血管模型人工狭窄的能力。
使用自行设计的狭窄模型（0%、25%、50%、75%和 100%狭窄程度；长度 40mm，内径 8mm，聚甲醛）来填充 Ferucarbotran（超顺磁性氧化铁纳米颗粒（SPION）示踪剂，500mmol（Fe）/l）。使用行波 MPI 扫描仪（空间分辨率2mm，梯度强度1.5T/m，视野：65mm 长，29mm 直径，频率 f=1050Hz 和 f=12150Hz）获取模型图像（每张图像 200ms 总采集时间，10 次平均）。采用标准化灰度标度来提高可比性。使用专用软件工具手动评估所有狭窄程度（n=80）。
MPI 可以以每秒 5 帧的帧率准确显示狭窄程度。与较高狭窄程度相比，较低狭窄程度的检测更精确，标准偏差更小。特别是，0%、25%、50%、75%和 100%狭窄模型的测量值分别为 3.7±2.7%（平均值±标准差）、18.6±1.8%、52.8±3.7%、77.8±14.8%和 100±0%。高狭窄程度的中心周围存在几何变形，导致与低狭窄程度相比，标准偏差更高。在本研究范围内，MPI 信号与 SPION 浓度呈线性关系，最低至 0.05mmol（Fe）/l。
实时 MPI 可准确可视化和量化血管模型中的不同狭窄程度。
