Department of Diagnostic and Interventional Radiology, University Hospital Heidelberg, Heidelberg, Germany.
Invest Radiol. 2013 Apr;48(4):213-22. doi: 10.1097/RLI.0b013e31827f6598.
The objective of this study was to test multimodal visibility (radiography, computed tomography [CT], and magnetic resonance imaging [MRI]) of microspheres for transarterial embolization in porcine kidneys.
Currently available embolization particles (microspheres) were modified. A dense x-ray material (barium sulfate) was added to create visibility for radiography and CT. A magnetic substance (iron oxide) was additionally added to create visibility for MRI. This chemical modification was performed for particles with sizes of 100 ± 25 and 700 ± 50 μm. Three different prototypes per size class (samples A, B, and C) resulted, each with a different degree of barium sulfate but with the same degree of iron oxide. The currently available embolization particles with sizes of 100 ± 25 and 700 ± 50 μm were used as controls (sample control). Eight renal arteries of 4 pigs were embolized. Study end points were size distribution evaluated in vitro as well as qualitative and quantitative particle visibility evaluated in vivo.
The size distribution of the particles with a size of 100 ± 25 μm was between 96 ± 11 μm for sample A and 102 ± 13 μm for the sample control without significant differences (n.s.). The size distribution of the particles with a size of 700 ± 50 μm was between 691 ± 20 μm for sample A and 716 ± 34 μm for sample C without significant differences (n.s.). For radiography, the particles with sizes of 100 ± 25 and 700 ± 50 μm for samples A, B, and C were definitely visible during the embolization. The sample control was definitely not visible. For CT and MRI (T1-weighted [T1w] and T2-weighted [T2w]), the particles with sizes of 100 ± 25 and 700 ± 50 μm for samples A, B, and C were definitely visible after the embolization. The sample control was definitely not visible. For CT, the signal-to-noise ratio for samples A, B, and C increased significantly after the embolization (eg, sample A, particles with a size of 100 ± 25 μm: 66.5% ± 23.7%, P < 0.05). The signal-to-noise ratio for the sample control did not change after the embolization (eg, sample control, particles with a size of 700 ± 25 μm: -0.2% ± 15.2%, n.s.). For MRI (T1w and T2w), the signal-to-noise ratio for samples A, B, and C decreased significantly after the embolization (eg, sample B, particles with a size of 700 ± 50 μm, T1w: -72.9% ± 6.6%; P < 0.05). The signal-to-noise ratio for the sample control did not change after the embolization (eg, sample control, particles with a size of 100 ± 25 μm, T2w: 6.2% ± 16.1%, n.s.).
In this study, the chemical modification of the currently available microspheres for transarterial embolization resulted in a size distribution comparable with the currently available microspheres and created multimodal visibility for radiography, CT, and MRI.
本研究旨在测试经动脉栓塞用微球的多模态可视性（射线照相、计算机断层扫描[CT]和磁共振成像[MRI]）在猪肾中的应用。
目前可用的栓塞颗粒（微球）经过修饰。添加致密射线照相材料（硫酸钡）以实现射线照相和 CT 的可视性。此外，还添加了磁性物质（氧化铁）以实现 MRI 的可视性。对粒径为 100±25μm 和 700±50μm 的颗粒进行了这种化学修饰。每个粒径类别（A、B 和 C 样品）都产生了三种不同的原型，每个原型的硫酸钡含量不同，但氧化铁含量相同。目前可用的粒径为 100±25μm 和 700±50μm 的栓塞颗粒作为对照（样品对照）。4 头猪的 8 条肾动脉被栓塞。研究终点是体外评估粒径分布以及体内评估定性和定量粒子可视性。
粒径为 100±25μm 的 A 样品的粒径分布在 96±11μm 至 102±13μm 之间，与样品对照无显著差异（n.s.）。粒径为 700±50μm 的 A 样品的粒径分布在 691±20μm 至 716±34μm 之间，与 C 样品无显著差异（n.s.）。对于射线照相，A、B 和 C 样品的粒径为 100±25μm 和 700±50μm 的颗粒在栓塞过程中均可清晰可见。样品对照则完全不可见。对于 CT 和 MRI（T1 加权[T1w]和 T2 加权[T2w]），A、B 和 C 样品的粒径为 100±25μm 和 700±50μm 的颗粒在栓塞后均可清晰可见。样品对照则完全不可见。对于 CT，A、B 和 C 样品的信号噪声比在栓塞后显著增加（例如，A 样品，粒径为 100±25μm：66.5%±23.7%，P<0.05）。栓塞后，样品对照的信号噪声比没有变化（例如，样品对照，粒径为 700±25μm：-0.2%±15.2%，n.s.）。对于 MRI（T1w 和 T2w），A、B 和 C 样品的信号噪声比在栓塞后显著降低（例如，B 样品，粒径为 700±50μm，T1w：-72.9%±6.6%；P<0.05）。栓塞后，样品对照的信号噪声比没有变化（例如，样品对照，粒径为 100±25μm，T2w：6.2%±16.1%，n.s.）。
在本研究中，经动脉栓塞用微球的化学修饰导致粒径分布与目前可用的微球相当，并产生了射线照相、CT 和 MRI 的多模态可视性。
