Sonnow Lena, Könneker Sören, Vogt Peter M, Wacker Frank, von Falck Christian
Department of Diagnostic and Interventional Radiology, Hannover, 30625, Germany.
Department of Plastic, Hand and Reconstructive Surgery, Hannover Medical School, Carl-Neuberg-Str. 1, 30625, Hannover, Germany.
BMC Med Imaging. 2017 Feb 14;17(1):16. doi: 10.1186/s12880-017-0187-7.
Magnesium alloys have recently been rediscovered as biodegradable implants in musculoskeletal surgery. This study is an ex-vivo trial to evaluate the imaging characteristics of magnesium implants in different imaging modalities as compared to conventional metallic implants.
A CE-approved magnesium Herbert screw (MAGNEZIX®) and a titanium screw of the same dimensions (3.2x20 mm) were imaged using different modalities: digital radiography (DX), multidetector computed tomography (MDCT), high resolution flat panel CT (FPCT) and magnetic resonance imaging (MRI). The screws were scanned in vitro and after implantation in a fresh chicken tibia in order to simulate surrounding bone and soft tissue. The images were quantitatively evaluated with respect to the overall image quality and the extent and intensity of artifacts.
In all modalities, the artifacts generated by the magnesium screw had a lesser extent and were less severe as compared to the titanium screw (mean difference of artifact size of solo scanned screws in DX: 0.7 mm, MDCT: 6.2 mm, FPCT: 5.9 mm and MRI: 4.73 mm; p < 0.05). In MDCT and FPCT multiplanar reformations and 3D reconstructions were superior as compared with the titanium screw and the metal-bone interface after implanting the screws in chicken cadavers was more clearly depicted. While the artifacts of the titanium screw could be effectively reduced using metal-artifact reduction sequences in MRI (WARP, mean reduction of 2.5 mm, p < 0.05), there was no significant difference for the magnesium screw.
Magnesium implants generate significantly less artifacts in common imaging modalities (DX, MDCT, FPCT and MRI) as compared with conventional titanium implants and therefore may facilitate post-operative follow-up.
镁合金最近作为肌肉骨骼手术中的可生物降解植入物被重新发现。本研究是一项体外试验，旨在评估与传统金属植入物相比，镁植入物在不同成像方式下的成像特征。
使用不同的成像方式对一个CE认证的镁制赫伯特螺钉（MAGNEZIX®）和一个相同尺寸（3.2×20毫米）的钛螺钉进行成像：数字X线摄影（DX）、多排螺旋计算机断层扫描（MDCT）、高分辨率平板CT（FPCT）和磁共振成像（MRI）。这些螺钉在体外以及植入新鲜鸡胫骨后进行扫描，以模拟周围的骨骼和软组织。对图像的整体图像质量、伪影的范围和强度进行定量评估。
在所有成像方式中，与钛螺钉相比，镁螺钉产生的伪影范围更小且程度较轻（DX单独扫描螺钉的伪影尺寸平均差异：0.7毫米，MDCT：6.2毫米，FPCT：5.9毫米，MRI：4.73毫米；p<0.05）。在MDCT和FPCT中，多平面重建和三维重建比钛螺钉更具优势，并且在将螺钉植入鸡尸体后，金属-骨界面的显示更清晰。虽然在MRI中使用金属伪影减少序列（WARP）可有效减少钛螺钉的伪影（平均减少2.5毫米，p<0.05），但镁螺钉之间无显著差异。
与传统钛植入物相比，镁植入物在常见成像方式（DX、MDCT、FPCT和MRI）中产生的伪影明显更少，因此可能有助于术后随访。
