Neuhaus Victor, Große Hokamp Nils, Abdullayev Nuran, Rau Robert, Mpotsaris Anastasios, Maintz David, Borggrefe Jan
Department of Diagnostic and Interventional Radiology, University Hospital Cologne, Kerpener Str. 62, 50937 Cologne, Germany.
Department of Diagnostic and Interventional Radiology, University Hospital Cologne, Kerpener Str. 62, 50937 Cologne, Germany.
Eur J Radiol. 2017 Aug;93:143-148. doi: 10.1016/j.ejrad.2017.05.013. Epub 2017 May 12.
The aim of the study was to investigate the performance and diagnostic value of metal artifact reduction in virtual monoenergetic images generated from dual-layer computed tomography (DLCT).
35 patients that received a DLCT at the University Hospital Cologne and had an orthopedic implant in the examined region were included in this study. For each DLCT virtual monoenergetic images of different energy levels (64keV, 70keV, 105keV, 140keV, 200keV and an optimized photon energy) were reconstructed and analyzed by three blinded observers. Images were analyzed with regard to subjective criteria (extent of artifacts, diagnostic image quality) and objective criteria (width and density of artifacts).
21 patients had implants in the spine, 8 in the pelvis and 6 patients in the extremities. Diagnostic image quality improved significantly at high photon energies from a Likert-score of 4.3 (±0.83) to 2.3 (±1.02) and artifacts decreased significantly from a score of 4.3 (±0.66) to 2.6 (±2.57). The average optimized photon energy was 149.2±39.4keV. The density as well as the width of the most pronounced artifacts decreased from-374.6±251.89HU to -12.5±205.84HU and from 14.5±8.74mm to 6.4±10.76mm, respectively.
Using virtual monoenergetic images valuable improvements of diagnostic image quality can be achieved by reduction of artifacts associated with metal implants. As preset for virtual monoenergetic images, 140keV appear to provide optimal artifact reduction. In 20% of the patients, individually optimized keV can lead to a further improvement of image quality compared to 140keV.
本研究旨在探讨双层计算机断层扫描（DLCT）生成的虚拟单能图像中金属伪影减少的性能及诊断价值。
本研究纳入了35例在科隆大学医院接受DLCT检查且检查区域有骨科植入物的患者。对于每个DLCT，由三名不知情的观察者重建并分析不同能量水平（64keV、70keV、105keV、140keV、200keV和优化光子能量）的虚拟单能图像。根据主观标准（伪影程度、诊断图像质量）和客观标准（伪影宽度和密度）对图像进行分析。
21例患者的植入物位于脊柱，8例位于骨盆，6例位于四肢。在高光子能量下，诊断图像质量从李克特评分4.3（±0.83）显著提高到2.3（±1.02），伪影从评分4.3（±0.66）显著减少到2.6（±2.57）。平均优化光子能量为149.2±39.4keV。最明显伪影的密度和宽度分别从-374.6±251.89HU降至-12.5±205.84HU，从14.5±8.74mm降至6.4±10.76mm。
使用虚拟单能图像，通过减少与金属植入物相关的伪影可显著提高诊断图像质量。如虚拟单能图像预设的那样，140keV似乎能提供最佳的伪影减少效果。在20%的患者中，与140keV相比，个体化优化的keV可进一步提高图像质量。
