Wang Fengdan, Zhang Yan, Xue Huadan, Han Wei, Yang Xianda, Jin Zhengyu, Zwar Richard
Department of Radiology, Peking Union Medical College Hospital, Beijing, PR China.
Statistics Office, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, PR China.
Acta Radiol. 2017 Jan;58(1):62-69. doi: 10.1177/0284185116631182. Epub 2016 Feb 25.
Spinal fusion surgery is an important procedure for treating spinal diseases and computed tomography (CT) is a critical tool for postoperative evaluation. However, CT image quality is considerably impaired by metal artifacts and image noise.
To explore whether metal artifacts and image noise can be reduced by combining two technologies, adaptive statistical iterative reconstruction (ASIR) and monochromatic imaging generated by gemstone spectral imaging (GSI) dual-energy CT.
A total of 51 patients with 318 spinal pedicle screws were prospectively scanned by dual-energy CT using fast kV-switching GSI between 80 and 140 kVp. Monochromatic GSI images at 110 keV were reconstructed either without or with various levels of ASIR (30%, 50%, 70%, and 100%). The quality of five sets of images was objectively and subjectively assessed.
With objective image quality assessment, metal artifacts decreased when increasing levels of ASIR were applied (P < 0.001). Moreover, adding ASIR to GSI also decreased image noise (P < 0.001) and improved the signal-to-noise ratio (P < 0.001). The subjective image quality analysis showed good inter-reader concordance, with intra-class correlation coefficients between 0.89 and 0.99. The visualization of peri-implant soft tissue was improved at higher ASIR levels (P < 0.001).
Combined use of ASIR and GSI decreased image noise and improved image quality in post-spinal fusion CT scans. Optimal results were achieved with ASIR levels ≥70%.
脊柱融合手术是治疗脊柱疾病的重要手段，计算机断层扫描（CT）是术后评估的关键工具。然而，CT图像质量会受到金属伪影和图像噪声的显著影响。
探讨自适应统计迭代重建（ASIR）和宝石能谱成像（GSI）双能量CT生成的单色成像这两种技术相结合能否降低金属伪影和图像噪声。
对51例植入318枚脊柱椎弓根螺钉的患者进行前瞻性扫描，采用快速千伏切换GSI在80至140 kVp之间进行双能量CT扫描。分别在不使用ASIR以及使用不同水平（30%、50%、70%和100%）的ASIR情况下重建110 keV的GSI单色图像。对五组图像的质量进行客观和主观评估。
通过客观图像质量评估，应用更高水平的ASIR时金属伪影减少（P < 0.001）。此外，在GSI中添加ASIR还降低了图像噪声（P < 0.001）并提高了信噪比（P < 0.001）。主观图像质量分析显示阅片者之间具有良好的一致性，组内相关系数在0.89至0.99之间。在较高的ASIR水平下，植入物周围软组织的可视化得到改善（P < 0.001）。
ASIR和GSI联合使用可降低脊柱融合术后CT扫描中的图像噪声并提高图像质量。ASIR水平≥70%时可获得最佳结果。
