Fukushima Yasuhiro, Matsuda Akira, Koizumi Koji, Honda Maya, Masamoto Kazutaka, Fujibayashi Shunsuke
Division of Clinical Radiology Service, Kyoto University Hospital, Kyoto, Japan.
Department of Diagnostic Imaging and Nuclear Medicine, Graduate School of Medicine, Kyoto University, Kyoto, Japan.
Acta Radiol. 2021 Oct;62(10):1333-1340. doi: 10.1177/0284185120961424. Epub 2020 Oct 5.
The major problems of computed tomography (CT) imaging include radiation exposure and severe artifacts caused by operative implants.
To evaluate the usefulness of the metal artifact reduction algorithm and model-based iterative reconstruction (MBIR) in postoperative low-dose (LD) spine CT.
A CT torso phantom was scanned at standard-dose (SD) and LD settings. The CT images were reconstructed by three methods: hybrid iterative reconstruction (HIR); metal artifact reduction; and MBIR. The radiation dose of the phantom imaging was evaluated by volume CT dose index (mGy), dose length product (DLP, mGy × cm), and effective dose (mSv). The image quality of the six images was visually evaluated and analyzed using Scheffe's paired comparison method. The average preference of each method was calculated based on the comparative scores. The task transfer function (TTF) and noise power spectrum for HIR and MBIR were also measured.
The respective radiation-dose-related parameters of the SD and LD conditions were: volume CT dose index = 10.2 and 1.2 mGy; DLP = 277.9 and 33.9 mGy × cm; and effective dose = 4.2 and 0.5 mSv. The average preference for diagnostic acceptability of MBIR at LD was not significantly different from the other reconstructions of SD data. MBIR successfully reduced metal artifacts in the LD condition. The 10% TTF was higher for HIR at SD and higher for MBIR at LD.
MBIR is useful for LD spine CT after spine surgery with metal implant.
计算机断层扫描（CT）成像的主要问题包括辐射暴露以及手术植入物引起的严重伪影。
评估金属伪影减少算法和基于模型的迭代重建（MBIR）在术后低剂量（LD）脊柱CT中的效用。
使用标准剂量（SD）和低剂量（LD）设置对CT躯干模型进行扫描。通过三种方法重建CT图像：混合迭代重建（HIR）；金属伪影减少；以及MBIR。通过容积CT剂量指数（mGy）、剂量长度乘积（DLP，mGy×cm）和有效剂量（mSv）评估模型成像的辐射剂量。使用谢费尔配对比较法对六幅图像的图像质量进行视觉评估和分析。根据比较分数计算每种方法的平均偏好度。还测量了HIR和MBIR的任务传递函数（TTF）和噪声功率谱。
SD和LD条件下各自与辐射剂量相关的参数分别为：容积CT剂量指数 = 10.2和1.2 mGy；DLP = 277.9和33.9 mGy×cm；以及有效剂量 = 4.2和0.5 mSv。LD条件下MBIR诊断可接受性的平均偏好度与SD数据的其他重建方法无显著差异。MBIR成功减少了LD条件下的金属伪影。SD条件下HIR的10% TTF较高，LD条件下MBIR的10% TTF较高。
MBIR对脊柱手术后有金属植入物的LD脊柱CT有用。
