Huang Shiqi, Liang Yuhong, Yao Xinqun, Qin Xiangyun, He Changguang, Luo Li'an, Huang Lveqin, Lv Yaping
Department of Radiology, Liuzhou Municipal Liutie Central Hospital, Liuzhou, China.
Siemens Healthineers Ltd., Guangzhou, China.
Quant Imaging Med Surg. 2024 Jul 1;14(7):4688-4702. doi: 10.21037/qims-24-19. Epub 2024 Jun 27.
Dual-energy computed tomography (DECT) and iterative metal artifact reduction (iMAR) algorithms are valuable tools for reducing metal artifacts. Different parameters of these technologies and their combination can achieve different performance. This study compared various polychromatic and monochromatic images obtained via DECT with and without using iMAR algorithm to reduce artifacts in patients with dental implants.
This study included 30 patients with dental implants who underwent DECT for head and neck imaging. The computed tomography (CT) image sets comprised DECT polychromatic image sets [dual-energy (DE) polychromatic] that linearly blended 100 kV and tin-filtered 140 kV images using composition ratios of -1, -0.6, -0.3, 0, and 0.6, and virtual monochromatic images (DE monochromatic) at 90, 110, 130, 150, and 170 keV. These image sets were obtained with and without using iMAR, resulting in a total of 20 image sets. For subjective analysis, metal artifacts and image quality were assessed using a 5-point Likert scale. For objective analysis, CT attenuation, standard deviation (SD), contrast-to-noise ratio (CNR) and artifact index (AI) were evaluated. In addition, subgroup analysis was performed based on implant size.
In the subjective evaluation, iMAR + DE polychromatic (-0.3) images exhibited the lowest metal artifact scores [median (interquartile range): 2 (2-3)]. iMAR + DE monochromatic (110 keV) images demonstrated optimal image quality scores [median (interquartile range): 2 (2-3)]. In the objective evaluation, none of the images demonstrated a significant difference in the CNR, except polychromatic images with a composition of -1 and 0.6. iMAR + DE polychromatic (0) exhibited the lowest AI [median (interquartile range): 8.7 (5.9-14.5)]. There was no significant difference between the two groups with different implant sizes for the techniques combined with iMAR (all P>0.05).
iMAR + DE polychromatic (-0.3 and 0) and iMAR + DE monochromatic (110 keV) images exhibited better image quality and substantial metal artifact reduction (MAR) compared with the other image sets. The performance of the techniques combined with iMAR was not affected by the size of the implant.
双能计算机断层扫描（DECT）和迭代金属伪影减少（iMAR）算法是减少金属伪影的重要工具。这些技术的不同参数及其组合可实现不同的性能。本研究比较了通过DECT获得的各种多色和单色图像，包括使用和不使用iMAR算法来减少牙种植体患者的伪影。
本研究纳入30例接受头颈部DECT成像的牙种植体患者。计算机断层扫描（CT）图像集包括DECT多色图像集[双能（DE）多色]，其使用-1、-0.6、-0.3、0和0.6的合成比线性混合100 kV和锡过滤的140 kV图像，以及90、110、130、150和170 keV的虚拟单色图像（DE单色）。这些图像集在使用和不使用iMAR的情况下获得，总共产生20个图像集。对于主观分析，使用5分李克特量表评估金属伪影和图像质量。对于客观分析，评估CT衰减、标准差（SD）、对比噪声比（CNR）和伪影指数（AI）。此外，根据种植体大小进行亚组分析。
在主观评估中，iMAR + DE多色（-0.3）图像的金属伪影得分最低[中位数（四分位间距）：2（2-3）]。iMAR + DE单色（110 keV）图像的图像质量得分最佳[中位数（四分位间距）：2（2-3）]。在客观评估中，除了合成比为-1和0.6的多色图像外，其他图像的CNR均无显著差异。iMAR + DE多色（0）的AI最低[中位数（四分位间距）：8.7（5.9-14.5）]。对于与iMAR结合的技术，不同种植体大小的两组之间无显著差异（所有P>0.05）。
与其他图像集相比，iMAR + DE多色（-0.3和0）和iMAR + DE单色（110 keV）图像表现出更好的图像质量和显著的金属伪影减少（MAR）。与iMAR结合的技术性能不受种植体大小的影响。
