ISSN 1004-4140
CN 11-3017/P

O-MAR联合迭代重建技术在腰椎内固定术后CT成像中的应用

Orthopedic metal artifact reduction combined with iterative reconstruction in CT imaging after lumbar internal fixation

  • 摘要: 目的:探讨 金属伪影抑制技术(O-MAR)联合迭代算法对腰椎内固定术后患者CT图像质量的影响,为术后效果评估提供准确依据。方法:回顾性分析20例行腰椎内固定术后CT检查,使用O-MAR和滤波反投影算法、iDose4重建骨算法图像(iDose4-1 ~ 7级)及软组织算法图像(iDose4-1 ~ 6级)。重组螺钉显示最佳的横断面和矢状面的骨算法图像及螺钉显示最佳及螺钉区域内椎间盘正中层面的横断面软组织算法图像,测量骨质和肌肉的噪声值(SD)并计算伪影指数(AI)。由两名放射科医师对骨及软组织算法图像的金属伪影抑制和诊断信息显示两方面分别评分。对主客观评价指标进行两组间比较和组间多重比较。结果:骨算法图像:使用O-MAR的图像SD、AI显著低于未使用的图像,不同等级iDose4图像的AI值随等级升高而逐渐降低;O-MAR图像金属伪影主观分显著提高,且iDose4-5 ~ 7评分高于FBP及iDose4-1 ~ 2;使用O-MAR时诊断信息评分显著提高,iDose4-2 ~ 4评分高于FBP及其他迭代等级,且iDose4-3为最佳。软组织算法图像:使用O-MAR的图像SD、AI低于未使用的图像;使用O-MAR的图像金属伪影评分高于未使用,诊断信息评分未使用O-MAR高于使用;对不同迭代等级,无论是否使用O-MAR,图像伪影和诊断信息评分均无差异。结论:建议联合使用O-MAR技术及中间迭代等级iDose4-3重建骨算法图像;软组织算法图像重建时不推荐使用迭代算法,建议同时重建使用和不使用O-MAR的图像以便配合观察。

     

    Abstract: Objective: Exploring the effect of metal artifact reduction (O-MAR) technology combined with iterative algorithms on the computed tomography (CT) image quality of patients after lumbar spine internal fixation surgery, to provide an accurate basis for postoperative effect evaluation. Methods: Computed tomography (CT) images were collected from 20 patients who underwent lumbar spine internal fixation surgery. Using O-MAR, filtered back projection (FBP), and iDose4 algorithms, bone (iDose4-1-7 levels) and soft tissue images (iDose4-1-6 levels) were reconstructed. Screws were displayed the best in transverse and sagittal bone reconstructed images. The screw area (center plane) of the transverse soft tissue images of the intervertebral disc was also reconstructed. Noise levels in standard deviation (SD) of bone and muscle were measured, and the artifact index (AI) was calculated. Two radiologists separately rated the metal artifact suppression and diagnostic information in the bone and soft tissue images. The subjective and objective evaluation indicators of the two groups were compared, conducting multiple comparisons between groups. Statistical analyses were further performed on subjective and objective evaluation indicators, including O-MAR comparisons and/or multiple comparisons between groups with different levels of iDose4. Results: In the bone images, the SD and AI of images using O-MAR were significantly lower than those without O-MAR, and the AI values of iDose4 images at different levels gradually decreased as the dose level increased. The subjective score of metal artifacts in O-MAR images significantly improved, and the score of iDose4-5-7 was higher than those of filtered back projection (FBP) and iDose4-1-2 . With O-MAR, the diagnostic information score significantly improved . The score of iDose4-2-4 was higher than that of FBP and other iterative levels , with iDose4-3 being the best. In soft tissue images, the SD and AI of images using O-MAR were lower than those without O-MAR . The metal artifact score of images using O-MAR was higher than that of images without, but the diagnostic information score of images not using O-MAR was higher than that of images with O-MAR ; For different iteration levels, regardless of whether O-MAR was used or not, no difference was observed in image artifacts and diagnostic information scores. Conclusions: We suggest combining O-MAR technology with intermediate iteration level iDose4-3 for bone image reconstruction. The use of iterative algorithms for image reconstruction using soft-tissue algorithms is not recommended. The images with and without O-MAR should be simultaneously reconstructed for comparative observations.

     

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