Kim Yeun Jeong, Cha Jang Gyu, Kim Hunji, Yi Ji Sook, Kim Hyun-Joo
Department of Radiology, Soonchunhyang, University, Bucheon Hospital, 170, Jomaru-ro, Bucheon, 14584, Republic of Korea.
Department of Radiology, Inje University College of Medicine, Haeundae Paik Hospital, Haeundae-gu, Busan, Republic of Korea.
AJR Am J Roentgenol. 2019 May;212(5):1106-1111. doi: 10.2214/AJR.18.20413. Epub 2019 Mar 5.
The purpose of this study was to compare the value of iterative metal artifact reduction (IMAR) with that of dual-energy CT (DECT) and filtered back projection (FBP) CT protocols for reducing metal artifacts and for facilitating visualization of the acetabular cortex in a loosening hip phantom model. CT scans were obtained with conventional FBP and dual-source CT for two types of hip phantom. For the quantitative study, attenuation was measured by placement of ROIs in the phantoms around the metallic hardware. The differences between mean attenuation in each ROI and the actual attenuation were compared among the three CT protocols. For the qualitative study, the visibility of the acetabular cortex in the artificial loosening area of the total hip arthroplasty model and in the joint space of the bipolar hemiarthroplasty model was evaluated by measurement of the obscured cortical angle. In the quantitative study, attenuation differences in the bipolar hemiarthroplasty model were markedly decreased with IMAR and DECT compared with FBP ( = 0.006-0.007). In the total hip replacement model, attenuation differences were significantly lower with IMAR than with FBP ( < 0.001). In the qualitative study, visibility of the acetabular cortex was markedly improved with IMAR compared with DECT and FBP ( < 0.001) for both hip models. CT with IMAR can reduce the distortion caused by metal artifacts more effectively than FBP and DECT can while preserving visibility of the acetabular cortex in both bipolar hemiarthroplasty and total hip arthroplasty phantoms.
本研究的目的是比较迭代金属伪影减少（IMAR）与双能CT（DECT）及滤波反投影（FBP）CT协议在减少金属伪影以及促进髋臼皮质在髋关节假体松动模型中可视化方面的价值。使用传统FBP和双源CT对两种类型的髋关节假体进行CT扫描。对于定量研究，通过在假体中金属硬件周围放置感兴趣区（ROI）来测量衰减。比较三种CT协议下每个ROI的平均衰减与实际衰减之间的差异。对于定性研究，通过测量髋臼皮质角来评估全髋关节置换模型人工松动区域和双极半髋关节置换模型关节间隙中髋臼皮质的可视性。在定量研究中，与FBP相比，IMAR和DECT使双极半髋关节置换模型中的衰减差异显著降低（P = 0.006 - 0.007）。在全髋关节置换模型中，IMAR的衰减差异显著低于FBP（P < 0.001）。在定性研究中，与DECT和FBP相比，IMAR使两种髋关节模型中髋臼皮质的可视性均显著提高（P < 0.001）。在双极半髋关节置换和全髋关节置换假体模型中，具有IMAR的CT在保留髋臼皮质可视性的同时，比FBP和DECT更有效地减少金属伪影引起的失真。
