能谱CT去金属伪影(MAR)技术用于减低单髋关节置换物伪影

目的评价能谱CT去金属伪影(MAR)技术减低单侧髋关节置换物伪影的效果。方法对33例单侧髋关节置换术后患者行能谱CT检查,获取扫描数据后重建70~140 keV(间隔10 keV)MAR和非MAR图像,计算图像伪影指数(AI)和信噪比(SNR),并进行主观评分。选取AI较低和主观评分较高的非MAR单能量图像进行分析,比较不同能级MAR图像和伪影较少非MAR图像的AI和SNR差异。结果非MAR图像110 keV条件下伪影较少。70~140 keV水平MAR图像关节前方、外侧肌肉组织和膀胱处AI值均低于110 keV非MAR图像(P均<0.05),110~140 keV水平MAR图像后方肌肉组织和100~140 keV水平MAR图像髋臼处的AI值均低于110 keV非MAR图像(P均<0.05)。110~140 keV水平MAR图像外侧方肌肉组织SNR高于110 keV非MAR图像(P均<0.05)。高keV水平MAR图像不同区域AI值较70 keV及80 keV减低(P均<0.05)。高于80 keV水平时,MAR图像主观评分均≥3分。结论MAR技术可有效减少单髋关节置换物伪影,提高解剖结构清晰度。

Energy spectrum CT metal artifacts reduction (MAR) for reducing artifacts of unilateral hip arthroplasty

Objective To evaluate the effect of energy spectrum CT metal artifacts reduction(MAR)technology in reducing artifacts of unilateral hip arthroplasty.Methods A total of 33 patients underwent energy spectrum CT after unilateral hip replacement.MAR and non-MAR images were reconstructed at 70-140 keV(interval of 10 keV).Then artifacts index(AI)and signal-to-noise ratio(SNR)of the images were calculated,and subjective scoring was performed.Non-MAR single-energy images with lower AI and higher subjective scores were selected for analysis,and the relative AI and SNR were compared.Results There were less artifacts in non-MAR image at 110 keV.AI values in the anterior,lateral muscle tissues of the joint and bladder at 70-140 keV MAR images were lower than those at 110 keV non-MAR images(all P<0.05).AI values in posterior muscle at 110-140 keV MAR images and in acetabulum at 100-140 keV MAR images were lower than those at 110 keV non-MAR images(all P<0.05).SNR in lateral muscle at 110-140 keV MAR images were higher than that in 110 keV non-MAR(all P<0.05).AI values in different regions at higher KeV level MAR images were lower than those at 70 keV and 80 keV MAR images(all P<0.05).At higher than 80 keV,the subjective scores of MAR images were all≥3.Conclusion MAR technology could effectively reduce artifacts of unilateral hip replacement and improve the clarity of anatomical structures.