能谱CT金属伪影消除技术和骨算法成像消减脊柱金属内固定物伪影的对比研究

目的 探讨能谱CT金属伪影消除(MARs)技术与普通CT骨算法重建在消减脊柱内固定术后伪影的价值。方法 回顾性分析2013年2月—2014年2月解放军第一一七医院22例行脊柱金属内固定置入患者的影像学资料。其中男14例、女8例,年龄30～77岁。22例患者术后不同时间分别行能谱CT MARs技术检查(MARs组)、骨算法成像检查(骨算法组)。测量并计算各组感兴趣区的伪影指数(AI),采用骨窗图像质量主观评估标准对骨窗图像质量进行评分,比较MARs组和骨算法组患者骨窗图像质量评分情况,以及不同单能量值MARs组和骨算法组间AI的分布差异。结果 MARs组中,随着单能量值的减低,AI值逐渐增高。MARs组各单能量值和骨算法组间比较,AI值差异有统计学意义(F=8.696, P<0.05);进一步组间LSD-t检验显示,在60~140 keV条件下,MARs组AI值均小于骨算法组,差异均有统计学意义(P值均<0.05)。骨窗图像质量评分比较,骨算法组(2.81±0.39)分,优于MARs组(2.00±0.53)分,差异有统计学意义(t=4.856, P<0.01)。结论 能谱CT MARs技术和骨算法成像对消减脊柱金属内固定伪影各有优点,应当结合临床需要选择合适的CT成像技术。

Comparison of clinical values of spectral CT with metal artifacts reduction system and high-spatial resolution algorithm CT scans in reducing metallic artifacts

Objective To investigate the clinical values of spectral CT with metal artifacts reduction system (MARs) and high-spatial resolution algorithm CT scans in the reduction of metal artifacts after internal spinal fixation.Methods The imaging data of 22 patients received internal spinal fixer implantation in the 117th Hospital of PLA from February 2013 to February 2014 were retrospectively analyzed. Of 22 patients, there were 14 males and 8 females, with age ranging from 30 to 77 years, and all the patients underwent spectral CT with MARs (MARs group) and bone algorithm CT scans (bone algorithm group) at different time after operation. The artifact index (AI) of each region of interest was measured and calculated, and the quality of bone window image was evaluated and scored by subjective assessment criteria of bone window image quality for comparison of the image quality of MARs group and bone algorithm group, followed by analysis of the differences in AI in MARs sub-groups with different single-energy values and bone algorithm groups.Results In the MARs group, AI was increased gradually with the decline of single-energy. There was significant difference in AI values of MARs sub-groups with different single-energy values and the bone algorithm group (F=8.696, P<0.05). Further LSD-t test between groups showed that, in the condition of 60-140 keV, AI values in MARs sub-groups were less than that of the bone algorithm group, and the differences were statistically significant (all P values<0.05). Furthermore, the quality of bone window image of the bone algorithm group was better than that of MARs sub-groups [(2.81±0.39) vs. (2.00 ± 0.53)], approaching the significant difference between the two groups (t= 4.856, P<0.01).Conclusions Spectral CT with MARs and high-spatial resolution algorithm CT scans have their own advantages in the reduction of metal artifacts after internal spinal fixation, so the appropriate CT imaging technology should be chosen according to clinical needs.