| 彭刚,张志伟,郁斌,郁仁强.不同CT扫描参数与迭代去金属伪影算法效果的相关性[J].中国医学影像技术,2020,36(4):601~605 |
| 不同CT扫描参数与迭代去金属伪影算法效果的相关性 |
| Correlations of different CT scanning parameters and the effect of iterative metal artifact reduction algorithm |
| 投稿时间：2019-04-03 修订日期：2019-12-02 |
| DOI：10.13929/j.issn.1003-3289.2020.04.030 |
| 中文关键词: 体层摄影术,X线计算机 图像处理,计算机辅助 伪影 |
| 英文关键词:tomography, X-ray computed image processing, computer-assisted artifacts |
| 基金项目:重庆医科大学附属第一医院科研培育基金项目（PYJJ2017-38）。 |
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| 中文摘要: |
| 目的 探讨不同CT扫描参数对迭代去金属伪影（IMAR）效果的影响。方法 采用不同管电压、不同管电流量及不同辐射剂量的管电压和管电流组合条件对植入及未植入金属螺钉的仿真胸部体模行CT扫描。分别以迭代重建和IMAR算法重建图像，采用四分法主观评价IMAR图像质量，测量及计算金属螺钉邻近肺实质和椎旁软组织CT值、噪声（CT值的标准差，SD）及CT值偏差（ΔHU），比较各方法采集图像质量差异。结果 相同管电流量条件下，IMAR图像中金属伪影随管电压增加而减少，图像质量主观评分差异有统计学意义（P<0.05）；肺及椎旁软组织SD（r=-0.91、-0.99）和ΔHU（r=-0.85、-0.97）均与管电压呈高度负相关（P均<0.01）。相同管电压条件下，管电流量增加后，IMAR图像中金属伪影无明显变化，图像质量主观评分差异无统计学意义（P>0.05），肺实质SD及椎旁软组织ΔHU与管电流量低度相关（r=0.20、0.29，P均<0.01），肺实质ΔHU及椎旁软组织SD与管电流量呈中等负相关（r=-0.59、-0.56，P均<0.01）。不同辐射剂量管电压和管电流组合条件下，IMAR图像质量主观评分及客观指标差异均有统计学意义（P均<0.05），低辐射剂量下采用高管电压、低管电流量扫描图像中金属伪影少于中、高辐射剂量。结论 管电压是影响IMAR效果的主要因素。采用IMAR去除金属伪影时，增加管电压对于改善图像质量效果更佳；在增加管电压的同时减少管电流量可减轻金属伪影对图像质量的影响，并降低辐射剂量。 |
| 英文摘要: |
| Objective To observe the impact of different CT scanning parameters on the effect of reducing metal artifacts with iterative metal artifact reduction (IMAR) algorithm. Methods CT scans of an anthropomorphic chest phantom were performed before and after implantation of spinal screws using different tube voltage and different tube current combinations under different radiation dose conditions. Then the data were reconstructed with iterative reconstruction and IMAR algorithm, respectively. Subjective evaluation of images quality of IMAR was performed by using 4-point method. CT values, noise (standard deviation of CT value, SD) and CT value deviation (ΔHU) of lung tissue and vertebral soft tissue adjacent metal screws were measured and calculated. The differences of image quality collected with various methods were compared. Results Under the same tube current condition, metal artifacts of IMAR images decreased with the increase of tube voltage, and statistical difference of subjective evaluation score of image quality was found (P<0.05). SD and ΔHU of lung parenchyma and paravertebral soft tissue decreased with the increase of tube voltage(r=-0.91, -0.99, 0.85, -0.97, all P<0.01),while the former was mildly (r=0.20, 0.29, all P<0.01)and the latter was moderately negatively related with the increase of tube current(r=-0.59, -0.56, all P<0.01). Under different radiation dose of different combination of tube voltage and tube current, there were statistical differences of both subjective scores and objective index for image quality (both P<0.05). Compared with the condition combination of medium or high radiation dose, metal artifact reduced under low radiation dose using combination of high voltage and low tube current. Conclusion Tube voltage has main impact on imaging quality of IMAR algorithm. For metal artifact reduction with IMAR, better imaging quality can be obtained through increasing tube voltage, and reducing tube current at the same time is able to limit the impact of metal artifacts on image quality and decrease radiation dose. |
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