| 郁斌,吕富荣,张黎,孙静坤,彭刚,王杰,郁仁强.胸部CT扫描中迭代去金属伪影算法减少金属伪影的有效性[J].中国医学影像技术,2017,33(4):590~593 |
| 胸部CT扫描中迭代去金属伪影算法减少金属伪影的有效性 |
| Effectiveness of iterative metal artifact reduction for reduction of metal artifact in chest CT scanning |
| 投稿时间：2016-07-04 修订日期：2016-12-23 |
| DOI：10.13929/j.1003-3289.201607021 |
| 中文关键词: 胸部 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:Thorax Tomography, X-ray computed Image processing, computer-assisted Artifacts |
| 基金项目:国家临床重点专科建设项目（[2013]544）。 |
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| 中文摘要: |
| 目的 评价胸部CT扫描中迭代去金属伪影算法（IMAR）减少金属伪影的有效性。方法 采用仿真胸部体模（仿真体模组），在T5椎体两侧各植入1枚椎弓根螺钉。以130 kV管电压和自动毫安秒（care dose 4D）技术，在植入螺钉前后行胸部CT扫描。对无金属图像进行滤波反投影（FBP）算法重建，对有金属螺钉的图像分别采用FBP算法和IMAR重建，选取螺钉邻近层面的主动脉、肺、椎旁软组织为ROI，测量噪声值和CT值，并计算CT值相对于无金属植入物图像CT值的偏移程度（ΔHU）。另回顾性分析我院26例接受胸部CT检查、且扫描范围内有椎弓根螺钉植入物的患者（病例组），扫描条件、图像重建方式参数同体模扫描，测量金属伪影邻近脊椎骨组织及背部软组织CT值，并由2名放射科医师分别对两种重建图像进行主观图像质量评价。结果 植入螺钉后，仿真体模组主动脉、肺、椎旁软组织IMAR重建图像的噪声值低于FBP重建图像（P均<0.05），IMAR重建的ΔHU明显小于FBP重建图像（P均<0.01）。病例组FBP重建和IMAR重建方式的脊椎骨组织CT值和背部软组织CT值差异均有统计学意义（P均<0.05）。对FBP重建和IMAR重建图像的主观评分差异有统计学意义（P<0.05）。结论 IMAR算法可明显减少条状伪影，并可校正受影响的组织CT值，使之更接近于无金属情况下的真实值。 |
| 英文摘要: |
| Objective To assess the effectiveness of iterative metal artifact reduction (IMAR) on metal artifacts reduction in thorax scan. Methods Thoracic phantom with two pedicle screws implanted in both sides of the T5 vertebrae was used, with the scan parameters of 130 kV and CARE Dose 4D, the phantom was scanned with and without the screws respectively. Images without screws were reconstructed with FBP. Images with screws were reconstructed with FBP and IMAR respectively. Three ROIs were selected on tissues including aorta, pulmonary and paravertebral soft tissue on image slice adjacent to the screws. The CT value and standard deviations (noise) of ROIs were measured, and the deviation of CT value (ΔHU) was calculated as the difference between CT values in images with and without screws. Twenty-six cases who received chest CT examination and with pedicle screw implant in scanning range were collected. The scanning parameters and image reconstruction methods were the same as phantom scan. The CT value (HU) of metal artifacts adjacent to vertebrae and dorsal soft tissue was measured, and the image quality of reconstructed image by two skilled radiologists independently was evaluated. Results In the phantom after implanted screws, the noise were significantly reduced by IMAR compared to FBP in all the three ROIs of aorta, pulmonary and paravertebral soft tissue (P<0.05), and the ΔHU was significantly smaller in IMAR compared to that with FBP (P<0.01). In 26 patients, there were significant differences in CT value of vertebral bone tissue and dorsal soft tissue between FBP and IMAR (P<0.05), and the subjective evaluation scores of the two image reconstruction methods showed a statistically significant difference (P<0.05). Conclusion IMAR can significantly reduce streak artifacts of metal implant and adjuste the CT values of artifact affected tissues to make it more close to the true value without metal implant. |
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