【摘要】 目的 探讨多排螺旋CT(MDCT)扫描参数及图像后处理方式对金属植入物伪影的影响,以期获得最佳方案减少金属伪影。方法 制作钛合金钢板水模,将其置入MDCT下通过调节不同参数进行扫描(包括管电压、管电流、螺距、焦点),然后测定所得图像伪影面积大小并评价其相关性;对常规扫描参数下获得的15例椎体内固定术后患者图像进行后处理,分别使用常规方式和优化方式重建,包括多平面重建(MPR)、调节窗宽窗位及容积再现技术(VRT),然后评价图像质量。结果 不同管电压、螺距、焦点下,伪影面积差异有统计学意义,随着管电压升高,伪影面积逐渐减小;随着螺距减小,伪影面积逐渐减小;使用小焦点扫描较大焦点伪影面积小;不同管电流下,伪影面积差异无统计学意义。图像后处理时骨窗重建选择软组织算法(Kernel B40f)、观察时选择窗位600 HU、窗宽2 000 HU及VRT三维重建可减少金属伪影。结论 选择适当的MDCT扫描参数及图像后处理方式可以减少金属伪影,提高图像质量,有助于影像诊断。更多还原

【Abstract】 Objective To explore the effect of multi-detector computed tomography(MDCT) scan parameters and imaging postprocessing methods on metallic artifacts,so as to achieve the perfection in reduction of artifacts caused by metallic implants.Methods Water phantom with titanium alloy steel plate was scanned under MDCT with alternating scan parameters including tube voltage,tube current,pitch and focal spot.The areas of image artifacts were measured and correlated with the scan parameters.Another 15postoperative patients with vertebral implantation scaned with the conventional scan parameters were also included in the study.Imaging post-processing including multi-planar reconstruction(MPR),window width and level adjustment,and volume rendering technique(VRT) was performed by using optimized and conventional methods,respectively,and then the image quality was evaluated.Results The areas of image artifacts under the differnt tube voltage,pitch,and focal spot were statistically different.With the increase of the tube voltage or the decrease of the pitch,the area of image artifacts decreased gradually.The area of image artifacts scanned with the small focal spot was smaller than the large one.There was no significant difference for the area of image artifacts scanned with the different tube currents.The metallic artifacts decreased by using the soft tissue algorithm(Kernel B40f) in the bone window reconstruction,wide windows(2 000 HU window width,600 HU window level) in observing,and VRT.Conclusion Selection of appropriate MDCT scan parameters and imaging post-processing methods can reduce the metal artifacts,improve the image quality and diagnosis.更多还原