能谱成像技术减除脊柱金属植入物伪影的临床应用价值

目的评价宝石CT能谱成像技术在减除脊柱金属植入物伪影方面的临床应用价值。方法对20例带有脊柱金属植入物的患者行宝石CT能谱扫描,扫描后获得(120Kvp)混合能量图像。用能谱分析软件(GSI viewer)进行分析,在40-140Kev(间距10Kev)重建11种单能量图像。然后选取最佳单能量图像行金属伪影消除重建(Metal-Artifacts Reduction System,MARs),获得MARs能谱图像(110Kev单能量+MARs图像)。由3名放射科医师采用4分量表对图像质量进行主观目测评分,测量椎弓根螺钉前端的放射状伪影长度以评价其伪影程度。对所获得数据采用SPSS17.0进行配对t检验分析。结果在11种单能量图像组中,110Kev单能量图像组的放射状金属伪影长度最短,主观评分最高,因此所有20例患者的图像均于110Kev行MARs重建。MARs能谱图像组(110Kev单能量+MARS图像)与混合能量图像组的主观评分及伪影长度之间均存在显著性差异(P=0.000<0.05),即MARs能谱图像组的金属伪影明显降低,图像质量明显优于混合能量图像组。结论在脊柱金属植入物患者的单能量图像组中,110Kev为图像质量最佳的单能量成像点。宝石CT能谱成像技术能够显著减少脊柱金属植入物的伪影,使CT图像的质量明显提高,具有较高的临床应用价值。

The value of Gemstone spectral imaging for reducing spinal metal artifacts

Objective To evaluate the practical value of gemstone spectral imaging(GSI) in reducing the metal artifacts of spine.Methods GSI examination were performed to twenty patients with metal implants of spine,and blend energy images were acquired at the same time.Gemstone spectral imaging(GSI) viewer was used to obtain 11 sets of monochromatic imagings(40-140keV with interval of 10keV) and 110keV+MARs images.Three radiologists reviewed all images respectively and assessed the image quality visually using 4-point scale.The lengths of the artifacts emanating from the anterior tips of the screw were used to evaluate the degree of artifact.Statistical analysis was accomplished with SPSS 17.0 soft package.Results In of the 11 sets of monochromatic images,110keV set had the highest score of image quality,the lengths of artifacts were lowest.There were significant statistical differences between energy spectral images and blend energy images(P<0.05),that is to say,the image quality of energy spectral were significantly better than those of blend energy images.Conclusion Patients with metal implants of spine,110keV was the best point for quality of monochromatic imaging.Gemstone spectral CT can effectively reduce artifacts of spine metal implants and will provide high image quality in the area with metal implants.