目的 比较能谱CT金属伪影去除算法及虚拟单能图像重建与传统迭代重建在减少脊柱金属植入物伪影的差异。方法 56例脊柱矫形术接受金属植入物行标准能谱CT检查,包括常规迭代重建、金属伪影去除算法和虚拟单能图像重建。测量衰减系数(HU)...目的 比较能谱CT金属伪影去除算法及虚拟单能图像重建与传统迭代重建在减少脊柱金属植入物伪影的差异。方法 56例脊柱矫形术接受金属植入物行标准能谱CT检查,包括常规迭代重建、金属伪影去除算法和虚拟单能图像重建。测量衰减系数(HU)和噪声(SD),以计算椎旁肌和椎管的信噪比。两名放射科医师独立评价图像质量和伪影减少程度。结果 与常规迭代重建相比,金属伪影去除算法和高keV虚拟单能图像显著降低低密度伪影及高密度伪影。与常规迭代重建相比,金属伪影去除算法和高keV虚拟单能图像椎旁肌(34.6±17.0HU vs. 26.1±13.5HU及34.6±17.0HU vs. 27.0±14.2)和椎管(102.5±60.1HU vs. 72.1±39.3HU及102.5±60.1HU vs. 60.1±38.0HU, P 均<0.05)的噪声伪影减少。观察者间评价主观图像质量的一致性良好,ICC=0.74。在主观图像质量评价中,金属伪影去除算法和高keV虚拟单能图像上表现出伪影减少分别为44/56例(78.6%)、48/56例(85.7%)。结论 能谱CT金属伪影去除算法和高keV虚拟单能图像重建上客观及主观伪像均减少,金属伪影去除算法联合虚拟单能图像的组合可能有希望进一步减少伪影。展开更多
目的比较口腔科常用的3种金属和2种陶瓷材料在0.35、1.5及3 T 3种场强磁共振成像(MRI)不同序列中形成伪影的差异。方法将3种金属和2种陶瓷材料制作成同样大小及厚度的中切牙内冠,将其置入盛满生理盐水的塑料罐体中,分别在0.35、1.5和3....目的比较口腔科常用的3种金属和2种陶瓷材料在0.35、1.5及3 T 3种场强磁共振成像(MRI)不同序列中形成伪影的差异。方法将3种金属和2种陶瓷材料制作成同样大小及厚度的中切牙内冠,将其置入盛满生理盐水的塑料罐体中,分别在0.35、1.5和3.0 T的磁共振(MR)机中扫描获得T1WI、T2WI影像。比较各种材料在不同场强的MR扫描中伪影的差异。结果氧化锆在3种场强的MR机中扫描无明显伪影;铸造陶瓷伪影极轻微;贵金属合金、烤瓷镍铬合金与烤瓷钴铬合金在3种场强MR扫描中均出现不同程度的伪影。结论氧化锆、铸造陶瓷这两种常用口腔陶瓷材料基本无伪影或伪影极轻微。贵金属合金、烤瓷镍铬合金与烤瓷钴铬合金3种常用口腔金属材料易引起MRI伪影,且随着主磁体场强增加,伪影面积增大。展开更多
Background Magnetic resonance imaging （MRI） is prone to be deformed by artifacts caused by the presence of metallic materials. The aim of this study was to evaluate the artifacts from galvano-ceramic and metal-ceram...Background Magnetic resonance imaging （MRI） is prone to be deformed by artifacts caused by the presence of metallic materials. The aim of this study was to evaluate the artifacts from galvano-ceramic and metal-ceramic crowns in MRI, in order to analyze their influences on diagnostic interpretation of MRI. Methods Galvano-ceramic and metal-ceramic crowns （Bio98, Wiron99, SP-78, BioKC97） were fabricated with the same model. All materials were imaged by means of 1.5T MRI apparatus with three different sequences, T1-weighted spin-echo （T1-weighted SE）, T2-weighted spin-echo （T2-weighted SE） and Gradient echo （GE）. Mean and standard deviation of distilled water signal intensity （St） around the sample in the region of interest （500 mm^2） enclosing the whole artifacts were determined, and compared for evaluation of the homogeneity of signal intensity. Images around the sample were acquired and evaluated. Results There were statistically significant differences in the values of signal intensity between acrylic resin control and BioKC97, Wiron99 in the three sequences （P〈0.001）. The mean values of signal intensity for Bio98, SP-78 were significantly different from that of acrylic resin control （RE） in GE sequence （P〈0.001）. No difference was showed between acrylic resin control and galvano-ceramic crown （P 〉0.05）. Images showed that the greatest artifact was a 25 mm ring with distortion in Wiron99 in GE sequence. Conclusions This in vitro study suggested that galvano-ceramic crown had no influence on the MRI, while metal-ceramic crowns caused moderate artifacts in the MRI. Therefore, galvano-ceramic restoration is a valuable alternative in dentistry.展开更多
文摘目的 比较能谱CT金属伪影去除算法及虚拟单能图像重建与传统迭代重建在减少脊柱金属植入物伪影的差异。方法 56例脊柱矫形术接受金属植入物行标准能谱CT检查,包括常规迭代重建、金属伪影去除算法和虚拟单能图像重建。测量衰减系数(HU)和噪声(SD),以计算椎旁肌和椎管的信噪比。两名放射科医师独立评价图像质量和伪影减少程度。结果 与常规迭代重建相比,金属伪影去除算法和高keV虚拟单能图像显著降低低密度伪影及高密度伪影。与常规迭代重建相比,金属伪影去除算法和高keV虚拟单能图像椎旁肌(34.6±17.0HU vs. 26.1±13.5HU及34.6±17.0HU vs. 27.0±14.2)和椎管(102.5±60.1HU vs. 72.1±39.3HU及102.5±60.1HU vs. 60.1±38.0HU, P 均<0.05)的噪声伪影减少。观察者间评价主观图像质量的一致性良好,ICC=0.74。在主观图像质量评价中,金属伪影去除算法和高keV虚拟单能图像上表现出伪影减少分别为44/56例(78.6%)、48/56例(85.7%)。结论 能谱CT金属伪影去除算法和高keV虚拟单能图像重建上客观及主观伪像均减少,金属伪影去除算法联合虚拟单能图像的组合可能有希望进一步减少伪影。
文摘目的比较口腔科常用的3种金属和2种陶瓷材料在0.35、1.5及3 T 3种场强磁共振成像(MRI)不同序列中形成伪影的差异。方法将3种金属和2种陶瓷材料制作成同样大小及厚度的中切牙内冠,将其置入盛满生理盐水的塑料罐体中,分别在0.35、1.5和3.0 T的磁共振(MR)机中扫描获得T1WI、T2WI影像。比较各种材料在不同场强的MR扫描中伪影的差异。结果氧化锆在3种场强的MR机中扫描无明显伪影;铸造陶瓷伪影极轻微;贵金属合金、烤瓷镍铬合金与烤瓷钴铬合金在3种场强MR扫描中均出现不同程度的伪影。结论氧化锆、铸造陶瓷这两种常用口腔陶瓷材料基本无伪影或伪影极轻微。贵金属合金、烤瓷镍铬合金与烤瓷钴铬合金3种常用口腔金属材料易引起MRI伪影,且随着主磁体场强增加,伪影面积增大。
文摘Background Magnetic resonance imaging （MRI） is prone to be deformed by artifacts caused by the presence of metallic materials. The aim of this study was to evaluate the artifacts from galvano-ceramic and metal-ceramic crowns in MRI, in order to analyze their influences on diagnostic interpretation of MRI. Methods Galvano-ceramic and metal-ceramic crowns （Bio98, Wiron99, SP-78, BioKC97） were fabricated with the same model. All materials were imaged by means of 1.5T MRI apparatus with three different sequences, T1-weighted spin-echo （T1-weighted SE）, T2-weighted spin-echo （T2-weighted SE） and Gradient echo （GE）. Mean and standard deviation of distilled water signal intensity （St） around the sample in the region of interest （500 mm^2） enclosing the whole artifacts were determined, and compared for evaluation of the homogeneity of signal intensity. Images around the sample were acquired and evaluated. Results There were statistically significant differences in the values of signal intensity between acrylic resin control and BioKC97, Wiron99 in the three sequences （P〈0.001）. The mean values of signal intensity for Bio98, SP-78 were significantly different from that of acrylic resin control （RE） in GE sequence （P〈0.001）. No difference was showed between acrylic resin control and galvano-ceramic crown （P 〉0.05）. Images showed that the greatest artifact was a 25 mm ring with distortion in Wiron99 in GE sequence. Conclusions This in vitro study suggested that galvano-ceramic crown had no influence on the MRI, while metal-ceramic crowns caused moderate artifacts in the MRI. Therefore, galvano-ceramic restoration is a valuable alternative in dentistry.
