Ghost artifacts occur in magnetic resonance imaging （MRI） reconstruction because odd and even echoes have different phase offsets. A method based on the projection in hybrid-space is described to remove ghost artifa...Ghost artifacts occur in magnetic resonance imaging （MRI） reconstruction because odd and even echoes have different phase offsets. A method based on the projection in hybrid-space is described to remove ghost artifacts. First, the projection of the even and odd lines along phase-encoding direction in hybrid-space was used to estimate the phase difference between odd and even echoes. Secondly, we fit the phase difference and used it to correct the phase of even or odd echoes. Finally, the corrected image was obtained by performing the inverse Fourier transform along phase-encoding direction in hybrid-space. The experimental results show that linear and nonlinear differences can be corrected and the intensity of ghost artifacts is significantly reduced. The effectiveness of the proposed method is demonstrated in ghost artifact removal.展开更多
目的通过对肺占位CT能谱成像的碘浓度、标准化碘浓度、水浓度、40 Ke V下CT值及能谱曲线斜率等多参数定量测量,探讨宝石CT能谱成像在鉴别肺占位性质的应用价值。方法选择2013年9月至2015年12月哈尔滨医科大学附属第一医院经CT普通平扫...目的通过对肺占位CT能谱成像的碘浓度、标准化碘浓度、水浓度、40 Ke V下CT值及能谱曲线斜率等多参数定量测量,探讨宝石CT能谱成像在鉴别肺占位性质的应用价值。方法选择2013年9月至2015年12月哈尔滨医科大学附属第一医院经CT普通平扫首次发现肺部存在一个或多个占位的72例患者为研究对象,所有患者均采用宝石能谱成像模式(GSI),得到的数据重建,传送到ADW 4.5工作站进行图像后处理和数据分析,获得70 Ke V能量下的单能量图、能谱曲线、碘含量以及水含量。整理炎症组(30例)与肺癌组(42例)病灶碘含量、40 Ke V下CT值、能谱曲线斜率、水含量之间的差异,以及肺癌组中鳞癌组(20例)和腺癌组(20例)碘含量、40 Ke V下CT值、能谱曲线斜率的差异。结果炎症组病灶碘含量浓度、标准化碘含量、能谱曲线斜率值、40 Ke V下CT值高于肺癌组[(1.87±0.20)g/L比(0.76±0.17)g/L、0.14±0.08比0.04±0.02、2.59±1.01比1.01±0.65、(177.83±27.98)HU比(86.16±22.45)HU](P<0.01)。肺癌组中鳞癌组病灶碘含量浓度、能谱曲线斜率值、40 Ke V下CT值低于腺癌组[(0.64±0.12)g/L比(1.27±0.36)g/L、0.76±0.11比1.26±0.23、(73.25±5.96)HU比(99.48±7.64)HU](P<0.01)。结论碘含量、标准化碘含量、40 Ke V下CT值、能谱曲线斜率值有助于区分肺部炎性占位和肺癌,水含量对区分肺部炎性占位和肺癌不具有诊断意义,宝石CT能谱成像技术对鉴别肺部炎性占位和肺癌具有较高的应用价值。展开更多
文摘Ghost artifacts occur in magnetic resonance imaging （MRI） reconstruction because odd and even echoes have different phase offsets. A method based on the projection in hybrid-space is described to remove ghost artifacts. First, the projection of the even and odd lines along phase-encoding direction in hybrid-space was used to estimate the phase difference between odd and even echoes. Secondly, we fit the phase difference and used it to correct the phase of even or odd echoes. Finally, the corrected image was obtained by performing the inverse Fourier transform along phase-encoding direction in hybrid-space. The experimental results show that linear and nonlinear differences can be corrected and the intensity of ghost artifacts is significantly reduced. The effectiveness of the proposed method is demonstrated in ghost artifact removal.
文摘目的通过对肺占位CT能谱成像的碘浓度、标准化碘浓度、水浓度、40 Ke V下CT值及能谱曲线斜率等多参数定量测量,探讨宝石CT能谱成像在鉴别肺占位性质的应用价值。方法选择2013年9月至2015年12月哈尔滨医科大学附属第一医院经CT普通平扫首次发现肺部存在一个或多个占位的72例患者为研究对象,所有患者均采用宝石能谱成像模式(GSI),得到的数据重建,传送到ADW 4.5工作站进行图像后处理和数据分析,获得70 Ke V能量下的单能量图、能谱曲线、碘含量以及水含量。整理炎症组(30例)与肺癌组(42例)病灶碘含量、40 Ke V下CT值、能谱曲线斜率、水含量之间的差异,以及肺癌组中鳞癌组(20例)和腺癌组(20例)碘含量、40 Ke V下CT值、能谱曲线斜率的差异。结果炎症组病灶碘含量浓度、标准化碘含量、能谱曲线斜率值、40 Ke V下CT值高于肺癌组[(1.87±0.20)g/L比(0.76±0.17)g/L、0.14±0.08比0.04±0.02、2.59±1.01比1.01±0.65、(177.83±27.98)HU比(86.16±22.45)HU](P<0.01)。肺癌组中鳞癌组病灶碘含量浓度、能谱曲线斜率值、40 Ke V下CT值低于腺癌组[(0.64±0.12)g/L比(1.27±0.36)g/L、0.76±0.11比1.26±0.23、(73.25±5.96)HU比(99.48±7.64)HU](P<0.01)。结论碘含量、标准化碘含量、40 Ke V下CT值、能谱曲线斜率值有助于区分肺部炎性占位和肺癌,水含量对区分肺部炎性占位和肺癌不具有诊断意义,宝石CT能谱成像技术对鉴别肺部炎性占位和肺癌具有较高的应用价值。
