目的评估脑深部电刺激(DBS)系统在帕金森病(PD)丘脑底核(STN)刺激术后磁共振成像(MRI)的安全性,分析扫描前后的伪影大小及其对电极阻抗的影响。方法纳入2023年5月—2024年6月在北京协和医院行DBS植入术后的23例PD患者,对所有入组患者行...目的评估脑深部电刺激(DBS)系统在帕金森病(PD)丘脑底核(STN)刺激术后磁共振成像(MRI)的安全性,分析扫描前后的伪影大小及其对电极阻抗的影响。方法纳入2023年5月—2024年6月在北京协和医院行DBS植入术后的23例PD患者,对所有入组患者行头部1.5 T MRI,记录扫描前后电极各触点阻抗值、温度和特殊吸收率(SAR)值,比较扫描前后各参数差异;分析患者扫描所得MRI图像的伪影,比较两种不同序列伪影体积的差别;探究电极阻抗变化与伪影体积的相关性。结果所有患者在1.5 T MRI扫描前后的温度和电极阻抗值差异无统计学意义,T 1序列双侧伪影体积平均值均大于T 2序列(P=0.001);扫描前后电极阻抗值变化与伪影体积无显著相关(r=-0.268,P=0.355;r=-0.389,P=0.170)。结论DBS植入术后1.5 T MRI扫描具备临床安全性,双侧电极植入引起的图像伪影在不同序列以及不同侧别的体积大小不同,但与扫描前后的阻抗值变化无明显相关。展开更多
During the process of magnetic resonance imaging （MRI）, the patient motion causes phase errors in collected signals and induces motion artifacts in the reconstructed image. Severe artifacts interfere with the focus ...During the process of magnetic resonance imaging （MRI）, the patient motion causes phase errors in collected signals and induces motion artifacts in the reconstructed image. Severe artifacts interfere with the focus location. Because the genetic algorithm （GA） has characteristics of parallel, random and adaptive stochastic searching, a correction method of motion artifacts is presented based on the algorithm. The method can correct the phase error in K-space signals step by step. Experiments show that the motion artifacts in MRI can be effectively suppressed by using the method.展开更多
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
文摘目的评估脑深部电刺激(DBS)系统在帕金森病(PD)丘脑底核(STN)刺激术后磁共振成像(MRI)的安全性,分析扫描前后的伪影大小及其对电极阻抗的影响。方法纳入2023年5月—2024年6月在北京协和医院行DBS植入术后的23例PD患者,对所有入组患者行头部1.5 T MRI,记录扫描前后电极各触点阻抗值、温度和特殊吸收率(SAR)值,比较扫描前后各参数差异;分析患者扫描所得MRI图像的伪影,比较两种不同序列伪影体积的差别;探究电极阻抗变化与伪影体积的相关性。结果所有患者在1.5 T MRI扫描前后的温度和电极阻抗值差异无统计学意义,T 1序列双侧伪影体积平均值均大于T 2序列(P=0.001);扫描前后电极阻抗值变化与伪影体积无显著相关(r=-0.268,P=0.355;r=-0.389,P=0.170)。结论DBS植入术后1.5 T MRI扫描具备临床安全性,双侧电极植入引起的图像伪影在不同序列以及不同侧别的体积大小不同,但与扫描前后的阻抗值变化无明显相关。
文摘During the process of magnetic resonance imaging （MRI）, the patient motion causes phase errors in collected signals and induces motion artifacts in the reconstructed image. Severe artifacts interfere with the focus location. Because the genetic algorithm （GA） has characteristics of parallel, random and adaptive stochastic searching, a correction method of motion artifacts is presented based on the algorithm. The method can correct the phase error in K-space signals step by step. Experiments show that the motion artifacts in MRI can be effectively suppressed by using the method.
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.
