This study addresses challenges in fetal magnetic resonance imaging (MRI) related to motion artifacts, maternal respiration, and hardware limitations. To enhance MRI quality, we employ deep learning techniques, specif...This study addresses challenges in fetal magnetic resonance imaging (MRI) related to motion artifacts, maternal respiration, and hardware limitations. To enhance MRI quality, we employ deep learning techniques, specifically utilizing Cycle GAN. Synthetic pairs of images, simulating artifacts in fetal MRI, are generated to train the model. Our primary contribution is the use of Cycle GAN for fetal MRI restoration, augmented by artificially corrupted data. We compare three approaches (supervised Cycle GAN, Pix2Pix, and Mobile Unet) for artifact removal. Experimental results demonstrate that the proposed supervised Cycle GAN effectively removes artifacts while preserving image details, as validated through Structural Similarity Index Measure (SSIM) and normalized Mean Absolute Error (MAE). The method proves comparable to alternatives but avoids the generation of spurious regions, which is crucial for medical accuracy.展开更多
Interbody disc spacers for anterior spine fusion are made of different materials, such as titanium alloys or carbon fiber reinforced polymers (CFRP). Implant-related susceptibility artifacts can decrease the quality o...Interbody disc spacers for anterior spine fusion are made of different materials, such as titanium alloys or carbon fiber reinforced polymers (CFRP). Implant-related susceptibility artifacts can decrease the quality of MRI scans. This cadaveric study aimed to demonstrate the extent that implant-related MRI artifacting affects the post fusion differentiation of the spinal canal (SC) and intervertebral disc space (IDS). In 6 cadaveric porcine spines, we evaluated the post-im- plantation MRI scans of a titanium and CFRP spacer that differed in shape and surface qualities. A spacer made of human cortical bone was used as a control. A defined evaluation unit was divided into regions of interest (ROI) to characterize the SC and IDS. Considering 15 different MRI sequences read independently by an interobserver-validated team of specialists artifact-affected image quality of the median MRI slice was rated on a modified score of 0-1-2-3. A maximum score of 15 points for the SC and 9 points for the IDS (100%) was possible. Turbo spin echo sequences produced the best scores for both spacers and the control. Only the control achieved a score of 100%. For the IDS the titanium and CFRP spacer maximally scored 0% and 74%, for the SC 80% and 99%, respectively. By using favored T1 TSE sequences the CFRP-spacer represented clear advantages in post fusion spinal imaging. Independent of artifact dimensions the used scoring system allowed us to create an implant-related ranking of MRI scan quality in reference to the bone control.展开更多
Aim: Intervertebral spacers for anterior spine fusion are made of different materials, such as titanium, carbon or cobalt-chrome, which can affect the post- fusion MRI scans. Implant-related susceptibility artifacts c...Aim: Intervertebral spacers for anterior spine fusion are made of different materials, such as titanium, carbon or cobalt-chrome, which can affect the post- fusion MRI scans. Implant-related susceptibility artifacts can decrease the quality of MRI scans, thwar- ting proper evaluation. This cadaver study aimed to demonstrate the extent that implant-related MRI artifacting affects the post-fusion evaluation of intervertebral spacers. Methods: In a cadaveric porcine spine, we evaluated the post-implantation MRI scans of 2 metallic intervertebral spacers (TiAL6V4, CoCrMo) that differed in shape, material, surface qualities and implantation technique. A spacer made of human cortical bone was used as a control. The median sagittal MRI slice was divided into 12 regions of interest (ROI). Results: No significant differences were found on 15 different MRI sequences read independently by an interobserver-validated team of specialists (P>0.05). Artifact-affected image quality was rated on a score of 0-1-2. A maximum score of 24 points (100%) was possible. Turbo spin echo sequences produced the best scores for all spacers and the control. Only the control achieved a score of 100%. The titanium and cobalt-chrome spacers scored 62.5% and 50%, respectively. Conclusions: Our scoring system allowed us to create an implant-related rank- ing of MRI scan quality in reference to the control that was independent of artifact dimensions. Even with turbo spin echo sequences, the susceptibility artifacts produced by the metallic spacers showed a high degree of variability. Despite optimum sequen- cing, implant design and material are relevant factors in MRI artifacting.展开更多
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
文摘This study addresses challenges in fetal magnetic resonance imaging (MRI) related to motion artifacts, maternal respiration, and hardware limitations. To enhance MRI quality, we employ deep learning techniques, specifically utilizing Cycle GAN. Synthetic pairs of images, simulating artifacts in fetal MRI, are generated to train the model. Our primary contribution is the use of Cycle GAN for fetal MRI restoration, augmented by artificially corrupted data. We compare three approaches (supervised Cycle GAN, Pix2Pix, and Mobile Unet) for artifact removal. Experimental results demonstrate that the proposed supervised Cycle GAN effectively removes artifacts while preserving image details, as validated through Structural Similarity Index Measure (SSIM) and normalized Mean Absolute Error (MAE). The method proves comparable to alternatives but avoids the generation of spurious regions, which is crucial for medical accuracy.
文摘Interbody disc spacers for anterior spine fusion are made of different materials, such as titanium alloys or carbon fiber reinforced polymers (CFRP). Implant-related susceptibility artifacts can decrease the quality of MRI scans. This cadaveric study aimed to demonstrate the extent that implant-related MRI artifacting affects the post fusion differentiation of the spinal canal (SC) and intervertebral disc space (IDS). In 6 cadaveric porcine spines, we evaluated the post-im- plantation MRI scans of a titanium and CFRP spacer that differed in shape and surface qualities. A spacer made of human cortical bone was used as a control. A defined evaluation unit was divided into regions of interest (ROI) to characterize the SC and IDS. Considering 15 different MRI sequences read independently by an interobserver-validated team of specialists artifact-affected image quality of the median MRI slice was rated on a modified score of 0-1-2-3. A maximum score of 15 points for the SC and 9 points for the IDS (100%) was possible. Turbo spin echo sequences produced the best scores for both spacers and the control. Only the control achieved a score of 100%. For the IDS the titanium and CFRP spacer maximally scored 0% and 74%, for the SC 80% and 99%, respectively. By using favored T1 TSE sequences the CFRP-spacer represented clear advantages in post fusion spinal imaging. Independent of artifact dimensions the used scoring system allowed us to create an implant-related ranking of MRI scan quality in reference to the bone control.
文摘Aim: Intervertebral spacers for anterior spine fusion are made of different materials, such as titanium, carbon or cobalt-chrome, which can affect the post- fusion MRI scans. Implant-related susceptibility artifacts can decrease the quality of MRI scans, thwar- ting proper evaluation. This cadaver study aimed to demonstrate the extent that implant-related MRI artifacting affects the post-fusion evaluation of intervertebral spacers. Methods: In a cadaveric porcine spine, we evaluated the post-implantation MRI scans of 2 metallic intervertebral spacers (TiAL6V4, CoCrMo) that differed in shape, material, surface qualities and implantation technique. A spacer made of human cortical bone was used as a control. The median sagittal MRI slice was divided into 12 regions of interest (ROI). Results: No significant differences were found on 15 different MRI sequences read independently by an interobserver-validated team of specialists (P>0.05). Artifact-affected image quality was rated on a score of 0-1-2. A maximum score of 24 points (100%) was possible. Turbo spin echo sequences produced the best scores for all spacers and the control. Only the control achieved a score of 100%. The titanium and cobalt-chrome spacers scored 62.5% and 50%, respectively. Conclusions: Our scoring system allowed us to create an implant-related rank- ing of MRI scan quality in reference to the control that was independent of artifact dimensions. Even with turbo spin echo sequences, the susceptibility artifacts produced by the metallic spacers showed a high degree of variability. Despite optimum sequen- cing, implant design and material are relevant factors in MRI artifacting.
文摘目的探讨不同磁场强度(1.5T和3.0 T)对镍铬合金固定修复体磁共振成像(MRI)中伪影的影响。方法以镍铬合金制作不同厚度的单冠、桥修复体及上半口修复体作为试样,置于盛有清水的容器中央,分别于1.5 T和3.0 T的磁场强度下进行MR扫描,勾画和计算伪影面积并进行比较分析,以相同形状和厚度的塑料修复体作为对照修复体。结果镍铬合金固定修复体在MRI中均可产生伪影,其面积随修复体体积的增加而扩大,而对照修复体未见伪影形成。与1.5 T MRI相比,3.0 T MRI上产生的伪影面积显著增大(P<0.05);相同磁场强度下,与扫描序列T_2WI相比,扫描序列T_1WI上所形成的伪影面积显著增大(P<0.05)。结论口腔内有镍铬合金固定修复体的患者在行MRI检查时,应选择较低的磁场强度及快速自旋回波序列进行扫描。应避免选用镍铬合金制作大范围固定修复体。
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。
