【摘要】 目的探讨基于3D表面扫描技术改良5 cm动物线圈,优化KM小鼠成像的实验研究。材料与方法采用3D表面扫描仪对5 cm动物线圈扫描,并个性化设计完成线圈专用小鼠扫描支架,用于在3.0 T上对KM小鼠进行多时间点优化成像研究。6只荷瘤KM小鼠腹腔麻醉后,在3.0 T磁共振仪上采用5 cm动物线圈进行扫描,对比采用支架前后MR图像,并记录预扫描次数,整个扫描过程和开始及结束时间。图像质量评估采用客观指标及主观指标,客观指标使用信噪比(signal to noise ratio,SNR)和对比信噪比(contrast to noise ratio,CNR);主观指标由两名读片医师对前后图像出现的自主运动伪影、呼吸伪影进行3等级评分。计量数据采用配对资料的t检验;等级资料采用配对Wilcoxon’s秩和检验,检验水准α=0.05;两位医师间的一致性分析采用Cohen’s Kappa检验评估。结果使用3D打印技术成功制备2个磁共振线圈平台支架(简称3D支架)。两位读片医师间对自主运动及呼吸运动伪影的判断进行一致性分析,其κ值均在0.7以上提示一致性良好。未采用3D打印支架时,总共预扫描需进行21次,成功率为28.57%(6/21),平均每只KM小鼠完成扫描时间为17.6min;采用3D支架后,总共预扫描6次(每个小鼠预扫描1次成功),成功率100%(6/6),平均每只KM小鼠完成扫描时间为10.8min,时间缩短了38.64%。使用3D支架前后SNR分别为2.16±0.18、2.41±0.14,CNR分别为1.48±0.11、1.86±0.14,进行配对Wilcoxon’s秩和检验,P均<0.05。与未使用3D打印支架相比,使用3D打印支架后降低了对检查部位的自主运动及呼吸运动伪影,两位读片医师分别对使用3D打印前后的自主运动伪影、呼吸运动伪影评分,进行配对Wilcoxon’s秩和检验,P<0.05。结论利用3D打印技术制作的磁共振动物线圈支架,增加了扫描定位成功率和图像的信号强度,缩短了成像时间并减少伪影,在磁共振动物模型扫描实验中具有重要的应用价值。更多还原

【Abstract】 Objective: To explore optimizing the imaging of KM mice based 5 cm animal coils improved by 3 D surface scanning technology. Materials and Methods: A 3 D surface scanner was used to scan the 5 cm animal coil, and a mouse scanning holder was designed for optimizing multi-time point imaging of KM mice on 3.0 T MRI. After intraperitoneal anesthesia, 6 KM mice with tumor were scanned with a 5 cm animal coil on a 3.0 T MRI. Compare the images before and after the holder, the number of pre-scans, the entire scanning process, and the start and end times were recorded. The image quality assessment adopted objective and subjective indicators. The objective indicators use SNR(signal to noise ratio) and CNR(contrast to noise ratio). The subjective indicators are graded to three levels by two radiologists by the artifacts of autonomic movement and breathe appearing in the images. The measurement data were analyzed by paired t-test; the ordinal data were analyzed by Wilcoxon’s rank sum test, and the test level α is 0.05; the consistency analysis between the two radiologists was evaluated by Cohen’s Kappa test. Results: Two magnetic resonance coil holders(referred to as 3 D holder) were successfully made using 3 D printing technology. Consistency analysis of the autonomic movement and breathe artifacts between the two radiologists showed that the κ values were all above 0.7, indicating good agreement. Without the 3 D printing holder, the total pre-scan needs 21 times with a success rate of 28.57%(6/21), and the average scanning time for per KM mouse is 17.6 minutes; after using the 3 D holder, it just needed 6 pre-scans in total(Each mouse was pre-scanned successfully once) with a success rate of 100%(6/6). The average scan time for per KM mouse was 10.8 minutes, so the time was shortened by 38.64%. The SNRs before and after using the holder were respectively 2.16±0.18, 2.41±0.14, and CNR were 1.48±0.11 and 1.86±0.14. Paired Wilcoxon’s rank sum test was performed, and P<0.05. Compared with the non-3 D-printed holder group, using 3 D printing holder reduces the autonomic movement and breathe artifacts. The two radiologists respectively graded the autonomous movement and breathe artifacts before and after the 3 D printing and performed a paired Wilcoxon’s rank sum test with P<0.05. Conclusions: The magnetic resonance animal coil holder using 3 D printing technology help to reduce the preparation time of animal MRI scanning, improve the comfort, facilitate the fixation, increase the success rate of scanning and image signal intensity, shorten the scanning time, reduces the artifacts caused by autonomous movement and breathe, which has important application value in magnetic resonance animal model experiments.更多还原