【作者】 刘凯； 柳澄； 陈青华； 巩若箴； 夏冰；

【Author】 LIU Kai, LIU Cheng, CHEN Qing-hua,et al. Shandong Provincial Medical Imaging Institute, Jinan 250021, China

【机构】 山东省医学影像学研究所；

【摘要】 目的:研究颞骨高分辨率CT是否能够达到各向同性并筛选出最佳扫描参数组合。方法:采用Phjlips公司Mx8000 4层螺旋CT机进行扫描,Mx VIEW工作站进行图像后处理。矩阵采用512×512,视野（FOV）为250mm×250mm,选用头颅标本4具,8耳,分别用准直0.5mm、重建间隔50%（0.3mm）、不同螺距（0.625、0.875、1.250、1.750）得到直接扫描轴、冠状面图像各4组。通过图像重建技术,得到准直0.5mm、重建间隔83.3%（0.5mm）,准直1.0mm、重建间隔50%（0.5mm）的重建图像各4组。轴面选用镫骨、弓形下窝、前庭上神经管、鼓膜张肌、前庭导水管等9个解剖结构,冠状面选用鼓膜张肌、锤骨外侧韧带、前庭下神经管、蜗窗等9个解剖结构。利用多平面重建（MPR）技术,采用上述解剖结构,分别将12组轴、冠状扫描图像与相应的重建图像的显示质量进行统计评分处理,验证能否达到各向同性并筛选出达到各向同性的最佳参数组合。利用这个最佳参数组合,采用患者组15耳进一步验证其正确性。结果:螺距0.625、0.875,准直0.5mm、重建间隔0.3mm 2组扫描参数的MPR图像与直接图像能够达到各向同性。(前组t_0.05（2）=-0.78,P>0.05;后组t_0.05（3）=-1.93,P>0.05]采用准直0.5mm、重建间隔0.3mm、螺距0.875参数组合的患者组MPR图像与直接扫描图像对比同样能够达到各向同性（P<0.05）。结论:（1）基础和临床研究结果表明,颞骨CT扫描中,采用合适的参数组合可以达到各向同性。（2）准直0.5mm、重建间隔0.3mm、螺距0.875在颞骨扫描中是达到各向同性的最佳参数组合。更多还原

【Abstract】 Objective:To study the possibility of isoti-opy scanning with high resolution CT（HRCT）in temporal bone, and to choose the best scan parameters.Methods:HRCT was performed on aquadniple helical scanner（Philips, Mx8000）with matrix 512×512 and FOV 250mm×250mm. Postprocessing was performed on MX VIEW workstation. 8 ears of 4 cranium specimens were scanned with collimation of 0.5mm, 50% increments（0.3 mm）, and different pitch（0.625, 0.875, 1.25, and 1.75）. Then 4 axial and 4 coronal direct-scanned groups were collected. After reconstruction, 4 axial and 4 coronal groups with collimation of 0.5 mm, 83.3% increments（0.5 mm）and collimation of 1.0 mm, 50% increments（0.5 mm）were collected respectively. Nine anatomic structures on axial images（such as stapes, subarcuate fossa, superior vestibular nerve canal, tensor tympani, vesti bular aqueduct, etc）and nine anatomic structures on coronal images（tensor tympani, lateral malleal ligament, inferior vestibular nerve canal, fenestra cochleae, etc）were selected. In order to testify the possibility of isotropy and choose the best scan parameters, image quality of axial and coronal direct scan in 12 groups was compared with the corresponding multi-planar reconstruction images（MPR）through the anatomic structures mentioned above, then they were graded and statistically analyzed. 15 ears of patients were used to test the validity of the best scan parameters. Results:MPR images with scan parameter of pitch 0.625 and 0.875, collimation0.5mm, and increment of 0.3mm could reach the isotropy. [the former t_0.05（2）=-0.78, P > 0.05; the latter t_0.05（3）=-1.93, P > 0.05]. MPR images of patients with scan parameter of pitch 0.875 collimation 0.5mm, and increment 0.3m could also reach the isotropy（0.02 < P < 0.05）.Conclusion:（1）Both the fundamental and clinical results show that isotropy can be reached with suitable scan parameters.（2）The best scan parameters are coUimation 0.5mm, increment 0.3mm, and pitch 0.875.更多还原