摘要
背景与目的:MRI是鼻咽癌诊疗的主要工具,但基于MRI的治疗计划系统并不成熟,临床上多采用CT/MRI融合的方法勾画靶区。本研究探讨3种CT/MRI融合方法在鼻咽癌诊疗中的应用,并比较3种方法的图像融合效果。方法:15例鼻咽癌患者模拟放射治疗的体位、采用面罩固定分别进行CT和MRI扫描,全部图像经网络传送到治疗计划工作站,分别采用标记点法、相关法和归一化互信息法进行CT/MRI融合。记录达到满意融合效果时花费的时间;测量X轴和Y轴方向上的融合误差;分别根据CT和MRI图像勾画上颌窦的轮廓,记录上颌窦中心坐标的差异。采用方差分析来比较3种融合方法花费的时间,X、Y坐标方向上的融合误差,上颌窦中心坐标的差异。结果:标记点法、相关法和归一化信息法融合3种融合方法花费的平均时间分别为(6.2±1.3)、(5.2±1.1)和(5.2±1.0)min,标记点法花费的时间最长(χ2=14.824,P=0.001),相关法和归一化互信息法花费的时间无显著性差异(χ2=0.62,P=0.78)。3种方法在X轴方向的平均融合误差为(0.68±0.21)、(0.71±0.19)、(0.69±0.27)mm(χ2=0.25,P=0.97),Y轴方向的平均融合误差分别为(1.13±0.16)、(1.15±0.21)、(1.15±0.18)mm(χ2=0.53,P=0.87)。上颌窦中心坐标在X轴方向的平均差异分别为(0.37±0.16)、(0.36±0.18)、(0.37±0.16)mm(χ2=0.25,P=0.97);在Y轴方向的平均差异分别为(0.54±0.17)、(0.55±0.15)、(0.54±0.16)mm(χ2=0.29,P=0.93);在Z轴方向的平均差异分别为(0.7±0.7)、(0.6±0.8)、(0.5±0.7)mm(χ2=0.91,P=0.68)。结论:标记点法、相关法和归一化互信息法都能达到满意的CT/MRI融合效果,标记点法花费的时间较长。
Background and purpose： Magnetic resonance imaging （MRI） has become a major tool in the treatment of nasopharyngeal carcinoma（NPC）, but a treatment planning system based on MRI is still under first phase of investigation. CT/MRI fusion is used to delineate target volumes. We explored the applicability of three methods for CT and MRI registration, and to compare the registration effects of the three methods. Methods： CT and MRI scans of 15 NPC patients were performed in treatment position with immobilization mask. All images were transmitted to the treatment planning system, and underwent CT/MRI registration using the following three methods, respectively： （1）Links and marks, （2）Interactive, （3）Normalized mutual information. The time needed to complete CT/MRI registration was recorded. Registration errors were measured both along X axis and Y axis. Contours of the maxillary sinus was delineated both on CT and MRI, differences between coordinates of the center of the maxillary sinus were recorded. One-way ANOVA was used to test the differences among the time, registration errors along both X axis and Y axis, as well as coordinates of the center of the maxillary sinus. Results： The mean time needed for the three methods to complete CT/MRI registration was （6.2±1.3）, （5.2±1.1）, and （ 5.2±1.0） min, respectively. Time needed for Links and marks method was the longest（ P = 0.001）, while there was no significant difference between the time needed for interactive and normalized mutual information method（ P = 0.78）. Mean registration error of the three methods along X axis was （0.68±0.21）, （0.71±0.19）, and （0.69±0.27） mm, respectively（ P =0.97）, and along Yaxis （1.13±0.16）, （1.15±0.21）, and （1.15±0.18） mm, respectively （P=0.87）. Differences among coordinates of the center of the maxillary sinus at X axis was （0.37±0.16）, （0.36±0.18）, and （ 0.37±0.16） mm, respectively（ P = 0.97）, and （0.54±0. 17）, （0.55±0.15）, （0.54±0.16） mm（ P = 0.93） at Y axis, and （0.7±0.7）, （ 0.6±0.8）, （ 0.5±0.7） mm at Z axis（ P = 0.68）. Conclusions： All the three registration methods-marks and links, interactive, normalized mutual information can achieve good CT/MRI registration results. More time is needed for the marks and links method.
出处
《中国癌症杂志》
CAS
CSCD
2008年第4期282-285,共4页
China Oncology
关键词
鼻咽肿瘤
X线计算机断层扫描
磁共振成像
图像融合
nasopharyngeal carcinoma
computed tomography
magnetic resonance imaging
image registration
