体位一致性对鼻咽癌CT-MR图像自动配准精度的影响

The effect of scan position consistency on automatic registration of computer tomography-magnetic resonance images in patients with nasopharyngeal carcinoma

目的研究鼻咽癌CT扫描与MR扫描时体位一致性对二者图像自动配准的影响。方法15例鼻咽癌患者在相同体位下行CT和MR定位扫描得到CT序列和MR-1序列，改变体位后再行1次MR扫描得到MR-2序列，采用互信息法将CT序列分别与MR-1序列和MR-2序列进行自动配准，使用标记点测量法评估配准误差。结果相同体位下的CT-MR图像自动配准误差约为1．32mm，改变体位后自动配准误差最小为2．00mm，最大可达3．83mm。结论保持体位一致性能提高CT-MR图像自动配准的精确度。

Objective To study the effect of scan position consistency on computer tomographymagnetic resonance （CT-MR） images automatic registration in patients with nasopharyngeal carcinoma. Methods Fifteen patients with nasopharyngeal carcinoma were enrolled in this study and scanned with the same position to acquire CT images and MR-1 images. Then they were rescanned with different position for MR-2 images. Image registration of CT-MR-1 and CT-MR-2 was finished using mutual information method. The registration errors were evaluated by measuring the distances between marks. Results The error of au- tomatic CT-MR registration with consistent scan position was 1.32 mm, comparing with the minimum of 2.00 mm and the maximum of 3.83 mm with different positions. Conclusion Keeping consistent scan position can improve the accuracy of image registration.