Zhao Yongming, Zhang Su, Chen Yazhu
Biomedical Instrument Institute, Shanghai Jiao Tong University, Shanghai, China.
Conf Proc IEEE Eng Med Biol Soc. 2005;2005:3237-40. doi: 10.1109/IEMBS.2005.1617166.
To register pre-operative MRI/CT images with intra-operative ultrasound images based on the vessels visible in both of the modalities, we presents a non-rigid registration method of multimodal medical images based on Free Form Deformation was proposed. When the images are aligned, the centerline points of the vessels in one image will align with the intensity ridge points in the other image. Rigid transformation was adopted in global registration while local deformation was described by a free form deformation (FFD) based on a modally controlled B-spline. The method applies an optimization strategy combining the genetic algorithm with the conjugated gradients algorithm to minimize the objective function. Two experiments were designed on phantom and clinical data to evaluate the method. The results indicate that the registration method is consistent and suggest that it is accurate. The average standard deviation of the final transformation parameters is sub-voxel, sub-millimeter, and within 0.010 radians. The results show that the method has good registration accuracy and convergence rate. And it can be applied efficiently in the ultrasound-image-guided surgery system.
为了基于两种模态中可见的血管将术前MRI/CT图像与术中超声图像配准，我们提出了一种基于自由形式变形的多模态医学图像非刚性配准方法。当图像对齐时，一幅图像中血管的中心线点将与另一幅图像中的强度脊点对齐。全局配准采用刚性变换，而局部变形则通过基于模态控制B样条的自由形式变形（FFD）来描述。该方法应用了一种将遗传算法与共轭梯度算法相结合的优化策略，以最小化目标函数。在体模和临床数据上设计了两个实验来评估该方法。结果表明，配准方法具有一致性且表明其是准确的。最终变换参数的平均标准差为亚体素、亚毫米且在0.010弧度以内。结果表明该方法具有良好的配准精度和收敛速度。并且它可以在超声图像引导手术系统中有效应用。
