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Computer Engineering ›› 2025, Vol. 51 ›› Issue (10): 270-283. doi: 10.19678/j.issn.1000-3428.0069093

• Graphics and Image Processing • Previous Articles     Next Articles

Registration Method of MRI-TRUS Images Based on Joint Learning and Multi-Level Wavelet Feature Pyramid

JIANG Honggui1, HU Jisu2, QIAN Xusheng2, ZHENG Yi2, ZHOU Zhiyong2, DAI Yakang1,2,*()   

  1. 1. School of Medical Imaging, Xuzhou Medical University, Xuzhou 221004, Jiangsu, China
    2. Suzhou Institute of Biomedical Engineering and Technology, Chinese Academy of Science, Suzhou 215163, Jiangsu, China
  • Received:2023-12-25 Revised:2024-06-05 Online:2025-10-15 Published:2024-08-12
  • Contact: DAI Yakang

基于联合学习和多级小波特征金字塔的MRI-TRUS图像配准方法

蒋宏贵1, 胡冀苏2, 钱旭升2, 郑毅2, 周志勇2, 戴亚康1,2,*()   

  1. 1. 徐州医科大学医学影像学院, 江苏 徐州 221004
    2. 中国科学院苏州生物医学工程技术研究所, 江苏 苏州 215163
  • 通讯作者: 戴亚康
  • 基金资助:
    国家自然科学基金面上项目(62271480); 中国科学院青年创新促进会(2021324); 江苏省重点研发计划(BE2021612); 苏州市科技计划项目(SKY2022052); 苏州市科技计划项目(SYG202321); 苏州市科技计划项目(SSD2023009); 苏州市临床重点病种诊疗技术专项(LCZX202107); 苏州市临床重点病种诊疗技术专项(LCZX202104)

Abstract:

The registration of Magnetic Resonance Imaging (MRI) images and TRansrectal UltraSound (TRUS) images is a combination of preoperative MRI image registration and intraoperative ultrasound image, combining the advantages of the two image modes to quickly locate the lesion area. This process plays an important role in assisting diagnosis, puncture, intraoperative navigation, and other medical surgery problems. Owing to the inherent representational differences between the two image modes, with significant intensity distortion and deformation, finding an exact dense correspondence relationship between them remains a challenge. To address this issue, this study proposes a weakly supervised deformable registration network framework based on joint learning and a Multi-level Wavelet Feature Pyramid (MWFP) to align MRI and TRUS images. Joint learning is a framework composed of a pre-trained semi-supervised segmentation network and a registration network. The segmentation and registration networks continue to alternate training, and the segmentation network provides prostate label constraint global registration for the registration network, which effectively solves the problem of insufficient labels in the registration network. MWFP is a registration network composed of multi-resolution wavelets. The multi-scale images generated by the wavelet pyramid filter the relevant noise and reduce the difference in representation between the two modes to improve the ability of the registration network to learn the multi-scale features. In addition, a Multi-Scale Feature Fusion Attention (MSFFM) module is designed in the registration network to further screen the features and provide local dense correspondence for registration. In addition, the deformable segmentation images and segmentation labels provided by the registration network are mixed with the original artificial labels and images, and the pseudo-labels and their images generated by the segmentation network are used as input for the segmentation network for additional training, which further improves the performance of multimodal image segmentation. Results on 642 publicly available prostate MRI images and a TRUS image biopsy dataset show that the proposed registration method achieves optimal Dice Similarity Coefficient (DSC), 95% Hausdorff Distance (HD95), Mutual Information (MI), and Structural Similarity (SSIM) of 81.05%±1.77%, 12.83±1.49 mm, 18.12%±4.63%, and 27.12%±4.63%, respectively, which are superior to those of traditional registration methods and advanced deep learning registration methods. In addition, the average registration time of the proposed method is 0.18±0.02 s, which is nearly 400 times higher than that of the traditional methods. The experimental results show that the proposed registration method can accurately estimate the deformation field between prostate MRI images and TRUS images in real time and has higher registration accuracy and registration speed.

Key words: joint learning, Multi-level Wavelet Feature Pyramid (MWFP), deformable registration, Multi-Scale Feature Fusion Attention (MSFFA) module, semi-supervised segmentation

摘要:

磁共振图像(MRI)和经直肠超声(TRUS)图像的配准是将术前MRI配准在超声图像上,结合两种模态图像的优势,快速定位病灶区域,在辅助诊断、穿刺、术中导航等医学手术中起重要作用。由于这两种图像模式之间固有的表征差异,具有显著的强度失真和变形,因此在这两种图像模式之间寻找精确的密集对应关系面临较大挑战。为此,提出一种基于联合学习和多级小波特征金字塔(MWFP)的弱监督可变形配准网络框架,对MRI和TRUS图像进行对齐。联合学习是基于预训练的半监督分割网络和配准网络组成的框架,在联合学习框架中分割网络和配准网络继续交替训练,分割网络为配准网络提供前列腺标签约束全局配准,有效解决了配准网络中标签不足的问题。MWFP是采用多分辨小波构成的配准网络,小波金字塔生成的多尺度图像过滤了噪声并减小了两种模式图像之间的表征差异,提高配准网络学习多尺度特征的能力,并在配准网络中设计多尺度特征融合注意力(MSFFA)模块,对特征进行更进一步筛选,为配准提供局部密集对应关系。此外,配准网络提供的形变分割图像和分割标签混合原有的人工标注标签和图像及其分割网络生成的伪标签和其图像放入分割网络继续训练,进一步提高多模态图像分割的性能。在642例公开前列腺MRI和TRUS图像活检数据集上的实验结果表明,所提的配准方法达到最优的Dice相似系数(DSC)值、95% Hausdorff距离(HD95)、互信息(MI)值和结构相似性(SSIM)值,分别是81.05%±1.77%、12.83±1.49 mm、18.12%±4.63%和27.12%±4.63%,优于对比的传统配准方法和先进的深度学习配准方法。此外,所提方法的平均配准时间为0.18±0.02 s,比传统的方法提升了近400倍。所提的配准方法能够准确实时地估计前列腺MRI和TRUS图像之间的形变场,具有更高的配准精度和更快的配准速度。

关键词: 联合学习, 多级小波特征金字塔, 可变形配准, 多尺度特征融合注意力模块, 半监督分割