arXiv:2603.05183eess.IV2026-03

用多视角隐空间引导,实现有限角度CT高精度重建。

Limited-Angle CT Reconstruction Using Multi-Volume Latent Consistency Model

  • 基于多视野隐空间表征,构建三维潜在一致性模型。
  • 60度角下MAE达10.12 HU,30度角下仍保持SSIM 0.9393。
  • 对未知投影角度也稳定有效,适合临床多样场景。

有限角度计算机断层扫描(LACT)重建是因缺失投影角度导致严重不适定的逆问题,缺乏先验知识时难以实现高精度图像恢复。近年来,以扩散模型为代表的机器学习方法展现出强大图像生成能力,但对器官和血管三维结构的精确还原及对比度保持仍具挑战,且不同临床成像条件(如视野FOV、投影角度范围)对重建精度的影响尚未充分研究。本研究提出一种多体积潜在扩散模型,利用多个有效视野获得的三维潜在表示作为引导,解决临床实际中的LACT重建问题。通过将一致性模型引入潜在空间,实现快速稳定的推理;借助多体积编码器从全局与中心区域不同尺度获取潜在变量,有效保留器官边界与内部结构信息。实验表明,该方法在60度有限角度条件下实现MAE 10.12 HU、SSIM 0.9677,极端30度条件下仍达MAE 16.69 HU、SSIM 0.9393。即使面对训练中未包含的未知投影角度,仍保持稳定性能,验证了其在临床多样化条件下的适用性。

原文摘要 · Abstract (English)

Limited-angle computed tomography (LACT) reconstruction is an inverse problem with severe ill-posedness arising from missing projection angles, and it is difficult to restore high-precision images without sufficient prior knowledge. In recent years, machine learning methods represented by diffusion models have demonstrated high image generation capabilities. However, accurate restoration of three-dimensional structures of organs and vessels and preservation of contrast remain challenges, and the impact of differences in diverse clinical imaging conditions such as field of view (FOV) and projection angle range on reconstruction accuracy has not been sufficiently investigated. In this study, we propose a multi-volume latent diffusion model that uses three-dimensional latent representations obtained from multiple effective fields of view as guidance for LACT reconstruction in clinical practical problems. The proposed method achieves fast and stable inference by introducing consistency models into latent space, and enables high-precision preservation of organ boundary information and internal structures under different FOV conditions through a Multi-volume encoder that acquires latent variables from different scales of the global region and central region. The evaluation experiments demonstrated that the proposed method achieved high-precision synthetic CT image generation compared to existing methods. Under the limited-angle condition of 60 degrees, MAE of 10.12 HU and SSIM of 0.9677 were achieved, and under the extreme limited-angle condition of 30 degrees, MAE of 16.69 HU and SSIM of 0.9393 were achieved. Furthermore, stable reconstruction performance was demonstrated even for unknown projection angle conditions not included during training, confirming the applicability to diverse imaging conditions in clinical practice.

CT重建扩散模型医学影像潜在空间

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