Department of Biomedical Engineering, School of Medicine, Tsinghua University, Beijing, 100084, China.
Int J Comput Assist Radiol Surg. 2022 Sep;17(9):1731-1743. doi: 10.1007/s11548-022-02672-6. Epub 2022 Jun 15.
4D reconstruction based on radiation-free ultrasound can provide valuable information about the anatomy. Current 4D US technologies are either faced with limited field-of-view (FoV), technical complications, or cumbersome setups. This paper proposes a spatiotemporal US reconstruction framework to enhance its ability to provide dynamic structure information.
We propose a spatiotemporal US reconstruction framework based on freehand sonography. First, a collecting strategy is presented to acquire 2D US images in multiple spatial and temporal positions. A morphology-based phase extraction method after pose correction is presented to decouple the compounding image variations. For temporal alignment and reconstruction, a robust kernel regression model is established to reconstruct images in arbitrary phases. Finally, the spatiotemporal reconstruction is demonstrated in the form of 4D movies by integrating the US images according to the tracked poses and estimated phases.
Quantitative and qualitative experiments were conducted on the carotid US to validate the feasibility of the proposed pipeline. The mean phase localization and heart rate estimation errors were 0.07 ± 0.04 s and 0.83 ± 3.35 bpm, respectively, compared with cardiac gating signals. The assessment of reconstruction quality showed a low RMSE (<0.06) between consecutive images. Quantitative comparisons of anatomy reconstruction from the generated US volumes and MRI showed an average surface distance of 0.39 ± 0.09 mm on the common carotid artery and 0.53 ± 0.05 mm with a landmark localization error of 0.60 ± 0.18 mm on carotid bifurcation.
A novel spatiotemporal US reconstruction framework based on freehand sonography is proposed that preserves the utility nature of conventional freehand US. Evaluations on in vivo datasets indicated that our framework could achieve acceptable reconstruction performance and show potential application value in the US examination of dynamic anatomy.
基于无辐射超声的 4D 重建可以提供有关解剖结构的有价值信息。目前的 4D US 技术要么面临有限的视野（FOV），技术复杂性，要么是繁琐的设置。本文提出了一种时空 US 重建框架，以增强其提供动态结构信息的能力。
我们提出了一种基于自由手超声的时空 US 重建框架。首先，提出了一种采集策略，以在多个空间和时间位置获取 2D US 图像。在进行姿态校正后，提出了一种基于形态的相位提取方法来解耦复合图像变化。对于时间对准和重建，建立了一个稳健的核回归模型，以重建任意相位的图像。最后，根据跟踪的姿势和估计的相位，通过集成 US 图像，以 4D 电影的形式展示时空重建。
在颈动脉 US 上进行了定量和定性实验，以验证所提出的管道的可行性。与心脏门控信号相比，平均相位定位和心率估计误差分别为 0.07 ± 0.04 s 和 0.83 ± 3.35 bpm。重建质量评估显示连续图像之间的 RMSE 较低（<0.06）。从生成的 US 体积和 MRI 重建的解剖结构的定量比较显示，在颈总动脉上的平均表面距离为 0.39 ± 0.09 mm，在颈动脉分叉处的地标定位误差为 0.53 ± 0.05 mm。
提出了一种基于自由手超声的新型时空 US 重建框架，保留了传统自由手 US 的实用性质。在体内数据集上的评估表明，我们的框架可以达到可接受的重建性能，并在动态解剖的 US 检查中显示出潜在的应用价值。
