IEEE Trans Med Imaging. 2020 Nov;39(11):3535-3547. doi: 10.1109/TMI.2020.2998509. Epub 2020 Oct 28.
Photoacoustic computed tomography (PACT) based on a full-ring ultrasonic transducer array is widely used for small animal wholebody and human organ imaging, thanks to its high in-plane resolution and full-view fidelity. However, spatial aliasing in full-ring geometry PACT has not been studied in detail. If the spatial Nyquist criterion is not met, aliasing in spatial sampling causes artifacts in reconstructed images, even when the temporal Nyquist criterion has been satisfied. In this work, we clarified the source of spatial aliasing through spatiotemporal analysis. We demonstrated that the combination of spatial interpolation and temporal filtering can effectively mitigate artifacts caused by aliasing in either image reconstruction or spatial sampling, and we validated this method by both numerical simulations and in vivo experiments.
基于全环超声换能器阵列的光声计算机断层成像（PACT）因其具有高的面内分辨率和全视场保真度，而被广泛应用于小动物全身和人体器官成像。然而，全环几何 PACT 中的空间混叠尚未得到详细研究。如果不满足空间奈奎斯特准则，空间采样中的混叠会导致重建图像出现伪影，即使时间奈奎斯特准则已经满足。在这项工作中，我们通过时空分析澄清了空间混叠的来源。我们证明，空间插值和时间滤波的组合可以有效地减轻图像重建或空间采样中混叠引起的伪影，并且我们通过数值模拟和体内实验验证了这种方法。
