Multi-Modality Medical Imaging Group, TechMed Centre, University of Twente, Enschede, The Netherlands; Department of Vascular Surgery, Rijnstate Hospital, Arnhem, The Netherlands; Physics of Fluids Group, TechMed Centre, University of Twente, Enschede, The Netherlands.
Department of Vascular Surgery, Rijnstate Hospital, Arnhem, The Netherlands; Medical Ultrasound Imaging Centre, Department of Medical Imaging, Radboud University Medical Centre, Nijmegen, The Netherlands.
Ultrasound Med Biol. 2024 Dec;50(12):1755-1763. doi: 10.1016/j.ultrasmedbio.2024.05.013. Epub 2024 Sep 7.
Local flow dynamics impact atherosclerosis yet are difficult to quantify with conventional ultrasound techniques. This study investigates the performance of ultrasound vector flow imaging (US-VFI) with and without ultrasound contrast agents in the healthy femoral bifurcation.
High-frame-rate ultrasound data with incremental acoustic outputs were acquired in the femoral bifurcations of 20 healthy subjects before (50V) and after contrast injection (2V, 5V and 10V). 2-D blood-velocity profiles were obtained through native blood speckle tracking (BST) and contrast tracking (echo particle image velocimetry [echoPIV]). As a reference, 4-D flow magnetic resonance imaging (4-D flow MRI) was acquired. Contrast-to-background ratio and vector correlation were used to assess the quality of the US-VFI acquisitions. Spatiotemporal velocity profiles were extracted, from which peak velocities (PSV) were compared between the modalities. Furthermore, root-mean-square error analysis was performed.
US-VFI was successful in 99% of the cases and optimal VFI quality was established with the 10V echoPIV and BST settings. A good correspondence between 10V echoPIV and BST was found, with a mean PSV difference of -0.5 cm/s (limits of agreement: -14.1-13.2). Both US-VFI techniques compared well with 4-D flow MRI, with a mean PSV difference of 1.4 cm/s (-18.7-21.6) between 10V echoPIV and MRI, and 0.3 cm/s (-23.8-24.4) between BST and MRI. Similar complex flow patterns among all modalities were observed.
2-D blood-flow quantification of femoral bifurcation is feasible with echoPIV and BST. Both modalities showed good agreement compared to 4-D flow MRI. For the femoral tract the administration of contrast was not needed to increase the echogenicity of the blood for optimal image quality.
局部流动动力学影响动脉粥样硬化，但用传统超声技术很难定量。本研究旨在探讨超声向量血流成像（US-VFI）在健康股动脉分叉处有无超声造影剂时的性能。
对 20 名健康受试者的股动脉分叉处进行了高帧率超声数据采集，分别在增强前（50V）和增强后（2V、5V 和 10V）进行。通过原生血斑跟踪（BST）和对比跟踪（回声粒子图像测速法[echoPIV]）获得 2-D 血流速度曲线。作为参考，还采集了 4-D 流磁共振成像（4-D flow MRI）。对比背景比和向量相关性用于评估 US-VFI 采集的质量。提取时空速度曲线，比较各模态的峰值速度（PSV）。此外，还进行了均方根误差分析。
US-VFI 在 99%的病例中成功，10V echoPIV 和 BST 设置可获得最佳 VFI 质量。10V echoPIV 和 BST 之间存在良好的相关性，PSV 平均差值为-0.5cm/s（一致性范围：-14.1-13.2）。两种 US-VFI 技术与 4-D flow MRI 比较良好，10V echoPIV 与 MRI 的 PSV 平均差值为 1.4cm/s（-18.7-21.6），BST 与 MRI 的 PSV 差值为 0.3cm/s（-23.8-24.4）。所有模态均观察到相似的复杂血流模式。
股动脉分叉处的 2-D 血流定量是可行的，echoPIV 和 BST 均可实现。与 4-D flow MRI 相比，两种方法均具有良好的一致性。对于股动脉，无需注射对比剂即可增加血液的回声强度，以获得最佳的图像质量。
