IEEE Trans Ultrason Ferroelectr Freq Control. 2024 Aug;71(8):925-944. doi: 10.1109/TUFFC.2024.3411711. Epub 2024 Aug 19.
A new approach for vascular super-resolution (SR) imaging using the erythrocytes as targets (SUper-Resolution ultrasound imaging of Erythrocytes (SURE) imaging) is described and investigated. SURE imaging does not require fragile contrast agent bubbles, making it possible to use the maximum allowable mechanical index (MI) for ultrasound scanning for an increased penetration depth. A synthetic aperture (SA) ultrasound sequence was employed with 12 virtual sources (VSs) using a 10-MHz GE L8-18i-D linear array hockey stick probe. The axial resolution was [Formula: see text]m) and the lateral resolution was [Formula: see text]m). Field IIpro simulations were conducted on 12.5- μ m radius vessel pairs with varying separations. A vessel pair with a separation of 70 μ m could be resolved, indicating a SURE image resolution below half a wavelength. A Verasonics research scanner was used for the in vivo experiments to scan the kidneys of Sprague-Dawley rats for up to 46 s to visualize their microvasculature by processing from 0.1 up to 45 s of data for SURE imaging and for 46.8 s for SR imaging with a SonoVue contrast agent. Afterward, the renal vasculature was filled with the ex vivo micro-computed tomography (CT) contrast agent Microfil, excised, and scanned in a micro-CT scanner at both a 22.6- μ m voxel size for 11 h and for 20 h in a 5- μ m voxel size for validating the SURE images. Comparing the SURE and micro-CT images revealed that vessels with a diameter of 28 μ m, five times smaller than the ultrasound wavelength, could be detected, and the dense grid of microvessels in the full kidney was shown for scan times between 1 and 10 s. The vessel structure in the cortex was also similar to the SURE and SR images. Fourier ring correlation (FRC) indicated a resolution capability of 29 μ m. SURE images are acquired in seconds rather than minutes without any patient preparation or contrast injection, making the method translatable to clinical use.
一种新的血管超分辨率（SR）成像方法，使用红细胞作为目标（SUper-Resolution ultrasound imaging of Erythrocytes (SURE) imaging），本文对其进行了描述和研究。SURE 成像不需要易碎的造影剂气泡，因此可以使用最大允许超声扫描机械指数（MI）来增加穿透深度。采用合成孔径（SA）超声序列，使用 10MHz GE L8-18i-D 线阵冰球探头，有 12 个虚拟源（VS）。轴向分辨率为[公式：见文本]m），横向分辨率为[公式：见文本]m）。Field IIpro 模拟在具有不同间隔的 12.5-μ m 半径血管对上进行。可以分辨出间隔为 70μ m 的血管对，表明 SURE 图像分辨率低于半波长。Verasonics 研究扫描仪用于体内实验，对 Sprague-Dawley 大鼠的肾脏进行扫描，最长可达 46 秒，通过处理 SURE 成像的 0.1 至 45 秒和 SonoVue 造影剂的 SR 成像的 46.8 秒的数据，来可视化其微血管。之后，将肾脏血管用体外微计算机断层扫描（CT）造影剂 Microfil 填充，切除，并在微 CT 扫描仪中以 22.6-μ m 体素大小扫描 11 小时，以 5-μ m 体素大小扫描 20 小时，以验证 SURE 图像。将 SURE 和微 CT 图像进行比较，结果显示可以检测到直径为 28μ m 的血管，其尺寸是超声波长的五分之一，在 1 到 10 秒的扫描时间内可以显示整个肾脏密集的微血管网格。皮质中的血管结构也与 SURE 和 SR 图像相似。傅立叶环形相关（FRC）表明分辨率能力为 29μ m。SURE 图像在几秒钟内即可获取，而无需任何患者准备或造影剂注射，因此该方法可转化为临床应用。
