Assessment of Super-Resolution Ultrasound Imaging Using the Erythrocytes Through Comparison with Micro-CT

This work presents a dual-sample validation study of Super-Resolution Ultrasound imaging using the Erythrocytes (SURE) and state-of-the-art laboratory micro-CT data of rat kidneys. The study hypothesizes that SURE images reliably depict cortical radial blood vessels in rat kidneys, assessed by comparing the depicted blood vessels and vessel diameter estimates from registered micro-CT data. Previous qualitative comparisons between SURE images and micro-CT were either made at an insufficient micro-CT voxel size or in a small region of a rat kidney cortex scanned at a higher resolution. Here, micro-CT data of entire rat kidneys scanned at a voxel size of 5 µm is compared to images from the SURE pipeline with peak detection done after blood flow separation. The separation is achieved using Hankel singular value decomposition before peak detection (SURE-Hankel). The analysis shows a consistent depiction of cortical radial vessels in the entire rat kidney using SURE-Hankel and that these blood vessels have estimated diameters around 50 µm to 100 µm. However, discrepancies in the registered images highlight the need for more accurate CT-to-ultrasound image registration techniques.