Transcutaneous Super-Resolution Ultrasound Imaging using Erythrocytes versus Microbubbles in a Rabbit Kidney

Contrast-free super-resolution ultrasound imaging (SRUS) approaches have recently been used to eliminate the injection of microbubbles (MB) into the bloodstream. However, the comparison of resolution with ultrasound localization microscopy (ULM) with MB and the feasibility of using contrast-free SRUS in transcutaneous in-vivo studies are always questioned. Recently, a super-resolution ultrasound imaging technique using erythrocytes (SURE) was introduced to create quantitative microvasculature images, flow directions, and velocity maps without contrast agents in just a few seconds. This study hypothesizes that SURE can transcutaneously reveal a comparable microvascular structure to ULM for just a few seconds of data without contrast agent injection. Plane-wave imaging is used to acquire data from a transcutaneous rabbit kidney using a Verasonic research scanner and a GE L3-12D linear probe. SURE and ULM are processed independently for a processed-blinded comparison of the approaches with two separate research groups. For one second of SURE, the detected vessel sizes were 128, 208, and 145 μm, while for five seconds of ULM, they were 112, 118, and 140 μm, when using an imaging wavelength of 308 μm.