Superresolution ultrasound for imaging and microscopy

A practical method for sub-millimeter imaging in vivo would provide considerable benefits to both laboratory investigations and clinical diagnosis. Consequently, numerous imaging modalities have sought to achieve this high-resolution. Ultrasound is a viable candidate for such imaging, due to its ability to penetrate deeply and safely into tissues. However, previous studies have approached the problem by using increasingly higher ultrasound frequencies. The unfortunate tradeoff for higher frequencies is a simultaneous increase in the level of ultrasound attenuation, which has allowed imaging only a few millimeters deep. Our investigation proposes a new method that could allow sub-millimeter in vivo imaging at substantially lower frequencies than previously reported, thus allowing significantly greater depth penetration. To achieve this, we introduce a new superresolution imaging technique designed to resolve objects significantly smaller than the imaging wavelength. Our method exploits unique properties of ultrasound in order to provide additional information than achieved with related optical techniques. Presently, we outline the method and then demonstrate the procedure by reconstructing images of a human hair, which is more than one order of magnitude smaller then the source wavelength.