Microultrasound and its application to longitudinal studies of mouse eye development and disease

Microultrasound imaging is a flexible high-resolution real-time in vivo imaging modality based on the transmission and the reception of ultrasound waves. Because of its high temporal (>250 Hz) and spatial (30-150 µm) resolutions and the noninvasive nature of ultrasound, microultrasound is used extensively in preclinical research to monitor functional and dynamic phenotypic changes in small animal models. Its ability to perform in vivo longitudinal monitoring of development, pathology, and therapeutic effectiveness is particularly advantageous. This article reviews the technology and the applications of high-frequency microultrasound for the study of mouse eye development from embryonic day E11.5 to postnatal day P16. Procedures for animal handling and scanning are given, and applications are described in the context of ocular development and disease. Quantitative analysis of the growth kinetics of the lens and the orbit is discussed. In addition, mouse models of retinoblastoma and glaucoma are followed as a function of disease progression to reveal their associated morphological and functional traits. Microultrasound is performed with high-frequency imaging equipment (from VisualSonics) operating at center frequencies between 15 and 50 MHz. These instruments provide both anatomical imaging as well as functional and molecular analyses of the living mouse.