Doppler ultrasound in mice

Color, power, spectral, and tissue Doppler have been applied to mice. Due to the noninvasive nature of the technique, serial intraindividual Doppler measurements of cardiovascular function are feasible in wild-type and genetically altered mice before and after microsurgical procedures or to follow age-related changes. Fifty-megahertz ultrasound biomicroscopy allows to record the first beats of the embryonic mouse heart at somite stage 5, and the first Doppler-flow signals can be recorded after the onset of intrauterine cardiovascular function at somite stage 7. Using 10- to 20-MHz ultrasound transducers in the mouse embryo, cardiac, and circulatory function can be studied as early as 7.5 days after postcoital mucous plug. Postnatal Doppler ultrasound examinations in mice are possible from birth to senescent age. Several strain-, age-, and gender-related differences of Doppler ultrasound findings have been reported in mice. Results of Doppler examinations are influenced by the experimental settings as stress testing or different forms of anesthesia. This review summarizes the present status of Doppler ultrasound examinations in mice and animal handling in the framework of a comprehensive phenotype characterization of cardiac contractile and circulatory function.