Ultrasound power Doppler imaging is a useful clinical tool for measuring perfusion. Sensitivity to slow moving blood flow is important for many clinical applications, but thick abdominal walls or the presence of bone such as ribs or the skull cause significant attenuation and thereby reduce the signal-to-noise ratio (SNR) and flow sensitivity. One way to improve SNR is to inject microbubble contrast agents into the vascular system, but this is impractical for many applications. An alternative approach is to use coded excitation, a signal processing technique that can drastically increase SNR within FDA safety limits without contrast agents. This work encompasses a method to design long coded pulses that are simple to implement along with a pulse compression technique to completely suppress range lobes, thereby recovering axial resolution, maintaining contrast, and improving SNR by as much as a factor of 10log10(code length). In simulations we show that this approach reliably improves the SNR of power Doppler imaging across a range of noise levels. As the noise level increases with respect to the blood, contrast and contrast-to-noise ratio are maintained with coded excitation whereas they drop precipitously without coded excitation. In vivo feasibility is also shown in transcranial and transthoracic cardiac B-Mode imaging. Both simulation and in vivo results match theoretical expectations of SNR gain. Finally, preliminary results showing in vivo power Doppler imaging in the liver are presented as well. Coded excitation is able to improve the blood vessel to background CNR and CR as compared to a standard approach.