Doppler ultrasound image showing an intrarenal arterial Doppler spectrum of the kidney in a healthy conscious horse.The color Doppler superimposed on the B-mode image was used to identify an arcuate artery, and the PW Doppler sample volume was placed at the intraluminal level (left side of the image). Normal intrarenal Doppler flow velocity waveforms corresponding to four consecutive cardiac cycles (right side of the image).