Color and pulsed-wave Doppler showing flow in right subclavian and innominate arteries. (a) Low velocity to- and- fro blood flow in the right subclavian artery. The very abnormal appearance of the spectral waveforms suggests more proximal severe stenosis. (b) To- and- fro blood flow in the innominate artery. There is spectral broadening present. Color flow image demonstrates retrograde flow in this single image.
