The use of color Doppler and spectral Doppler has demonstrated great value for the evaluation of kidney obstruction, for renal artery stenosis and for the control of kidney grafts.
The most common complication of renal transplants is arterial stenosis. This is demonstrated in spectral Doppler as a significantly increased velocity followed by turbulence. For dialysis patients, Doppler is very important for controlling the potency of A-V fistulas.