主要适用于多处狭窄性病变 CFDS classification of renal artery disease Normal - renal artery peak systolic velocities <180cm/sec and a normal RAR <3.5 <60% - a focal increase in peak systolic velocities>180cm/sec but a normal RAR <3.5 >60% - increased velocities >200cm/sec, post stenotic turbulence, abnormal RAR >3.5 and possible delay of acceleration time (AT) of waveforms distal to the stenosis Occluded - no flow in imaged renal arteries, small kidney<9cm, no flow or very dampened flow with delayed AT of waveforms in kidney