Renal artery stenosis on magnetic resonance angiography

Doppler ultrasound without elevated velocities (170 cm/s at the origin) but poor waveforms especially in the distal artery (slow to reach a diminished peak velocity, also called "parvus tardus"). A subsequent renal MRA was performed showing decreased perfusion to the smaller right kidney and a high-grade proximal stenosis (arrow). DSA confirmed the stenosis (dashed arrow) which was treated with stenting showing resolution of narrowing (arrowhead). After stenting, a repeat Doppler ultrasound revealed improvement in peak systolic velocity at the renal artery origin (now 82 cm/s) with more robust, normal waveforms in the mid and distal artery.