[Imaging strategies for renovascular disease]

Renovascular disease (RVD) is detected with increasing frequency because with an aging population, atherosclerosis and its consequences are seen more frequently. RVD has three component parts: renal artery stenosis (RAS), renovascular hypertension (RVH), and ischemic nephropathy (IN). Each component should be recognized by the appropriate diagnostic tool. The proper techniques and procedures to establish an anatomical RAS diagnosis are: computed tomography angiography, magnetic resonance (MR) angiography and catheter angiography, which is the gold standard. The presence of RAS can also be disclosed through increased systolic blood flow velocity at the level of the narrowed renal artery by an echo color-Doppler. Once the presence of RAS is demonstrated the diagnosis of RVH and/or IN should be performed. The RVH diagnosis needs to demonstrate a causal link between RAS and blood pressure (BP) increase; a causal link between RAS and the reduction in glomerular filtration rate (GFR) is mandatory for the IN diagnosis. Techniques and procedures suggesting that BP is increased and/or GFR is reduced based on RAS are captopril enhanced renoscintigraphy, BP gradient across the stenosis, captopril modification of Doppler parameters and captopril modification of MR curves. The resistive index obtained by color-Doppler could be a structural damage marker of the intrarenal arterioles. A rational approach to the problem demands that each technique is chosen according patient clinical characteristics.