1. To learn about the most common causes of transplanted kidney dysfunction. There are two types of AV shunts for haemodialysis: AV fistulas and AV by-pass. The former have the longest life duration and the latter are implanted when fistulas fail. No systematic follow-up of these shunts is required. But imaging plays a major role to define causes of dialysis dysfunction and to treat complications. Main dysfunctions are a decrease of pump flow, evocative for occlusive disease located up-stream the arterial needle, and an increased venous pressure, evocative for occlusive disease located down-stream the venous needle. Other problems are an increased dialysis time, difficulties in needle placement, clotting, etc. Clinical examination must focus on sites of anastomoses and along the shunt looking for decreased thrill, decrease of shunt tension, and abnormal thrill areas. Color Doppler must cover the entire shunt from the afferent artery to the subclavian vein, looking for stenoses, usually located on the venous side, aneurysms, mural thrombus, acute thrombosis, steel phenomenon or collections. When a stenosis is present, measurement of velocity ratio helps in quantifying its severity, being significant when > 3. The risk of thrombosis increases when flow decreases within the shunt. Angioplasty is required when stenosis is significant and/or when pressure increases or flow decreases on successive dialyses. Auto-expansive stents are implanted when stenoses recur. Acute thromboses are treated by mechanical thrombolysis using aspiration or mechanical devices. Contrast agents, both iodine-and gadolinium-based, are generally safe and are very widely utilised. However, there is concern about inducing contrast-induced nephropathy (CIN) associated with iodinated contrast media (ICM) and nephrogenic systemic fibrosis (NSF) following the administration of certain types of gadoliniumbased contrast media (Gd-CM) in patients with advanced renal impairment. CIN is associated with further deterioration in renal function, may speed the need for dialysis, and increase the morbidity and mortality of the affected patients. Unfortunately all ICM have the potential of inducing CIN in patients with reduced renal function. This complication can be minimised by volume expansion and reducing the dose of the contrast agent. Large volume of data indicates that NSF is caused by the release of free gadolinium from Gd-CM with low kinetic and thermodynamic stability such as the non-ionic linear agents. This complication can be avoided with the use of the lowest possible dose of the highly stable macrocyclic agents.