Percutaneous treatment can be proposed as a first-line treatment in iatrogenic renal arterial injuries, resulting in a safe and effective procedure.

BackgroundArteriovenous malformations (AVMs) are communications between an artery and a vein outside the capillary level. This pathologic communication may be either a fistula, a simple communication between a single artery and a dilated vein, or a more complex communication, a nidus of tortuous channels between one or more arteries/arterioles and one or more draining veins. The latter type of lesion is most frequently seen in the extremities; in the kidney they tend to appear more rarely. The most common clinical presentation of renal arteriovenous malformations (RAVMs) is haematuria. Percutaneous treatment with selective endovascular techniques offers a minimally invasive, nephron-sparing option in comparison to the more invasive surgical approaches. The purpose of this pictorial review is to highlight the general lines of management and to show the range of imaging findings of the percutaneous treatment of RAVMs.MethodsThe imaging characteristics of a selection of cases of percutaneously managed congenital RAVMs are presented and the most common lines of approach are discussed.ConclusionThe imaging spectrum of diagnosis and percutaneous treatment of RAVMs is presented in order to aid interpretation and endovascular management.Teaching points• Renal arteriovenous malformations are very rare lesions.• Clinical expression is usually haematuria.• Diagnosis is made with CT or MRI but the gold standard is digital subtraction angiography.• Catheter-directed treatment with the use of coils or liquid embolics is minimally invasive, safe and effective.

Percutaneous radiofrequency ablation (RFA) can be as effective as surgical resection in terms of overall survival and recurrence-free survival rates in patients with small hepatocellular carcinoma (HCC). Effectiveness of RFA is adversely influenced by heat-sink effect. Other ablative therapies could be considered for larger tumors or for tumors located near the vessels. In this regard, recent improvements in microwave energy delivery systems seem to open interesting perspectives to percutaneous ablation, which could become the ablation technique of choice in the near future. Microwave ablation (MWA) has the advantages of possessing a higher thermal efficiency. It has high efficacy in coagulating blood vessels and is a relatively fast procedure. The time required for ablation is short and the shape of necrosis is elliptical with the older systems and spherical with the new one. There is no heat-sink effect and it can be used to ablate tumors adjacent to major vessels. These factors yield a large ablation volume, and result in good local control and fewer complications. This review highlights the most relevant updates on MWA in the treatment of small (<3 cm) HCC. Furthermore, we discuss the possibility of MWA as the first ablative choice, at least in selected cases.

The advantages of the Ovation device's unique sealing mechanism come at the expense of a median area inflow stenosis of ∼ 60%. This stenosis does not cause a hemodynamically significant pressure drop. Future modification of the graft ring design may be needed in order to reduce this stenosis.