This is a prospective study conducted on a population with an aortic endoprosthesis in the context of an abdominal aortic aneurysm. The study's objective is to standardize the ultrasound methodology in the monitoring of aortic endoprosthesis in immediate post-operative care by comparing the results with CT-scan (gold standard). To improve ultrasound methodology, the investigators propose to use the VESMA protocol for ultrasound diameter measurement at four incidences. In addition, the use of ultrasonic contrast agents increases the accuracy of vascular structures, the quality of the ultrasound blood flow image and the duration of signal enhancement. This makes it possible to visualize small gauge vessels and those with slow flows. In this way, the investigators could improve the ultrasound technique for measuring aneurysm bag diameters and endoleak detection. Moreover, the toxicity of iodinated contrast agents is the third cause of acute renal failure in hospitalized patients and is all the more frequent when the investigators increase injections. Improving the quality of ultrasound investigations for the monitoring of aortic endoprosthesis would therefore allow us to reduce the number of CT-scan performed in this population and thus reduce irradiation and the injection of nephrotoxic products. Thereby, the investigators would like to integrate the technique into the systematic follow-up of patients who have benefited from the placement of an aortic endoprosthesis by replacing the CT-scan.

Inclusion Criteria:

• Patients over 18 years of age.
• Abdominal aortic aneurysm treated with aortic stent.
• Signature of informed consent.
• Person affiliated or beneficiary of a social security scheme

Exclusion Criteria:

• Hypersensitivity to sulphur hexafluoride or to these excipients (Macrogol 4000, Distearoylphosphatidylcholine, Dipalmitoylphosphatidylglycerol sodé, Palmitic acid).
• Right-left shunt patient
• Patient with severe pulmonary hypertension (pulmonary blood pressure > 90 mm Hg),
• Patient with uncontrolled systemic hypertension
• Adult patients with respiratory distress syndrome.
• Dobutamine patient in patients with a pathology suggesting cardiac instability
• Hypercoagulation, recent thromboembolic accident
• Fenestrated aortic stent
• Pregnant or nursing woman.
• Severe heart failure.
• Person deprived of liberty by judicial or administrative decision.
• Person subject to legal protection.