Intérèts de la tomographie à émission de positons dans le suivi et le pronostic des anévrysmes de l'aorte abdominale

Rupture of abdominal aortic aneurysm (AAA) remains a major cause of death in the elderly. Its prediction is a serious challenge for public health. Despite its regular use to identify patients requiring surgical treatment, the diameter of AAA is not a sufficiently precise and reliable parameter for discriminating aneurysms at high risk of rupture. A better targeting of high risk patients needs understanding in deep the processes and mechanisms directing wall rupture. Inflammation is a significant element in the progression ofAAA and can be visualized using medical imaging techniques such as positron emission tomography (PET) using a glucose derivative (FDG) as radiotracer. Studies conducted in our department have established a relationship between PET positivity and the presence of symptoms such as accelerated growth of the aneurysm or pain, signs generally considered as predictive of rupture. Moreover, activation of leukocytes coupled to cellular and molecular alterations of the aneurysmal wall in the sites of FDG uptake may lead to its instability and incompetence to resist blood pressure and rupture. PET therefore represents a new original exploration method to characterize the severity of AAA progression allowing to assess the need for a surgical treatment much better than does the AAA diameter.