Role of multidetector CT angiography and contrast-enhanced ultrasound in redefining follow-up protocols after endovascular abdominal aortic aneurysm repair

Abstract

Contrast-enhanced ultrasonography (CEUS) is an appealing alternative to computed tomography angiography (CTA) for the follow-up of patients who underwent endovascular abdominal aortic aneurysm repair (EVAR). We sought to evaluate the accuracy of CEUS compared with a particularly tailored protocol of CTA performed with a 64-row multidetector CT. The study prospectively enrolled 88 consecutive patients for CEUS and CTA imaging during follow-up after EVAR, yielding 142 paired examinations. The outcome is represented by three main goals: identification and characterisation of endoleaks, evaluation of graft patency and measurement of aneurysm diameter. Triple-phase CTA was the gold standard. Sensitivity and specificity of CEUS compared with CTA in endoleak and graft patency evaluation were 91.89% and 100% and 72% and 100%, respectively. A very high correlation between CTA and CEUS diameter measurements was established. CEUS did not appear superior to CTA in endoleak detection, probably because a tailored CTA protocol with a delayed phase (180 s) allows detection of low-flow endoleaks. Patient management was not different following CEUS and CTA results. CTA cannot yet be completely replaced, but several limitations (radiation exposure, contrast agent) encourage redefining the routine follow-up imaging modality. We suggest an algorithm of surveillance alternating CTA and CEUS.