Purpose: To assess the magnitude of variations in size of the proximal neck of the abdominal aortic aneurysm (AAA) in patients selected to undergo endovascular abdominal aortic aneurysm repair (EVAR) and the potential effect on choice of endograft diameter by using 64-section dynamic electrocardiographically (ECG)-gated computed tomographic (CT) angiography.
Materials and methods: A prospective single-center study was performed in 40 patients with AAA who underwent both static and dynamic ECG-gated CT angiography. The ethical conduct of the study was approved by the departmental review board, and all patients provided written informed consent. Dynamic ECG-gated data sets were acquired with a low-dose acquisition protocol (100 kV) by using a 0.625-mm-section collimation (40 mL iomeprol [400 mg of iodine per milliliter] versus 80 mL). Pulsatility measurements were taken at suprarenal, juxtarenal, and infrarenal levels within the aneurysmal neck. Manual CT angiographic measurements were performed on modified axial images. On static axial images, one vascular surgeon and one interventional radiologist selected the diameter of the main body of the potential infrarenal stent-graft to implant. The diameter of the main body of the stent-graft selected was compared with the dynamic measurements obtained to calculate the potential relative oversizing performed.
Results: A total of 40 patients were enrolled. Significant aortic pulsatility was demonstrated within the aneurysmal neck (mean variation, 9.01% ± 4.81 [standard deviation]; absolute change, 1.83 mm ± 1.01; P < .05). When compared with dynamic measurements, the diameter of the endograft selected on the basis of static images would be potentially changed in 12 of 40 (30%) patients. Comparing the minimum or maximum diameter of the aneurysmal neck with the diameter of the endograft selected on the basis of static images, the relative oversizing performed was considered inadequate in seven of 40 (18%) patients.
Conclusion: Dynamic ECG-gated CT may provide information in regard to pulsatile motion that could change the diameter of the endograft selected on the basis of static imaging measurements.
© RSNA, 2011.