Dual-source dual-energy CT: dose reduction after endovascular abdominal aortic aneurysm repair

This study was done to evaluate the possibility of reducing the dose of ionising radiation by using dual-source dual-energy computed tomography (CT) in patients undergoing CT angiography of the aorta to search for endoleaks after endovascular aneurysm repair (EVAR).

One hundred and forty-eight patients (117 M, 31 F; mean age 75 ± 6.5) underwent 171 CT angiography scans for follow-up after EVAR. For each patient we performed a triple-phase acquisition protocol consisting of a nonenhanced phase, an arterial phase and a delayed phase; the latter acquired in dual energy. Two radiologists jointly evaluated the nonenhanced, arterial and delayed phase, and a third radiologist evaluated only the delayed phase and its virtual noncontrast (VNC) reconstruction. Moreover, we compared the cumulative effective doses of the triple-phase acquisition with the dual-energy acquisition.

We detected 34 endoleaks (19.8 %), with 100 % agreement between the triple-phase and dual-energy acquisitions. The effective dose of dual-energy acquisition performed during the delayed phase was 61.7 % lower than that of the triple-phase acquisition.

A dual-energy CT scan acquired during the delayed phase and its VNC reconstruction allow detection of endoleaks with a substantial reduction of effective dose and a complete diagnostic agreement with a triple-phase acquisition protocol.