Endoleaks after endovascular aortic aneurysm repair: Improved detection with noise-optimized virtual monoenergetic dual-energy CT

Purpose: To assess image quality and diagnostic performance of a noise-optimized algorithm to reconstruct virtual monoenergetic images (VMI+) for the detection of endoleaks after endovascular abdominal aortic aneurysm repair (EVAR) using dual-energy CT angiography (DE-CTA). Materials and methods: Seventy-five patients (42 men; 66.2 +/- 11.7 years) underwent DE-CTA following EVAR. Arterial phase images were acquired in dual-energy mode for the reconstruction of standard linearly-blended M 0.5, VMI+ and traditional monoenergetic images (VMI) at 40-100 keV in 10-keV intervals. Contrast-to-noise ratios (CNR) were calculated for the area of leakage in patients with endoleaks. Diagnostic accuracy for endoleak detection was evaluated by three blinded radiologists using the objectively best series for each reconstruction technique. Results: Thirty-four out of 75 patients showed endoleaks. Quantitative image parameters were highest at 40-keV VMI+ (CNR, 21.3 +/- 11.1), compared to M 0.5 (CNR, 10.9 +/- 5.5) and all VMI series that showed highest values at 70 keV (CNR, 13.5 +/- 6.6; all P < 0.001). ROC analysis for endoleak detection revealed an area under the curve (AUC) of 0.992 for 40-keV VMI+ series, which was significantly higher (P <= 0.039) compared to 70keV VMI (0.914) and M 0.5 series (0.916). Conclusions: Noise-optimized VMI+ series at 40 keV improve diagnostic accuracy for the detection and rule-out of endoleaks after EVAR.