A noise-optimized virtual monochromatic reconstruction algorithm improves stent visualization and diagnostic accuracy for detection of in-stent re-stenosis in lower extremity run-off CT angiography

To evaluate the impact of noise-optimized virtual monochromatic imaging (VMI+) on stent visualization and accuracy for in-stent re-stenosis at lower extremity dual-energy CT angiography (DE-CTA). We evaluated third-generation dual-source DE-CTA studies in 31 patients with prior stent placement. Images were reconstructed with linear blending (F_0.5) and VMI+ at 40-150 keV. In-stent luminal diameter was measured and contrast-to-noise ratio (CNR) calculated. Diagnostic confidence was determined using a five-point scale. In 21 patients with invasive catheter angiography, accuracy for significant re-stenosis (aeyen50 %) was assessed at F_0.5 and 80 keV-VMI+ chosen as the optimal energy level based on image-quality analysis. At CTA, 45 stents were present. DSA was available for 28 stents whereas 12 stents showed significant re-stenosis. CNR was significantly higher with aecurrency sign80 keV-VMI+ (17.9 +/- 6.4-33.7 +/- 12.3) compared to F_0.5 (16.9 +/- 4.8; all p < 0.0463); luminal stent diameters were increased at aeyen70 keV (5.41 +/- 1.8-5.92 +/- 1.7 vs. 5.27 +/- 1.8, all p < 0.001) and diagnostic confidence was highest at 70-80 keV-VMI+ (4.90 +/- 0.48-4.88 +/- 0.63 vs. 4.60 +/- 0.66, p = 0.001, 0.0042). Sensitivity, negative predictive value and accuracy for re-stenosis were higher with 80 keV-VMI+ (100, 100, 96.4 %) than F_0.5 (90.9, 94.1, 89.3 %). 80 keV-VMI+ improves image quality, diagnostic confidence and accuracy for stent evaluation at lower extremity DE-CTA. aEuro cent The impact of noise-optimized virtual monochromatic imaging on stent visualization was assessed. aEuro cent Virtual monochromatic imaging significantly improves stent lumen visualization and diagnostic confidence. aEuro cent At 80 keV diagnostic performance for detection of in-stent restenosis was increased. aEuro cent 80 keV virtual monochromatic images are recommended for stent evaluation of lower extremity vasculature.