The diagnostic value of dual-energy CTA for visualising below the knee arteries in peripheral arterial disease: A systematic review.

Background: Computed tomography angiography (CTA) of below the knee (BTK) arteries in patients with peripheral arterial disease (PAD) is often challenging due to reduced contrast enhancement and the presence of arterial wall calcifications. Several studies have been published using dual energy (DE) techniques to improve image quality and diagnostic performance of CTA. This systematic review aims to assess diagnostic performance of dual energy CTA (DECTA) in BTK arteries of patients with PAD. Methods: A systematic literature search was conducted to identify studies reporting on DECTA of BTK arteries. Studies were included if they assessed imaging quality using qualitative or objective parameters, or provided data on diagnostic accuracy. The search was performed in Pubmed, Embase and Cochrane Library. Results: The initial search yielded original 440 articles. 15 studies were included in the final analysis, with 10 studies using bone removal software and 5 studies using virtual monochromatic imaging (VMI+). Pooled sensitivity and specificity for bone removal software for detecting significant stenosis below the knee was 94.8 % (95 % CI 88.1-97.8 %) and 59.3 % (95 % CI 43.3-73.6 %), respectively. All studies on VMI+ reported an increase in signal-to-noise ratio and contrast-to-noise ratio as the energy level decreased. Low energy VMI+ images had consistently higher qualitative imaging scores compared to both high energy and 120 kV blended reconstructions. Conclusion: DECTA provides high sensitivity and moderate specificity for detecting significant stenosis below the knee using bone removal software. Based on available literature, optimal imaging of BTK arteries can be achieved by using low energy VMI+ reconstructions.