Abstract
PurposeThe presence of metal implants may reduce angiographic image quality due to automated beam adjustments. Digital variance angiography (DVA) is reported to be superior to digital subtraction angiography (DSA) with increased contrast-to-noise ratio (CNR) and better image quality. The aim of the study was to evaluate whether DVA could counterbalance the image quality impairment of lower-limb angiographies with metal implants.Materials and MethodsFrom November 2019 to January 2020, 85 raw lower-limb iodine contrast angiograms of 12 patients with metal implants were processed retrospectively with DVA analyses. For objective comparison, CNR of DSA and DVA images was calculated and the ratio CNRDVA/CNRDSA was determined. Visual image quality was evaluated in a paired comparison and by a five-grade Likert scale by three experienced radiologists.ResultsThe CNR was calculated and compared in 1252 regions of interest in 37 image pairs containing metal implants. The median ratio of CNRDVA/CNRDSA was 1.84 with an interquartile range of 1.35–2.32. Paired comparison resulted in 84.5% in favour of DVA with an interrater agreement of 83.2% (Fleiss κ 0.454, p < 0.001). The overall image quality scores for DSA and DVA were 3.64 ± 0.08 and 4.43 ± 0.06, respectively (p < 0.001, Wilcoxon signed-rank test) with consistently higher individual ratings for DVA.ConclusionOur small-sample pilot study shows that DVA provides significantly improved image quality in lower-limb angiography with metal implants, compared to DSA imaging. The improved CNR suggest that this approach could reduce radiation exposure for lower-limb angiography with metal implants.Level of EvidenceLevel 4, case studies
Highlights
Over the last decades, advances in endovascular technology and interventional therapy have broadened the percutaneous treatment options of peripheral vascular diseases offering an alternative to open surgery in patients with cardiovascular comorbidities
Our small-sample pilot study shows that Digital variance angiography (DVA) provides significantly improved image quality in lowerlimb angiography with metal implants, compared to digital subtraction angiography (DSA) imaging
contrast-to-noise ratio (CNR) values were calculated and compared in a total of 1252 manually selected regions of interest (ROI) in 37 image pairs containing metal implants, and the R-value of CNRDVA/CNRDSA was calculated for every ROI pair
Summary
Advances in endovascular technology and interventional therapy have broadened the percutaneous treatment options of peripheral vascular diseases offering an alternative to open surgery in patients with cardiovascular comorbidities. Balloon angioplasty and stenting are the mainstays of endovascular therapy in peripheral arterial disease (PAD), while drug-coated balloons and stents, adjunctive devices for crossing chronic total occlusions and debulking plaque with atherectomy, offer other treatment options. Vessels are made visible with injection of iodine contrast agents under X-ray radiation in digital subtraction angiography (DSA) technique [1, 2]. In DSA, a native image mask is recorded followed by a series of contrast images. The native mask is subtracted from contrast image series to visualize only the structures filled with contrast agents, whilst leaving out other anatomical structures [3]
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