Initial evidence of a 50% reduction of contrast media using digital variance angiography in endovascular carotid interventions

In previous clinical studies Digital Variance Angiography (DVA) provided higher signal-to-noise ratio (SNR) and better image quality than Digital Subtraction Angiography (DSA). Our aim was to investigate whether this quality reserve of DVA provides an opportunity for the reduction of iodinated contrast media (ICM) in carotid X-ray angiography (CXA).

Our prospective study enrolled 26 patients (67.0 ± 8.1 years) undergoing carotid percutaneous transluminal angioplasty. The SNR of DSA and DVA image pairs obtained by a standard (100 %, 6 mL ICM) or a low-dose (50 %, 3 mL ICM) protocol were compared. Visual evaluation of all images was performed by five specialists using a 5-grade rating scale. The quality of DSA₁₀₀ and DVA₅₀ videos was also compared.

DVA provided more than two-fold SNR, the median SNR_DVA/SNR_DSA ratio was 2.06 (100 %) and 2.25 (50 %). In the visual evaluation, the DVA₁₀₀ score (3.73 ± 0.06) was significantly higher than the DSA₁₀₀ score (3.52 ± 0.07, Wilcoxon p < 0.001), and the DVA₅₀ score (3.64 ± 0.13) was also significantly higher than the DSA₅₀ score (3.01 ± 0.17, Wilcoxon p < 0.001). While the low-dose protocol significantly decreased the DSA score (Mann-Whitney p < 0.01, DSA₁₀₀ vs DSA₅₀), it had no effect on the DVA score (DVA₁₀₀ vs DVA₅₀). There was no statistical difference between the DSA₁₀₀ and DVA₅₀ scores. Evaluators preferred the diagnostic value of DVA₅₀ to DSA₁₀₀ videos in 61% of comparisons, the interrater agreement was 69 % (Fleiss' kappa 0.35, p < 0.001).

Our data show that DVA allows a substantial (50 %) ICM reduction in CXA without affecting the quality and diagnostic value of angiograms.