Semmelweis University Budapest, Heart and Vascular Center, Hungary
Purpose: In previous clinical studies, a novel X-ray image processing algorithm called Digital Variance Angiography (DVA) provided higher Contrast-to-Noise Ratio (CNR) and better image quality than Digital Subtraction Angiography (DSA). Our aim was to investigate whether the observed quality reserve of DVA provides opportunity for reduction of iodinated contrast medium (ICM) in carotid X-ray angiography (CXA).
Material and Methods: Our prospective pilot study enrolled 26 patients undergoing CXA for carotid endovascular procedures between January 1st and June 30th, 2018. [Mean±SD age (years): 67.0±8.1, 23 males 67.3±8.1, 3 females 64.7±9.8.] We compared the CNR of DSA and DVA image pairs using a standard (100% ICM) or a low-dose (50% ICM) protocol. Visual evaluation of single DVA or DSA images was performed by specialists using a 5-grade rating scale. The quality of DSA and DVA videos was also compared. Interrater agreement was described by percent agreement and Fleiss’ kappa.
Results: DVA provided a more than two-fold CNR, the median CNR(DVA)/CNR(DSA) ratio was 2.06 (100%) and 2.25 (50%). In visual evaluation the DVA(100%) score (3.73±0.06) was significantly higher than the DSA(100%) score (3.52±0.07, p<0.001), and the DVA(50%) score (3.64±0.13) was also significantly higher than the DSA(50%) score (3.01±0.17, p < 0.01). There was no statistical difference between the DSA(100%) and DVA(50%) scores. Evaluators preferred DVA(50%) over DSA(100%) videos in 61 % of comparisons, the interrater agreement was 81% (Fleiss’ kappa 0.35, p<0.001)
Conclusions: DVA allows a substantial, 50% ICM reduction in CXA without affecting the quality and diagnostic value of angiograms.