Digital Variance Angiography (DVA) is a proprietary innovative parametric imaging method that outperforms Digital Subtraction Angiography (DSA) in vascular imaging in the following three aspects: enhanced image quality, X-ray dose reduction, and contrast agent dose reduction. DVA technology is implemented in the CE-marked (Class IIa) and FDA-approved Kinepict Medical Imaging Tool, available for use in the operating room in Europe and the USA.
Cardiovascular disorders are the leading cause of death worldwide. Their diagnosis and treatment are key objectives of the global healthcare systems. Currently, Digital Subtraction Angiography (DSA) is the imaging method used for interventional radiology to visualize blood vessels in cardiovascular disorders – however, the image quality is not always appropriate (CO2 angiography) and the iodinated contrast media (ICM) and radiation applied during the procedure might cause complications for patients. A solution might be Digital Variance Angiography (DVA), a new image processing technology developed recently by Kinepict Health Ltd. The method is based on the principles of kinetic imaging [Szigeti et al., 2014], thereby it can obtain more information from medical examinations using penetrating radiation than the currently used image processing algorithms. In 2D X-ray angiography, the gold standard is DSA, which records a contrast-enhanced image series and subtracts one of these images (the mask) from the other frames. These subtracted images compose the DSA video and their appropriate integration yields the DSA image. In contrast, DVA uses all frames of an unsubtracted series and calculates the standard deviation of intensity for each pixel. This proprietary algorithm enhances the functional motion-related information (i.e. the flow of contrast agents) but suppresses the noise, therefore the contrast-to-noise ratio (CNR), and consequently the image quality is greatly improved compared to DSA, providing a quality reserve.
This quality reserve was verified in three recent clinical studies, where DVA provided higher CNR and better image quality than DSA in lower limb angiography using either iodinated contrast media [Gyano et al., 2019, Bastian et al., 2021] or carbon dioxide [Orias et al., 2019] as a contrast agent. The most important benefit of DVA is that the quality reserve can be used for dose management, i.e. for the reduction of radiation exposure or contrast media use. The dose management capabilities of DVA were investigated in two further clinical studies. The first study [Orias et al., 2020] investigated the possibility of contrast media reduction in X-ray carotid angiography. The authors applied two protocols; a normal one with 6 ml and a reduced one with 3 ml iodinated contrast media (ICM). According to the results, DVA provided better image quality than DSA in both protocols. While the reduction of ICM volume resulted in a very significant deterioration of DSA image quality, it had no effect on DVA image quality, indicating that the quality reserve of DVA allows a 50% ICM reduction without affecting the quality of angiograms.
The second study [Gyano et al., submitted] investigated the possibility of radiation exposure reduction in lower limb angiography. Again, a normal (1.2 µGy/frame) and a reduced (0.36 µGy/frame) protocol were used. The results show that DVA images obtained with the low dose protocol provide similar or even better image quality than DSA images with the normal dose, indicating that the quality reserve of DVA allows 70 % radiation dose reduction under these conditions.
The advantages of DVA are the most obvious in carbon dioxide angiography, where both he quality enhancement and dose management capabilities can be observed.
DVA technology is implemented in the Kinepict Medical Imaging Tool: X-Safe (Kinepict Health Ltd, Budapest). This is an angiography platform-independent software with a Class IIa CE mark and FDA approval. Integration of the Kinepict workstation into an angiography system provides a real-time operation during the intervention.
The KMIT workstation can be connected theoretically with any angiography system. So far more than several thousand patients were examined and 100,000 DVA images were generated in cooperation with Siemens, GE, and Philips suites in Hungary, Germany, and Austria. The software is clinically validated and used for daily routine work at 4 Hungarian cath labs. Since March 2021 we have accelerated our innovation process thanks to the EIC Accelerator Grant.
