Can image enhancement allow radiation dose to be reduced whilst maintaining the perceived diagnostic image quality required for coronary angiography?

Abstract

Digital image processing used in modern cardiac interventional x-ray systems may have the potential to enhance image quality such that it allows for lower radiation doses. The aim of this research was to quantify the reduction in radiation dose facilitated by image processing alone for percutaneous coronary intervention (PCI) patient angiograms, without reducing the perceived image quality required to confidently make a diagnosis. Incremental amounts of image noise were added to five PCI patient angiograms, simulating the angiogram having been acquired at corresponding lower dose levels (by 10-89% dose reduction). Sixteen observers with relevant background and experience scored the image quality of these angiograms in three states - with no image processing and with two different modern image processing algorithms applied; these algorithms are used on state-of-the-art and previous generation cardiac interventional x-ray systems. Ordinal regression allowing for random effects and the delta method were used to quantify the dose reduction allowed for by the processing algorithms, for equivalent image quality scores. The dose reductions [with 95% confidence interval] from the state-of-the-art and previous generation image processing relative to no processing were 24.9% [18.8- 31.0%] and 15.6% [9.4-21.9%] respectively. The dose reduction enabled by the state-of-the-art image processing relative to previous generation processing was 10.3% [4.4-16.2%]. This demonstrates that statistically significant dose reduction can be facilitated with no loss in perceived image quality using modern image enhancement; the most recent processing algorithm was more effective in preserving image quality at lower doses.