Improving image quality and resolution of coronary arteries in coronary computed tomography angiography by using high-definition scans and deep learning image reconstruction

Background: Coronary computed tomography angiography (CTA) has been increasingly used to identify the degree of coronary artery stenosis and plaque lesions in vessels. This study evaluated the feasibility of using high-definition (HD) scanning with high-level deep learning image reconstruction (DLIR-H) to improve the image quality and spatial resolution when imaging calcified plaques and stents in coronary CTA as compared to the standard definition (SD) reconstruction mode with adaptive statistical iterative reconstruction-V (ASIR-V). Methods: A total of 34 patients (age 63.3 +/- 10.9 years; 55.88% female) with calcified plaques and/or stents who underwent coronary CTA in HD-mode were included in this study. Images were reconstructed with SD-ASIR-V, HD-ASIR-V, and HD-DLIR-H. Subjective image quality with image noise and clarity of vessels, calcifications, and stented lumens was evaluated by 2 radiologists using a 5-point scale. The kappa (kappa) test was used to analyze the interobserver agreement. Objective image quality with image noise, signal-to-noise-ratio (SNR), and contrast-to-noise-ratio (CNR) was measured and compared. Image spatial resolution and beam-hardening artifacts (BHAs) were also evaluated using the calcification diameter and CT numbers in 3 points along the stented lumen (inside, at the proximal and distal ends just outside stent). Results: There were 45 calcified plaques and 4 coronary stents. HD-DLIR-H images had the highest overall image quality score (4.50 +/- 0.63) with the lowest image noise (22.59 +/- 3.59 HU) and the highest SNR (18.30 +/- 4.88) and CNR (26.56 +/- 6.33), followed by SD-ASIR-V50% image quality score (4.06 +/- 2.49), image noise (35.02 +/- 8.09 HU), SNR (12.77 +/- 1.59), CNR(15.67 +/- 1.92) and HD-ASIR-V50% image quality score (3.90 +/- 0.64), image noise (57.7 +/- 12.03 HU), SNR (8.16 +/- 1.86), CNR ( 10.01 +/- 2.39). HD-DLIR-H images also had the smallest calcification diameter measurement (2.36 +/- 1.58 mm), followed by HD-ASIR-V50% (3.46 +/- 2.07 mm) and SD-ASIR-V50% (4.06 +/- 2.49 mm). HD-DLIR-H images had the closest CT value measurements for the 3 points along the stented lumen, indicating much less BHA. Interobserver agreement on the image quality assessment was good to excellent (HD-DLIR-H:. value =0.783; HD-ASIR-V50%:. value =0.789; SD-ASIR-V50%:. value =0.671). Conclusions: Coronary CTA with HD scan mode and DLIR-H significantly improves the spatial resolution for displaying calcifications and in-stent lumens while simultaneously reducing image noise.

Automated summary

This study evaluates the feasibility of using high-definition scanning and deep learning image reconstruction to improve the imaging of calcified plaques and stents in coronary CTA. The results show that high-definition imaging with deep learning reconstruction significantly improves image quality and spatial resolution while reducing image noise.