Coronary CT Angiography with Knowledge-Based Iterative Model Reconstruction for Assessing Coronary Arteries and Non-Calcified Predominant Plaques.
OBJECTIVE
To assess the effects of iterative model reconstruction (IMR) on image quality for demonstrating non-calcific high-risk plaque characteristics of coronary arteries.


MATERIALS AND METHODS
This study included 66 patients (53 men and 13 women; aged 39-76 years; mean age, 55 ± 13 years) having single-vessel disease with predominantly non-calcified plaques evaluated using prospective electrocardiogram-gated 256-slice CT angiography. Paired image sets were created using two types of reconstruction: hybrid iterative reconstruction (HIR) and IMR. Plaque characteristics were compared using the two algorithms. The signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) of the images and the CNR between the plaque and adjacent adipose tissue were also compared between the two reformatted methods.


RESULTS
Seventy-seven predominantly non-calcified plaques were detected. Forty plaques showed napkin-ring sign with the IMR reformatted method, while nineteen plaques demonstrated napkin-ring sign with HIR. There was no statistically significant difference in the presentation of positive remodeling, low attenuation plaque, and spotty calcification between the HIR and IMR reconstructed methods (all p > 0.5); however, there was a statistically significant difference in the ability to discern the napkin-ring sign between the two algorithms (χ² = 12.12, p < 0.001). The image noise of IMR was lower than that of HIR (10 ± 2 HU versus 12 ± 2 HU; p < 0.01), and the SNR and CNR of the images and the CNR between plaques and surrounding adipose tissues on IMR were better than those on HIR (p < 0.01).


CONCLUSION
IMR can significantly improve image quality compared with HIR for the demonstration of coronary artery and atherosclerotic plaques using a 256-slice CT.
['Li|Tao|T|0000-0001-6689-2951', 'Tang|Tian|T|0000-0002-3094-5211', 'Yang|Li|L|0000-0001-8373-8198', 'Zhang|Xinghua|X|0000-0002-1482-1235', 'Li|Xueping|X|0000-0002-9406-1861', 'Luo|Chuncai|C|0000-0001-5602-6320']
D000328:Adult D000368:Aged D000465:Algorithms D000072226:Computed Tomography Angiography D003331:Coronary Vessels D004562:Electrocardiography D005260:Female D006801:Humans D008297:Male D008875:Middle Aged D058226:Plaque, Atherosclerotic D011446:Prospective Studies D011857:Radiographic Image Interpretation, Computer-Assisted D059629:Signal-To-Noise Ratio
Atherosclerosis Computed tomography angiography Coronary artery disease Image reconstruction Multidetector computed tomography