Evidence map›Paper›PMID 41992180›Full record

ArticleBMC medical informatics and decision making2026

CycleGAN-based image-to-image translation for synthetic contrast enhancement in non-contrast cardiac CT: a ViT-CNN hybrid deep learning approach.

Doyoung Park, Jinsoo Kim, Xucong Ruan, Weien Chow, Lohendran Baskaran

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Article in BMC medical informatics and decision making, 2026. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Not yet cited in PubMed.

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5 · Who and what money

Authors and funding

5 authors.

Doyoung ParkNational Heart Research Institute Singapore, National Heart Centre Singapore, Singapore, Singapore.
Jinsoo KimIndependent Researcher, Seoul, Republic of Korea.
Xucong RuanDepartment of Cardiology, Changi General Hospital, Singapore, Singapore.
Weien ChowDepartment of Cardiology, Changi General Hospital, Singapore, Singapore.
Lohendran BaskaranCVS.AI, National Heart Research Institute of Singapore, Singapore, Singapore. lohendran_baskaran@duke-nus.edu.sg.

Funding

National Medical Research Council NMRC/CG2/001a/2021NHCS, CG21APR1006, TA21nov-0001SingHealth-Duke-NUS ACP NCRS grant 07/FY2021/P2/12-A93SingHealth-Duke-NUS ACP Philanthropy grant HRDUK230600
6 · The paper itself

Abstract

backgroundContrast-enhanced computed tomography (CECT) is essential for visualizing cardiac structures and stenosis; however, it is unsuitable for patients with contrast agent allergies. To address this, we propose RICAUNet-v2, a ViT-CNN hybrid architecture designed for CycleGAN-based similarity-guided unpaired NCCT-to-CECT translation.

methodsRICAUNet-v2 integrates RICA blocks and Vision Transformer (ViT) layers to capture local and global features. We compared our architecture against UNet, RICAU-Net, MaskGAN, and a supervised pix2pix-RICAUNet-v2 using metrics including Mean Absolute Error (MAE), Peak Signal-to-Noise Ratio (PSNR), Structural Similarity Index Measure (SSIM), and Fréchet Inception Distance (FID). Statistical significance was assessed using the Wilcoxon signed-rank test, and a blinded reader study conducted by two clinicians evaluated perceptual realism.

resultsCycleGAN-RICAUNet-v2 achieved the lowest FID score (0.0639). Although pix2pix-RICAUNet-v2 attained the best MAE (92.72) and SSIM (0.5380), and MaskGAN achieved the highest PSNR (13.50), the superior FID score of CycleGAN-RICAUNet-v2 indicates better perceptual realism for unpaired translation. Ablation studies confirmed that using three-channel windowed inputs and similarity-guided sampling reduced the FID compared to single-channel input and unpaired cross-patient sampling (FID of 0.0802). Clinical evaluation demonstrated 100% precision and 15% recall, with a Cohen’s kappa of 0.40, suggesting that most misclassifications of real images as synthetic may be due to conservative or expectation bias rather than a lack of realism.

conclusionsRICAUNet-v2 improves perceptual realism in similarity-guided unpaired NCCT-to-CECT translation by integrating ViT and RICA blocks. Although further clinically relevant validation of diagnostic utility is required, the proposed architecture demonstrates potential for contrast-free cardiac CT enhancement.

trial registrationNot applicable.

Indexed as

Contrast MediaDeep LearningHeartImage Processing, Computer-AssistedTomography, X-Ray ComputedConvolutional Neural NetworksGenerative Adversarial NetworksHumansContrast MediaCardiac CTConvolutional neural network (CNN)CycleGANImage-to-image translation (I2I translation)NCCT-to-CECT translationSynthetic contrast enhancementVision Transformer (ViT)

Identifiers

PMID41992180
PMCPMC13202901

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LicenceCC BY-NC-ND
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Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.