Assessment of image quality and radiation dose in low-dose, low-contrast computed tomography coronary angiogram: a systematic review and meta-analysis

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Abstract

AIM: Coronary artery disease (CAD) remains a leading cause of morbidity and mortality worldwide. Computed tomography coronary angiography (CTCA), a noninvasive test, requires contrast volume and radiation dose. Low-contrast, low-dose CTCA using reduced tube potential and reconstruction minimises nephropathy and radiation exposure while maintaining quality. MATERIALS AND METHODS: This systematic review followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) 2020 guidelines and was registered with International Prospective Register of Systematic Reviews (PROSPERO); PubMed, Scopus, and Web of Science (2014-2025) databases were searched for studies evaluating low-contrast, low-dose CTCA. Outcomes included signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), computed tomography dose index volume (CTDIvol), dose-length product (DLP), and effective dose (ED). Leave-one-out sensitivity and within-study subgroup analyses were performed. RESULTS: Five studies with 353 participants were analysed. Low-dose, low-contrast CTCA maintains high image quality while reducing radiation exposure. At 80 kV, combined SNR and CNR were 27.1 (95% confidence interval [CI]: 17.85-36.26) and 31.2 (95% CI: 22.21-40.28), respectively, with CTDIvol: 2.08 mGy, DLP: 38.8 mGy·cm, and ED: 0.37 mSv. At 100 kV, combined SNR and CNR were 22.1 (95% CI: 10.89-33.25) and 24.0 (95% CI: 15.78-32.19), respectively, with CTDIvol: 5.59 mGy, DLP: 84.8 mGy·cm, and ED: 1.24 mSv. Subgroup analysis showed an 80-kV reduced radiation dose by 54-56% while keeping image quality similar, with 5-15% difference in SNR and CNR values. The leave-one-out analysis confirmed robustness of the pooled estimates. CONCLUSION: Low-dose, low-contrast CTCA using 80-100 kV with iterative or deep learning image reconstruction (DLIR) maintains image quality while reducing iodine and radiation exposure. Compared with 100 kV, 80 kV provides lower radiation dose with minimal image-quality differences, supporting use in selected patients.

Abstract as published, via PubMed.