Medicine (Baltimore). 2025 Oct 31;104(44):e45725. doi: 10.1097/MD.0000000000045725.
ABSTRACT
Coronary CT angiography (CCTA) in obese patients is challenging due to high radiation exposure, elevated iodine load, and increased image noise. We evaluated a tripartite low-dose strategy combining high-iodine-concentration contrast media (HCM, 400 mgI/mL), 80-kVp scanning, and deep learning image reconstruction (DLIR) in obese patients (BMI ≥30 kg/m2) to simultaneously reduce radiation and iodine dose while maintaining diagnostic quality. In this prospective, single-center trial, 100 obese patients were randomized to either a low-dose group (80 kVp, HCM at 0.6 mL/kg, DLIR reconstruction; n = 50) or a standard-dose group (120 kVp, 350 mgI/mL contrast at 0.9 mL/kg, adaptive statistical iterative reconstruction [ASiR]-V 50% reconstruction; n = 50). Low-dose scans were also reconstructed with ASiR-V 50% for internal comparison. Objective (noise, signal-to-noise ratio, contrast-to-noise ratio) and subjective (5-point scale by blinded radiologists) image quality, radiation dose, total iodine load, and diagnostic performance (vs invasive coronary angiography in a 20-patient subgroup) for detecting ≥50% stenosis were compared. The low-dose protocol significantly reduced effective radiation dose by 48.6% (1.06 ± 0.26 mSv vs 2.27 ± 0.42 mSv; P <.001) and total iodine load by 23.8% (19.2 ± 2.1 gI vs 25.2 ± 2.4 gI; P <.001) compared to standard protocol. DLIR at 80-kVp significantly reduced image noise (aortic root: 16.5 ± 3.0 HU vs 25.1 ± 4.0 HU for ASiR-V at 80 kVp; P <.001) and improved contrast-to-noise ratio (e.g., proximal left anterior descending: +41.6%, P <.001) and signal-to-noise ratio (e.g., distal right coronary artery: +63.8%, P <.001). Subjective image quality scores were significantly higher for DLIR (mean 4.4 ± 0.5) versus low-dose ASiR-V (3.0 ± 0.7) and standard-dose ASiR-V (4.1 ± 0.7; P <.001), with excellent inter-observer agreement (κ = 0.88). 94% of DLIR datasets received optimal noise scores (≥4/5) versus 0% for low-dose ASiR-V. Against invasive coronary angiography, the low-dose protocol achieved 100% patient-level sensitivity and negative predictive value, with 91.7% vessel-level accuracy. Combining HCM, 80-kVp scanning, and DLIR significantly reduces radiation exposure and iodine load in obese CCTA patients without compromising image quality or diagnostic accuracy compared to standard protocols, offering a safer alternative, particularly for patients with renal impairment.
PMID:41261582 | DOI:10.1097/MD.0000000000045725
