Photon-counting CT scanners may obviate the need for sublingual nitroglycerin in patients being evaluated for coronary artery disease, researchers have reported.
The finding is from a comparison of imaging among patients who underwent coronary CT angiography (CCTA) scans with a photon-counting CT scanner with or without nitroglycerin, with no statistically significant improvement in diagnostic performance between the scans, noted lead author Ismail Kabakus, MD, of the Medical University of South Carolina in Charleston, and colleagues.
“If confirmed, a more selective approach to nitroglycerin administration could simplify workflow, avoid unnecessary medication administration in selected patients, and reduce the potential for nitroglycerin-related adverse effects while maintaining diagnostic performance,” the group wrote. The study published August 22 in the Journal of Cardiovascular Computed Tomography.
Sublingual nitroglycerin is routinely administered before CCTA to induce coronary vasodilation and improve vessel visualization, the authors explained. Most prior supporting evidence for its use comes from older CT systems and focuses on image quality rather than diagnostic accuracy.
Photon-counting CT scanners are newer and offer substantially improved spatial resolution, reduced noise, and superior contrast-to-noise ratio. The impact of nitroglycerin on CCTA scans performed with these scanners is unknown, according to the authors.
To bridge the gap, the researchers identified consecutive patients who underwent photon-counting CT CCTA at a single center between January 2023 and November 2025. The final cohort comprised 124 patients: 61 received 0.4 mg sublingual nitroglycerin and 63 did not. Invasive coronary angiography performed within 30 days served as the reference standard. The team assessed performance on a per-patient and per-vessel basis.
Representative case from the non-nitroglycerin cohort. A 92-year-old man who did not receive sublingual nitroglycerin because of severe aortic stenosis. The Agatston coronary artery calcium score was 5438. (A) Curved multiplanar reformatted CCTA image reconstructed at 0.4-mm slice thickness using a Bv60 kernel and QIR strength 3 demonstrates diffuse multifocal mild luminal stenoses related to extensive calcified atherosclerotic plaque. (B) Invasive coronary angiography confirmed multifocal mild stenoses without evidence of obstructive coronary artery disease.Journal of Cardiovascular Computed TomographyOn per-patient analysis, sensitivity was similar between the nitroglycerin and non-nitroglycerin cohorts (90.3% versus 90.9%), as was negative predictive value (86.4% versus 88.9%). The non-nitroglycerin cohort showed numerically higher specificity (80.0% versus 63.3%), positive predictive value (83.3% versus 71.8%), and overall accuracy (85.7% vs. 77.0%).
The researchers observed no significant differences on per-vessel analysis. They also reported that nitroglycerin increased coronary attenuation but did not improve signal-to-noise ratio or contrast-to-noise ratio.
“Although our findings do not support changing current clinical practice based on a single retrospective study, they suggest that the necessity of routine nitroglycerin administration in photon-counting CCTA should be re-evaluated in larger prospective studies,” the authors wrote.
The full study is available here.
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