Photon-counting CT scanners may eliminate the need for sublingual nitroglycerin in coronary artery disease evaluation, as a new study found no significant difference in diagnostic performance between scans performed with or without the medication, potentially simplifying clinical workflow and reducing unnecessary drug exposure.
- Photon-counting CT technology offers improved spatial resolution, reduced noise, and superior contrast compared to older CT systems, potentially reducing nitroglycerin dependency
- Study results showed similar sensitivity (90.3% vs 90.9%) and comparable diagnostic accuracy between patients who received nitroglycerin and those who did not
- Clinical benefits include simplified workflow, avoided unnecessary medication administration, and reduced risk of nitroglycerin-related adverse effects while maintaining diagnostic performance
- Larger prospective studies are needed before changing current clinical practice, as researchers emphasize these findings come from a single retrospective study of 124 patients
- Nitroglycerin's role has been based on evidence from older CT systems; its necessity with newer photon-counting technology requires further evaluation
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 Tomography
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.
![Examples of ultrasound findings and techniques. (A) Images in a 39-year-old male patient with a mass in the left thigh. The mass is heterogeneous on the B-mode US image (compared with the patient in D) and showed increased microvascularity (superb microvascular imaging [SMI]) and shear-wave elastography (SWE) values. Undifferentiated pleomorphic sarcoma was diagnosed at biopsy (with pleomorphic rhabdomyosarcoma in surgical specimen). (B) Images in an 18-year-old male patient with a mass in the left leg. The mass is hypoechoic on the B-mode image, with no other findings suggestive of malignancy. The lesion is in contact with the cortex of the tibia, which is slightly irregular. CT revealed a doubtful anteromedial tibial erosion. The microvascular study demonstrated high vascularization, suggestive of malignancy. Periosteal Ewing sarcoma was diagnosed with both histologic and immunohistochemical confirmation. (C) Images in a 69-year-old female patient with a lump growing on the outside of the left leg. Multiple SWE examinations were performed (please note the high values obtained in the measurements, whereas the color map highlights the stiffness relative to adjacent tissues). SMI showed areas of increased vascularization to target for sampling. Undifferentiated spindle cell sarcoma was diagnosed at biopsy, with residual leiomyosarcoma in the surgical specimen after neoadjuvant therapy. (D) Images in a 56-year-old female patient with a mass in the right thigh. The mass is heterogeneous at both B-mode ultrasound (similar to patient A) and MRI (coronal T2-weighted spectral attenuated inversion recovery [SPAIR]; T1-weighted pre-contrast and postcontrast imaging), which even shows uptake after the administration of paramagnetic contrast material, which is traditionally suggestive of malignancy. Low values at SMI and elastography are suggestive of benignity. Spindle cell lipoma was diagnosed at biopsy, with atypical spindle cell lipomatous tumor in the surgical specimen.](https://img.auntminnie.com/mindful/smg/workspaces/default/uploads/2026/08/images-radiol250278fig2.APCFLSvX6p.jpg?auto=format%2Ccompress&fit=crop&h=100&q=70&w=100)
![Examples of ultrasound findings and techniques. (A) Images in a 39-year-old male patient with a mass in the left thigh. The mass is heterogeneous on the B-mode US image (compared with the patient in D) and showed increased microvascularity (superb microvascular imaging [SMI]) and shear-wave elastography (SWE) values. Undifferentiated pleomorphic sarcoma was diagnosed at biopsy (with pleomorphic rhabdomyosarcoma in surgical specimen). (B) Images in an 18-year-old male patient with a mass in the left leg. The mass is hypoechoic on the B-mode image, with no other findings suggestive of malignancy. The lesion is in contact with the cortex of the tibia, which is slightly irregular. CT revealed a doubtful anteromedial tibial erosion. The microvascular study demonstrated high vascularization, suggestive of malignancy. Periosteal Ewing sarcoma was diagnosed with both histologic and immunohistochemical confirmation. (C) Images in a 69-year-old female patient with a lump growing on the outside of the left leg. Multiple SWE examinations were performed (please note the high values obtained in the measurements, whereas the color map highlights the stiffness relative to adjacent tissues). SMI showed areas of increased vascularization to target for sampling. Undifferentiated spindle cell sarcoma was diagnosed at biopsy, with residual leiomyosarcoma in the surgical specimen after neoadjuvant therapy. (D) Images in a 56-year-old female patient with a mass in the right thigh. The mass is heterogeneous at both B-mode ultrasound (similar to patient A) and MRI (coronal T2-weighted spectral attenuated inversion recovery [SPAIR]; T1-weighted pre-contrast and postcontrast imaging), which even shows uptake after the administration of paramagnetic contrast material, which is traditionally suggestive of malignancy. Low values at SMI and elastography are suggestive of benignity. Spindle cell lipoma was diagnosed at biopsy, with atypical spindle cell lipomatous tumor in the surgical specimen.](https://img.auntminnie.com/mindful/smg/workspaces/default/uploads/2026/08/images-radiol250278fig2.APCFLSvX6p.jpg?auto=format%2Ccompress&dpr=2&fit=crop&h=167&q=70&w=250)
