FEMH Magazine

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  • 2026-09-01

Photon-Counting CT: Improving Coronary Imaging in Patients with Heavy Calcification and Coronary Stents

Department of Medical Imaging Dr. Shih-Yen Cheng
PIC

Specialties:

  • Interpretation of coronary computed tomography (CT) angiography and cardiac magnetic resonance imaging (MRI)
  • Mammography
  • Breast ultrasonography
  • Breast magnetic resonance imaging (MRI)
  • Mammography-guided needle localization of breast lesions
  • Ultrasound-guided breast biopsy
  • MRI-guided needle localization of breast lesions
  • MRI-guided breast biopsy
PIC
Figure 1. Photon-counting CT reduces image artifacts caused by coronary calcification and metallic stents, allowing clearer visualization of the coronary lumen and improved detection of in-stent restenosis. (Image courtesy of Siemens Healthineers.)

Does chest tightness or chest pain always mean a blocked coronary artery? Many patients undergo coronary computed tomography angiography (CCTA) to evaluate their coronary arteries. However, when there is extensive coronary artery calcification or a previously implanted coronary stent, conventional CT scanners may be affected by calcium and metal-related artifacts, commonly known as the "blooming artifact." These artifacts can make the arterial lumen appear narrower than it actually is, making it difficult to determine whether a true blockage exists. As a result, some patients still need to undergo invasive coronary angiography for a definitive diagnosis.

The latest photon-counting CT (PCCT) offers significantly higher spatial resolution and effectively reduces image artifacts caused by coronary calcification and metallic stents. This enables physicians to visualize the coronary artery lumen more clearly. Even in patients with high coronary calcium scores or previously implanted stents, PCCT provides a more accurate assessment of the severity of coronary artery narrowing and helps detect in-stent restenosis. Studies have also shown that this technology improves diagnostic accuracy, reduces unnecessary invasive coronary angiography, and allows patients who require treatment to receive appropriate care more promptly.

If you experience chest discomfort or chest pain, or have risk factors such as hypertension, diabetes, hyperlipidemia, smoking, or a history of coronary stent implantation, consult your physician about whether coronary CT angiography is appropriate for you. At Far Eastern Memorial Hospital, the latest photon-counting CT technology provides high-resolution, non-invasive cardiovascular imaging, enabling clearer visualization of the coronary arteries and more accurate diagnosis.