PhD Scientific Days 2025

Cardiovascular Medicine and Research I.

The effect of dose modulation settings on plaque composition using photon-counting detector CT: an ex vivo study

Name of the presenter

Száraz Lili

Institute/workplace of the presenter

Semmelweis University, Medical Imaging Centre

Authors

Lili Száraz¹, Attila Fülöp², Bálint Tamás³, Ibolyka Dudás¹, Attila Fintha⁴, Sámuel Beke¹, Kristóf Nagy¹, Barnabás Baksa¹, Béla Merkely⁵, Pál Maurovich-Horvat¹

1: Semmelweis University, Medical Imaging Centre
2: Budapest University of Technology and Economics
3: University of Zurich, Brain Research Institute
4: Semmelweis University, Department of Pathology and Experimental Cancer Research
5: Semmelweis University, Heart and Vascular Center

Text of the abstract

Introduction: Photon-counting detector CT with dose modulation (CarekV) settings can significantly reduce radiation exposure during coronary CT angiography examinations. However, its impact on image quality (IQ) and total plaque volume remains uncertain.
Aims: We aimed to evaluate the effect of CarekV settings on total plaque volume, composition, and IQ.
Methods: We conducted repeated scans on ex vivo hearts using clinical protocol (140 kV/CarekV75), 140 kV/CarekVoff, 140 kV/CarekV10, 20, and 40 settings. Image noise (IN), signal-to-noise ratio (SNR), and contrast-to-noise ratio (CNR) were calculated. A custom in-house built Python script was used to calculate IN, SNR, CNR, as well as plaque composition and volume with the following classification: calcified plaque (CP) >350 HU; non-calcified plaque (NCP): 30–350 HU; low-attenuation plaque (LAP) <30 HU
Results: A total of 25 plaques from five ex vivo hearts were analyzed. IN, SNR, and CNR values varied significantly across dose modulation settings (p<0.05). The lowest IN value was observed with the 140 kV/CarekVoff setting (10.40±0.28 HU), whereas higher values were recorded for the clinical protocol (15.78±0.42 HU) and CarekV40/20/10 settings (21.07±0.99 / 30.23±1.04 / 39.60±1.32 HU, respectively). In contrast, SNR and CNR showed an inverse trend. Total plaque volume remained unchanged across dose-modulated scans (145.53±104.51 mm³). The volume of CP remained stable (p>0.05). However, the proportion of LAP and NCP shifted signifantly: LAP increased from 13.63±13.19 mm³ (clinical protocol) to 20.02±15.20 mm³ (140 kV/CarekV10). NCP decreased from 79.04±53.03 mm³ (clinical protocol) to 71.81±48.21 mm³ (140 kV/CarekV10).
Conclusion: CarekV20 and 10 settings should be avoided due to deterioration in diagnostic IQ and plaque composition shifts. The CarekV40 setting provides diagnostic IQ under ex vivo conditions with minimal plaque composition alteration. Dose modulation affects the ratio of LAP and NCP components, while CP volume remains unchanged.
Funding: Project no. 2023-2.1.2-KDP-2023-00016  has been implemented with the support provided by the Ministry of Culture and Innovation of Hungary from the National Research, Development and Innovation Fund, financed under the KDP-2023  funding scheme.