Improved coronary calcification quantification using photon-counting-detector CT: an ex vivo study in cadaveric
Mårten Sandstedt1,2, Jeffrey Marsh3, Kishore Rajendran4
1Center for Medical Image Science and Visualization (CMIV), Linköping University, Linköping, Sweden.
European Radiology
|March 13, 2021
Summary
Photon-counting detector CT (PCD-CT) offers more accurate coronary calcium quantification than energy-integrating detector CT (EID-CT). PCD-CT, especially with a sharp kernel, improves accuracy and reduces image noise for better morphological depiction of coronary calcifications.
Area of Science:
- Medical Imaging
- Radiology
- Cardiovascular Imaging
Background:
- Coronary artery calcification (CAC) is a marker of atherosclerosis.
- Accurate quantification of CAC is crucial for cardiovascular risk assessment.
- Photon-counting detector CT (PCD-CT) offers potential advantages over conventional energy-integrating detector CT (EID-CT) in image quality and quantification.
Purpose of the Study:
- To compare the accuracy of coronary calcium quantification between PCD-CT and EID-CT.
- To evaluate the impact of different reconstruction kernels on PCD-CT accuracy.
- To assess image noise characteristics of PCD-CT versus EID-CT.
Main Methods:
- Cadaveric coronary specimens were scanned using both PCD-CT and EID-CT subsystems.
- Matched scanning and reconstruction parameters (120 kV, 9.3-9.4 mGy CTDIvol, D50 kernel) were used.
- PCD-CT images were also reconstructed with a sharper kernel (D60).
- Micro-CT served as the reference standard for calcified volumes.
- Half-maximum thresholding was used for calcification segmentation.
- Statistical analysis included Friedman and Wilcoxon signed rank tests for volume differences and ANOVA for image noise.
Main Results:
- Volume measurements showed a trend: EID-D50 > PCD-D50 > PCD-D60 > micro-CT.
- Median calcified volumes were 22.1 (EID-D50), 21.0 (PCD-D50), 18.2 (PCD-D60), and 14.6 (micro-CT) mm³ (p < 0.05).
- Average image noise was 60.4 HU (EID-D50), 56.0 HU (PCD-D50), and 113.6 HU (PCD-D60) (p < 0.01).
Conclusions:
- PCD-CT system quantified coronary calcifications more accurately than EID-CT.
- A sharp PCD-CT kernel (D60) further improved quantification accuracy.
- PCD-CT images exhibited lower image noise compared to EID-CT at matched radiation dose and reconstruction kernel.
- High spatial resolution of PCD-CT reduces partial volume averaging, improving morphological depiction.
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