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Reproducibility of coronary calcium quantification in repeat examinations with retrospectively ECG-gated multisection
B Ohnesorge1, T Flohr, R Fischbach
1Siemens Medical Solutions, Division CT, CTS C, Siemensstrasse 1, 91301 Forchheim, Germany. Bernd.Ohnesorge@siemens.com
Insights
High reproducibility in coronary calcium scoring is crucial for follow-up CT scans. Multisection spiral CT (MSCT) with overlapping increments significantly improves inter-examination reproducibility for Agatston score, volume, and mass measurements.
Area of Science:
- Cardiovascular Imaging
- Radiology
- Medical Physics
Background:
- High reproducibility is essential for serial coronary calcium scoring.
- Coronary artery calcification (CAC) assessment requires precise and repeatable measurements for monitoring disease progression.
- Multisection spiral CT (MSCT) is a common modality for CAC quantification.
Purpose of the Study:
- To evaluate the inter-examination reproducibility of coronary calcium scoring using retrospectively ECG-gated MSCT.
- To assess the impact of different slice reconstruction increments on measurement variability.
- To determine the optimal parameters for reproducible CAC quantification.
Main Methods:
- Fifty patients underwent two MSCT examinations.
- Coronary calcium scoring was performed using retrospectively ECG-gated MSCT with 3-mm slice width and 125-ms temporal resolution.
- Agatston score, calcium volume (with/without isotropic interpolation), and calcium mass were calculated.
- Interscan variability was analyzed using non-overlapping and overlapping reconstruction increments (2, 1.5, 1 mm).
Main Results:
- Overlapping reconstruction increments significantly reduced interscan variability.
- Minimum mean variability for Agatston score was 12% (median 9%).
- Minimum mean variability for calcium volume and mass was 7.5% (median 5%).
Conclusions:
- Retrospectively ECG-gated MSCT provides high reproducibility for coronary calcium quantification in follow-up examinations.
- Utilizing overlapping reconstruction increments minimizes partial-volume errors and enhances measurement consistency.
- MSCT with optimized parameters is suitable for reliable longitudinal monitoring of coronary calcification.
Abstract:
High reproducibility is a key requirement for coronary calcium scoring in follow-up examinations. We investigated the inter-examination reproducibility of calcium scoring with retrospectively ECG-gated multisection spiral CT (MSCT). Fifty patients were examined twice with MSCT. Slices were reconstructed with retrospective ECG gating in the diastolic phase with 3-mm slice width and up to 125-ms temporal resolution. We calculated the Agatston score, calcium volume with and without isotropic interpolation, and calcium mass, and derived the mean and median variability. We investigated the change of variability with use of 3-mm non-overlapping and overlapping increments (2, 1.5, 1 mm). Use of overlapping increment results in considerably reduced interscan variability. We observed a minimum mean variability of 12% and a minimum median variability of 9% for the Agatston score. For volume and mass quantification we obtained a minimum mean variability of 7.5% and a minimum median variability of 5%. Multisection spiral CT enables coronary calcium quantification with high reproducibility in follow-up examinations mainly founded on image data with reduced partial-volume errors due to overlapping increment.