Coronary Calcium Screening Using Low-Dose Lung Cancer Screening: Effectiveness of MDCT with Retrospective Reconstruction

OBJECTIVE: The purpose of our study was to show the usefulness of nongated low-dose chest CT for coronary screening by comparing the results of coronary artery calcium measurement with that of dedicated calcium-scoring CT. MATERIALS AND METHODS: One hundred twenty-eight consecutive participants (all men; mean age, 52 +/- 7 years) underwent low-dose chest CT and calcium-scoring CT with prospective ECG gating using 40-MDCT. Low-dose chest CT volume data were reconstructed as 25-cm field of view and three slice thicknesses: 1, 2.5, and 5 mm. For each examination, the lesion area, Agatston calcium score, and calcium mass were measured at 90- and 130-H thresholds. All measurements (130-H threshold) from the calcium-scoring CT were used as reference standards. Spearman's correlation test was used to compare the results. RESULTS: Among the low-dose chest CT examinations, sensitivity was best determined with a 1-mm slice thickness at 130 H and 2.5-mm slice thickness at 90 H. Specificity was best determined with a 5-mm slice thickness at 130 H. Accuracy (90%) was best determined with a 2.5-mm slice thickness at 130 H. Of all protocols, calcium area, score, and mass from a 2.5-mm slice thickness at 130 H correlated best with the reference results (r = 0.89 for all three criteria). CONCLUSION: Using a low radiation dose and nongated MDCT, we can detect coronary artery calcium and obtain results comparable to those obtained with dedicated calcium-scoring CT that uses a higher dose and ECG gating.