Coronary artery calcium quantification with non-ECG-gated low-radiation dose CT of the chest

To evaluate the feasibility of quantifying coronary artery calcification in low-radiation dose chest CT (LDCT) studies performed in an early lung cancer detection program by comparing the results of this technique with those of dedicated retrospectively ECG-gated cardiac CT. After obtaining informed consent, we evaluated the CT studies of 48 consecutive asymptomatic smokers (44 male, 4 female; mean age 59.7 years) included in an early lung cancer detection trial who underwent multislice LDCT (Volume Zoom, Siemens) of the chest and a retrospectively ECG-gated cardiac CT specifically dedicated to quantifying coronary artery calcification. LDCT examinations were reconstructed to reproduce cardiac CT parameters. Coronary calcium values were compared using the Wilcoxon signed-rank test. The concordance correlation coefficient (CCC) was calculated to determine the agreement between the two methods. Coronary calcium values ranged from 0 to 1,908.4 (median: 89.6; IQR: 3.2; 227.4) in LDCT exams and from 0 to 1,486.6 (median: 81.3; IQR: 2.5; 316.4) in cardiac CT studies. No statistically significant difference was observed in the estimation of total coronary calcium score (p=0.28). The concordance between the two techniques was excellent (CCC > or = 0.81). The LDCT study performed in lung cancer early detection trials enables coronary artery calcification to be quantified with the same accuracy as the dedicated retrospectively ECG-gated cardiac CT examination.