Coronary artery calcium score on low-dose computed tomography for lung cancer screening

Table 1 Demographics n (%)

Clinical characteristics	Population (n = 60)
Age (yr, mean ± SD)	73.4 ± 7.1
Male gender	30 (50)
BMI (kg/m², mean ± SD)	25.9 ± 4.5
BSA (m², mean ± SD)	1.8 ± 0.2
Mean heart rate (bpm, mean ± SD)	73.0 ± 15.7
Additional negative chronotropic drugs	None

Baseline characteristics of study population. BMI: Body mass index; BSA: Body surface area.

Table 2 scan and reconstruction parameters

Parameters	gCCT	ngCCT
Scan parameters
Technique	Spiral	Spiral
kV	120	120
mAs	150	30
Gantry rotation time (ms)	330	330
Individual detector width (mm)	1.2	0.6
Number of detectors	20 × 2	32 × 2
ECG gating	Yes	No
Prospective ECG modulation of tube current	Yes	No
Table feed/s (mm)	14.4	86.4
Pitch	0.2	1.5
Scan range	Carina-Apex	Chest
DLP (mGy; mean ± SD)	116 ± 51	84 ± 16a
Effective dose (mSv; factor = 0.014; mean ± SD)	2.0 ± 0.9	1.2 ± 0.5a
Effective dose (mSv; factor = 0.014; median, IQR)	1.61; 1.15-2.0	1.13; 1.05-1.20a
Reconstruction parameters
Effective slice width (mm)	3.0	5.0
Reconstruction increment (mm)	1.5	5.0
FOV (mm)	140-160	250-300
Kernel filtering	B35f1	B30f(medium-smooth)

The Table shows the scan parameters for gCCT and ngCCT. gCCT vs ngCCT,

^aP < 0.05;

¹Dedicated filter for calcium scoring. gCCT: ECG gated cardiac computed tomography; ngCCT: Non-gated chest computed tomography; FOV: Field of view; ECG: Electrocardiogram; DLP: Dose length product.

Table 3 coronary artery calcium score values

Parameters (mean ± SD)	gCCT	ngCCT	Delta (absolute)	Delta	P	r	R2
Volume	418.1 ± 746.5	332.0 ± 596.9	-86.1 ± 263.8	-21%	< 0.05	0.947	0.896
Mass	88.9 ± 151.2	77.9 ± 140.5	-11.1 ± 35.5	-12%	< 0.05	0.973	0.946
Agatston	480.8 ± 853.7	427.7 ± 776.3	-53.1 ± 188.4	-11%	< 0.05	0.978	0.956

The Table shows the mean values of CACS Volume, Mass, and Agatston score for the study population. On average gCCT shows CACS values significantly higher with a high correlation to ngCCT. The percentage underestimation (delta) of ngCCT of Agatston score is -11%. CACS: Coronary artery calcium score; gCCT: ECG gated cardiac computed tomography; ngCCT: Non-gated chest computed tomography.

Table 4 Cardio vascular risk stratification based on absolute coronary artery calcium score classes n (%)

CACS class	gCCT	ngCCT
0	6 (10)	10 (16.7)
1-10	6 (10)	7 (11.7)
11-100	14 (23.3)	10 (16.7)
101-400	14 (23.3)	17 (28.3)
400-1000	14 (23.3)	10 (16.7)
> 1000	6 (10)	6 (10)

The Table shows how the total Agatston score distributed using the Mayo Clinic Classification (Rumberger et al[17]) with gCCT and ngCCT within the same population. In total 23 (38.3%) patients shifted to a different cardiovascular risk group. gCCT: ECG gated cardiac computed tomography; ngCCT: Non-gated chest computed tomography.