Sinogram-Affirmed Iterative Reconstruction Negatively Impacts the Risk Category Based on Agatston Score: A Study Combining Coronary Calcium Score Measurement and Coronary CT Angiography

Table 3

Patients’ number (n1) in different risk categories of all patients () between FBP and all levels of SAFIRE.

Risk category	FBP	SAFIRE 1	SAFIRE 2	SAFIRE 3^★	SAFIRE 4^★◎■	SAFIRE 5^★◎■◆
^#	0	0	0	0	1 (1.1%)	1 (1.1%)
	11 (12.4%)	14 (15.7%)	14 (15.7%)	16 (18.0%)	19 (21.3%)	19 (21.3%)
	40 (44.9%)	38 (42.7%)	38 (42.7%)	39 (43.8%)	37 (41.6%)	38 (42.7%)
	25 (28.1%)	27 (30.3%)	28 (31.5%)	25 (28.1%)	25 (28.1%)	25 (28.1%)
	13 (14.6%)	10 (11.2%)	9 (10.1%)	9 (10.1%)	7 (7.9%)	6 (6.7%)

FBP: filtered back projection; SAFIRE: sinogram-affirmed iterative reconstruction.^#The risk category of one patient was reassigned from 2 to 1 according to the Agatston score reduced to zero using SAFIRE 4. The percentages (n1/89) were gradually increased for the low risk category (e.g., ) and decreased for the high risk category (e.g., ).^★ compared with FBP, ^◎ compared with SAFIRE 1, ^■ compared with SAFIRE 2, and ^◆ compared with SAFIRE 3.