Impact of iterative reconstruction on CT coronary calcium quantification.
OBJECTIVE
We evaluated the influence of sinogram-affirmed iterative reconstruction (SAFIRE) on the coronary artery calcium (CAC) score by computed tomography (CT).


METHODS
Seventy patients underwent CAC imaging by 128-slice dual-source CT. CAC volume, mass and Agatston score were calculated from images reconstructed by filtered back projection (FBP) without and with incremental degrees of the SAFIRE algorithm (10-50 %). We used the repeated measuring test and the Steel-Dwass test for multiple comparisons of values and the difference ratio among different SAFIRE groups using the FBP as reference.


RESULTS
The median Agatston score (range) decreased with incremental SAFIRE degrees: 163 (0.1 - 3,393.3), 158.4 (0.3 - 3,079.3), 137.7 (0.1 - 2,978.0), 120.6 (0 - 2,783.6), 102.6 (0 - 2,468.4) and 84.1 (0 - 2,186.9) for 0 % (FBP), 10 %, 20 %, 30 %, 40 % and 50 % SAFIRE, respectively (P < 0.05). In comparison with FBP, CAC volume (from 8.1 % to 47.7 %), CAC mass (from 5.3 % to 44.7 %) and CAC Agatston score (from 7.3 % to 48.4 %) all decreased with increasing SAFIRE from 10 % to 50 %, respectively (P < 0.05). High-grade SAFIRE resulted in the disappearance of detectable calcium in three cases with low calcium burden.


CONCLUSIONS
SAFIRE noise reduction techniques significantly affected the CAC, which potentially alters perceived cardiovascular risk.
Department of Radiology, Erasmus Medical Centre, 's-Gravendijkwal 230, 3015CE, Rotterdam, The Netherlands, akuratasan2000@gmail.com.
Akira
A
Kurata
Anoeshka
A
Dharampal
Admir
A
Dedic
Pim J
PJ
de Feyter
Gabriel P
GP
Krestin
Marcel L
ML
Dijkshoorn
Koen
K
Nieman
D000328:Adult; D000368:Aged; D000465:Algorithms; D002114:Calcinosis / Q000000981:diagnostic imaging*; D002118:Calcium / Q000032:analysis*; D017023:Coronary Angiography; D003324:Coronary Artery Disease / Q000000981:diagnostic imaging*; D003331:Coronary Vessels / Q000737:chemistry* / Q000000981:diagnostic imaging*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011829:Radiation Dosage; D011857:Radiographic Image Interpretation, Computer-Assisted / Q000379:methods*; D012307:Risk Factors; D014057:Tomography, X-Ray Computed / Q000379:methods
D002118:Calcium