Comparison of adaptive statistical iterative and filtered back projection reconstruction techniques in quantifying coronary calcium.
BACKGROUND
Adaptive statistical iterative reconstruction (ASIR) has been used to reduce radiation dose in cardiac computed tomography. However, change of image parameters by ASIR as compared to filtered back projection (FBP) may influence quantification of coronary calcium.


OBJECTIVE
To investigate the influence of ASIR on calcium quantification in comparison to FBP.


METHODS
In 352 patients, CT images were reconstructed using FBP alone, FBP combined with ASIR 30%, 50%, 70%, and ASIR 100% based on the same raw data. Image noise, plaque density, Agatston scores and calcium volumes were compared among the techniques.


RESULTS
Image noise, Agatston score, and calcium volume decreased significantly with ASIR compared to FBP (each P < 0.001). Use of ASIR reduced Agatston score by 10.5% to 31.0%. In calcified plaques both of patients and a phantom, ASIR decreased maximum CT values and calcified plaque size.


CONCLUSIONS
In comparison to FBP, adaptive statistical iterative reconstruction (ASIR) may significantly decrease Agatston scores and calcium volumes.
Department of Diagnostic Radiology of Saitama Medical University International Medical Center, 1397-1 Yamane, Hidaka, Saitama 350-1298, Japan.
Masahiro
M
Takahashi
Department of Diagnostic Radiology of Saitama Medical University International Medical Center, 1397-1 Yamane, Hidaka, Saitama 350-1298, Japan. Electronic address: fkimura@saitama-med.ac.jp.
Fumiko
F
Kimura
Department of Diagnostic Radiology of Saitama Medical University International Medical Center, 1397-1 Yamane, Hidaka, Saitama 350-1298, Japan.
Tatsuya
T
Umezawa
Department of Diagnostic Radiology of Saitama Medical University International Medical Center, 1397-1 Yamane, Hidaka, Saitama 350-1298, Japan.
Yusuke
Y
Watanabe
Departmenf of Cardiology of Saitama Medical University International Medical Center, 1397-1 Yamane, Hidaka, Saitama 350-1298, Japan.
Harumi
H
Ogawa
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000465:Algorithms; D003198:Computer Simulation; D017023:Coronary Angiography / Q000379:methods*; D003324:Coronary Artery Disease / Q000000981:diagnostic imaging*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015233:Models, Statistical; D011856:Radiographic Image Enhancement / Q000379:methods; D011857:Radiographic Image Interpretation, Computer-Assisted / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D059629:Signal-To-Noise Ratio; D014057:Tomography, X-Ray Computed / Q000379:methods*; D061205:Vascular Calcification / Q000000981:diagnostic imaging*
ASIR; Agatston score; CT attenuation values; Coronary artery calcium score; Coronary artery calcium volume; Filtered back projection; Iterative reconstruction; Pixel CT values