Optimal cardiac phase for coronary artery calcium scoring on single-source 64-MDCT scanner: least interscan variability and least motion artifacts.
OBJECTIVE
The purpose of our study was to investigate the cardiac phase with the least interscan variability and motion artifacts on coronary artery calcium studies using a 64-MDCT scanner.


METHODS
Ninety-one patients with suspected coronary artery disease were scanned twice on retrospective ECG-gated helical scans. Images with 2.5-mm thickness and 1.25-mm interval at nine cardiac phases (center of cardiac phase: 40-80% in 5% increments) were reconstructed. The interscan variability of coronary artery scores (Agatston, volume, and mass) per patient and motion artifact scores per branch, subjectively assigned by motion artifact grading (1, none; 2, minor; and 3, major), were compared between cardiac phases for all patients, low (< 65 beats per minute [bpm]) and high (>or= 65 bpm) heart rate patient groups.


RESULTS
For all patients, two-factor factorial analysis of variance revealed that the interscan variability was different between cardiac cycles (p < 0.01); however, this was not statistically significant between scoring algorithms (p = 0.46). The least variability was obtained at 70% on Agatston (8%) and volume (7%) and at 75% on mass (7%). Adjacent categories logit model analysis revealed that the motion artifact score was the least at 75% (left anterior descending coronary artery, 1.3; left circumflex coronary artery, 1.4; and right coronary artery, 1.9 in all patients) and that a smaller difference in calcium scores between the scans led to a smaller motion artifact score (p < 0.05).


CONCLUSIONS
Middiastole reconstruction (center of cardiac phase: 70-75%), with the least interscan variability and the least motion artifacts, is recommended on 64-MDCT.
Matsuura
Noriaki
N
Department of Radiology, Division of Medical Intelligence and Informatics, Programs for Applied Biomedicine, Graduate School of Biomedical Sciences, Hiroshima University, Hiroshima, Japan.
Horiguchi
Jun
J
Yamamoto
Hideya
H
Hirai
Nobuhiko
N
Tonda
Tetsuji
T
Kohno
Nobuoki
N
Ito
Katsuhide
K
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000465:Algorithms; D016477:Artifacts; D002114:Calcinosis / Q000000981:diagnostic imaging*; D017023:Coronary Angiography / Q000379:methods*; D003324:Coronary Artery Disease / Q000000981:diagnostic imaging*; D004562:Electrocardiography / Q000379:methods; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D008297:Male; D008875:Middle Aged; D009038:Motion; D011856:Radiographic Image Enhancement / Q000379:methods*; D011857:Radiographic Image Interpretation, Computer-Assisted / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000379:methods*