A novel model to test accuracy and reproducibility of MDCT scan protocols for coronary calcium in vivo.
OBJECTIVE
We compared the accuracy and reliability of prospectively triggered, retrospectively ECG gated, and non-gated CT image reconstruction for measurements of coronary artery calcification (CAC) in vivo using a novel animal model.


METHODS
In six Yorkshire farm pigs, prefabricated chains of cortical bone fragments were sutured over the epicardial bed of the major coronary arteries. Using a 4-slice MDCT scanner, each animal was imaged with two different protocols: sequential acquisition with prospective ECG triggering, and spiral acquisition with retrospectively ECG gated image reconstruction- non-gated reconstructions were also generated from these latter scans. Two independent observers measured the 'Agatston score' (AS), the calcified volume (CV), and mineral mass (MM). To calculate accuracy of MM measurements the ash weight of the burned bone fragments was compared to MDCT derived MM.


RESULTS
Six pigs successfully underwent surgery and CT imaging (mean heart rate: 86+/-12 bpm). MM measurements from prospectively ECG triggered CT sequential scans were more accurate (p<0.02) and reproducible (p=0.05) than sequential CT scans without ECG triggering or spiral acquisition using retrospective ECG gating.


CONCLUSIONS
At high heart rates prospective ECG triggered image reconstruction is more accurate and reproducible for CAC scoring than retrospective ECG gated reconstruction and non-gated reconstruction.
Rosol
Michael
M
Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA.
Sachdev
Karina
K
Enzweiler
Christian N
CN
Kwait
Dylan C
DC
Millea
Ryan
R
Titus
James
J
Handwerker
Jason
J
Wicky
Stephan
S
Achenbach
Stephen
S
Brady
Thomas J
TJ
Hoffmann
Udo
U
D000704:Analysis of Variance; D000818:Animals; D002114:Calcinosis / Q000000981:diagnostic imaging*; D003327:Coronary Disease / Q000000981:diagnostic imaging*; D004562:Electrocardiography; D005240:Feasibility Studies; D007091:Image Processing, Computer-Assisted; D015203:Reproducibility of Results; D013552:Swine; D036542:Tomography, Spiral Computed / Q000379:methods*