A Novel Model to Test Accuracy and Reproducibility of MDCT Scan Protocols for Coronary Calcium in Vivo

The International Journal of Cardiovascular Imaging (2006) 22: 111118 Springer 2005

DOI 10.1007/s10554-005-6535-7A novel model to test accuracy and reproducibility of MDCT scan protocols

for coronary calcium in vivoMichael Rosol1,4, Karina Sachdev1, Christian N. Enzweiler1, Dylan C. Kwait1, Ryan

Millea2, James Titus2, Jason Handwerker1, Stephan Wicky1, Stephen Achenbach1,3,

Thomas J. Brady1 & Udo Homann11Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA;2Department of Cardiac Surgery, Massachusetts General Hospital and Harvard Medical School, Boston, MA,

USA;3Department of Internal Medicine II, University of Erlangen, Germany; 4Department of Radiology,

Childrens Hospital Los Angeles and the University of Southern California Keck School of Medicine, Los Angeles,

CA, USAReceived 8 February 2005; accepted in revised form 27 April 2005Key words: artery imaging, calcium scoring, coronary artery imaging, MDCTAbstractObjectives: We compared the accuracy and reliability of prospectively triggered, retrospectively ECG gated,

and non-gated CT image reconstruction for measurements of coronary artery calcication (CAC) in vivo

using a novel animal model. Materials and 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 dierent protocols: sequential acquisition with

prospective ECG triggering, and spiral acquisition with retrospectively ECG gated image reconstructionnon-gated reconstructions were also generated from these latter scans. Two independent observers measured the Agatston score (AS), the calcied 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.IntroductionCoronary artery calcium (CAC) may improve risk

prediction for coronary artery disease (CAD) [13]

and has the potential to track the progression of

CAD [46]. Despite the unique opportunity to

directly image and quantify coronary atherosclerosis, considerable controversy concerning the use

of CAC for clinical decision-making remains [7].