Myung Jin Chung MD, Abstract Co-Author: Nothing to Disclose

Sung Mok Kim MD, Abstract Co-Author: Nothing to Disclose

Younga Bae MD, Presenter: Nothing to Disclose

Jong-Woon Song MD, Abstract Co-Author: Nothing to Disclose

Chin A. Yi MD, PhD, Abstract Co-Author: Nothing to Disclose

Kyung Soo Lee MD, Abstract Co-Author: Nothing to Disclose

Yeon Hyeon Choe MD, PhD, Abstract Co-Author: Nothing to Disclose

Ji Young Lee MD, Abstract Co-Author: Nothing to Disclose

To prove usefulness of low dose ungated chest CT (LDCT) for coronary screening by comparing the results of coronary artery calcium (CAC) measurement obtained with LDCT for lung cancer screening to dedicated calcium scoring CT (CSCT)

One Hundred and twenty eight consecutive subjects (all male, mean age; 52.years ± 7) underwent LDCT (120kVp, 30mAs, 0.5 second gantry rotation, and table pitch of 1.3) and CSCT (120kVp, 196 mAs, and axial scan with prospective ECG gating) by using 40 slice MDCT. LDCT volume data were retrospectively reconstructed as 25 cm FOV and three different slice thickness (ST); 1, 2.5, 5 mm. For each examination, the area of lesions, Agatston calcium score, and calcium mass were measured at 90-HU and 130-HU threshold by using commercial CAD workstation. All measurements (130-HU threshold) from CSCT were used as reference. Spearman’s correlation test was used to compare measurements between the examinations.

The correlation coefficient of CAC measurements between LDCT and CSCT were as follows (protocol; area, score, mass): 1mm ST / 130-HU; 0.848, 0.869, and 0.865, 2.5mm ST / 130-HU; 0.888, 0.892, and 0.893, 5mm ST / 130-HU; 0.802, 0.808, and 0.807, 1mm ST / 90-HU; 0.584, 0.626, and 0.588, 2.5mm ST / 90-HU; 0.797, 0.834, and 0.819, 5mm ST / 90-HU; 0.793, 0.808, and 0.814. Of all, the result from 2.5mm ST / 130-HU is correlated best with reference results. For the aspect of each coronary branches, correlation is lowest (r = 215) in posterior descending artery but high enough in other coronary branches (r > 0.654).

In spit of using low radiation dose and un-gated scan, lung cancer screening CT can detect CAC and proved results of CAC quantification comparable to those obtained with dedicated calcium scoring CT with high dose and ECG gating.

Un-gated MDCT with low dose is comparable to dedicated CSCT with high dose and ECG gating for measurement of CAC and can be an altenative of CSCT in persons who undergo LDCT for lung cancer screening

Chung, M, Kim, S, Bae, Y, Song, J, Yi, C, Lee, K, Choe, Y, Lee, J, Coronary Calcium Screening Using Low Dose Chest CT for Lung Cancer Screening: Comparison of Ungated Fast Scan with Retrospective Reconstruction to Dedicated Coronary Calcium Scoring CT.  Radiological Society of North America 2007 Scientific Assembly and Annual Meeting, November 25 - November 30, 2007 ,Chicago IL. http://archive.rsna.org/2007/5010827.html