Correlation between calcium score on attenuation correction ct and gated non-contrast computed tomography

IntroductionQuantification of coronary artery calcification with non-contrast gated cardiac CT has been well validated using Agatston method. While visual estimation of CCS using attenuation correction CT (CTAC) images obtained during positron emission tomography (PET) appears to agree with CAC scans, the quantification of CCS by CTAC has not been extensively studied. The aim of this analysis is to determine the correlation between coronary artery calcium score (CCS) using a low dose radiation non ECG gated CTAC and a dedicated ECG gated non contrast Cardiac CT (CAC).MethodsWe included 147 patients (mean age 62 years, 52% male) who underwent myocardial perfusion positron emission tomography (PET) and coronary calcium score in the same setting. Calcium score was calculated twice on both non-contrast gated CT (120Kvp, 200mA, 2.5mm slice thickness), and computed tomography attenuation correction CTAC (120Kvp, 20mA, 3.8mm slice thickness) using Agatston method by two physicians blinded to the results of the other study. A threshold of 130 HU was used to define detected calcium.ResultsNearly half of the patients included in the study were obese (median BMI >31kg/m2). 92 cases (63%) had CCS>0. There was a strong statistical correlation between calcium score obtained from the two scans at patient level (R=0.897, P<0.0001) and at vessel level (r=0.827, P