Diagnostic performance of fusion of myocardial perfusion imaging (MPI) and computed tomography coronary angiography.

BACKGROUND: We evaluated the incremental diagnostic value of fusion images of coronary computed tomography angiography (CTA) and myocardial perfusion imaging (MPI) over MPI alone or MPI and CTA side-by-side to identify obstructive coronary artery disease (CAD > 50% stenosis) using invasive coronary angiography (ICA) as the gold standard. METHODS: 50 subjects (36 men; 56 +/- 11 years old) underwent rest-stress MPI and CTA within 12-26 days of each other. CTAs were performed with multi-detector CT-scanners (31 on 64-slice; and 19 on 16-slice). 37 patients underwent ICA while 13 subjects did not because of low (<5%) pre-test likelihood (LLK) of disease. Three blinded readers scored the images in sequential sessions using (1) MPI alone (2) MPI and CTA side-by-side, (3) fused CTA/MPI images. RESULTS: One or more critical stenoses during ICA were found in 28 patients and non-critical stenoses were found in 9 patients. MPI, side-by-side MPI-CTA, and fused CTA/MPI showed the same normalcy rate (NR:13/13) in LLK subjects. The fusion technique performed better than MPI and MPI and CTA side-by-side for the presence of CAD in any vessel (overall area under the curve (AUC) for fused images: 0.89; P = .005 vs MPI, P = .04 vs side-by-side MPI-CTA) and for localization of CAD to the left anterior descending coronary artery (AUC: 0.82, P < .001 vs MPI; P = .007 vs side-by-side MPI-CTA). There was a non-significant trend for better detection of multi-vessel disease with fusion. CONCLUSIONS: Using ICA as the gold standard, fusion imaging provided incremental diagnostic information compared to MPI alone or side-by-side MPI-CTA for the diagnosis of obstructive CAD and for localization of CAD to the left anterior descending coronary artery.

Calculation of coronary age using calcium scores in multiple ethnicities.

Coronary artery calcium (CAC) accumulation, a marker of atherosclerosis burden, differs significantly among patients of different ethnicities. It has been proposed that CAC scores can be used to assess the number of life years lost or gained by an individual with a given amount of coronary artery calcium. Therefore, we sought to develop a method to calculate the coronary age of an individual based on the extent of CAC in this subject compared to that of individuals of the same race, age and sex. We used median CAC scores from previously published data from the Multi-Ethnic Study of Atherosclerosis (MESA) to derive the predicted coronary age of subjects from 4 ethnic groups (White, Black, Hispanic and Chinese) of both sexes. With this method a 50-year-old white man with a CAC score of 40 has a coronary age of a 61-year-old white man; for a black man with a score of 40 the coronary age is 70. This method should allow patients to better understand the prognostic significance of their test results and may ensure a better compliance with preventive regimens.