Abstract 17424: Extracellular Volume Fraction Assessed by Cardiac CT Demonstrated Strong Association With Age
Background: Assessment of extracellular volume (ECV) fraction measured by extracellular contrast medium may provide detection of extracellular matrix expansion, which is considered to be a fundamental feature of adverse myocardial remodeling. However, it is not clear if CT is accurate enough to demonstrate increasing ECV associated with normal aging.
Purpose: To investigate if age-related increase of ECV can be assessed by CT.
Method: Among 101 patients with known or suspected coronary artery disease who underwent comprehensive cardiac CT study, we identified 32 subjects without coronary artery stenosis, stress perfusion deficits or myocardial delayed enhancement. After exclusion of subjects without hematocrit (Hct) measurement (n=5), calcium score of >100 (n=5), technical failure (n=1), and a patient with rheumatoid arthritis (n=1), 20 subjects (ages 45-80, median 68 years, 5 females) comprise the study population. Based on the 16-segment model, ECV was calculated with the following equation: ECV = (ΔHUm /ΔHUb)[[Unable to Display Character: ⋅]](1–Hct), where ΔHUm and ΔHUb are the changes in attenuation of the myocardium and the LV blood, respectively, before and after contrast administration.
Result: Mean ECV for each subject by CT was 26.1%±2.2 (range 22.6-29.7%) which is in excellent agreement with previous reports by MRI (mean ECV: 24.8-26.6%). In univariate analysis, ECV was positively correlated with age (R=0.813, p<0.001) and negatively with Hct (R=-0.618, p=0.004). Stepwise multiple regression analysis revealed that age was the only independent predictor of ECV (β=0.782, p=0.001) among other factors such as Hct, gender, eGFR, hypertension, diabetes, hyperlipidemia, EF, and LV volumes.
Conclusion: Age-related increase of ECV was clearly demonstrated using CT, which indicates robustness of this technique. Moreover, our result may serve as fundamental data in the evaluation of extracellular matrix expansion in various pathological conditions.
- © 2013 by American Heart Association, Inc.