| Summary: | Background: Dual-energy CT (DECT) permits the simultaneous operation of two different kV levels,
providing a potential method toward the assessment of diffuse myocardial fibrosis. The purpose of this
study was to determine the accuracy of DECT for evaluation of the myocardial extracellular volume (ECV)
fraction in comparison with single-energy CT (SECT).
Methods: Myocardial ECV was quantified in fifteen dogs using DECT and dynamic equilibrium SECT
before and after doxorubicin administration. Cardiac magnetic resonance imaging (CMRI) was used to assess
myocardial function. The histological collagen volume fraction (CVF) was calculated as the gold standard.
The Bland-Altman analysis was performed to compare the agreement between DECT-ECV and SECTECV.
The association among ECV values derived from DECT and SECT, CVF, and left ventricular ejection
fraction (LVEF) were determined by correlation analysis. The variations of these values were evaluated using
repeated ANOVA.
Results: The DECT- and SECT-ECV were increased with the elongation of modeling time (pre-modeling
vs. 16-week models vs. 24-week models: DECT-ECV 24.1%±1.1%, 35.1%±1.3% and 37.6%±1.4%; SECTECV
22.9%±0.8%, 33.6%±1.2% and 36.3%±1.0%; n=30 in per-subject analysis, all P<0.05). Both ECV
values of DECT and SECT correlated well with the histological CVF results (R=0.935 and 0.952 for the
DECT-ECV and SECT-ECV; all P<0.001; n=13). Bland-Altman plots showed no significant differences
between DECT- and SECT-ECV.
Conclusions: DECT-ECV correlated well with both SECT-ECV and histology, showing the feasibility of
DECT in evaluating doxorubicin-induced diffuse myocardial interstitial fibrosis.
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