Quantification of doxorubicin-induced interstitial myocardial fibrosis in a beagle model using equilibrium contrast-enhanced computed tomography: A comparative study with cardiac magnetic resonance T1-mapping.

Abstract

BACKGROUND: The noninvasive equilibrium contrast-enhanced cardiac computed tomography (CCT) has potential for myocardial tissue characterization. The objective of this study was to test the feasibility of CCT-based extracellular volume (ECV) fraction in beagle models of doxorubicin-induced interstitial myocardial fibrosis, with cardiac magnetic resonance (CMR) as the reference. METHODS: This study was approved by local ethics committee. Thirteen beagles were included with ECV quantified by CCT and CMR at baseline, 16 and 24&#x202f;weeks after modeling. Spearman correlation analysis was used to determine the association between CT ECV, CMR ECV, collagen volume fraction (CVF), LVEF and serum fibrosis index (Hyaluronic acid [HA], Laminin [LN] and Type-III procollagen [PCIII]). RESULTS: Median ECV values in CT and CMR at 16 and 24&#x202f;weeks were significantly higher than those at baseline (CT ECV: 34.4% and 37.7% vs. 25.2%; CMR ECV: 32.2% and 37.4% vs. 22.7%; P&#x202f;<&#x202f;0.001). A strong correlation was found between CCT and CMR for ECV (r&#x202f;=&#x202f;0.899, P&#x202f;<&#x202f;0.001). Both correlated well with CVF (r&#x202f;=&#x202f;0.951 and 0.879 for CT and MR ECV vs. CVF, P&#x202f;<&#x202f;0.001), serum fibrosis index (r&#x202f;=&#x202f;0.830-0.907 for CT and MR ECV vs. HA, LN, PCIII, respectively, P&#x202f;<&#x202f;0.05) and were inversely related to LVEF (r&#x202f;=&#x202f;-0.846 and -0.804 for CCT and CMR, P&#x202f;<&#x202f;0.001). Bland-Altman analysis showed a small bias (1.5%), with 95% limits of agreement of -2.7% and 5.6%. CONCLUSIONS: CCT-derived ECV correlates well with CMR, histology and serum fibrosis index, suggesting that CCT is capable of myocardial tissue characterization.