Association between myocardial extracellular volume and strain analysis through cardiovascular magnetic resonance with histological myocardial fibrosis in patients awaiting heart transplantation

Abstract

BackgroundCardiovascular magnetic resonance (CMR)-derived extracellular volume (ECV) and tissue tracking strain analyses are proposed as non-invasive methods for quantifying myocardial fibrosis and deformation. This study sought (1) to histologically validate myocardial ECV against the collagen volume fraction (CVF) measured from tissue samples of patients undergoing heart transplantation and (2) to detect the correlations between myocardial systolic strain and the myocardial ECV and histological CVF in patients undergoing heart transplantation.MethodsA total of 12 dilated cardiomyopathy (DCM) and 10 ischaemic cardiomyopathy (ICM) patients underwent T1 mapping with the Modified Look Locker Inversion recovery (MOLLI) sequence, T2 mapping and ECV. Myocardial systolic strain, including left ventricular global longitudinal (GLS), circumferential (GCS) and radial strain (GRS), were quantified using CMR cine images with tissue tracking analysis software. Tissue samples were collected from each of 16 segments of the explanted hearts and were stained with picrosirius red for histological CVF quantification.ResultsA strong relationship was observed between the global myocardial ECV and histological CVF in the DCM and ICM patients based on a per-patient analysis (r = 0.904 and r = 0.901, respectively, p < 0.001). In the linear mixed-effects regression analysis, ECV correlated well with the histological CVF in the DCM and ICM patients on a per-segment basis (β = 0.838 and β = 0.915, respectively, p < 0.001). In the multivariate linear regression analysis, histological CVF was the strongest independent determinant of ECV in the patients awaiting heart transplantation (standardised β = 0.860, p < 0.001). However, the T2 time, GLS, GCS and GRS showed no significant associations with ECV and CVF in the patients awaiting heart transplantation.ConclusionsECV derived from CMR correlated well with histological CVF, indicating its potential as a non-invasive tool for the quantification of myocardial fibrosis. Additionally, impaired myocardial systolic strains were not associated with the ECV and CVF in the patients awaiting heart transplantation.

Cardiovascular magnetic resonance native T2 and T2* quantitative values for cardiomyopathies and heart transplantations: a systematic review and meta-analysis

“…The similar T 2 values of patients and controls in this study might be related to their ROI placement, since they explicitly excluded positive LGE segments from the ROI, while all other studies used the entire myocardium without excluding positive LGE segments [164][165][166][167][168][169]. Nevertheless, the T 2 values of positive and negative LGE segments were similar in all studies that reported T 2 values of both segments [166][167][168]. The overall meta-analysis confirmed the significantly higher T 2 values in DCM patients (SMD = 1.90, 95% CI [1.07, 2.72], P < 0.01, I 2 = 89%, Fig.…”

“…The weighted mean T 2 values at 1.5 T in DCM patients was 62.9 ± 5.7 ms and 55.4 ± 3.5 ms in controls [164][165][166][167][168][169] (Table 1, Fig. 5).…”

Role of Cardiac Imaging: Cardiac Magnetic Resonance and Cardiac Computed Tomography

“…More importantly, there is growing evidence that CMR-derived strain analysis is a predictor of adverse events in patients with nonischemic DCM [99][100][101]. In particular, global longitudinal strain analysis has independent and incremental prognostic value to other risk factors including LVEF, LGE, and ECV [99][100][101][102][103]. Peak circumferential strain in association with the absence of LGE and LV mass were found to be predictive of LVRR [104].…”

Cardiac magnetic resonance T1 mapping. Part 2: Diagnostic potential and applications

“…The association of myocardial native T1 or ECV estimates with diffuse myocardial fibrosis in systemic inflammatory diseases like sarcoidosis, systemic lupus erythematosus, rheumatoid arthritis, or systemic sclerosis is limited (Table 1), as increased native T1 and ECV values in these diseases reflect "myocardial edema-related" disease activity scores rather than "fibrosis-related" disease progression [2,[40][41][42]. Recognition of these acute stages in systemic inflammatory diseases could be supported by additional acquisition of myocardial T2 maps, depicting myocardial edema without major interference of myocardial fibrosis [2,43,44].…”

“…Numerous studies have reported globally increased native T1 and ECV values in both ischemic and non-ischemic DCM (Fig. 2 and Appendix B), limiting the ability to differentiate them using a quantitative scale [44,82]. Correlations of native T1 and ECV with histologic parameters in eccentric LV hypertrophy are controversial (Table 1 and Appendix A).…”