A kinematic model-based analysis framework for 3D Cine-DENSE-validation with an axially compressed gel phantom and application in sheep before and after antero-apical myocardial infarction

Purpose Myocardial strain is increasingly used to assess left ventricular (LV) function. Incorporation of LV deformation into finite element (FE) modeling environment with subsequent strain calculation will allow analysis to reach its full potential. We describe a new kinematic model-based analysis framework (KMAF) to calculate strain from 3D cine-DENSE (displacement encoding with stimulated echoes) MRI. Methods Cine-DENSE allows measurement of 3D myocardial displacement with high spatial accuracy. The KMAF framework uses cine cardiovascular magnetic resonance (CMR) to facilitate cine-DENSE segmentation, interpolates cine-DENSE displacement, and kinematically deforms an FE model to calculate strain. This framework was validated in an axially compressed gel phantom and applied in 10 healthy sheep and 5 sheep after myocardial infarction (MI). Results Excellent Bland-Altman agreement of peak circumferential (E-cc) and longitudinal (E-ll) strain (mean difference = 0.021 +/- 0.04 and -0.006 +/- 0.03, respectively), was found between KMAF estimates and idealized FE simulation. E-rr had a mean difference of -0.014 but larger variation (+/- 0.12). Cine-DENSE estimated end-systolic (ES) E-cc, E-ll and E-rr exhibited significant spatial variation for healthy sheep. Displacement magnitude was reduced on average by 27%, 42%, and 56% after MI in the remote, adjacent and MI regions, respectively. Conclusions The KMAF framework allows accurate calculation of 3D LV E-cc and E-ll from cine-DENSE.

Automated summary

This study introduces a new kinematic model-based analysis framework for calculating strain from 3D cardiac MRI, which was validated in a gel phantom and applied in sheep models. The KMAF framework allows accurate calculation of LV strain and shows significant spatial variation in healthy and post-MI sheep.