Dynamic registration of multiple-view-US and MRI for the characterization of hypertrophic cardiomyopathy

The relationship between strain and fibrosis for patients with hypertrophic cardiomyopathy (HCM) remains unclear. This work aims to fuse (i) myocardial fibrosis assessed from late-galodinium-enhanced MRI (LGE) sequence and, (ii) myocardial strain from multiple-view 2D speckle tracking echocardiography (STE). A spatio-temporal alignment is performed between segmented data extracted from cine-MRI short-axis-view and STE apical two- and four-chamber views. Dynamic Time Warping (DTW) and Fourier descriptors are used to handle the non-linear relationship between the cardiac phases of input sequences and the different levels of details provided by the two modalities. An expert evaluated the results visually, leading to a percentage of exploitable cardiac segments of 87%. Finally, MRI-LGE image was superimposed to the corresponding mid-diastolic STE contours to perform the combined tissue and strain analysis. Results on ten patients suggest that myocardial fibrosis is associated with a decrease in longitudinal strain and therefore that STE can be used to detect myocardial fibrosis.