Featured Article

Improved Myocardial Motion Estimation Combining Tissue Doppler and B-Mode

A. Porras, M. Alessandrini, M. De Craene, N. Duchateau, M. Sitges, B. Bijnens, H. Delingette, M. Sermesant, J. D’hooge, A Frangi, G. Piella
IEEE Trans Med Imaging vol. 33, issue 11: 2098-2106, November 2014

(Video presented with sound)

A registration framework that integrates both B-mode and tissue Doppler ultrasound images acquired interleaved for an accurate motion estimation is presented in this work, minimizing the drawbacks of using each modality separately. The velocity field is modeled continuously both in time and space using B-splines, so B-mode and tissue Doppler information do not have to coincide at specific spatial or temporal discrete locations and no data interpolation is necessary.  In addition, the spatiotemporal transform is constrained to be diffeomorphic. Images before scan conversion are used to improve the accuracy of the estimation. The similarity measure includes a model of the speckle pattern distribution of B-mode images. It also penalizes the disagreement between tissue Doppler velocities and the estimated velocity field. Registration accuracy is evaluated and compared to other alternatives using a realistic synthetic dataset, obtaining mean displacement errors of about 1 mm. Finally, the method is demonstrated on data acquired from six volunteers, both at rest and during exercise. Robustness is tested against low image quality and fast heart rates during exercise. Results show that our method provides a robust motion estimate in these situations.