  Temporal patterns of cardiac motion provide important information for cardiac
disease diagnosis. This pattern could be obtained by three-directional CINE
multi-slice left ventricular myocardial velocity mapping (3Dir MVM), which is a
cardiac MR technique providing magnitude and phase information of the
myocardial motion simultaneously. However, long acquisition time limits the
usage of this technique by causing breathing artifacts, while shortening the
time causes low temporal resolution and may provide an inaccurate assessment of
cardiac motion. In this study, we proposed a frame synthesis algorithm to
increase the temporal resolution of 3Dir MVM data. Our algorithm is featured by
1) three attention-based encoders which accept magnitude images, phase images,
and myocardium segmentation masks respectively as inputs; 2) three decoders
that output the interpolated frames and corresponding myocardium segmentation
results; and 3) loss functions highlighting myocardium pixels. Our algorithm
can not only increase the temporal resolution 3Dir MVMs, but can also generates
the myocardium segmentation results at the same time.
