  Magnetic resonance imaging (MRI) is a widely known medical imaging technique
used to assess the heart function. Deep learning (DL) models perform several
tasks in cardiac MRI (CMR) images with good efficacy, such as segmentation,
estimation, and detection of diseases. Many DL models based on convolutional
neural networks (CNN) were improved by detecting regions-of-interest (ROI)
either automatically or by hand. In this paper we describe Visual-Motion-Focus
(VMF), a module that detects the heart motion in the 4D MRI sequence, and
highlights ROIs by focusing a Radial Basis Function (RBF) on the estimated
motion field. We experimented and evaluated VMF on three CMR datasets,
observing that the proposed ROIs cover 99.7% of data labels (Recall score),
improved the CNN segmentation (mean Dice score) by 1.7 (p < .001) after the ROI
extraction, and improved the overall training speed by 2.5 times (+150%).
