Object tracking in medical imaging using a 2D active mesh system

This article proposes a technique for tracking moving organs in medical imaging. It can be split into two stages. We first initialize a 1D-triangular mesh on the first image of the sequence. We distinguish different objects of interest by grouping together the triangles that make them up. Afterwards, we deform this mesh on the successive images in order to track each identified object. The tracking stage uses optical flow by adding a node relaxation step to avoid mesh deteriorations. The mesh deformations analysis provides access to motion information along the sequence. This technique is applied to a cine-MRI sequences of the heart and allows the analysis of ventricular motions. The obtained results are quite precise, all the more as the implemented techniques are rather robust to noise and to contrast variations.

I. Introduction

Medical imaging takes nowadays a significant part in the establishment of cardiac disease diagnosis. The development of new acquisition techniques during the last decades allowed to produce dynamic image sequences (ultrasounds, X-Rays, NMR) with increasing temporal definition, These sequences opened access to motion information and aroused the development of numeric techniques adapted to the specific conditions of these image types (noise, distortion, contrast variation).