METHOD FOR DETERMINATION OF LEFT ATRIAL MYOCARDIUM CONTOURS ON MR IMAGES USING MULTI-PLANAR RECONSTRUCTIONS

摘要

FIELD: medicine.SUBSTANCE: invention refers to medicine, x-ray diagnostics, and can be used in processing of MR images with delayed contrasting, determining the structure of the left atrial myocardium (LM) in the patients with atrial fibrillation (AF). It is necessary to perform MRT of the heart with delayed staining. On the basis of the obtained series of images one performs multi-plane reconstruction of LM in three mutually perpendicular planes: frontal, sagittal, axial. On the basis of multi-plane reconstruction data one performs searching of cardiac structures and artefacts, which can be mistaken for LM myocardium, in the following sequence. First, one determines topography of LM and adjoining structures, for which purpose it is necessary to determine topography of the mitral ring in the obtained planes, the first layer of atrial myocardium is immediately above the level of ring of mitral valve. Then, on the axial plane, one draws a longitudinal axis of the left ventricle (LV) and its transverse axis at the level of the mitral valve. Along the constructed transverse axis of LV at all axial sections of LM one draws the boundary between LV and LM. Then one determines the oesophagus and its boundary with the back wall of LM. One determines the aortic valve ring, descending aorta, differentiating these structures with LM wall in places of their closest location. One determines the route of the left coronary artery near LM loop as a band of an intensive signal migrating from layer to layer towards lateral wall of LV. Then one outlines LM contours, for which purpose it is necessary to first outline LM endocardial contour using as a reference point LM back wall. Then one outlines the atrial myocardium in the medial direction and backwards from the defined boundary between LM and LV. Front wall and LM loop are outlined above the upper boundary of the ring of mitral valve. Then one outlines LM epicardial circuit. Finally, one excludes artefacts, for which purpose he detects in LM myocardium zones with brightness more intense than brightness of the wall of the aorta in this layer. One views such zones in different planes while interpreting the zone as not related to LM myocard. Such zone is manually cut out from its boundaries.EFFECT: this method makes its possible to accurately outline LM myocard contour and ensures standardization of procedure of working with MR-images, which allows to obtain comparable results.3 cl, 8 dwg