PECULIARITIES OF THE FORMATION OF THE LATERAL SULCUS OF THE CEREBRAL HEMISPHERE OF THE BRAIN IN HUMAN FETUS: A MORPHOMETRIC STUDY OF MAGNETIC RESONANCE TOMOGRAMS

The lateral sulcus of the cerebral hemispheres is one of the most stable and well-visualized structures during the fetal period of prenatal ontogenesis, making it a recognizable and convenient object for morphometric studies aimed at assessing the dynamics of human brain development. The purpose of the study was to develop a method for determining the relative depth of the lateral sulcus of the human cerebral hemispheres and to identify the characteristics of its morphogenesis during the fetal period of prenatal ontogenesis. Material and methods. This study was conducted using magnetic resonance imaging scans of human fetal brains (n=20) at gestational ages of 20–39 weeks. Morphometric analysis was performed using the Image Tool software. The relative depth of the lateral sulcus was determined using an original methodology. Results. The relative depth of the lateral sulcus ranged from 16.45% to 39.24%, with no statistically significant interhemispheric differences. The dynamics of this parameter included three periods: rapid increase (20–25 weeks), relative stability (25–35 weeks) with a slight decrease at 29–33 weeks, which correlates with the growth of the insular lobe, and a subsequent increase after 35 weeks. Conclusions. 1. The lateral sulcus of the cerebral hemispheres is a stable structure that is clearly visualized on magnetic resonance tomograms starting from the 20th week of gestation. 2. The dynamics of the relative depth of the lateral sulcus in the fetal period is characterized by rapid growth at 20-25 weeks, relative stability at 25-35 weeks and further increase after 35 weeks. 3. The absence of statistically significant interhemispheric differences indicates the synchrony of the processes of morphogenesis of the lateral sulcus in the right and left hemispheres. 4. Using the relative depth of the lateral sulcus is an appropriate approach to assess its development, as it eliminates the influence of the variability of the absolute dimensions of the cerebrum and simplifies the comparison of results across different studies. 5. The proposed method for determining the relative depth of the lateral sulcus can be used for further studies of the morphogenesis of brain structures in the prenatal period.