OBSERVATION OF THE NORMAL DEVELOPMENTAL PATTERN OF FETAL CEREBRAL SULCI BETWEEN 18 TO 32 WEEKS OF GESTATIONAL AGE BY USING ULTRASONOGRAPHY - A CORRELATIONAL STUDY BETWEEN TWO MATERNAL AGE GROUPS

Background: Anomalous or absent fetal sulci and gyri may be associated with abnormal brain development and increased incidence of the neurological and psychomotor problems like refractory epilepsy or developmental delay, later in the infant life. Lissencephaly, is a condition with "smooth brain," with the absence of normal convolutions (folds) in the cerebral cortex. Neuronal migration disorders result when the post mitotic neurons fail to migrate from the ventricular zone to the cortical plate, resulting in a wide spectrum of cortical malformations. The most common clinical manifestations include severe psychomotor retardation, developmental delay, refractory seizures, and failure to thrive. Aim. The research aims at observing normal developmental pattern of fetal cerebral sulci between 18 to 32 weeks of gestational age by using ultrasonography. Material and Methods. This is a Cross-sectional observational study, performed among 110 antenatal women investigated under the Department of Radio Diagnosis, Shri Sathya Sai medical college and research institute, Ammapettai. The appearance and complete formation of sulci and fissures such parieto-occipital sulci, cingulate sulci, calcarine sulci and convexity sulci and also the insula/sylvian fissure were identified. Results and Discussion. Parietooccipital fissure wass identified as dot pattern by 18-19 weeks and complete by 24 weeks. Calcarine fissure identified as dot pattern by 18 -19 weeks and almost complete by 22 weeks. Cingulate sulci were identified as dot pattern by 23-24 weeks, with Y pattern appearing by 27-28 weeks and complete by 31-33 weeks. By 19-20 weeks Smooth surface Sylvian fissure was present and predominant till 20-21 weeks. By 22-23 weeks Obtuse angle Sylvian fissure was predominant and by 29-30 weeks Acute angle Sylvian fissure was complete. Convexity sulci was absent till 23 weeks 6 days and started appearing after 24 weeks. The Convexity sulci fully appeared after 28 weeks. The mean Period of Gestation (weeks) of the appearance of Dot, V and Y patterns of each fissure and sulci between the mother of below and above 35 years were not statistically significant. Conclusion. Parietooccipital fissure, Sylvian fissure and Calcarine fissure started appearing by 18-19 weeks, and complete by 24 weeks (except Sylvian fissure which was complete by 30 weeks). Convexity and Cingulate sulci started appearing early by 23 weeks, complete by 28 weeks and 33 weeks respectively.