The Study Of The Relationship Between Gestational Age And Parameters Of Cerebellum, The Depth Of Cisterna Magna In Fetuses By Ultrasound

Background: With interest in the posterior fossa increased, more congenital abnormalities in posterior fossa will be discovered and recognized. Prenatal ultrasonographic detection of the posterior fossa has recently become a focus of study. It is very important to identify the normal sonographic measurements of the cerebellum and the cisterna magna in the posterior fossa, as well as regular development with advancing gestational age.Objective: To analyze the relationship between gestational age and transverse cerebellar diameter (TCD), cerebellar hemisphere area (CHA), cerebellar hemisphere circumference (CHC), the depth of cisterna magna respectively, in the second and third trimester of pregnancy and to understand their clinical significance.Methods: 235 singleton pregnancies between 16 and 40 weeks of gestation were included in this study and underwent transabdominal ultrasonographic detection. All fetuses were individed into 25 groups by gestational age. Sonographic measurements made in transcerebellar plane included TCD, CHA, CHC and the depth of cisterna magna. Other biometric indices included biparietal diameter(BPD), head circumference (HC),abdominal circumference(AC),femur length(FL),humerus length (HL). Pearson's correlation coefficient was used to evaluate the correlation between the measurements and gestational age, other fetal biometric indices, respectively.Results: Statistically significant relationship between gestational age and TCD,CHA,CHC were found (Pearson's correlation: r=0.951,0.958 and 0.965 respectively ; p<0.01). The relationship between the depth of the cisterna magna and gestational age was found (r=0.405,p=0.038). Measured parameters of cerebellum mentioned before correlated significantly with other biometric indices which included BPD,HC,AC,FL,HL(all r>0.90,all p<0.01).Conclusions: In second and third trimester of pregnancy , CHA,CHC can be used as parameters to assess the fetal cerebellar development and to evaluate the gestational age, but the depth of the cisterna magna can't be used.