MRI analysis of gallbladder changes with gestational weeks between fetuses with type I congenital choledochal cyst and healthy fetuses

Purpose: To retrospectively analyze the prenatal MRI image characteristics of fetuses with type I congenital choledochal cyst and healthy fetuses, and to clarify the changes of gallbladder with gestational weeks. Methods We retrospectively reviewed prenatal MRI features of healthy fetuses and fetuses with type I choledochal cysts confirmed by operation after birth from January 2018 to March 2022. Clinical data and image findings (the maximum transverse and longitudinal diameters of gallbladder, liver and spleen, the diameters of choledochal cysts at transverse, coronal and sagittal planes and the maximum diameters of portal vein) were recorded. The features in two groups were then analyzed. Results A total of 139 fetuses were included, 100 in the healthy fetuses and 39 in the type I choledochal cysts. We found a nonlinear relationship between gestational weeks and gallbladder size with two inflection points of 27 and 34 in fetuses with type I choledochal cyst, after adjusting for potential confounders. In normal fetuses, however, the relationship is linear. Conclusions The relationship between gestational weeks and gallbladder size is non-linear in fetuses with type I choledochal cyst, with gallbladder size shrinking and spleen enlargement compared to healthy fetuses.