胎儿期Ⅰ型先天性胆总管囊肿的MRI影像特征和肝胆发育的参数测量

Prenatal MRI findings of type I congenital choledochal cyst and parameter measurement of liver and gallbladder

目的观察胎儿期Ⅰ型先天性胆总管囊肿(congenital choledochal cyst,CCC)的MRI表现,分析CCC胎儿肺肝比值、肝脏、脾脏、胆囊以及门静脉测量参数与正常胎儿的差异。材料与方法随访分析31例出生后经手术证实的CCC患儿的临床资料以及胎儿期的MRI表现,观察CCC病灶的形态、走行方向、是否与胆管或胆囊相连、病灶下缘与肝脏下缘的关系,并测量计算胆总管囊肿的体积。以90例健康胎儿为对照组,比较两组胎儿肺肝比值、肝脏(左右径、上下径、最大截面面积、肝实质表观弥散系数)、脾脏(长径、厚度、最大截面面积)、胆囊(长径、短径、长径与短径比值、最大截面面积)以及门静脉直径的差异。并分析CCC胎儿胆总管囊肿体积与MRI测量指标的相关性。结果31例CCC患儿中,男9例,女22例,男女比率约为1∶2.4;其中26例胆总管囊肿病灶为椭圆形,5例为类圆形;31例病灶上端均可见尖角征;29例胆总管囊肿病灶的下缘未及肝脏下缘,2例病灶下缘超过了肝脏下缘;26例病灶的走行方向为右上-左下。CCC组与对照组胎儿的肺肝比值、肝脏(左右径、上下径、最大截面面积、表观弥散系数)、脾脏(长径、厚度)、胆囊(长径、短径、最大截面面积)的差异没有统计学意义(P>0.05);CCC组与对照组胎儿脾脏的最大截面面积、门静脉直径以及胆囊长径与短径的比值差异有统计学意义(P<0.05);进一步统计分析CCC组胆总管囊肿体积与胎儿脾脏最大截面面积、胆囊长径与短径比值以及门静脉直径的相关性,结果表明病灶体积与胎儿脾脏的最大截面面积、胆囊长径与短径的比值以及门静脉直径没有相关性(P>0.05)。结论CCC多见于女性,胎儿期的MRI表现为:病灶多呈椭圆形,一般不超过肝脏下缘,病灶的走行方向多为右上-左下,病变上端可见尖角征。患儿脾脏增大,门静脉增宽,胆囊长径与短径的比值增大。但病灶体积与胎儿脾脏的最大截面面积、门静脉直径、胆囊长径与短径的比值无相关性。

Objective:To observe the MRI findings of type I congenital choledochal cyst(CCC)during the fetal period,analyze the differences in CCC fetal lung-to-liver ratio,liver,spleen,gallbladder,and portal vein measurement parameters compared to normal fetuses.Materials and Methods:Follow-up analysis of clinical data and fetal MRI manifestations of 31 confirmed postnatally operated CCC patients.Observations included the morphology,course,connection with bile duct or gallbladder,relationship between the lower edge of the lesion and the lower edge of the liver,and measurement and calculation of the volume of the choledochal cyst.A control group of 90 healthy fetuses was used for comparison,analyzing differences in fetal lung to liver signal intensity ratio,liver(left and right diameters,upper and lower diameters,maximum cross-sectional area,apparent diffusion coefficient of the liver),spleen(length,thickness,maximum cross-sectional area),gallbladder(length,short diameter,length-to-short diameter ratio,maximum cross-sectional area),and portal vein diameter.The correlation between choledochal cyst volume and MRI measurement parameters was also analyzed.Results:Among the 31 CCC patients,there were 9 male fetuses and 22 female fetuses,with a male-to-female ratio of approximately 1∶2.4.Among them,26 cases had elliptical-shaped lesions,and 5 cases had cystic lesions.In all 31 cases,a pointed angle sign was observed at the upper end of the lesions.The lower edge of the lesions did not exceed the lower edge of the liver in 29 cases,while in 2 cases,the lower edge extended beyond the liver.The course of the lesions in 26 cases was from the upper right to the lower left.There was no statistically significant difference(P>0.05)in fetal lung to liver signal intensity ratio,liver dimensions(left and right diameters,upper and lower diameters,maximum cross-sectional area,apparent diffusion coefficient),spleen dimensions(length,thickness),gallbladder dimensions(length,short diameter,maximum cross-sectional area)between the CCC group and the control group.However,there were statistically significant differences(P<0.05)in the maximum cross-sectional area of the spleen,portal vein diameter,and the ratio of gallbladder length to short diameter between the lesion group and the control group fetuses.Further statistical analysis revealed no correlation(P>0.05)between the volume of the choledochal cyst and the maximum cross-sectional area of the fetal spleen,the ratio of gallbladder length to short diameter,and portal vein diameter.Conclusions:CCC is more common in females.The fetal MRI manifestations include elliptical-shaped lesions,generally not extending beyond the lower edge of the liver.The course of the lesions is often from the upper right to the lower left,with a pointed angle sign at the upper end.The affected fetuses exhibit an enlarged spleen,widened portal vein,and an increased ratio of gallbladder length to short diameter.However,there is no correlation between the volume of the lesion and the maximum cross-sectional area of the fetal spleen,portal vein diameter,and the ratio of gallbladder length to short diameter.