A new method of three-dimensional computer assisted reconstruction of the developing biliary tract

A three-dimensional (3-D) computer assisted reconstruction of the biliary t ract was performed in human and rat embryos at Carnegie stage 23 to describ e and compare the biliary structures and to point out the anatomic relation s between the structures of the hepatic pedicle. Light micrograph images fr om consecutive serial sagittal sections (diameter 7 mm) of one human and 16 rat embryos were directly digitalized with a CCD camera. The serial views were aligned automatically by software. The data were analysed following se gmentation and thresholding, allowing automatic reconstruction. The main bi le ducts ascended in the mesoderm of the hepatoduodenal ligament. The extra hepatic bile ducts: common bile duct (CD), cystic duct and gallbladder in t he human, formed a compound system which could not be shown so clearly in h istologic sections. The hepato-pancreatic ampulla was studied as visualised through the duodenum. The course of the CD was like a chicane. The gallbla dder diameter and length were similar to those of the CD, Computer-assisted reconstruction permitted easy acquisition of the data by direct examinatio n of the sections through the microscope. This method showed the relationsh ips between the different structures of the hepatic pedicle and allowed est imation of the volume of the bile duct. These findings were not Obvious in two-dimensional (2-D) views from histologic sections. Each embryonic stage could be rebuilt in 3-D, which could introduce the time as a fourth dimensi on, fundamental for the study of organogenesis.