ANATOMY OF THE HUMAN BILIARY SYSTEM STUDIED BY QUANTITATIVE COMPUTER-AIDED 3-DIMENSIONAL IMAGING TECHNIQUES

The branching geometry of the normal, cholangiographically identifiabl e human biliary tree was studied with an innovative computer-aided thr ee-dimensional (3D) imaging technique, In addition, a serially section ed conventional paraffin block from a normal donor liver was used to c reate and quantitatively study a microscopic 3D image, Finally, a geom etric model was developed to estimate the enlargement of biliary surfa ces imparted by microvilli, The images created by these techniques cou ld be viewed in stationary modes or rotating around any preselected ax is, Approximately 7 (+/- 3) intrahepatic duct orders were cholangiogra phically identified, Computerized measurements of the images from thre e normal livers suggested that the mean total volume of duct orders 1 to 7 shown in the cholangiograms was 16.6 cm(3). The volume of the ent ire macroscopic duct system was estimated to be between 14 and 24 cm(3 ) (mean, 20.4 cm(3)), with an internal surface of 336 to 575 cm(2) (me an, 398 cm(2)), A geometric model based on electron micrographs sugges ted that this surface is magnified approximately 5.5-fold by the prese nce of microvilli, Volume and surface area (SA) measurements of all du cts in the same orders increased nearly exponentially from the first t oward the seventh branching order (i.e., from the hilus toward the per iphery of the liver), and probably beyond, The microscopic computerize d reconstruction of a septal bile duct with its tributaries also allow ed volume measurements; the imaged duct system represented 2.7% of the portal tract volume, The data presented herein may help to better eva luate branching patterns of the biliary tree and, eventually, the quan titative aspects of site-restricted cholangiocyte function and their r ole in the development of biliary diseases.