3-DIMENSIONAL COMPUTED-TOMOGRAPHY CHOLANGIOGRAPHY - A NEW TECHNIQUE FOR BILIARY-TRACT IMAGING

Knowledge of the segmental anatomy and intersegmental biliary connecti ons is an essential prerequisite to the effective management of patien ts with complex biliary strictures. Three dimensional (3D) imaging has the ability to demonstrate complex anatomical relationships that are difficult to appreciate on simple noninvasive two dimensional (2D) ima ging. Our aim was to develop a technique for accurate, non-invasive 3D computed tomography (CT) cholangiography. Contiguous 4 mm CT sections were obtained through the liver during a dynamic bolus of 200 ml IV c ontrast. 3D surface reconstructions were then performed, the biliary s ystem was isolated from surrounding hepatic parenchyma using segmentat ion and contrast threshold algorithms. 14 patients (six females, eight males, median age 68 years (range 48-82)) were studied. 13/14 had mal ignant biliary obstruction and one had obstruction secondary to a panc reatic pseudocyst. Obstruction was at the liver hilum in eight, the co mmon bile duct in five and the common hepatic duct in one. Four patien ts had biliary endoprostheses but were symptomatic from inadequate dra inage. There was good demonstration of the biliary anatomy, obstructed segments and intersegmental biliary connections in 13/14; irregular b iliary dilatation secondary to primary sclerosing cholangitis rendered interpretation difficult in one. 3D cholangiography provided a useful adjunct to other imaging techniques. In particular, in patients with complex hilar strictures it aided implementation of appropriate interv entional drainage procedures.