'''Percutaneous transhepatic cholangiography''' ('''PTHC''' or '''PTC''') is a diagnosticradiologic testtechnique used to visualize the [[anatomy]] of the [[biliary tract]]. A [[contrast medium]] is injected into a bile duct in the [[liver]], after which [[X-ray]]s are taken. It hasallows variousaccess purposes, such as the visualisation ofto the biliary tree in cases where [[endoscopic retrograde cholangiopancreatography]] (ERCP) has been unsuccessful. Initially reported in 1937, the procedure became popular after a 1952 report in the English-language literature.<ref>{{cite journal |author=Carter RF, Saypol GM |title=Transabdominal cholangiography |journal=Journal of the American Medical Association |volume=148 |issue=4 |pages=253–5 |year=1952 |pmid=14888454 |doi=}}</ref><ref>{{cite journal |author=Atkinson M, Happey MG, Smiddy FG |title=Percutaneous transhepatic cholangiography |journal=Gut |volume=1 |issue= |pages=357–65 |year=1960 |pmid=13684978 |pmc=1413224}}</ref>
It is predominatly now performed as a therapeutic technique. There are less invasive means of imaging the biliary tree including transabdominal ultrasound, [[MRCP]], [[computed tomography]] and [[endoscopic ultrasound]]. If the biliary system is obstructed, PTC may be used to drain bile until a permanent solution for the obstruction is performed (e.g. surgery). Advancementof the percutaneous cannula through the biliary tract to the [[duodenum]] may aid in visualising the [[ampulla of Vater]] during further attempts at ERCP. Following access to the biliary treeAdditionally, self expanding metal stents can be placed over a guidewire across malignant biliary strictures. Percutaneous placement of metal stents can be utilised when therapeutic [[ERCP]] has been unsuccessful,anatomy is altered precluding endoscopic access to the duodenum, or where there has been separation of the segmental biliary drainage of the liver, allowing more selective placement of metal stents. It is generally accepted that percutanous biliary procedures have a higher complcationcomplication raterates than therapeutic ERCP and thus a multidisciplinary approach to malignant strictures involving the biliary tree should be adopted, with consultation between interventional radiologists, endoscopists and surgeons.
