Interventional Biliary Radiology, born from the development of the instrumental procedures linked to transhepatic cholangiography, plays a leading role in the management of patients with obstructive jaundice. In fact it includes several diagnostic tools, such as cytological examination of the bile, transhepatic brushing and biopsy, percutaneous cholangioscopy, manometric and perfusional biliary studies, which are extremely successful in the diagnosis of nature of the obstructive lesions. On the other hand it includes some therapeutical procedures, deriving from angiographic techniques, which allow the placement of drainage catheters into the biliary tree. These drainage systems, used to decompress the bile ducts, are the external drainage catheter, which divert the bile out of the organism; the external-internal drainage catheter, which restores the physiological biliary flow; the endoprosthesis, a cylindric tube, with sideholes, pushed into the obstructive lesion. All these devices may have a preoperative or definitive-palliative finality.
Xeroradiography allows visualisation of the arterial system after intravenous injection of contrast media. This method has proved particularly useful for diagnosis of changes in the arteriovenous fistulas of 20 patients on chronic haemodialysis. In all cases transvenous xeroangiography gave information about morphologic alterations of vessels and soft tissues. Among the commonly used angiographic methods, transvenous xeroangiography appears the technique of choice.
The physical patterns ruling the information of a xeroradiographic image allow the visualization of the arterial system with a lower concentration of contrast medium. So you can visualize the arterial branches both with intravenous injection of the usual angiographic concentration of contrast medium or with intraarterial injection of diluted contrast medium at a very low concentration. A prerequisite to successful xeroangiography was the commercial diffusion of a changer for xerox cassettes allowing several exposures according to standardized programs.
