Therapeutic methods in diagnostic radiology.

During the past 15 year period we have experienced enormous and rapidly expanding changes in technology in the field of diagnostic radiology, as regards both equipment and methods. The diagnostic methods have become less invasive, which has resulted in less discomfort for the patient and reduced risks for complications. During the same period, however, an increasing number of invasive procedures have been performed because the radiologist participates more actively in therapeutic methods. Some of these methods are increasing continuously in number, while some disappear soon after their introduction because they are found to be not as beneficial as was originally expected, or they are replaced by better and often less invasive methods. For example, percutaneous transhepatic portography was used extensively for occlusion of the left gastric vein in portal hypertension, but it has now been replaced by endoscopic treatment of varices. Percutaneous transhepatic drainage was used as a routine method for drainage of the biliary tree in obstructive jaundice caused by a tumor, but has now been more or less replaced by endoscopic drainage of the biliary system. Percutaneous extraction of stones in the renal pelvis will similarly to a great extent be replaced by external shock wave therapy. There are, however, interventional methods which are highly efficient and which will survive because they are less hazardous and less traumatic than surgical procedures. Percutaneous nephrostomy, for example, is one important method, another is the angioplastic technique in the coronary, renal and peripheral arteries. Drainage of abscesses and cysts will also survive as interventional radiologic methods. Occlusion of vessels in patients with arteriovenous fistulas or bleeding will be used in selected situations. In oncologic radiology, various attempts have been made to destroy tumors. Over a long period, cytotoxic