Endoscopic retrograde cholangiopancreatography : an evaluation of ERCP in various pancreatic and biliary diseases

Endoscopie retrograde cholangiopancreatography was introduced into clinical practice just 10 years ago and has become increasingly popular. The main advantage of ERCP is that it allows a clear definition of the pancreatie and biliary ducts, sarnething which is not easily avaible by other means. ERCP was performed for the first time in Dijkzigt Hospital in 1973, and during the past 8 years 903 such investigations hav_e been dorre. The introduetion of a new diagnostic technique should be foliowed by an evaluation of its place in various clinical situations. An evaluation of a diagnostic methad can be concerned with various aspects of patient management- diagnostic accuracy, safety, cast, effect of the result on deelsion making and effect of the result on the prognosis,- all of these where possible in camparisen withother available techniques. We therefore decided to perfarm a retrospective analysis of the Dijkzigt hospita} series of ERCP' s. By the nature of this analysis it was impossible to derive information on the cost-effectiveness aspects of the investigation. The monetary cost might with some difficulty, be computed for this hospita} but it is extremely difficult to determine the effect of ERCP on decision making and well-nigh impossible to discover its effect, if any, on the prognosis of the patient. These latter two aspects could possibly be stuclied in a prospective fashion. We decided to limit the study to an examinatien of the diagnostic value of ERCP in various biliary and pancreatie disorders. Where possible the final diagnosis with which the various radiologkal techniques are compared is that diagnosis which is abtairred from histological examina ti on of biopsy or autopsy materiaL One of the problems encountered in this study was that radiological diagnoses are usually based on the recognition of patterns of changes and are therefore subjective in nature. Measurements of the various structures are also liable to error duetovariatien in magnification. The second problem could largely be solved for the pancreatie and biliary ducts by camparing the diameter on the X-ray film with the diameter of the scope. lt was also possible to derive objective criteria for the shape of the choledochus duet by camparing ihe diameter at various fixed points with totallength of the duet. When it became clear that single features or criteria were not sufficient to distinguish between various diseases, we turned to statistica} methods- multivariate discriminant analysis - to see whether combination of criteria might lead to a higher degree of diagnostic accuracy.