3.2 Technique ............. '. . . . . . . 123 3.3 Drainage Catheters: Materials and Selection . 139 3.4 The Loop Catheter . . . . . . . . . . 141 4 Aspiration of Pancreatic Pseudocysts 145 E. Concluding Remarks 149 151 References " Subject Index . 158 VII List of Contributors BURGER, H. R, Dr. med., Oberarzt, Institut fur Pathologie, Univer­ sitiit Zurich, SchmelzbergstraBe 12, CH-8091 Zurich EINIGHAMMER, H.J., Dipl. Phys., Dr. rer. nat., Neurologische Uni­ versitatsklinik, MoorenstraBe 5, 0-4000 Dusseldorf HAUKE, R, Dipl., Phys., Dr. rer. nat., Gesellschaft fur Medizin. Techn. Informationssysteme, MarienstraBe 2,0-7910 Neu-Ulm PEmo, G., Professor Dr. med., Leitender Arzt, Abteilung fUr Zytolo­ gie, Institut fur Pathologie, Universitatsspital, CH-8091 Zurich " ... so it is not good for men to fear all that is not already known and settled, and thus feel that it is bad and harmful to strive for a greater perfection than already exists." Holderlin to his mother, 16. November 1799 A. Introduction 1 General The modem cross-sectional imaging methods of sonography and computed to­ mography, developed in the early 1970s, have contributed greatly to noninva­ sive studies of the parenchymatous organs and permit the evaluation of patho­ logic changes in areas that were previously accessible only to invasive, indirect, or inadequate examination.