CT-guided percutaneous core biopsy. Effective accuracy, diagnostic utilityand effective costs.

Purpose: The value of a diagnostic technique does not only depend on its se nsitivity, specificity and accuracy, but also on how its results affect cli nical management. This effect is represented by the values effective accura cy and the diagnostic utility which were determined for Cr-guided coaxial c ore biopsies in this study. Materials and methods: 180 consecutive biopsies were analyzed. The results were analyzed with the help of a logistic regre ssion analysis with regard to the organ regions biopsied, the size of the n eedle used, and the number of tissue cores taken. Correct results that were not accepted as diagnostic clinically and resulted in additional biopsies were scored together with the false results under negative utility coeffici ents. Results: The sensitivity, specificity and accuracy of all the tests a mounted to 91.1%, 100%, and 93.3%, respectively. The diagnostic utility of the biopsies varied between 66% for the liver and pancreatic lesions, and 8 8% for the non-organ related retroperitoneum. In those cases where more tha n three tissue cores were taken the results were statistically significantl y better in terms of effective accuracy and diagnostic utility. No signific ant differences were found with regard to different needle sizes in the bio psied organ regions. The lowest clinical acceptance was observed for the hi stological findings "scar tissue" and "inflammation". Conclusion: CT-guided coaxial biopsies offer a high degree of sensitivity, specificity and accur acy, as well as a low rate of therapeutically relevant complications. With increasing use of differentiated strategies in therapy for malignomas percu taneous biopsies play a very important role in the management of these dise ases. Prospective studies should further evaluate the effective accuracy an d diagnostic utility of core biopsies also in comparison to fine needle asp iration biopsies (FNAP).