[CT-guided percutaneous core biopsy: Effective accuracy, diagnostic utility and effective costs]

The value of a diagnostic technique does not only depend on its sensitivity, specificity and accuracy, but also on how its results affect clinical management. This effect is represented by the values effective accuracy and the diagnostic utility which were determined for CT-guided coaxial core biopsies in this study.

180 consecutive biopsies were analyzed. The results were analyzed with the help of a logistic regression analysis with regard to the organ regions biopsied, the size of the needle 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 coefficients.

The sensitivity, specificity and accuracy of all the tests amounted to 91.1 %, 100 %, and 93.3 %, respectively. The diagnostic utility of the biopsies varied between 66 % for the liver and pancreatic lesions, and 88 % for the non-organ related retroperitoneum. In those cases where more than three tissue cores were taken the results were statistically significantly better in terms of effective accuracy and diagnostic utility. No significant differences were found with regard to different needle sizes in the biopsied organ regions. The lowest clinical acceptance was observed for the histological findings "scar tissue" and "inflammation".

CT-guided coaxial biopsies offer a high degree of sensitivity, specificity and accuracy, as well as a low rate of therapeutically relevant complications. With increasing use of differentiated strategies in therapy for malignomas percutaneous biopsies play a very important role in the management of these diseases. Prospective studies should further evaluate the effective accuracy and diagnostic utility of core biopsies also in comparison to fine needle aspiration biopsies (FNAP).