title: Number of biopsies in diagnosing pulmonary nodules.
abstract: OBJECTIVE
  To determine the number of specimens to be obtained from pulmonary lesions to get the highest possible accuracy in histological work-up.
  
  
  METHODS
  A retrospective evaluation (January 1999 to April 2004) covered 260 patients with thoracic lesions who underwent computer tomography (CT)-guided core-cut biopsy in coaxial technique. All biopsies were performed utilizing a 19 gauge introducer needle and a 20 gauge core-cut biopsy needle. In all, 669 usable biopsies were taken (from 1-5 biopsies in each setting). The specimens were marked sequentially and each biopsy was worked up histologicaly. The biopsy results were correlated to histology after surgery, clinical follow-up or autopsy. The number of biopsies was determined that is necessary to achieve the highest possible accuracy in diagnosing pulmonary lesions.
  
  
  RESULTS
  In 591 of 669 biopsies (88.3%), there were correct positive results. The overall accuracy was 87.4%. In 193 of 260 (74.2%) patients, a suspected malignancy was confirmed. In 50 of 260 (19.2%) patients, a benign lesion was correctly diagnosed. Seventeen (6.5%) patients were lost to follow-up. The first, second and third biopsies had cumulative accuracies of 63.6%, 89.2% and 91.5%, respectively (P < 0.02). More biopsies did not show any higher impact on accuracy.
  
  
  CONCLUSIONS
  For the highest possible accuracy in diagnosing pulmonary lesions by CT-guided core-cut biopsy, at least three usable specimens are recommended to be taken.
authors.affiliation: Department of Radiology, Medical University of Graz, Austria.
authors.forename: M
authors.initials: M
authors.lastname: Wehrschuetz
authors.forename: E
authors.initials: E
authors.lastname: Wehrschuetz
authors.forename: H R
authors.initials: HR
authors.lastname: Portugaller