Bone and soft-tissue lesions: what factors affect diagnostic yield of image-guided core-needle biopsy?

PURPOSE: To assess lesion-related and technical factors that affect diagnostic yield in image-guided core-needle biopsy (CNB) of bone and soft-tissue lesions.

MATERIALS AND METHODS: Institutional review board approval and verbal informed consent were obtained for a HIPAA-compliant prospective study of 151 consecutive CNBs of bone (n = 88) and soft-tissue (n = 63) lesions. Each CNB specimen was reported separately in the final pathology report. Diagnostic yield (total number of biopsies that yield a diagnosis divided by total number of biopsies) was calculated for all lesions and subgroups on the basis of lesion composition (lytic, sclerotic, soft tissue), lesion size (< or = 2, > 2 to 5, or > 5 cm), biopsy needle gauge, image guidance modality, number of specimens obtained, and specimen length (< 5, 5-10, or > 10 mm). The minimum number of specimens required to obtain a diagnosis was determined on the basis of the specimen number at which the diagnostic yield reached a plateau. Chi(2) And Wilcoxon rank-sum tests were performed in bivariate analyses to evaluate associations between each factor and diagnostic yield. Significant factors were evaluated with multivariate logistic regression.

RESULTS: Diagnostic yield was 77% for all lesions. Yield was 87% for lytic bone lesions and 57% for sclerotic bone lesions (P = .002). Diagnostic yield increased with larger lesions (54% for lesions < or = 2 cm, 75% for lesions > 2 to 5 cm, and 86% for lesions > 5 cm [P = .006]). There was no difference in diagnostic yield for bone versus soft-tissue lesions or according to needle gauge or image guidance modality. Diagnostic yield was 77% for bone lesions and 76% for soft-tissue lesions (P = .88). Yield was 83%, 72%, 77%, and 83% for biopsies performed with 14-, 15-, 16-, and 18-gauge needles, respectively (P = .57). Yield was 77% with computed tomographic guidance and 78% with ultrasonographic guidance (P = .99). Diagnostic yield increased with number of specimens obtained and with longer specimen length; it reached a plateau at three specimens for bone lesions and four specimens for soft-tissue lesions.

CONCLUSION: Diagnostic yield is higher in lytic than in sclerotic bone lesions, in larger lesions, and for longer specimens. Obtaining a minimum of three specimens in bone lesions and four specimens in soft-tissue lesions optimizes diagnostic yield.