In vitro CT visualization of the biopsy location by filling the core biopsy needle with contrast media

BACKGROUND: When performing computed tomography (CT)-guided biopsy procedures with non-disposable, automatic biopsy instruments, the actual course of the biopsy needle is not registered. PURPOSE: To evaluate the ability to visualize the sampling location after CT-guided biopsy in vitro using a novel method, where the space between the inner needle and the outer cannula in a core biopsy needle is filled with contrast media; and to compare the grade of visibility for two different concentrations of contrast media. MATERIAL AND METHODS: Core needle biopsies were performed in a tissue phantom using biopsy needles primed with two different iodine contrast media concentrations (140 mg I/mL and 400 mg I/mL). Commercially available needle-filling contraptions with sealing membranes were used to fill the needles. Each biopsy was imaged with CT, and the visibility was evaluated twice by three senior radiologists in a randomized order. RESULTS: The presence of traces was confirmed after biopsy, almost without exception for both concentrations. The visibility was sufficient to determine the biopsy location in all observations with the 400 mg I/mL filling, and in 7/10 observations with the 140 mg I/mL filling. The grade of visibility of the trace and the proportion of the biopsy needle course outlined were higher with the 400 mg I/mL filling. CONCLUSION: With CT-guided biopsy in vitro, the sampling location can be visualized using a novel method of priming the biopsy needle with iodine contrast media, specifically highly concentrated contrast media.