Freehand versus guided breast biopsy: comparison of accuracy, needle motion, and biopsy time in a tissue model.

OBJECTIVE: Freehand ultrasound-guided breast biopsy may present difficulties in needle visualization within the scanning plane of the ultrasound image. Scanning plane and needle misalignment, an unknown needle insertion site (relative to the ultrasound image), needle trajectory before insertion, and physician experience play roles in the difficulty of these biopsy procedures. The objective of our study was to compare the currently used freehand technique with the use of a needle guidance system that limits needle motion to within the ultrasound scanning plane for breast biopsy. MATERIALS AND METHODS: We developed a needle guidance system for breast biopsy that is composed of an electronically tracked passive mechanical arm and braking mechanism. The system was attached to an ultrasound transducer, and biopsy needles were inserted through the guidance arm. Both experienced and inexperienced radiologists performed ultrasound-guided biopsy on simulated breast lesions with and without the guidance system. Success rates were scored on the basis of the presence of lesions in the core biopsy samples. The biopsy procedures were analyzed using procedure time and total needle tip travel distance before firing. RESULTS: The biopsy success rates were greater using the guidance system (p < 0.05) than using the freehand technique. Experienced radiologists and inexperienced radiologists performed biopsy significantly faster using the needle guidance system (p < 0.001). Additionally, needle tip motion was significantly greater when using the freehand technique (p < 0.001) than using the guidance system. CONCLUSION: Biopsy using the developed needle guidance system is feasible and its use decreases procedure time and decreases needle motion; thus, it has the potential to reduce patient morbidity. Moreover, less operator experience is required for a successful breast biopsy using the needle guidance system than using the freehand technique.