Accuracy of CT biopsy: Laser guidance versus conventional freehand techniques

Rationale and Objectives. The purpose of this study was to determine whethe r laser-guided computed tomographic (CT) biopsy is more accurate than CT-gu ided bi biopsy with conventional freehand techniques. Materials and Methods. Two independent operators performed an equal number of freehand and laser-guided needle passes at varying single and double ang les (0 degrees, 30 degrees, 60 degrees, 25 degrees/30 degrees, and 25 degre es/60 degrees) on targets within six pork and beef phantoms. A total of 180 biopsy passes were performed, and error distances of needle tip to target were tabulated. Data were analyzed by means of repeated measures analysis o f variance (ANOVA) to compare the accuracy of laser guidance with freehand passes. ANOVA and correlation analysis were also used to confirm the relati ve equivalency of phantom targets and biopsy parameters. Results. Overall, laser-guided passes were statistically significantly more accurate than freehand passes. Mean error with laser guidance was 5.01 mm (standard error [SE] = 0.41 mm), whereas mean error with freehand technique s was 10.58 mm (SE = 0.82 mm) (F = 52.0, df = 1.17, P = .0001). Ninety-thre e percent of laser-guided passes and 56% of freehand passes were within 1 c m of the intended target. Error increased for both laser-guided and freehan d techniques with larger angles or double-angle biopsies, but the increases were greater with free-hand technique. No statistically significant differ ences existed between the targets themselves or biopsy parameters for the t wo operators. Conclusion. Laser-guided CT biopsies were more accurate than freehand CT bi opsies. Practical advantages of laser guidance over freehand CT biopsy meth ods may include decreased procedure times and reduced patient morbidity.