Accuracy of CT biopsy: laser guidance versus conventional freehand techniques

The purpose of this study was to determine whether laser-guided computed tomographic (CT) biopsy is more accurate than CT-guided biopsy with conventional freehand techniques.

Two independent operators performed an equal number of freehand and laser-guided needle passes at varying single and double angles (0 degree, 30 degrees, 60 degrees, 25 degrees/30 degrees, and 25 degrees/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 of variance (ANOVA) to compare the accuracy of laser guidance with freehand passes. ANOVA and correlation analysis were also used to confirm the relative equivalency of phantom targets and biopsy parameters.

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 techniques was 10.58 mm (SE = 0.82 mm) (F = 52.0, df = 1.17, P = .0001). Ninety-three percent of laser-guided passes and 56% of freehand passes were within 1 cm of the intended target. Error increased for both laser-guided and freehand techniques with larger angles or double-angle biopsies, but the increases were greater with freehand technique. No statistically significant differences existed between the targets themselves or biopsy parameters for the two operators.

Laser-guided CT biopsies were more accurate than freehand CT biopsies. Practical advantages of laser guidance over freehand CT biopsy methods may include decreased procedure times and reduced patient morbidity.