A phantom study comparing ultrasound-guided liver tumor puncture using new real-time 3D ultrasound and conventional 2D ultrasound.

OBJECTIVE: The purpose of this study is to compare the accuracy of ultrasound-guided puncture using new real-time 3D (4D) ultrasound and conventional 2D ultrasound for focal hepatic masses using a liver phantom.
MATERIALS AND METHODS: A 4D ultrasound system equipped with a 5-MHz 4D probe displayed both axial and orthogonal images parallel to a puncture line plane. We used a liver phantom that contained four simulated spherical masses in an acrylic box (length × width × height, 300 × 299 × 150 mm) with two different sizes (15 and 30 mm in diameter) in two different positions (30 and 80 mm from the surface). Four inexperienced and four experienced physicians attempted punctures on these four simulated masses twice using 2D and 4D ultrasound guidance in a total of 128 punctures (eight operators, two techniques, and eight punctures per session). The error distance of the puncture was defined as the perpendicular distance from the center of a target mass (sphere) to the line of the puncture needle in the coronal plane of the target center, which was measured manually on the basis of the 3D volume data on off-line analysis.
RESULTS: On each tumor model, the average error distance with 4D ultrasound was significantly smaller than that with 2D ultrasound, except for one tumor model that was 15 mm in diameter and 30 mm in depth. The average error distances for the experienced group tended to be smaller than those for the inexperienced group, with both techniques and on each tumor model, and there was a statistically significant difference between the two groups on one tumor model (30 mm in diameter and 80 mm in depth) on 4D ultrasound (p < 0.05).
CONCLUSION: Four-dimensional ultrasound-guided puncture for liver tumors can markedly improve puncture accuracy for both experienced and inexperienced physicians compared with conventional 2D ultrasound guidance.