Value of three-dimensional US for optimizing guidance for ablating focal liver tumors

PURPOSE: To determine if three-dimensional ultrasound (3D US), by nature of its ability to simultaneously evaluate structures in three orthogonal plan es and to study relationships of devices to tumor(s) and surrounding anatom ic structures from any desired orientation, adds significant additional inf ormation to real-time 2D US used for placement of devices for ablation of f ocal liver tumors. MATERIALS AND METHODS: Sixteen patients underwent focal ablation of 23 live r tumors during two intraoperative cryoablation (CA) procedures, three intr aoperative radiofrequency ablation (RFA) procedures, 11 percutaneous ethano l injections (PEI) procedures, and six percutaneous RFA procedures. After s atisfactory placement of the ablative device(s) with 2D US guidance, 3D US was used to reevaluate adequacy to device position. Information added by 3D US and resultant alterations in device deployment were tabulated. RESULTS: 3D US added information in 20 of 22 (91%) procedures and caused th e operator to readjust the number or position of ablative devices in 10 of 22 (45%) of procedures. Specifically, 3D US improved visualization and conf ident localization of devices in 13 of 22 (59%) procedures, detected unacce ptable device placement in 10 of 22 (45%), and determined that 2D US had in correctly predicted device orientation to a tumor in three of 22 (14%). CONCLUSIONS: Compared to conventional 2D US, 3D US provides additional rela tionship information for improved placement and optimal distribution of abl ative agents for treatment of focal liver malignancy.