Abstract No. 534 Percutaneous Abdominal and Pelvic Biopsies: Comparison of an Electromagnetic Navigation System and CT Fluoroscopy

To compare electromagnetic navigation (EMN) with CT fluoroscopy (CTF) for guiding percutaneous biopsies in the abdomen and pelvis. Retrospective matched-cohort design comparing biopsies of retroperitoneal lymph nodes, renal, adrenal, pelvic, and hepatic masses performed with either EMN (consecutive cases, n = 50) or CTF in intermittent mode (n = 100). Cases were matched 1:2 (EMN:CTF) for target organ and lesion size (± 10 mm). Technical success, diagnostic yield, complication rate, angle of approach to the target, radiation dose to the operator and patient, and procedure time were compared. The population was well-matched (median age, 65 vs. 65 years, target size 2.0 vs. 2.1 cm, distance-to-target 11.4 vs. 10.7 cm, median cores 3 vs. 3, P > 0.05, EMN vs. CTF respectively). Comparing EMN and CTF, technical success (98 vs. 100%), diagnostic yield (98 vs. 95%), complications (2 vs. 5%), false negatives (0 vs. 1%), and median procedure time (33 vs. 31 min) were not statistically different (P > 0.05). Mean radiation dose to the operator was less with EMN than CTF (0.04 vs. 1.2 μGy, P < 0.001), but patient dose was larger (30.1 mSv vs. 9.6 mSv, P < 0.001) due to the greater number of helical scans during EMN guidance (mean, 3.9 vs. 2.1, P< 0.001). CTF was performed with a mean of 29.7 tap scans per case. Three (3%) CTF cases were performed with gantry tilt, while the mean angle out of plane for EMN cases was 13.4 degrees. Percutaneous biopsies guided by EMN and CTF were closely matched for technical success, diagnostic yield, procedure time, and complications in a matched cohort of patients. EMN cases were more likely to be performed outside of the axial plane. Radiation dose to the operator was higher with CTF, and patient radiation dose was higher with EMN. Further study with a wider array of procedures and anatomic locations appears warranted.