The present study was undertaken to measure the gain observed in the liver-to-
tumor contrast of perioperative images when using
mangafodipir trisodium, a liver-specific
contrast agent, during percutaneous
cryosurgery of the liver performed under the guidance of magnetic resonance images. Retrospective quantitative analyses of MR images were performed on eleven patients having a total of 30 liver
tumors treated by MR-guided percutaneous
cryosurgery. An initial group of four patients were treated with no
contrast agent, and was compared with a second group of 7 patients who received an
intravenous injection of 5 microM/kg of
mangafodipir for their
cryosurgery. The percutaneous
cryosurgery was monitored under the near-real-time-imaging mode of a 0.5T open-configuration MRI system using a T(1)-weighted Gradient-recalled echo pulse sequence. A significant improvement in the liver-to-
tumor contrast-to-noise ratio was observed with
mangafodipir (p < 0.05, paired t test) in 0.5T preoperative images. Along with the stability of the
mangafodipir contrast enhancement during the entire cryosurgical procedure, the resulting gain in contrast allowed for better visualizing the presence of residual untreated
tumor margins at the periphery of the
cryosurgery iceball directly from perioperative images acquired with patients under
narcosis. Consequently, it not only became easier for the interventionalist to determine the need for an additional cryoprobe to increase the size of the iceball during the procedure, but also to decide on the appropriate end point of the
cryosurgery.