IMAGING OF HUMAN COLON-CANCER XENOGRAFT WITH GADOLINIUM-TEXAPHYRIN

RATIONALE AND OBJECTIVES. The authors explore the efficacy of gadolini um (Gd)-texaphyrin (PCI-0101), an expanded porphyrin, as a contrast me dium for magnetic resonance imaging of nude mice implanted with the hu man colon cancer xenograft LS174T. METHODS. Magnetic resonance images were obtained in six nude mice 7 to 8 days after implantation of LS174 T cells in dorsal subcutaneous tissues, Spin-echo T1-weighted images w ere obtained at baseline and at 5, 15, and 60 minutes after injection of 10 or 20 mu mol/kg of Gd-texaphyrin. Delayed images were obtained a t 24 and 48 hours after injection. Region-of-interest measurements wer e taken of the tumors and of enhancing tumor rims at all time points. Percent enhancement was calculated and compared among the various time points. RESULTS. All tumors were enhanced after injection of Gd-texap hyrin, Heterogeneous patterns of enhancement were seen, with peak enha ncement seen at the 15-minute time point; however, greater enhancement was seen at 48 hours than at 24 hours after Gd-texaphyrin intravenous injection. CONCLUSIONS. Gadolinium-texaphyrin may prove to be a usefu l contrast medium for magnetic resonance imaging of tumors.