Interstitial T1-weighted MR lymphography: Lipophilic perfluorinated gadolinium chelates in pigs

PURPOSE: To investigate the enhancement of the regional lymph nodes, lympha tic vessels, and thoracic duct after interstitial administration of lymphot ropic perfluorinated gadolinium chelates at magnetic resonance (MR) imaging . MATERIALS AND METHODS: Two perfluorinated gadolinium chelates, gadofluorami de and gadofluorine 8, were injected subcutaneously into the hind legs of 1 0 pigs, respectively. Both contrast media were studied at doses of 10 and 2 5 (mu mol per kilogram of body weight. T1-weighted three-dimensional gradie nt-echo and maximum intensity projection images were obtained at 1.5 T betw een 1 and 210 minutes and 24 hours after injection. The contrast agents wer e qualitatively compared regarding enhancement and depiction of the regiona l lymph nodes, lymphatic vessels, and thoracic duct. RESULTS: The inguinal and iliac lymph nodes and lymphatic vasculature enhan ced substantially within 10 minutes after subcutaneous administration of bo th lymphotropic contrast agents. Gadofluorine 8 showed a lymphographic effe ct superior to that of gadofluoramide. The paraaortic lymph nodes and thora cic duct were best visualized 10-50 minutes after injection of 25 mu mol/kg of gadofluorine 8. Lymphatic system enhancement diminished after 2 hours, and the liver and bowel tract enhanced within 24 hours. CONCLUSION: Interstitial administration of perfluorinated gadolinium chelat es offers great potential for T1-weighted MR lymphography with positive enh ancement of the lymph nodes and lymphatic vasculature.