MACROMOLECULAR INTRAVENOUS CONTRAST AGENT FOR MR LYMPHOGRAPHY - CHARACTERIZATION AND EFFICACY STUDIES

PURPOSE: To determine the pharmacokinetic and magnetic resonance (MR) imaging properties of diethylenetriaminepentaacetic acid (DTPA) conjug ated with a polyglucose-associated macrocomplex (PGM), which accumulat es in lymph nodes. MATERIALS AND METHODS: In 124 normal and 20 tumor-b earing rats, Gd-DTPA PGM was administered intravenously in doses of 2, 10, 20 mu mol gadolinium per kilogram of tissue. RESULTS: Mean blood half-life was 2 hours. Maximum accumulation in peripheral (33.0% injec ted dose [ID]/ g +/- 16.2 [standard deviation]) and central lymph node s (63.2% ID/g +/- 16.5) was observed within 24 hours after administrat ion. The optimum dose range was 10-20 mu mol Gd/kg in rats. At 24 hour s after administration of 20 mu mol Gd/kg, the signal-to-noise ratio i ncreased from 30.9 +/- 0.4 to 83.2 +/- 5.2 in normal lymph nodes (P < .001 ). Differentiation between normal and metastatic lymph nodes was improved. CONCLUSION When labeled with Gd-DTPA, the PGM-based graft co polymer significantly increases signal intensity at MR imaging of norm al but not metastatic lymph nodes without causing distortion artifacts .