Macromolecular intravenous contrast agent for MR lymphography: characterization and efficacy studies.
OBJECTIVE
To determine the pharmacokinetic and magnetic resonance (MR) imaging properties of diethylenetriaminepentaacetic acid (DTPA) conjugated with a polyglucose-associated macrocomplex (PGM), which accumulates in lymph nodes.


METHODS
In 124 normal and 20 tumor-bearing rats, Gd-DTPA PGM was administered intravenously in doses of 2, 10, 20 mumol gadolinium per kilogram of tissue.


RESULTS
Mean blood half-life was 2 hours. Maximum accumulation in peripheral (33.0% injected dose [ID]/g +/- 16.2 [standard deviation]) and central lymph nodes (63.2% ID/g +/- 16.5) was observed within 24 hours after administration. The optimum dose range was 10-20 mumol Gd/kg in rats. At 24 hours after administration of 20 mumol Gd/kg, the signal-to-noise ratio increased 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.


CONCLUSIONS
When labeled with Gd-DTPA, the PGM-based graft copolymer significantly increases signal intensity at MR imaging of normal but not metastatic lymph nodes without causing distortion artifacts.
Harika
L
L
Department of Radiology, Massachusetts General Hospital, Boston, USA.
Weissleder
R
R
Poss
K
K
Papisov
M I
MI
D000818:Animals; D003287:Contrast Media; D005260:Female; D019786:Gadolinium DTPA; D006168:Guinea Pigs; D006207:Half-Life; D007205:Indium Radioisotopes; D007275:Injections, Intravenous; D008198:Lymph Nodes / Q000473:pathology*; D008207:Lymphatic Metastasis / Q000175:diagnosis; D046911:Macromolecular Substances; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008325:Mammary Neoplasms, Experimental / Q000473:pathology; D051379:Mice; D008807:Mice, Inbred BALB C; D009942:Organometallic Compounds / Q000493:pharmacokinetics; D004369:Pentetic Acid / Q000031:analogs & derivatives* / Q000493:pharmacokinetics; D051381:Rats; D011916:Rats, Inbred F344; D017207:Rats, Sprague-Dawley; D014018:Tissue Distribution
D003287:Contrast Media; D007205:Indium Radioisotopes; D046911:Macromolecular Substances; D009942:Organometallic Compounds; D004369:Pentetic Acid; D019786:Gadolinium DTPA