Interstitial MR and CT lymphography with Gd-dTPA-co-alpha, omega-diaminoPEG(1450) and Gd-dTPA-co-1,6-diaminohexane polymers: preliminary experience.
OBJECTIVE
The authors assessed the efficacy of two gadolinium-based polymers used as lymphotrophic contrast media for computed tomography (CT) and magnetic resonance (MR) imaging.


METHODS
Two gadolinium-based polymers, gadolinium diethylenetriaminepentaacetic acid (DTPA)-co-1,6-diaminohexane (NC 22181) and Gd-DTPA-co-alpha, omega-diamino-polyethylene glycol(1450) (NC-66368), were formulated at a concentration of 80 mmol/L gadolinium. Doses of 0.1, 0.25, 1.0, or 2.0 mL per paw were administered subcutaneously into the hindpaws of normal rabbits. Spin-echo T1-weighted MR imaging (1.5 T) of rabbit popliteal and iliac nodes was performed before and immediately, 10 minutes, 2-3 hours, and 24 hours after injection. CT was performed 2-3 hours after injection of the high doses only.


RESULTS
MR imaging revealed prompt enhancement of the popliteal nodes with both polymers at doses of 0.25 mL and above. For doses of 1.0 mL or less per paw, nodal percentage enhancement was maximal at 2 hours and then declined at 24 hours. At the highest doses, however, a reservoir of subcutaneous contrast material remained at the injection site and resulted in peak enhancement at 24 hours. At CT, popliteal node enhancement was faintly visible 2-3 hours after the administration of NC 22181. At lower doses, no enhancement was appreciable at CT.


CONCLUSIONS
At 80 mmol/L formulations, the two gadolinium-based polymers provide excellent popliteal nodal enhancement on MR images. In addition, high doses of one polymer (NC 22181) were sufficiently concentrated in popliteal nodes to be visible on CT scans. Thus, this agent may be useful for both CT and MR lymphography.
Desser
T S
TS
Department of Radiology, VA Palo Alto Health Care System, 3801 Miranda Ave, Palo Alto, CA 94304, USA.
Rubin
D L
DL
Muller
H
H
McIntire
G L
GL
Bacon
E R
ER
Hollister
K R
KR
D000818:Animals; D003287:Contrast Media / Q000737:chemistry; D003959:Diamines; D019786:Gadolinium DTPA / Q000031:analogs & derivatives*; D006614:Hindlimb; D008208:Lymphatic System / Q000033:anatomy & histology*; D008220:Lymphography / Q000379:methods*; D008279:Magnetic Resonance Imaging; D011092:Polyethylene Glycols; D011817:Rabbits; D014057:Tomography, X-Ray Computed
D003287:Contrast Media; D003959:Diamines; C088921:gadolinium diethylenetriaminepentaacetic acid polyethylene glycol; C443800:poly-(Gd-DTPA)-co-(1,6-diaminohexane); D011092:Polyethylene Glycols; D019786:Gadolinium DTPA