Early MR lymphography with gadofluorine M in rabbits.
OBJECTIVE
To investigate the dose and time dependency of gadofluorine M for lymph node imaging and the detection of lymph node metastases in an animal model and to compare gadofluorine M with Gadomer (both, Schering, Berlin, Germany) for lymph node enhancement.


METHODS
Enhancement of popliteal and iliac lymph nodes was studied in VX2 tumor-bearing rabbits before injection and at 5-120 minutes and 24 hours after intravenous bolus injection of 0.025, 0.05, and 0.1 mmol gadolinium per kilogram of body weight gadofluorine M (six rabbits) or 0.5 mmol/kg Gadomer (eight rabbits). Effects of treatment and time point at enhancement were evaluated with repeated measures analysis of variance. Means were separated with all-pairs comparison with Tukey-Kramer adjustment. After 1.5-T magnetic resonance (MR) imaging, lymph nodes were removed, and prepared sections were stained with hematoxylin-eosin for microscopic examination.


RESULTS
MR images in VX2 tumor-bearing rabbits revealed rapid and strong signal intensity increase in the functional lymph node tissue by 15 minutes after intravenous injection of gadofluorine M. Maximum enhancement of 165%-309% was observed 60-90 minutes after injection (enhancement with 0.05 and 0.1 mmol/kg significantly different from that with 0.025 mmol/kg, P < or =.05). Metastatic tissue showed only slight enhancement at early time points, resulting in high-contrast differentiation between functional and metastatic tissue. Intravenous injection of the blood-pool agent Gadomer induced only short and inhomogeneous lymph node enhancement (enhancement significantly lower [P < or =.05] than that with gadofluorine M).


CONCLUSIONS
Findings in the study showed that gadofluorine M produces rapid lymph node accumulation. Diagnosis of lymph node metastases was shown with intravenous injection of gadofluorine M with a minimum effective diagnostic dose of 0.025 mmol/kg.
Misselwitz
Bernd
B
Corporate Research Business Area Diagnostics and Radiopharmaceuticals, MRI and X-Ray Research, Schering, Müllerstrasse 178, D-13342 Berlin, Germany. bernd.misselwitz@schering.de
Platzek
Johannes
J
Weinmann
Hanns-Joachim
HJ
D000818:Animals; D003287:Contrast Media / Q000008:administration & dosage; D005260:Female; D005682:Gadolinium / Q000008:administration & dosage; D006119:Groin; D006614:Hindlimb; D007275:Injections, Intravenous; D008198:Lymph Nodes / Q000473:pathology*; D008207:Lymphatic Metastasis / Q000175:diagnosis*; D008279:Magnetic Resonance Imaging; D009374:Neoplasms, Experimental / Q000175:diagnosis* / Q000473:pathology; D009942:Organometallic Compounds / Q000008:administration & dosage; D011817:Rabbits
D003287:Contrast Media; D009942:Organometallic Compounds; C477144:gadofluorine; C402765:gadomer 17; D005682:Gadolinium