Lymphatic drainage imaging of breast cancer in mice by micro-magnetic resonance lymphangiography using a nano-size paramagnetic contrast agent.
BACKGROUND
The presence of lymph node metastases is an important factor in breast cancer patient prognosis. Therefore, the precise identification of sentinel lymph nodes in these patients is critical. Improving current magnetic resonance (MR) imaging methods using a newly synthesized nano-size paramagnetic molecule, G6, as a contrast agent, provides an attractive means toward attaining this goal.


METHODS
A four-dimensional method of micro-MR lymphangiography using G6 (9 nm/240 kd) was developed to visualize the lymphatic ducts and lymph nodes draining mouse mammary tumors over time. The ability of micro-MR lymphangiography with the G6 contrast agent to visualize lymphatic drainage of normal mouse mammary tissue was compared with that of the conventional MR contrast agent, Gd-[DTPA]-dimeglumine (<1 kd). Lymphatic drainage in spontaneous and xenografted breast tumor models was visualized using the G6 contrast agent.


RESULTS
Draining lymphatic ducts and lymph nodes were clearly visualized in the mammary tissue of normal mice and in spontaneous and xenografted breast tumor models after a direct mammary gland or peritumoral injection of G6. Gd-[DTPA]-dime-glumine, by contrast, failed to depict lymphatic flow from the mammary tissue in normal mice using the same method. Micro-MR lymphangiography using the G6 contrast agent revealed the absence of filling in the metastatic foci of affected lymph nodes.


CONCLUSIONS
The superior temporal and spatial resolution of micro-MR lymphangiography using the contrast agent G6 may facilitate the study of tumor lymphatic drainage and lymphatic metastasis in both experimental animals and clinical medicine. In addition, this may be a powerful new method for sentinel lymph node localization in human breast cancer.
Kobayashi
Hisataka
H
Metabolism Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892-1374, USA. kobayash@mail.nih.gov
Kawamoto
Satomi
S
Sakai
Yoshio
Y
Choyke
Peter L
PL
Star
Robert A
RA
Brechbiel
Martin W
MW
Sato
Noriko
N
Tagaya
Yutaka
Y
Morris
John C
JC
Waldmann
Thomas A
TA
D000818:Animals; D003287:Contrast Media; D005260:Female; D019786:Gadolinium DTPA; D021621:Imaging, Three-Dimensional; D008198:Lymph Nodes / Q000000981:diagnostic imaging / Q000473:pathology*; D008207:Lymphatic Metastasis; D008220:Lymphography / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000295:instrumentation; D008325:Mammary Neoplasms, Experimental / Q000000981:diagnostic imaging / Q000473:pathology*; D051379:Mice; D008807:Mice, Inbred BALB C; D036103:Nanotechnology; D014183:Transplantation, Heterologous
D003287:Contrast Media; D019786:Gadolinium DTPA