Assessment of normal, inflammatory, and tumor-bearing lymph nodes with contrast-enhanced interstitial magnetic resonance lymphography: preliminary results in rabbits.
OBJECTIVE
To assess different gadolinium (Gd)-based contrast agents for interstitial magnetic resonance (MR) lymphography in normal, inflammatory, and tumor-bearing lymph nodes in rabbits.


METHODS
Three paramagnetic contrast agents were assessed: a standard extracellular 0.5 M Gd-chelate, gadoterate meglumine (Gd-DOTA), and two macromolecular agents, P792 and P760 (all Guerbet, Aulnay-sous-Bois, France). A volume of 0.5 mL of each agent were injected subcutaneously into the dorsal footpads of six rabbits (three groups, 18 rabbits). Imaging was performed prior to as well as two weeks following induction of either reactive (complete Freund adjuvant) or tumorous (VX2 tumor) lymph nodes. T1-weighted three-dimensional gradient-echo and maximum intensity projection (MIP) images were obtained up to 120 minutes as well as 24 hours after administration of the different compounds. Signal-to-noise ratios (SNRs) of enhancing lymph nodes were calculated. The different compounds were compared regarding nodal enhancement over time, depiction of regional nodes, and lymphatic vessels. Furthermore, enhancement patterns were compared between normal, inflammatory, and metastasized nodes.


RESULTS
Inguinal and iliac lymph nodes and lymph vessels revealed enhancement following interstitial injection of all evaluated compounds. For all agents, inflammatory lymph nodes revealed no significantly different SNRs compared to normal nodes (P > 0.2), whereas tumorous nodes showed signal voids and significantly lower SNRs (P < 0.05). Compared to P760 and P792, depiction of tumor-bearing nodes with Gd-DOTA was less reliable.


CONCLUSIONS
Interstitial MR lymphography with P760 and P792 allows differentiation of tumor-bearing lymph nodes from reactive inflammatory and normal nodes based on a contrast uptake pattern assessed qualitatively as well as quantitatively.
Herborn
Christoph U
CU
Department of Diagnostic and Interventional Radiology, University Hospital Essen, Germany. christoph.herborn@uni-essen.de
Vogt
Florian M
FM
Lauenstein
Thomas C
TC
Goyen
Mathias
M
Dirsch
Olaf
O
Corot
Claire
C
Debatin
Jörg F
JF
Ruehm
Stefan G
SG
D000818:Animals; D003287:Contrast Media; D006571:Heterocyclic Compounds; D007089:Image Enhancement; D008198:Lymph Nodes / Q000033:anatomy & histology* / Q000473:pathology; D008199:Lymphadenitis / Q000175:diagnosis* / Q000473:pathology; D008207:Lymphatic Metastasis / Q000175:diagnosis* / Q000473:pathology; D046911:Macromolecular Substances; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D009942:Organometallic Compounds; D011817:Rabbits
D003287:Contrast Media; D006571:Heterocyclic Compounds; D046911:Macromolecular Substances; D009942:Organometallic Compounds; C050823:gadolinium 1,4,7,10-tetraazacyclododecane-N,N',N'',N'''-tetraacetate