Differentiation between Reactive and Metastatic Lymph Nodes with Diffusion-weighted and SPIO Enhanced MRI

Thursday, October 11, 2012 — Poster Session III
10:00 a.m. – Noon	Natcher Conference Center, Building 45	NIBIB	IMAG-32

Authors

• Fan Zhang
• Lei Zhu
• Xingl Huang
• Guang Lu
• Gang Niu
• Xiaoy Chen

Abstract

Objective: We aim to distinguish tumor metastatic lymph nodes and reactive lymph nodes with diffusion weighted and superparamagnetic iron oxide enhanced magnetic resonance imaging (MRI). Materials and methods: Ipsilateral popliteal lymph node metastases and lymphadenitis were developed by hock injection of either luciferase-expressing murine breast cancer 4T1 cells and Complete Freund Adjuvant (CFA) in male Balb/C mice, respectively. At different time points after inoculation, bioluminescence imaging, T2-weighted, diffusion weighted and iron oxide enhanced MRI were performed using an IVIS system and a 7T MRI scanner. Results: Size enlargement was observed in both tumor draining lymph nodes (TLNs) and reactive lymph nodes (RLNs). At day 28, TLNs showed strong BLI signal and much bigger size than RLNs. TLNs also showed heterogeneous ADC map with significant higher average ADC value over that of the RLNs (p < 0.05). On supermagnetic iron oxide enhanced MRI, both TLNs and RLNs showed distinct T2 signal reduction at day 21 after inoculation. At day 28, TLNs demonstrated partial uptake of the iron oxide particles, which was confirmed by Prussian blue staining. Conclusion: Both diffusion-weighted and SPIO enhanced MRI can distinguish tumor metastatic lymph nodes from reactive lymph nodes.

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