Increased volume of popliteal lymph nodes in tumor necrosis factor-transgenic (TNF-Tg) mice. (a) A representative post-contrast magnetic resonance imaging slice from a TNF-Tg and wild-type (WT) mouse (5 months old). (b) Using a semi-automated segmentation procedure in Amira software, the synovial (yellow) and lymph node (red) volumes were quantified and visualized in TNF-Tg and WT mice. *p < 0.05 versus WT samples (n = 5). (c) Representative hematoxylin-and-eosin sections (× 4) demonstrate differences in lymph node size between TNF-Tg and WT animals.