Figure 3 from VCAM-1–targeted MRI Improves Detection of the Tumor-brain Interface

Anti-VCAM-1–targeted MRI reveals tumor margins in MDA231Br-GFP brain metastases. Pre-/post-gadolinium T1-weighted images from rat brains either with intrastriatal MDA231Br-GFP tumors (A and B) or injected intrastriatally with PBS (C). Matched pre-/post-MPIO T2*-weighted images from the same anatomic locations and same animals as for A and B, injected intravenously with either VCAM-MPIO contrast (D), or IgG-MPIO (E). F, Pre-/post-MPIO T2*-weighted images from a rat injected intrastriatally with PBS and VCAM-MPIO intravenously. Dashed red line encircles visible hypointense regions. G,T2-weighted images showing areas of tumor-associated hyperintensity (white arrowhead). H, Representative MR images of MDA231Br-GFP tumor-bearing rat brain with hypointensities (green pixels) from T2*-weighted imaging overlaid on contrast-enhanced T1-weighted imaging. Note the green pixels extend into regions of the striatum with no associated T2 hyperintensity (red arrowheads). Scale bar = 2 mm. I, Graph showing volumes of hypointensities post-T2*-weighted MRI; data shown as mean ± SD, blue = ipsilateral striatum, yellow = contralateral striatum. **, P < 0.01; ***, P < 0.001; post hoc Tukey test (n = 8 MDA231Br-GFP groups and n = 3 PBS group). J, Representative T2*-weighted MR image slice of a MDA231Br-GFP tumor, with white box highlighting the invasive tumor margin confirmed histologically (K); scale bar = 500 μm. L, Corresponding high-power magnification of highlighted regions of interest (black and red boxes) from stained adjacent sections, demonstrating bound VCAM-MPIO beads (black arrowhead/brown spheres) in a VCAM-1–positive vessel lumen (brown); scale bar = 10 μm.