Fibrosarcoma-bearing mouse before and after injection of tTF-NGR. (A) Photograph of a fibrosarcoma-bearing mouse before and after injection of tTF-NGR (1.5 mg/kg body weight). The tumor was blackened after tTF-NGR injection, indicating blood pooling due to vascular disruption. (B) Measurement of the vascular volume fraction (VVF) by contrast enhanced MRI. By measuring the VVF, a significantly reduced blood volume in the tTF-NGR–treated mouse was detected compared with saline controls, whereas non-targeted tTF had only minor effects. The change in the transverse relaxation rate (ΔR2*), as displayed in the color coded overlay, was significantly reduced after treatment with tTF-NGR. (C) H&E staining of the tTF-NGR–treated tumor showed thrombosis in blood vessels, blood pooling, and vascular disruption. (D) The tumor in the saline-treated mouse exhibited no thrombosis.