Figure 1.

Imaging protocol for evaluation of rabbit VX2 tumors (circled) and representative images at baseline and 2 weeks post yttrium-90 radioembolization. Rabbits were maintained on 98% O2 with 2% isoflurane gas anesthesia at 1L/min. Anatomical T2-weighted imaging was used to identify intrahepatic VX2 tumor growth as 1–2 cm heterogeneously hyperintense lesions. R2* mapping with complete tumor coverage was performed using a 4-echo respiratory-gated GRE sequence during oxygen breathing and gas anesthesia was subsequently switched to room air (20% O2, 78% N2, 2% isoflurane). Pre-contrast T1-weighted GRE imaging was acquired and at least 10 minutes were allowed prior to steady-state R2* mapping during room air breathing. Contrast-enhanced imaging after administration of dimeglumine gadopentate (Magnevist) allowed evaluation of tumor enhancement.