Initial Computed Tomography Imaging Experience Using a New Macromolecular Iodinated Contrast Medium in Experimental Breast Cancer

OBJECTIVE:The objective of this study was to evaluate computed tomography (CT) enhancement characteristics for a new iodinated macromolecular contrast medium (MMCM), PEG12000-Gen4-triiodo, for angiographic effect and for assessment of abnormal vascular permeability in cancer. MATERIALS AND METHODS:Time persistence of angiographic effect was evaluated on rat CT images acquired over 30 minutes using the iodinated polyethyleneglycol- (PEG) based macromolecule. Dynamic CT imaging after PEG12000-Gen4-triiodo-enhancement in tumor-bearing rats was used to quantitatively estimate plasma volume and microvascular transendothelial permeability for both tumor and normal soft tissue. Using identical doses of iodine, 300 mg iodine/kg, blood curves for this MMCM and iohexol were compared. RESULTS:Serial whole-body CT angiograms using PEG12000-Gen4-triiodo showed diagnostic vascular detail through 20 minutes, and the blood enhancement curve was higher and more persistent thanwith small-molecular iohexol. Permeability estimates were significantly (P < 0.02; paired t test) higher in tumors (48.2 ± 18.1 μL/min100 mL) than in muscle (2.5 ± 5.7 μL/min100 mL). CONCLUSIONS:Use of PEG-based MMCM for experimental CT allowed for a persistent angiographic enhancement and for quantitative estimation of tumor microvascular characteristics.