Contrast-enhanced MRI with gadodiamide injection in rabbit carcinoma models

This study was designed to demonstrate the broad utility of contrast-enhanced magnetic resonance imaging (MRI) for diagnosis of carcinoma. Twenty-six New Zealand White rabbits of either sex (1.7-3.4 kg) were used for the investigation. VX2 carcinoma (squamous cell carcinoma) was implanted in either the brain, lung, ovary, bone or muscle of rabbits. Contrast agent, Gadodiamide Injection, was administered intravenously at a dose of 0.1 mmol/kg. MR images were obtained by a 1.5 T, or a 2.0 T magnetic field strength super-conductive MRI unit. The intensity of the signal for the carcinoma was increased after administration of contrast agent, and the detectability or diagnostic information of post-contrast images was superior to that of pre-contrast images in all models. In addition, no significant side effects were observed during the MRI examination. After diagnosis using MRI, morphological damage in each model was assessed by gross and histopathological examinations. In contrast-enhanced MRI, though there were variations between the models employed, contrast effects in brain and muscle carcinoma models were generally related to differences in capillary permeability, while imaging in lung, ovary and bone carcinoma models was dependent on differences in blood flow rate and the size of interstitial spaces. Overall, our results demonstrate that contrast-enhanced MRI is a useful and safe method for diagnosing tumors.