In vivo magnetic resonance imaging of mice liver tumors using a new gadolinium-based contrast agent

We compared the enhancement effect between a newly synthesized tissue-specific contrast agent, (Gd-DOTA-FPbG), and a commercially available agent, (Gd(DOTA)) � ,i n a murine model of liver tumor using a clinical magnetic resonance imaging scanner. The colon cancer cell lines with and without b-glucuronidase (bG) expression were implanted into the liver of mice. Self-synthesized gadolinium-based magnetic resonance contrast agent, (Gd(DO- TA-FPbG)), was administered to measure enhancement on magnetic resonance images using a commercially available agent, (Gd(DOTA)) � , as control in a clinical 3.0 tesla (T) magnetic resonance scanner. In vivo fluorescence imaging and histopathology of the liver were also per- formed to compare and correlate with the magnetic resonance studies. The in vivo fluores- cence imaging failed to depict a sufficiently intense signal for liver or liver tumor of mice without exposure of the liver following an incision on the abdominal wall. The tissue- specific magnetic resonance agent, (Gd(DOTA-FPbG)), caused significantly stronger enhance- ment in tumors expressing bG (CT26/mbG-eB7) than in tumors not expressing b G( CT26) (p < 0.05). In the magnetic resonance imaging studies using control agent (Gd(DOTA)) � ,t he tumors with and without bG expression depicted no significant difference in enhancement on the T1-weighted images. The (Gd(DOTA-FPbG)) also provided significantly more contrast uptake in the CT26/mbG-eB7 tumor than in the normal liver parenchyma, whereas the