MRI CONTRAST ENHANCEMENT BY GD-DTPA-MONOCLONAL ANTIBODY IN 9L GLIOMA RATS

To achieve a tissue-specific enhancement in diagnosis of brain tumor, a magnetic resonance imaging (MRI) study was performed using conjugate of Gd-DTPA and monoclonal antibody (MoAb) against 9L glioma cells. Fi sher 344 strain rats were used for this study. MoAb against 9L glioma cells was conjugated with Gd-DTPA according to the method of Hnatowich et al. (1983) and used for the MRI study. The gadolinium (Gd) concent ration in the Gd-MoAb injected to the rats was 0.01-0.03 mmol/kg. The enhancement effect increased gradually and persisted for 24 hours afte r the injection. This was longer than Gd-DTPA, which showed a peak of enhancement effect within 30 minutes after injection and was washed ou t within 120 min. This result was compatible with scintigraphy studies using I-125 labeled anti 9L monoclonal antibody, in which the accumul ation of the I-125 antibody increased at 24, 48 and 72 hours after the injection. By using tumor-specific contrast agents such as Gd-MoAb, i t may be possible to differentiate among tumor, perifocal edema and ra diation injury.