Sequential changes of contrast enhancement of cerebral tumors following Gd-DTPA administration

Nine patients with cerebral tumors underwent magnetic resonance (MR) imaging after iv injection of 0.05, 0.10, or 0.15 mmol/kg of Gd-DTPA. Satisfactory enhancement was obtained with any amount of the contrast agent. Sequential MR imaging for 3 hr revealed that the enhancement effect was the maximum 60 min after injection, and thereafter decreased gradually. This was almost the same as that obtained for water-soluble iodinated contrast agents in X-ray CT scanning. T1-weighted sequence (SE 600/45) with Gd-DTPA produced the most sensitive differential enhancement of tumor from its surrounding edema. In view of the great enhancement with a small amount and lack of adverse effects, the use of Gd-DTPA would be of value in improving the sensitivity of MR imaging, thereby allowing the differentiation of isomagnetic tissues, the functional evaluation of target organs and the measurement of tissue perfusion. (Namekawa, K.)