Kinetic evaluation of an IV bolus of MR contrast media

Currently, it is assumed that the pharmacokinetic properties of the first m inutes of an I.V. MR contrast media bolus are similar to those of an I.V. i odinated contrast media bolus used in CT. Correct timing of an MRA examinat ion is crucial for obtaining sufficient arterial contrast. This study sough t to evaluate the temporal change of arterial signal intensity within 150 s after I.V. bolus injection of Gd-DTPA. Thirty consecutive patients (14 wom en/16 men; mean age: 51 +/- 11 years) were prospectively examined with a 1. 0 Tesla clinical scanner. A single axial slice was acquired in 1.25 sec wit h manufacturer provided gradient echo sequence through the aorta at the lev el of the renal arteries. Investigation was started simultaneously to the a pplication of contrast media (0.1 mmol/kg bodyweight Gd-DTPA at three diffe rent rates 2 mL/sec, 3 mL/sec and 4 mL/sec) and repeated for 2.5 min. An ad ditional echo Doppler examination excluded patients with any cardiac disord ers. Maximum signal (1300% increase compared to the basic value) in the aor ta was achieved 20 +/- 6 sec after start of bolus injection. Then a plateau phase was maintained for the remaining investigation time (2.5 min). No si gnificant difference was shown for different injection rates. After a bolus injection of Gd-DTPA the arterial contrast remains on a high level for at least 2 min. However, correct timing of the bolus arrival is still crucial to discriminate arteries and veins. An injection rate between 2 mL/sec and 4 mL/sec has no influence on early contrast media dynamics. (C) 2001 Elsevi er Science Inc. All rights reserved.