methods for infusing the interior of a blood vessel are practiced with a catheter having an infusion lumen , a plurality of elution holes , a movable barrier between the infusion lumen and the elution holes , an occlusion balloon , and an inflation lumen . the methods include sealing the elution holes with the movable barrier , inserting the catheter into the blood vessel , inflating the occlusion balloon , unsealing the elution holes , injecting the therapeutic agent through the infusion lumen , deflating the occlusion balloon and removing the catheter from the blood vessel . the methods also preferably include testing the occlusion balloon and priming the infusion lumen prior to sealing the infusion ports and inserting the catheter into the blood vessel .