A balloon catheter which allows for faster preparation and effective purging of air. The catheter includes an elongated, flexible catheter having a tubular outer member and a tubular inner member each having a respective lumen. The inner member is at least partially disposed in the outer member lumen such that an outer surface of the inner member and an inner surface of the outer member together define an annular inflation lumen. The outer member has micropores or micro-holes configured such that when a contrast agent is injected into the inflation lumen, the micropores or micro-holes allow air to pass therethrough and thereafter become clogged by the contrast agent. The catheter also has a balloon member having its ends secured to and circumferentially around the outer member such that an inner surface of the balloon member and the outer surface of the outer member define an inflatable balloon interior.