A method of making an ultrasonic catheter, disposing an ultrasound member in the main lumen of a flexible catheter body； providing an intermediate member and a tip, wherein at least a tip maximum-diameter portion is disposed in the intermediate member, wherein an intermediate-member outer diameter substantially matches a main lumen inner diameter, and wherein a tip distal cross-section has a tip distal cross-section area less than a tip proximal cross-section area of a tip proximal cross-section； and attaching the intermediate member to the catheter body and to the tip, wherein at least one of the tip and the intermediate member is configured to prevent separation of the tip of the ultrasound member from the catheter body.
