An IVUS catheter is advantageously provided with a particular radio-opaque pattern enabling detection of catheter rotation angle with respect to an X-ray imaging source for co-registering IVUS image data with angiographic X-ray or CT image data, for example. An ultrasound catheter system supports orientation and display of intra-vascular ultrasound imaging data. The system comprises an ultrasound catheter for acquiring ultrasound images comprising a body having a pattern of radio-opaque material on the external surface of the catheter body. The pattern varies with angular rotation of the catheter and indicates an angle of rotation of a predetermined reference orientation of the catheter relative to an X-ray radiation source, so that an X-ray image of the catheter body indicates the pattern and the pattern is analyzable by an image data processor to determine the angle of rotation.
