Optimized intravascular ultrasound probe catherers

The present invention provides intravascular diagnostic catheters that include a centrally disposed intravascular ultrasound (IVUS) imaging element and radially extendable, wall-contacting optical probe arms of a novel design for improving the IVUS imaging aspect of combined IVUS and optical analysis. In one embodiment, the dimension of the portion of the probe arm(s) that is in the field-of-view of the IVUS imaging element is minimized. In another embodiment, thin tethers are disposed in the field-of-view of the IVUS imaging element, rather than a continuation of the probe arm itself into the IVUS field. In still another embodiment, the probe arms at least substantially do not impinge on the field-of-view of the IVUS imaging element and tethers that are not within the field-of-view of the IVUS imaging element are used to control the probe arms, thereby providing a clear field-of-view for the IVUS imaging element.