Catheter device for insertion into a vessel of a human or animal body, comprising a guide catheter and, incorporated in same, an OCT catheter with an OCT imaging device, the guide catheter having a balloon inflatable via a supply line for occluding the vessel, as well as a device for delivering a liquid or gas to the vascular region to be recorded by means of the OCT imaging device, in particular the vascular region located distally to the balloon, wherein there is provided on the guide catheter a second inflatable balloon spaced apart from the first balloon for occluding the vessel, wherein the section of the guide catheter between the two balloons is transparent, at least in sections, to the OCT radiation emittable by the OCT imaging device disposed inside the guide catheter.