A method for radiographic imaging of a body cavity includes imaging the body cavity using computerized tomography (CT) to form a CT image, registering a tracking system with the CT image, inserting into the body cavity a guidewire, including a position sensor, operating in the tracking system, attached to a distal end of the guidewire, in response to signals from the position sensor acquired by the tracking system, displaying a position of the distal end of the guidewire on the CT image. The method further includes assigning voxels within a predefined imaging volume relative to the distal end and having a radiodensity less than a predetermined threshold to have a uniform radiodensity of a predefined default value, incorporating the voxels with the assigned predefined default value into the CT image so as to form an updated CT image, and displaying the updated CT image.