摘要 |
Apparatus and methods are described including generating a road map of a blood vessel in a portion of a subject's body. A given feature that is within the portion of the subject's body is identified in the road map, the given feature being visible even in images of the portion the generation of which does not include use of a contrast agent. A tool is inserted into the blood vessel, and a current location of a portion of the tool is determined with respect to the given feature, by imaging the tool and the feature. In response to the determined current location, a current position of the tool within the road map is determined. In response to determining the current position of the tool within the road map, the current position of the tool with respect to the road map is displayed. Other embodiments are also described. |