A method is disclosed to accurately determine spatial parameters (for example, the diameter, cross-sectional area and segment length) of bodily structures like human arteries. This is done by determining the three-dimensional position of these structures from two monoplane X-ray angiographic images obtained at arbitrary but different orientations with respect to the structure of interest. The images may be taken at a different moment, so a monoplane X-ray system can be used. Movement of the structure of interest in between the two X-ray exposures is allowed. The three-dimensional information obtained this way is subsequently used to correct the measurements of above mentioned parameters for commonly encountered error sources.