1. A system for determining a dimension of an anatomical structure using an appropriate set of 2-D slice images obtained by scanning said anatomical structure, said system comprising: means for assembling said set of scanned 2-D slice images into a 3-D database; means for extracting an anatomical feature from the information contained in said 3-D database; means for specifying a measurement to be made based on said extracted anatomical feature; and means for calculating the measurement so specified.