Medical image retrieval by spatial features

A content-based indexing technique is proposed. The image features used are derived from the relative spatial relationships among internal image entities. The similarity measurement is based on causality (probability) which indicates the degree of similarity between a user´s query and images. The index structure contains a set of causality-based similarity trees with nodes connected to an information causal net. For a given (weighted) query, the initial set of similar images is identified via similarity trees and then refined through the information causal net. The method is introduced with an example using magnetic resonance chest images