Analysis of pulmonary scans representative of a patient's pulmonary structure can be used to classify a patient into one or more of a plurality of populations. The patient's scan can be mapped to a reference domain and analyzed to determine one or more fissure features associated with a plurality of regions in the reference domain. Comparison of the determined fissure features with a plurality of fissure atlases, each associated with different population, can be performed to classify the patient into one or more of the populations. Data from different fissure atlases can be compared to determine regions in the fissure atlases that distinguish one population from another. Such distinguishing regions can improve the ability to classify the patient while reducing errors based on false classifications.