This work applies a clustering method developed for image analysis of lung ventilation with hyperpolarized 129Xe to data acquired in a different centre with 129Xe and 3He. Results show that the current method is not readily transferable using published reference values. A different normalization method that increases the reproducibility of ventilation categorization is proposed. After optimization, the technique was applied in groups of patients with chronic obstructive pulmonary disease and cystic fibrosis. Results show significant differences of ventilation distribution indices between patient and healthy control groups.