Landmark-defined two-dimensional lung configuration in women with osteogenesis imperfecta type III: an exploratory geometric morphometric pilot study

Osteogenesis imperfecta (OI) type III is a rare disorder in which severe thoracic deformity may alter pulmonary anatomy. This exploratory pilot study assessed whether the relative two-dimensional configuration of four reproducible pulmonary landmarks differs between adult women with OI type III and female comparison participants. Frontal computed tomography scout views acquired at full inspiration were evaluated in seven women with genetically confirmed OI type III and seven female comparison participants. Four fixed landmarks (apex, hilum, cardiophrenic angle, and costophrenic angle) were digitized for each lung. After Procrustes superimposition, side-specific group comparisons were performed; thin-plate spline maps and principal component analysis were used for descriptive visualization. Forced vital capacity and forced expiratory volume in 1 s were measured by conventional forced spirometry with a handheld Contec SP-10 spirometer, performed by qualified medical personnel as part of the study protocol. Testing followed SEPAR guidance and ATS/ERS acceptability and repeatability criteria (difference < 150 mL between the two best acceptable maneuvers), and GLI 2012 equations were used for percentage-predicted values. These functional variables were not derived from CT or morphometric data. No statistically significant group difference was detected for the landmark-defined configuration of the right lung ( p = 0.204). A difference was detected for the left lung ( p = 0.016), which remained below the Bonferroni sensitivity threshold of 0.025 for two side-specific tests. The largest left-sided displacement involved the configuration defined by the hilum, cardiophrenic angle, and costophrenic angle. These findings are exploratory because of the small availability-based sample. This pilot study provides preliminary evidence of a group difference in the four-landmark two-dimensional configuration of the left lung. It does not establish a difference in the complete lung contour, a causal mechanism, a shape-function association, or current clinical utility. Multicentre studies with larger and sex-inclusive samples, contour semilandmarks, a dedicated three-dimensional correspondence protocol, and prespecified functional analyses are required.