Hen-Tzy (Jill) Lin

Craniosynostosis is a serious and common pediatric disease caused by the early fusion of the sutures of the skull. Premature suture fusion results in severe malformation in calvarial shapes. A single surgery, i.e. cranioplasty, is required to release the fused suture and reshape the deformed calvaria in order to prevent further deformation in skull shapes and impairment in neuropsychological development. Even though no concrete evidence suggests whether or not surgical complications and neurobehavioral developments are directly affected by different calvarial shapes, radiologists and surgeons often use cases of similar shapes that were previously resolved as guidelines to prepare for pre-surgical planning and post-surgical evaluation. With the increasing amount of imaging data, a systematic and quantitative approach is required to help physicians capture information embedded in images and define image similarities between cases. We have designed and implemented a shape-based image retrieval system that will objectively and quantitatively retrieve cases of similar shapes that were previous treated or established to help physicians in the decision making process of the reconstruction of the skull.

Currently, most imaging studies in patients with craniosynostosis emphasize the description of qualitative features and relegate quantitative assessments to the measurement of a ratio or an angle between anthropometric landmarks. In order to objectively detect inter- and intra-class differences between shapes in the image retrieval system, we have developed a novel shape measurement called the symbolic shape descriptor (SSD) to refine and establish quantitative definitions of skull phenotype. Our experiments show that the SSD has classification performance that is better than or comparable to other shape descriptors, uses less space, and is much faster than competitors. We have also conducted a regression analysis to determine the correlation between skull shapes and neuropsychological development in children with isolated sagittal synostosis. The result of this study is incorporated in the retrieval system for prediction of mental and psychomotor scores in order to help psychologists decide whether to initiate intervention on affected children.