There are several disease conditions such as obesity, polycystic ovary syndrome, and Down’s Syndrome that are associated with upper airway restrictive disorders which often lead to obstructive sleep apnea syndrome (OSAS). If pediatric OSAS is not properly treated, then its sequelae may include mood, behavioral, and learning difficulties, together with co-morbidities such as heart disease, stroke, glucose intolerance, and hypertension. To better understand these conditions and the effects of treatment, it is important to take into account the dynamic nature of the upper airway in the natural breathing state. As such, dynamic imaging protocols have been investigated in the study of the upper airway including MRI, CT, and Optical CT (OCT). While OCT offers high spatial and temporal resolution, it is intrusive, has poor depth of penetration, and has shadowing effects. CT affords good spatial and reasonable temporal resolution but has poor contrast resolution for soft tissue structures and is associated with radiation exposure, which is especially problematic for dynamic imaging and for imaging of children. Therefore, dynamic MRI is currently the imaging modality of choice for studying these diseases.
We have been studying pediatric OSAS for over 10 years via 3D and 4D MR image analysis for deriving image-based quantitative biomarkers. In this domain, we have developed 3D MRI segmentation methods based on AAR, minimally interactive 4D MRI segmentation methods, and quantitative image analytics. Some examples appear in the following figures. In the first figure, renditions of the upper airway structure segmented from a patient 4D image covering 10 phases (from top left to bottom right) over a respiratory cycle are displayed. The second figure shows heat maps illustrating differences in the relationships among the shape lengths of 14 objects in the vicinity of the upper airway for obese children without (left) and with (right) OSAS.
References:
1. Tong Y, Udupa JK, Sin S, Liu Z, Wileyto EP, Torigian DA, Arens R. MR Image Analytics to Characterize the Upper Airway Structure in Obese Children with Obstructive Sleep Apnea Syndrome. PLoS One. 2016;11(8):e0159327. doi: 10.1371/journal.pone.0159327. PubMed PMID: 27487240; PMCID: PMC4972248.
2. Tong Y, Udupa JK, Odhner D, Wu C, Sin S, Wagshul ME, Arens R. Minimally interactive segmentation of 4D dynamic upper airway MR images via fuzzy connectedness. Med Phys. 2016;43(5):2323. doi: 10.1118/1.4945698. PubMed PMID: 27147344; PMCID: PMC4833751.