MR Imaging of Upper Airway Dynamics in Obstructive Sleep Apnea

描述(由申请人提供)：这项研究的总体目标是：1)利用磁共振成像(MRI)对阻塞性睡眠呼吸暂停(OSA)患者在清醒和睡眠期间的上呼吸道动力学进行表征；2)确定清醒期间收集的数据是否可以预测OSA的发生。OSA的特征是睡眠期间反复部分或完全关闭呼吸道，具有重要的临床意义，从睡眠中断、白天过度嗜睡和生活质量低下的后遗症到不良的心血管或代谢结果。虽然多导睡眠图和基于呼吸道压力和阻力测量的研究提供了丰富的上呼吸道生理学信息，但它们无法评估上呼吸道的三维解剖结构及其在呼吸过程中的构象变化。了解这种结构的形态和力学行为对于更全面地了解上呼吸道阻塞的发生是至关重要的。这样的信息可以通过成像技术获得，这也是本研究的重点。我们建议使用最先进的MRI工具来量化三组受试者的上呼吸道动力学：1)OSA患者；2)打鼾者；3)年龄和体重匹配的健康对照组，以供比较。受试者将接受磁共振成像，以评估清醒和自然睡眠期间潮气呼吸期间的上呼吸道形态测量和呼吸道大小的变化，同时测量鼻腔-口腔血流分区以及睡眠状态和阶段。将从MR图像重建患者特定的动态上呼吸道形态测量模型，并从中计算出各种解剖标记。这些标记物在不同组间和不同阶段(清醒与睡眠)之间的差异将被评估。关于潮气呼吸时上呼吸道构象变化的研究将为识别导致气流阻塞的几何异常提供新的手段。这项建议是解决目前尚未满足的治疗指南的临床需求的第一步，该指南考虑了上呼吸道的动态性质。这些研究的完成还将为未来的建模研究奠定基础，该研究将把患者特定的上呼吸道动力学与详细的流动模拟结合起来，以更好地了解上呼吸道的生物力学特性和用于优化治疗的流动驱动机制。这项研究开发的方法将直接适用于所有患有上呼吸道功能障碍的患者。

DESCRIPTION (provided by applicant): The overall objectives of this research are 1) to characterize upper airway dynamics during wakefulness and sleep in patients with obstructive sleep apnea (OSA) using magnetic resonance imaging (MRI) and 2) to determine if data collected during wakefulness can predict the occurrence of OSA. OSA is characterized by recurrent partial or complete airway closure during sleep, and has important clinical implications ranging from disruption of sleep with daytime sequelae of excessive sleepiness and poor quality of life to adverse cardiovascular or metabolic outcomes. While polysomnography and studies based on measurements of airway pressures and resistance have provided a wealth of information on upper airway physiology, they are unable to assess the three-dimensional anatomy of the upper airway and its conformational changes during breathing. Knowledge of the morphology and mechanical behavior of this structure is essential for a more complete understanding of the occurrence of upper airway obstruction. Such information can be obtained with imaging technology and is the focus of this study. We propose to use state-of-the-art MRI tools to quantify upper airway dynamics in three groups of subjects: 1) OSA patients; 2) snoring volunteers; and 3) healthy age and weight-matched controls for comparison purposes. Subjects will undergo MR imaging to assess upper airway morphometry and changes in airway size during tidal breathing both during wakefulness and natural sleep with simultaneous measurement of nasal-oral flow partition and sleep state and stages. Dynamic patient-specific models of upper airway morphometry will be reconstructed from the MR images from which various anatomical markers will be calculated. Differences in these markers between groups and between stages (awake vs. asleep) will be evaluated. The proposed studies of characterizing the conformational change of the upper airway during tidal breathing will provide a new means of identifying geometrical abnormalities that lead to airflow obstruction. This proposal is a first step in addressing a currently unmet clinical need for treatment guidelines tha take into account the dynamic nature of the upper airway. Completion of these studies will also lay the groundwork for future modeling studies that will combine patient-specific upper airway dynamics with detailed flow simulations to provide better insight in biomechanical properties of the upper airway and flow-driven mechanisms on which to optimize therapeutic treatment. The methods developed in this research will be directly applicable to all patient populations with upper airway dysfunction.