Using Dynamic Contrast-Enhanced Magnetic Resonance Imaging (DCE-MRI) to Establish Objective Clinical Outcome Measures for Mandibular Osteoradionecrosis

 描述（由申请人提供）：头颈部癌症流行病学的变化导致越来越多的年轻和健康患者接受明确的外照射放疗（EBRT）。在具有良好临床结局和延长预期寿命的患者人群中，放射治疗的长期后遗症在治疗相关发病率和死亡率的管理中变得越来越重要。 下颌骨放射性骨坏死（ORN）是一个与放射有关的具有挑战性的问题，发生在高达16%的各种类型的头颈部癌症患者中。改变的骨血管分布和口腔内的机会性感染有助于ORN的发展，导致不遵循正常愈合事件顺序的骨破坏的不可阻挡的过程。早期ORN通常使用抗生素，局部伤口护理和高压氧（HBO）进行管理。晚期ORN需要手术切除和用健康的非辐射组织重建。这种疾病过程的成功管理需要提高识别有ORN风险的患者的能力，监测保守治疗的有效性，并改善术前计划以确保切除时边缘清晰。然而，目前还没有一个标准化的、客观的ORN分期和监测系统。 动态对比增强磁共振成像（DCE-MRI）是一种临床可用的定量成像方法，在头颈部实体瘤的研究中越来越多地用于评估微血管功能。在我们的机构，DCE-MRI被集成到一个多模态临床算法，旨在改善头颈部肿瘤的诊断，分期和肿瘤学监测。DCE-MRI可以检测与骨愈合、坏死和转移灶相关的骨血管改变，具有良好的空间分辨率。我们假设DCE-MRI可用于检测放射后骨血管分布的变化，以监测ORN的临床进展和对治疗的反应。为了验证这一假设，我们将评估DCE-MRI识别有风险的患者的潜力， 下颌骨ORN，监测对保守治疗的反应，并确定晚期下颌骨ORN的范围以协助手术计划。 成功完成这一建议有可能彻底改变下颌骨ORN的诊断和管理。临床医生将首次能够识别有ORN风险的患者，并适当管理放疗后护理。目前采用的保守措施的有效性可以使用客观的措施进行测试，改进的术前计划可以降低由于残余骨受损而导致的手术失败率。

 DESCRIPTION (provided by applicant): Changes in the epidemiology of head and neck cancers have resulted in an increasing number of younger and healthier patients being treated with definitive external beam radiotherapy (EBRT). The long-term sequelae of radiotherapy in a patient population with good clinical outcomes and extended life expectancy are becoming increasingly relevant in the management of treatment-associated morbidity and mortality. Osteoradionecrosis (ORN) of the mandible is a challenging issue related to irradiation, occurring in up to 16% of patients with various types of head and neck cancers. Altered bone vascularity and opportunistic infections within the oral cavity contribute to the development of ORN, leading to an inexorable process of bone destruction that does not follow the normal sequence of healing events. Early-stage ORN is often managed using antibiotics, local wound care, and hyperbaric oxygen (HBO). Advanced ORN requires surgical resection and reconstruction with healthy non-irradiated tissue. Successful management of this disease process requires an enhanced ability to identify patients at risk for ORN, monitor the effectiveness of conservative management, and improve preoperative planning to ensure clear margins at the time of resection. However, a standardized, objective staging and monitoring system for ORN is not currently available. Dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) is a clinically available quantitative imaging method that is increasingly employed to assess microvascular function in the study of solid tumors of the head and neck. At our institution, DCE-MRI is integrated into a multimodality clinical algorithm aimed at improving the diagnosis, staging, and oncologic surveillance of head and neck tumors. DCE-MRI can detect altered bone vascularity associated with bone healing, necrosis and metastatic involvement, with excellent spatial resolution. We hypothesize that DCE-MRI can be used to detect alterations in bone vascularity following irradiation to monitor ORN clinical progression and response to treatment. To test this hypothesis, we will evaluate the potential of DCE-MRI to identify patients at risk for mandibular ORN, monitor response to conservative management, and determine the extent of advanced mandibular ORN to assist in surgical planning. Successful completion of this proposal has the potential to revolutionize the diagnosis and management of mandibular ORN. For the first time, clinicians will be able to identify patients at risk for ORN and manage post-radiotherapy care appropriately. The effectiveness of currently employed conservative measures could be tested using an objective measure and improved preoperative planning could reduce the rate of surgical failure due to residual compromised bone.