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

 描述(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的患者接受明确的体外放射治疗(EBRT)。放射治疗的长期后遗症在患者群体中具有良好的临床结果和延长的预期寿命，在管理与治疗相关的发病率和死亡率方面变得越来越重要。下颌骨放射性骨坏死(ORN)是一个与放射相关的具有挑战性的问题，高达16%的头颈部癌症患者会发生ORN。改变的骨血管和口腔内的机会性感染有助于ORN的发展，导致一个不可阻挡的骨破坏过程，不遵循正常的愈合事件顺序。早期ORN通常使用抗生素、局部伤口护理和高压氧(HBO)治疗。晚期ORN需要手术切除，并用健康的非辐射组织进行重建。这一疾病过程的成功管理需要增强识别有ORN风险的患者的能力，监测保守治疗的有效性，并改进术前计划以确保在切除时有明确的切缘。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，在头颈部实体肿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被集成到一个多模式临床算法中，旨在改善头颈部肿瘤的诊断、分期和肿瘤监测。DCE-MRI可以发现与骨愈合、坏死和转移相关的骨血管改变，具有良好的空间分辨率。我们假设DCE-MRI可以用来检测放射后骨血管的变化，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在识别有风险的患者方面的潜力。 下颌骨ORN，监测保守治疗的反应，并确定进展性下颌ORN的范围，以帮助手术计划。这项建议的成功完成有可能使下颌骨ORN的诊断和治疗发生革命性的变化。临床医生将首次能够识别有ORN风险的患者，并适当地管理放射治疗后的护理。目前采用的保守措施的有效性可以用客观的方法来测试，改进的术前计划可以降低由于残留的骨质破坏而导致的手术失败的比率。

 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.