Quantitative periprosthetic PET/CT

描述(由申请人提供)：在美国目前每年进行的大约350,000例关节置换手术中，有相当一部分将需要提前翻修手术。疼痛植入物最具挑战性的诊断方面之一是区分无菌性骨溶解，即对磨损碎屑渗透的炎症反应，以及关节周围组织的感染。目前的诊断技术，如普通射线照相、实验室和核医学测试，都有严重的缺陷。同时，感染的漏诊会使翻修手术的结果急剧恶化，发病率和死亡率急剧增加，而对无菌性骨溶解程度的低估可能会导致翻修手术的错误时机。计算机断层扫描(CT)和正电子发射断层扫描(PET)都被认为是诊断这两种疾病的潜在替代方法，具有极好的敏感性和特异性。然而，当使用现代多模式PET/CT设备获取CT图像时，CT存在严重的图像伪影，不仅使CT图像无法诊断，还会对PET数据的可用性产生负面影响。在我们机构一项专门的影像体模的初步研究中，CT金属伪影的算法减少被证明是基于CT的无菌性骨溶解诊断的有效方法。这项拟议研究的主要目标是将这项工作扩展到PET/CT，从而创建一种新的一站式诊断工具，既可用于无菌骨溶解，也可用于感染。这项建议的实验重点是建立一个骨溶解和感染体模模拟器来优化和测试我们的金属伪影减少算法，并在一项对20名髋关节或膝关节假体疼痛患者进行的小型研究中测试PET/CT联合扫描比单独PET更有用的假设。此外，基于后续的CT成像，我们将第一次能够评估直接靠近种植体的无菌性骨溶解的进展率。我们相信，一种新的金属伪影校正的PET/CT扫描将提供无菌性骨溶解和感染的鉴别诊断，从而确保患者的安全，并将有助于改进手术计划，避免误诊骨溶解和感染及其痛苦和昂贵的后果。公共卫生相关性：人工髋关节和膝关节置换术已成为治疗骨性关节炎和其他关节疾病的非常成功的手术选择。由于接受这种治疗的患者数量很多，因此发生疼痛松动的植入物比例很小，导致需要接受翻修手术的患者比例很高。正确诊断引起疼痛的并发症是重要的，以确保最佳的患者管理和手术计划。我们建议克服与使用X射线计算机断层扫描对金属植入物进行成像相关的技术挑战，并将该技术与正电子发射断层扫描相结合，为早期诊断可能导致植入失败的并发症提供一种新的综合工具。

DESCRIPTION (provided by applicant): Of the approximately 350,000 total joint replacements that are currently performed in the U.S. each year, a significant number will require premature revision operation. One of the most challenging diagnostic aspects of the painful implant is the differentiation between aseptic osteolysis, an inflammatory response to infiltration of wear debris, and infection of the tissue surrounding the joint. Current diagnostic techniques such as plain radiography, laboratory and nuclear medicine tests have severe shortcomings. At the same time, failed diagnosis of infection can dramatically worsen the outcome of a revision operation with sharply increased morbidity and mortality, and underestimation of the extent of aseptic osteolysis may lead to wrong timing of the revision. Both Computed Tomography (CT) and Positron Emission Tomography (PET) have been recognized as potential diagnostic alternatives with excellent sensitivity and specificity for both conditions. However, CT suffers from severe image artifacts in the presence of metallic implants that not only render the CT images undiagnostic but also negatively influence the usability of PET data when they are obtained with modern multimodality PET/CT equipment. In a pilot study at our institution on a dedicated imaging phantom, algorithmic reduction of CT metal artifact was shown to be effective for CT-based diagnosis of aseptic osteolysis. The main objective of the proposed research is to extend this work to PET/CT and thereby create a novel one-stop diagnostic tool for both aseptic osteolysis and infection. The experimental focus of this proposal is to build an osteolysis and infection phantom simulator to optimize and test our metal artifact reduction algorithms, and to test the hypothesis that a combination PET/CT scan is more useful than standalone PET in a small study of 20 patients with painful hip or knee prostheses. Furthermore, based on follow-up CT imaging we will for the first time be able to assess progression rates of aseptic osteolysis directly next to the implant. We believe that a novel metal artifact-corrected PET/CT scan will ensure patient safety by providing a differential diagnosis of both aseptic osteolysis and infection and will help improve surgical planning and avoid misdiagnosis of osteolysis and infection with its painful and costly consequences. PUBLIC HEALTH RELEVANCE: Joint replacement with artificial hips and knees has become a very successful surgical choice to treat osteoarthritis and other joint diseases. Because of the large number of patients so treated, the small fraction of implants that develop painful loosening results in a large rate of patients needing to undergo revision surgery. It is important to correctly diagnose the complication causing the pain to ensure optimal patient management and surgical planning. We propose to overcome the technical challenges associated with using X-ray computed tomography for imaging of metallic implants and use the technique in combination with Positron Emission Tomography to provide a novel comprehensive tool for the early diagnosis of the complications that would otherwise lead to implant failure.