MRI methods for high resolution imaging of the lung

摘要 肺部疾病带来了巨大的经济和社会负担，需要改进诊断工具， 阶段和后续治疗反应。为了评估异质性和局限性肺部疾病， 通常进行断层成像，最常见的是计算机断层扫描（CT）或放射性示踪剂 （SPECT/PET）。虽然这些技术分别提供了结构和功能信息， 相当大的辐射剂量，限制了在辐射敏感和儿科人群中的使用。 该提案旨在通过使磁共振成像技术成为一种新的成像技术， 共振成像（MRI）是肺成像的有价值的方式。MRI不提供电离辐射，因此可以 用于放射敏感人群的纵向随访或筛查。此外，MRI还提供了多个 基于微观结构、通气、灌注、细胞代谢和炎症的参数对比， 可以改善肺部疾病的评估。不幸的是，无辐射和多参数的好处 的MRI目前在临床上不可用于肺部成像，因为肺部信号较低，对 运动与当前的成像方法。我们集团和其他方面最近的事态发展表明， 可以修改MRI采集范例，以使肺部的可视化得到显著改善 在通气和合作的受试者中与CT相媲美， 对比度然而，患者通常患有肺功能差和/或难以依从，这 导致当前MRI技术无法处理的复杂、不规则的呼吸和整体运动。 我们提出了下一代肺部MRI技术，旨在解决和克服 运动和低肺信号的限制，同时还结合了多种MR软组织对比机制。 这些解决了MRI扫描的所有方面，包括患者准备和经验，MRI采集， 以及从数据重建图像。具体来说，我们开发了一个视听生物反馈系统， 改善患者体验，同时降低复杂运动的可能性，开发多对比度 最大化嵌入的运动信息并创建重建的MRI采样策略 该架构直接利用MRI数据来估计和校正运动，即使在 复杂运动这些方法将有益于表征多种肺部疾病，包括 儿童和成人人群，包括肺结节、肺栓塞、间质纤维化、囊性 纤维化、COPD、哮喘和肺部感染。它们将对儿科产生最重要的影响， 其中迫切需要限制电离辐射暴露。预期应用于这一人群， 我们纳入了对儿科受试者的广泛评价和对以下疾病的特定儿科影像学评价： 其他原发性恶性肿瘤的肺结节。这些结核评价是最常用的 儿科胸部CT，因此代表了减少剂量的巨大机会。

ABSTRACT There is an enormous economic and social burden of lung disease that demands improved tools to diagnose, stage, and follow treatment response. To assess heterogeneous and localized pulmonary diseases, cross- sectional imaging is often performed, most commonly with computed tomography (CT) or radioactive tracers (SPECT/PET). While these techniques provide structural and functional information, respectively, they deliver considerable radiation dose which limits use in radiosensitive and pediatric populations. This proposal aims to shift the current clinical practice paradigms for pulmonary imaging by making magnetic resonance imaging (MRI) a valuable modality for lung imaging. MRI delivers no ionizing radiation and can thus be used for longitudinal follow-up or screening in radio-sensitive populations. Furthermore, MRI provides multi- parametric contrast based on microstructure, ventilation, perfusion, cellular metabolism, and inflammation that can improve the assessment of lung diseases. Unfortunately, the radiation-free and multi-parametric benefits of MRI are not currently clinically available for lung imaging due to low signal in the lung and sensitivity to motion with current imaging methods. Recent developments by our group and others have demonstrated that the MRI acquisition paradigm can be modified to enable dramatic improvements in the visualization of the lung that rival CT in ventilated and cooperative subjects with the added benefit of providing improved soft tissue contrast. However, patients often suffer from poor lung function and/or have difficulty with compliance, which leads to complex, irregular breathing and bulk motion that cannot be handled by current MRI techniques. We propose a next generation of pulmonary MRI techniques that are designed to address and overcome the limitations of motion and low lung signal while also incorporating multiple MR soft tissue contrast mechanisms. These address all aspects of MRI scanning including patient preparation and experience, the MRI acquisition, and the reconstruction of images from the data. Specifically, we develop an audiovisual biofeedback system to improve the patient experience while also reducing the likelihood for complex motion, develop multi-contrast MRI sampling strategies which maximize embedded motion information, and create a reconstruction architecture which leverages the MRI data directly to estimate and correct for motion even in the case of complex motion. These methods would be beneficial for characterizing numerous diseases of the lung, both in pediatric and adult populations, including pulmonary nodules, pulmonary embolism, interstitial fibrosis, cystic fibrosis, COPD, asthma, and pulmonary infection. They will have the most significant impact in pediatrics, where there is an urgent need to limit ionizing radiation exposure. Anticipating applications to this population, we have included a broad evaluation in pediatric subjects and a specific pediatric imaging evaluation of pulmonary nodules from other primary malignancies. These nodule evaluations are most common use of pediatric chest CT at our institutions, and thus represent a substantial opportunity for dose reduction.