Improving liver lesion biopsy in the CT suite through fusion with PET images

描述(申请人提供)：PET成像提供有关肿瘤功能或代谢特征的信息，而CT主要评估肿瘤的解剖和形态特征。鉴于在同一肿瘤没有CT相关性的情况下，PET能够定位恶性肿瘤，PET/CT引导下的活检有助于提高肝脏病变活检的诊断率。然而，在目前的实践中，即使是来自PET/CT混合机的PET图像的诊断效果也受到呼吸运动伪影的严重影响。CT数据采集速度很快，代表了呼吸周期中相对瞬时的快照。相比之下，PET数据采集通常需要至少一分钟使用 最新的扫描仪，但往往需要长达五分钟的每个龙门台位置。这些长时间的采集导致PET图像中的呼吸运动伪影，这在下肺野和肝脏特别明显。这些伪影导致CT和PET数据之间的空间对应不一致，潜在地导致不准确的肿瘤定位和不正确的肿瘤分期。因此，开发一种有效的PET-CT引导的肝脏病变活检方法需要一种强大的呼吸运动校正技术。该项目的总体目标是通过将呼吸补偿的PET/CT与介入CT套装中的CT图像融合来提高肝脏病变活检的临床效果。在第一阶段，我们开发了一种运动补偿技术，使用相位匹配的呼吸门控PET和CT数据来生成无运动的高质量PET和CT图像。该方法被证明可以生成高质量的、无运动的PET图像。使用模拟的PET和CT体模数据进行了验证。该方法被集成到我们的开源图像引导手术软件工具包(IGSTK)中。此外，我们扩展了工具包的能力，以处理PET图像数据并生成临床上有效的融合PET/CT可视化。然后，我们将这些方法集成到一个应用原型中，并将其用于靶向植入拟人模型中的18F脱氧葡萄糖(FDG)填充的球形小瓶，从而证明了这些方法的可行性。在这一第二阶段的工作中，我们建议通过1)使用患者数据改进和评估我们的呼吸运动补偿技术；以及2)进行临床试验可行性研究来证明这些技术的临床实用性。 公共卫生相关性：PET/CT成像在可疑病变的早期发现、分期和评估中起着关键作用。PET成像提供有关肿瘤功能或代谢特征的信息，而CT主要评估肿瘤的解剖和形态特征。通过融合这两种成像技术，并结合先进的图像配准和呼吸运动补偿技术，临床医生可以更有效地对肝脏病变进行活检，这将提高癌症筛查和诊断水平。

DESCRIPTION (provided by applicant): PET imaging provides information on functional or metabolic characteristics of tumors, whereas CT predominately assesses tumor's anatomical and morphological features. Given the ability of PET to localize malignancies in situations where the same tumors do not have a CT correlate, PET/CT guided biopsy helps to improve the diagnostic yield of liver lesion biopsies. However, the diagnostic benefit of PET images, even from hybrid PET/CT machines, is gravely affected by respiratory motion artifacts in current practice. CT data acquisition is rapid and represents a relatively instantaneous snapshot during the breathing cycle. In contrast, PET data acquisition typically requires at least one minute using the newest scanners, but often requires as long as five minutes per gantry table position. These prolonged acquisitions lead to respiratory motion artifacts in the PET images, which are particularly pronounced in the lower lung fields and in the liver. These artifacts cause discrepancies in the spatial correspondence between the CT and PET data, potentially leading to inaccurate tumor localization and incorrect tumor staging. Hence, the development of an effective PET-CT guided biopsy methodology for liver lesions requires a robust respiratory motion correction technique. The overall goal of this project is to improve the clinical effectiveness of liver lesion biopsy by fusing respiratory- compensated PET/CT with CT images in the interventional CT suite. During Phase I, we developed a motion compensation technique that uses phase-matched respiratory-gated PET and CT data to generate motion-free high quality PET and CT images. The method was shown to generate high-quality, motion-free PET images. It was validated using simulated PET and CT phantom data. The method was integrated into our open source image-guided surgery software toolkit (IGSTK). In addition, we extended the toolkit's ability to handle PET image data and generate clinically effective fused PET/CT visualization. We then demonstrated the feasibility of these methods by integrating them into an application prototype and using it to target 18Fluordeoxyglucose (FDG) filled spherical vials implanted in an anthropomorphic phantom. In this Phase II effort, we propose to demonstrate the clinical utility of these techniques by 1) refining and evaluating our respiratory motion-compensation technique using patient data; and 2) conducting a clinical trial feasibility study. PUBLIC HEALTH RELEVANCE: PET/CT imaging plays a key role in early detection, staging, and evaluation of suspicious lesions. PET imaging provides information on functional or metabolic characteristics of tumors, whereas CT predominately assesses the tumor's anatomical and morphological features. By fusing these two imaging techniques and incorporating advanced image registration and respiratory motion compensation techniques, clinicians can more effectively biopsy liver lesions, which would improve cancer screening and diagnosis.