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

描述（由申请人提供）：本提案的总体目标是通过在CT套件中融合呼吸补偿PET与CT图像来提高肝脏病变活检的临床有效性。仅凭CT成像，肝脏病变的定位可能具有挑战性，特别是在肿瘤与邻近肝实质难以区分的特定病例中。鉴于PET能够在同一肿瘤没有CT相关性的情况下定位恶性肿瘤，我们认为PET-CT引导活检可以通过指导针对代谢活跃的病变或较大肝病变内特定的“代谢热点”来提高肝病变活检的诊断率。然而，使用PET扫描（即使是混合PET/CT机器）的诊断效益受到呼吸运动伪影的严重影响。CT数据在短时间内获得，表示呼吸周期期间的瞬时快照。另一方面，每个龙门台位置的PET数据采集平均需要3-10分钟。对于典型的程序，平均需要5 -7个龙门位置。这些延长的采集时间导致图像中的呼吸运动伪影。这些伪影又会导致CT和PET数据在空间对应上的差异、不准确的肿瘤定位和不正确的肿瘤分期。因此，开发有效的PET-CT引导肝脏病变活检需要强大的呼吸运动校正技术。我们建议开发适合腹部成像的呼吸运动校正和配准组件，并扩展我们的开源图像引导手术系统（IGSTK），使PET/CT引导的肝脏病变活检在CT套件中成为可能。呼吸运动校正算法将利用相位匹配的呼吸门控PET和CT数据和超分辨率重建算法来生成无运动的高质量PET图像。我们将开发一种新的图像配准算法来补偿呼吸引起的器官滑动。传统的配准方法假定一幅图像可以平滑地变形为下一幅图像，因此不能很好地处理器官滑动。

DESCRIPTION (provided by applicant): The broad objective of this proposal is to improve the clinical effectiveness of liver lesion biopsy by fusing respiratory-compensated PET with CT images in the CT suite. On CT imaging alone, localization of liver lesions can potentially be challenging, particularly in selected cases where differentiation of the tumor from adjacent liver parenchyma may be difficult. Given the ability of PET to localize malignancies in situations where the same tumors do not have a CT correlate, we believe that PET-CT guided biopsy would improve the diagnostic yield of liver lesion biopsies by providing guidance in targeting a metabolically active lesion or a specific "metabolic hot spot" within a larger liver lesion. However, the diagnostic benefit of using PET scans (even from hybrid PET/CT machines) is gravely affected by respiratory motion artifacts. CT data is acquired in a short time representing an instantaneous snapshot during the breathing cycle. On the other hand, PET data acquisition takes an average 3-10 minutes per gantry table position. For typical procedures, 5 -7 gantry positions are required on average. These prolonged acquisition times lead to respiratory motion artifacts in the images. These artifacts, in turn, cause discrepancy in spatial correspondence between the CT and PET data, inaccurate tumor localization, and incorrect tumor staging. Hence, development of an effective PET-CT guided biopsy for liver lesions requires a robust respiratory motion correction technique. We propose to develop respiratory motion correction and registration components suitable for abdominal imaging and extend our open source image-guided surgery system (IGSTK) to enable PET/CT guided liver lesion biopsy in the CT suite. The respiratory motion correction algorithm will utilize phase matched respiratory-gated PET and CT data and super- resolution reconstruction algorithm to generate a motion-free high quality PET image. We will develop a novel image registration algorithm that will compensate for respiration-induced organ- sliding. Organ-sliding is not handled well by traditional registration methods which assume that one image can be smoothly deformed into the next. 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 effectively biopsy liver lesions.