Novel acquisition strategies for cardiovascular functional and molecular imaging

描述(由申请人提供)：单光子发射断层扫描(SPECT)心肌灌注成像对于诊断和评估冠状动脉疾病(CAD)仍然至关重要。区分正常心肌区域和缺血或梗死心肌区域的能力对于患者管理和确定患者预后至关重要。目前，心脏SPECT成像需要至少两次成像，以获得负荷和休息条件下的血流灌注图像，每次成像持续15至20分钟。此外，现在已经有了第二代SPECT/CT成像仪，它可以结合心肌灌注成像和计算机断层扫描对心脏的解剖评估；因此，SPECT/CT有可能在单一的双模式成像过程中提供完整的灌注研究，并结合CT评估心脏力学(射血分数、每搏量、心肌增厚)、冠状动脉开放程度和冠状动脉钙化状态。然而，SPECT/CT联合心肌检查将需要长达60分钟，而SPECT几乎需要所有这些时间，这将使这一昂贵设备在临床上的利用率很低，因此可能会使成本过高。因此，在这项研究中，研究人员建议开发多针孔SPECT成像技术，目标是与当前的SPECT成像技术相比，在保持或提高空间分辨率的同时将检测效率提高20倍。此外，研究人员假设，这种方法将允许同时进行双同位素成像，因为多针孔方法的信噪比得到了改善，这意味着研究时间进一步减少。本研究的具体目标包括以下几个方面：(1)我们将开发和建立一个20针孔准直器成像系统，该系统优化了临床心肌灌注成像。(2)我们将进行实验，以确定多针孔准直器的最小观察次数，足以将心脏的角度采样伪影降至最低。我们将使用SPECT获得拟人体模的心肌灌注图像，并将其与高分辨率的CT解剖图像相关联，并将实现使用先验结构信息校正SPECT图像的衰减的方法。(3)我们将使用多针孔准直器评价同步双核素心肌灌注成像。在这项研究中，我们将证明，与平行孔准直器相比，使用多针孔准直器获取的投影数据可以显著改善201TI/99mTC同时成像的串扰校正。总体而言，多针孔SPECT/CT的成功开发有望大幅提高全面评估心肌状态和心功能的可行性和成本效益，从而促进改善对冠心病患者的护理和管理。‘

DESCRIPTION (provided by applicant): Myocardial perfusion imaging with single photon emission tomography (SPECT) remains critically important for diagnosing and assessing coronary artery disease (CAD). The ability to differentiate normal myocardial regions from those that are ischemic or infarcted is essential for patient management and for determining patient prognosis. Currently, cardiac SPECT imaging requires at least two imaging sessions to obtain perfusion images under stress and under rest conditions, with each imaging session lasting 15 to 20 min. Furthermore, second generation SPECT/CT imagers now are available that can combine myocardial perfusion imaging with anatomical assessment of the heart with computed tomography; SPECT/CT therefore has the potential to provide a complete perfusion study combined with CT assessment of cardiac mechanics (ejection fraction, stroke volume, myocardial thickening), coronary patency, and status of coronary calcification in a single dual-modality imaging session. However, a combined SPECT/CT myocardial protocol would take up to 60 min, with virtually all of this time needed for SPECT, and would make poor utilization of this expen- sive equipment in the clinic and therefore may be cost prohibitive. Therefore, in this study the investigators propose to develop multipinhole SPECT imaging techniques with the goal of improving detection efficiency by 20-fold while maintaining or improving the spatial resolution in comparison to current SPECT imaging techniques. In addition, the investigators hypothesize that this method will allow simultaneous dual isotope imaging due to an improved signal to noise ratio of the multipinhole approach, which represents a further reduction in study time. The study encompasses the following specific aims: (1) We will develop and build a 20-pinhole collimator imaging system optimized for clinical myocardial perfusion imaging. (2) We will perform experiments to determine the minimal number of views of a multipinhole collimator sufficient to minimize angular sampling artifacts of the heart. We will obtain myocardial perfusion images of an anthropomorphic phantom with SPECT that are correlated with high-resolution anatomical images with CT and we will implement methods of correcting the SPECT image for attenuation using a priori structural information. (3) We will evaluate simultaneous dual-isotope imaging of myocardial perfusion with a multipinhole collimator. In this study, we will demonstrate that cross-talk correction of simultaneous 201TI/99mTc imaging can be improved significantly in the projection data acquired with a multipinhole collimator versus that obtained with a parallel hole collimator. Overall, successful development of multipinhole SPECT/CT promises to substantially increase the feasibility and cost-effectiveness of a comprehensive assessment of myocardial status and cardiac function in a way that will promote improved care and management of patients with coronary artery disease. '