Sparse multispectral processing for accelerated EPR oximetry in three dimensions

用于三维加速 EPR 血氧测定的稀疏多光谱处理

• 批准号: 7659869
• 负责人: Lee C. Potter
• 金额: $ 14.28万
• 依托单位: OHIO STATE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-06-01 至 2011-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7659869
• 关键词: Acceleration; Arts; Biological; Cardiac; Cardiovascular Diseases; Cardiovascular system; Data; Development; Dimensions; Disease; Electron Spin Resonance Spectroscopy; Feasibility Studies; Free Radicals; Frequencies; Functional disorder; Hour; Image; Imaging Techniques; Injury; Ischemia; Joints; Maps; Measurement; Measures; Methods; Modeling; Myocardial; Oxygen; Oxygen saturation measurement; Partial Pressure; Particulate; Play; Process; Publishing; Radio; Recovery; Reperfusion Therapy; Reporting; Research; Resolution; Role; Sampling; Signal Transduction; Spectrum Analysis; Techniques; Time; Tissues; Width; absorption; base; clinical application; computerized data processing; data acquisition; detector; imaging modality; minimally invasive; novel; optimism; public health relevance; response; time use; tissue oxygenation; tumor; two-dimensional

DESCRIPTION (provided by applicant): Electron paramagnetic resonance (EPR) spectroscopy enables noninvasive measurement of free radicals in biological samples. EPR can be used to measure the partial pressure of oxygen by observing oxygen-induced broadening in the lineshape of an introduced paramagnetic probe. In tumors, the oxygen concentration is useful in determining the response to different treatment options. Likewise, the presence of oxygen plays a critical role in the pathophysiology of myocardial injury during both ischemia and subsequent reperfusion. Therefore, the ability of EPR to measure oxygen over time can provide vital information to characterize the progression of a disease state and to determine the efficacy of different treatment options. Unfortunately, long data acquisition times have limited the use of EPR for these applications. The objective of this proposal is to develop and verify processing methods that reduce acquisition time for mapping partial pressure of oxygen in three dimensions using EPR imaging. The two aims in the research plan present a strategy for reducing by a factor of 80 the acquisition time when imaging with particulate spin probes. The opportunity for the proposed improvement in acquisition time is created by the recent development of particulate paramagnetic probes. In the first aim, the proposed approach fully utilizes all energy in the resonance signal by jointly processing multiple harmonics of both the absorption and dispersion components. With multi-spectral processing, we access approximately four times more signal energy than is present in the first harmonic absorption spectrum alone. In the second aim, we incorporate the sparse, but unstructured, distribution of spins presented by particulate probes. These two aims provide processing gains that result in fewer projections, narrower sweep widths and faster sweep rates for achieving a desired image resolution. Preliminary results demonstrate feasibility of the hypothesized ambitious reductions in acquisition time. First, our team has developed particulate spin probes capable of sensing and reporting cellular and tissue pO2 with remarkable oxygen sensitivity (better than 0.1 Torr), repeatability, bio-stability, and narrow line width. Second, for two dimensional spectral-spatial imaging we have demonstrated a 38:1 improvement in acquisition time by directly estimating Lorentzian line parameters, rather than first imaging a spectral-spatial object. Third, we have demonstrated oxygen mapping in three dimensions using sparse distribution of particulate spin probes to reduce the number of projections from 1024 to 32. Thus, preliminary results give optimism for turning hours to minutes and minutes to seconds. PUBLIC HEALTH RELEVANCE: Electron paramagnetic resonance (EPR) oximetry provides a direct, minimally invasive measure of oxygen concentration. Oximetry is useful in predicting the response of tumors to different treatment options and in understanding the pathophysiology of cardiac recovery following injury due to cardiovascular disease. However, weak signal strength and long data acquisition times prohibit widespread use of EPR oximetry. The objective of this proposal is to develop signal processing methods that accelerate data acquisition. The approach fully accesses all observable signal energy in the radio frequency resonance signal and exploits the inherent sparseness of newly developed particulate spin probes. Preliminary results demonstrate the feasibility of reducing acquisition time from tens of minutes to tens of seconds.

描述(申请人提供)：电子顺磁共振(EPR)光谱学能够对生物样品中的自由基进行非侵入性测量。EPR可以通过观察氧在引入的顺磁探针线形中引起的展宽来测量氧分压。在肿瘤中，氧浓度在确定对不同治疗方案的反应时是有用的。同样，氧的存在在缺血和随后再灌流期间的心肌损伤的病理生理学中起着关键作用。因此，EPR随时间测量氧气的能力可以提供重要信息，以表征疾病状态的进展并确定不同治疗方案的疗效。不幸的是，较长的数据采集时间限制了EPR在这些应用中的使用。这项建议的目的是开发和验证处理方法，以减少使用EPR成像绘制三维氧气分压图的采集时间。研究计划中的这两个目标提出了一种策略，将使用颗粒自旋探针成像时的采集时间减少到原来的1/80。颗粒顺磁探头的最新发展创造了拟议缩短采集时间的机会。在第一个目标中，该方法通过联合处理吸收分量和色散分量的多个谐波，充分利用了共振信号中的所有能量。使用多光谱处理，我们获得的信号能量大约是仅一次谐波吸收光谱中的四倍。在第二个目标中，我们结合了粒子探测器呈现的稀疏但非结构化的自旋分布。这两个目标提供处理增益，从而产生更少的投影、更窄的扫描宽度和更快的扫描速率，以实现所需的图像分辨率。初步结果表明，假设的雄心勃勃的收购时间缩短是可行的。首先，我们的团队开发了能够感知和报告细胞和组织PO2的颗粒自旋探头，具有显著的氧气灵敏度(优于0.1 Torr)、重复性、生物稳定性和窄线宽。其次，对于二维光谱-空间成像，我们通过直接估计洛伦兹线参数，而不是首先成像光谱-空间对象，证明了捕获时间的38：1改进。第三，我们使用稀疏分布的颗粒自旋探针演示了三维氧气映射，将投影数量从1024减少到32。因此，初步结果给出了将小时转变为分钟、将分钟转变为秒的乐观情绪。公共卫生相关性：电子顺磁共振(EPR)血氧仪提供了一种直接、微创的氧气浓度测量方法。血氧饱和度测定有助于预测肿瘤对不同治疗方案的反应，并有助于了解心血管疾病损伤后心脏恢复的病理生理学。然而，微弱的信号强度和较长的数据采集时间限制了EPR血氧仪的广泛应用。这项提议的目标是开发能够加速数据采集的信号处理方法。这种方法充分利用了射频共振信号中所有可观察到的信号能量，并利用了新开发的粒子自旋探测器固有的稀疏性。初步结果表明，将捕获时间从几十分钟减少到几十秒是可行的。