IMPROVED SPACIAL LOCALIZATION FOR SPECTROSCOPIC IMAGING

这个子项目是许多利用 由NIH/NCRR资助的中心赠款提供的资源。子项目和 研究者（PI）可能从另一个NIH来源获得了主要资金， 因此可在其他CRISP条目中表示。所列机构为 研究中心，而研究中心不一定是研究者所在的机构。 项目摘要 授权编号： 项目正式开始：2005年5月9日 项目开始日期：2008年5月9日 项目结束日期：2011年2月28日 体内磁共振质子波谱已被证明是临床上有价值的评估和定位肿瘤的前列腺。然而，由于MR光谱成像（MRSI）中固有的低信噪比（SNR），测量时间可能非常长。因此，为了实际用于临床前列腺MRSI，必须减少这些时间，并且空间分辨率通常非常低。与低分辨率数据采集相关的MRSI中的一个重要问题是可能存在显著的振铃，即，一种从邻近甚至远距离体素向感兴趣体素中的信号污染的渗出。来自未抑制的脂质或水信号的污染可能特别成问题，在某些情况下，使前列腺光谱对诊断无用。一种新的混合空间编码方法正在开发中。该方法被称为PSF-Choice，保持了标准傅立叶编码的简单性，同时包括非傅立叶编码的灵活性，以形成点扩展函数（PSF）。利用这种方法，可以实现没有脂质污染的前列腺的实际光谱成像，而没有成像时间的额外成本或分辨率或SNR的损失。 对NCIGT的好处 磁共振波谱成像正在成为一种常见的模式，用于诊断前列腺癌的IGT计划。不幸的是，如一些研究所示，患者检查的许多体素中的光谱被脂质泄漏破坏，并且光谱不具有诊断质量。在某些患者中，这可能多达体素的90%。PSF-Choice提供了消除这种污染的可能性，从而大大提高了MRSI检查的诊断质量。该方法正在基于PROSE序列进行编程，该序列被其他团体用于前列腺光谱学。这种合作的好处是，如果项目成功，一个大大改进的光谱序列将可用于前列腺计划，也可以传播到外部团体。 对项目的好处 IGT资源为R21项目提供了必要的支持。序列开发的编程环境（部分）通过资源成像核心的支持进行维护。此外，IGT资源的培训研究员Joe Roebuck既是放射科医生又是光谱学家，他正在参与R21项目的实验工作。他能够为该项目提供临床重点，并就光谱学相关事宜提供专家建议-特别是光谱数据的处理。他已经制造了一个前列腺光谱模型供该项目使用。最后，该资源提供了一个基本的临床环境，在其中可以验证所开发的方法。一旦技术开发完成，将使用通过与IGT资源合作招募的患者进行可行性研究。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Project Summary Grant Number: Project Official Start: 09-MAY-2005 Project Start: 09-MAY-2008 Project End: 28-FEB-2011 In-vivo MR proton spectroscopy has been shown to be clinically valuable for assessing and localizing tumors in the prostate. However, due to the inherently low signal-to-noise ratio (SNR) in MR spectroscopic imaging (MRSI), measurement times can be very long. Thus, to be practical for clinical prostate MRSI, these times must be reduced and spatial resolution is generally very low. A significant problem in MRSI, related to low-resolution data acquisition, is that there can be significant ringing, i.e., a kind of bleeding of signal contamination into the voxel-of-interest, from neighboring and even distant voxels. Contamination from unsuppressed lipid or water signal can be especially problematic, in some cases, rendering prostate spectra useless for diagnosis. A new hybrid spatial encoding method is being developed. The method, called PSF-Choice, maintains the simplicity of standard Fourier encoding while including the flexibility of non-Fourier encoding to shape the point-spread-function (PSF). With this method, practical spectroscopic imaging of the prostate that is free from lipid contamination can be achieved with no additional cost in imaging time or loss in resolution or SNR. Benefits to NCIGT MR spectroscopic imaging is becoming a common modality used in the IGT program for diagnosis of prostate cancer. Unfortunately, as some studies show, the spectra in many voxels of a patient exam are corrupted by lipid leakage and the spectra are not of diagnostic quality. In some patients this may be as many as 90 percent of the voxels. The PSF-Choice offers the possibility of eliminating this kind of contamination and, thus, greatly improving the diagnostic quality of the MRSI exams. The method is being programmed based on the PROSE sequence which is used by other groups for prostate spectroscopy. The benefit to the resource of this collaboration is that, if the project is successful, a much improved spectroscopic sequence will be available to the prostate program and can also be disseminated to external groups. Benefits to the Project The IGT resource provides an essential support to the R21 project. The programming environment for development of the sequence is maintained (in part) through support from the imaging core of the resource. In addition, a training fellow attached to the IGT resource, Joe Roebuck, who is both a radiologist and an spectroscopist, is participating in the experimental work of the R21 project. He is able to give clinical focus to the project as well as expert advice on matters pertaining to spectroscopy - in particular, processing of the spectroscopic data. He has built a prostate spectroscopic phantom for use by the project. Finally, the resource provides an essential clinical environment in which the method developed can be validated. Once technical development is completed, a feasibility study will be conducted using patients recruited through collaborations withing the IGT resource.