IMPROVED SPACIAL LOCALIZATION FOR SPECTROSCOPIC IMAGING

这个子项目是许多研究子项目中利用 资源由NIH/NCRR资助的中心拨款提供。子项目和 调查员(PI)可能从NIH的另一个来源获得了主要资金， 并因此可以在其他清晰的条目中表示。列出的机构是 该中心不一定是调查人员的机构。 活体核磁共振质子光谱学已被证明是有临床价值的评估和定位的前列腺肿瘤。然而，由于磁共振光谱成像(MRSI)固有的低信噪比(SNR)，测量时间可能非常长。因此，为了实用于临床的前列腺MRSI，这些时间必须减少，并且空间分辨率通常很低。在MRSI中，与低分辨率数据采集相关的一个重要问题是可能存在显著的振铃，即来自邻近甚至远处的体素的一种信号污染渗入感兴趣体素。不受抑制的脂质或水信号的污染可能特别有问题，在某些情况下，使前列腺谱无法诊断。一种新的混合空间编码方法正在开发中。该方法称为PSF-Choice，保持了标准傅立叶编码的简单性，同时包含了非傅立叶编码的灵活性，以整形点扩展函数(PSF)。使用这种方法，可以在不增加成像时间或分辨率或信噪比损失的情况下，实现没有脂质污染的实用的前列腺光谱成像。 项目开工时间：2005年5月9日 项目结束：30-APR-2008 协作给NCIGT带来的好处 磁共振光谱成像正在成为诊断前列腺癌的IGT计划中使用的一种常见方式。不幸的是，正如一些研究表明的那样，患者检查的许多体素的光谱受到脂质泄漏的破坏，并且光谱不具有诊断质量。在一些患者中，这可能是多达90%的体素。PSF-Choice提供了消除这种污染的可能性，从而极大地提高了MRSI检查的诊断质量。该方法是根据其他组织用于前列腺光谱分析的散文序列编写的。这一合作对资源的好处是，如果该项目成功，前列腺癌计划将获得一个大大改进的光谱序列，也可以传播给外部小组。 给项目带来的好处 IGT资源为R21项目提供了必要的支持。用于序列开发的编程环境(部分地)通过来自资源的成像核心的支持来维护。此外，隶属于IGT资源的培训研究员Joe Roebuck既是一名放射学家，也是一名光谱学家，正在参与R21项目的实验工作。他能够将临床重点放在该项目上，并就与光谱学有关的问题提供专家建议-特别是光谱学数据的处理。他已经建造了一个前列腺光谱体模，供该项目使用。最后，该资源提供了一个基本的临床环境，可以在其中验证所开发的方法。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。 U41助学金申请中的协作声明 这个R21项目没有包括在最初的赠款申请中，因为它从那时起就得到了资助。 承认R21和U41奖助金的期刊出版物 Panych LP，Roebuck Jr和Chen N-K。使用部分抑制的水信号来校正MRSI数据中的中心频率变化。2007年ISMRM，柏林。

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. 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. Project Start: 09-MAY-2005 Project End: 30-APR-2008 Benefits of the Collaboration 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. Statement of the Collaboration in the U41 Grant Application This R21 project was not included in original grant application because it has been funded since then. Journal publications Acknowledging both the R21 and the U41 Grants Panych LP, Roebuck JR and Chen N-K. Correcting for center frequency variations in MRSI data using the partially suppressed water signal. 2007 ISMRM, Berlin.