Department of Radiological Sciences, David Geffen School of Medicine, University of California, Los Angeles, CA, 90095, USA.
NMR Biomed. 2014 Jan;27(1):53-66. doi: 10.1002/nbm.2991. Epub 2013 Jul 31.
Prostate cancer (PCa) is the second most common type of cancer among men in the United States. A major limitation in the management of PCa is an inability to distinguish, early on, cancers that will progress and become life threatening. One-dimensional (1D) proton ((1)H) MRS of the prostate provides metabolic information such as levels of choline (Ch), creatine (Cr), citrate (Cit), and spermine (Spm) that can be used to detect and diagnose PCa. Ex vivo high-resolution magic angle spinning (HR-MAS) of PCa specimens has revealed detection of more metabolites such as myo-inositol (mI), glutamate (Glu), and glutamine (Gln). Due to the J-modulation and signal overlap, it is difficult to quantitate Spm and other resonances in the prostate clearly by single- and multivoxel-based 1D MR spectroscopy. This limitation can be minimized by adding at least one more spectral dimension by which resonances can be spread apart, thereby increasing the spectral dispersion. However, recording of multivoxel-based two-dimensional (2D) MRS such as J-resolved spectroscopy (JPRESS) and correlated spectroscopy (L-COSY) combined with 2D or three-dimensional (3D) magnetic resonance spectroscopic imaging (MRSI) using conventional phase-encoding can be prohibitively long to be included in a clinical protocol. To reduce the long acquisition time required for spatial encoding, the echo-planar spectroscopic imaging (EPSI) technique has been combined with correlated spectroscopy to give four-dimensional (4D) echo-planar correlated spectroscopic imaging (EP-COSI) as well as J-resolved spectroscopic imaging (EP-JRESI) and the multi-echo (ME) variants. Further acceleration can be achieved using non-uniform undersampling (NUS) and reconstruction using compressed sensing (CS). Earlier versions of 2D MRS, theory of 2D MRS, spectral apodization filters, newer developments and the potential role of multidimensional MRS in PCa detection and management will be reviewed here.
前列腺癌（PCa）是美国男性中第二常见的癌症类型。在 PCa 的管理中，一个主要的局限性是无法早期区分那些会进展并危及生命的癌症。一维（1D）质子（(1)H）磁共振波谱（MRS）可提供代谢信息，如胆碱（Ch）、肌酸（Cr）、柠檬酸（Cit）和精胺（Spm）的水平，可用于检测和诊断 PCa。PCa 标本的体外高分辨率魔角旋转（HR-MAS）显示，检测到更多的代谢物，如肌醇（mI）、谷氨酸（Glu）和谷氨酰胺（Gln）。由于 J 调制和信号重叠，通过单和多体素 1D MRS 很难清楚地定量前列腺中的 Spm 和其他共振峰。通过增加至少一个额外的光谱维度，可以最小化这种限制，从而增加光谱的分散度，通过该维度可以使共振峰分开。然而，记录基于多体素的二维（2D）MRS，如 J 分辨光谱（JPRESS）和相关光谱（L-COSY），结合使用常规相位编码的二维或三维（3D）磁共振波谱成像（MRSI），可能由于采集时间过长而无法纳入临床方案。为了减少空间编码所需的长采集时间，回波平面波谱成像（EPSI）技术已与相关光谱结合，给出了四维（4D）回波平面相关光谱成像（EP-COSI）以及 J 分辨光谱成像（EP-JRESI）和多回波（ME）变体。使用非均匀欠采样（NUS）和压缩感知（CS）重建可以进一步加速。本文将回顾二维 MRS 的早期版本、二维 MRS 的理论、光谱调幅滤波器、新的发展以及多维 MRS 在 PCa 检测和管理中的潜在作用。
