Dennis W. J. Klomp^1
1UMC Utrecht

In this course, the basics of maximizing SNR while minimizing sensitivity to system imperfections in MRSI of the human body are discussed using example applications in brain, prostate, breast, and body tuned for the nucleus of ¹H, ³¹P and ¹⁹F.

Peter B Barker^1
1Radiology, Johns Hopkins Univ School of Medicine, Baltimore, MD, United States

The efficient and accurate analysis of whole brain MR spectroscopic imaging (MRSI) data is critical for the acceptance of this technique into both research and clinical usage. This presentation will review methods for the processing of MRSI data collected with extended brain coverage and high spatial resolution, quantitive analysis methods, creation of metabolic images, and recognition/removal of unwanted artifacts.

Sarah Nelson^1
1Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, CA, United States

MR spectroscopic imaging (MRSI) makes it possible to study changes in metabolism that are associated with disease progression and response to therapy. Advances in MR hardware and software have provided new opportunities for obtaining data in a clinical feasible time and have therefore opened the door to a much broader range of applications than was previously considered. These applications will be demonstrated and future opportunities described.

M. Albert Thomas¹, Zohaib Iqbal¹, Manoj Kumar Sarma¹, and Rajakumar Nagarajan^1
1Radiology, UCLA Geffen School of Medicine, Los Angeles, CA, United States

In one-dimensional (1D) MR Spectroscopy (MRS), it is difficult to resolve the multitude of metabolite peaks that exist over a small spectral range. Spectral-editing techniques target a particular J-coupled metabolite selectively, such as lactate, GABA, glutamate, etc. with a drawback that only one metabolite is selected for each recording. Due to the added 2^nd dimension, two-dimensional (2D) MRS can unambiguously resolve many overlapping peaks non-selectively. Instead of a standard 1D spectrum plotting intensity versus a single-axis (i.e., chemical shift + J-coupling), 2D MRS techniques produce a 2D spectrum plotting intensity versus two frequency axes, the dimensions of which depend on the specific 2D MRS technique. A major goal of this presentation is to give an overview of the basics of 2D MRS and describe several localized 2D MRS sequences which have been implemented on the whole body 1.5T, 3T, and 7T MRI scanners. 
 

Rolf F Schulte^1
1GE Global Research, Munich, Germany

Main goal of in vivo Magnetic Resonance Spectroscopy (MRS) is the determination of individual metabolite concentrations in organs like the brain. Spectrally two-dimensional spectroscopy can help to encode more spectral information during the acquisition, and hence disentangle the overcrowded proton spectra. In order to quantify the 2D spectra most accurately, it is necessary to fit them to 2D metabolite basis spectra, hence utilising the full amount of available prior information. Reasons for fitting along with the actual fitting methods are explained in this educational talk.

Saadallah Ramadan^1
1University of Newcastle, Australia

Different types of 2D MRS can offer different types of information to understand the complexities underlying pathophysiology of disease. Technical developments specific to 2D method development and advanced post-processing methods will allow for the identification of biomarkers of diseases at an early stage. Acceleration of signal acquisition, as well as automated data processing algorithms are essential to introduce 2D MRS methods into the clinic.

Atiyah Yahya^1,2
1Department of Oncology, University of Alberta, Edmonton, AB, Canada, ²Department of Medical Physics, Cross Cancer Institute, Edmonton, AB, Canada

In-vivo proton magnetic resonance spectra exhibit poor spectral resolution due to the overlap of peaks with similar chemical shifts.  Spectral editing techniques have been designed and implemented to enable retention of peaks from metabolites of interest while suppressing background contaminating peaks.  The purpose of the lecture is to describe two important spectral editing techniques, namely, difference editing and multiple quantum filtering.  Basic principles and pulse sequences for each of the methods is presented along with how spatial localization can be incorporated.  In addition, examples of applications of the sequences are provided.      

Richard A. E. Edden^1
1Russell H Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD, United States

This presentation will cover the major steps required for the analysis of edited spectra, which include the standard steps used for all spectroscopy (Fourier transformation, windowing/filtering, integration/fitting) and some steps that are specifically required by editing (subtraction, frequency-and-phase correction of time-resolved data).

Wolfgang Bogner^1
1High-field MR Center, Department of Biomedical Imaging and Image-guided Therapy, Medical University Vienna, Vienna, Austria

Performing proton MR spectroscopy (¹H-MRS) at higher static magnetic field strengths (B₀) generally improves spectral resolution and, thereby, allows detection of a larger number of metabolites. However, even at very high B₀ and in particular on clinical MR scanners the spectral resolution is often not sufficient for an unambiguous quantification of several important J-coupled metabolites such as GABA, GSH, 2GH, Asc, or Lac. Their resonances are strongly overlapping with other more abundant metabolite resonances, which makes their accurate and reliable quantification via conventional ¹H-MRS difficult. Spectral editing methods can be applied to selectively quantify these J-coupled metabolites. This opens the window for numerous clinical and neuro-scientific applications.