Using spatial prior knowledge in the spectral fitting of MRS images

B. Michael Kelm, Frederik O. Kaster, Anke Henning, Marc André Weber, Peter Bachert, Peter Boesiger, Fred A. Hamprecht, Bjoern H. Menze

Research output: Contribution to journalArticle

12 Scopus citations

Abstract

We propose a Bayesian smoothness prior in the spectral fitting of MRS images which can be used in addition to commonly employed prior knowledge. By combining a frequency-domain model for the free induction decay with a Gaussian Markov random field prior, a new optimization objective is derived that encourages smooth parameter maps. Using a particular parameterization of the prior, smooth damping, frequency and phase maps can be obtained whilst preserving sharp spatial features in the amplitude map. A Monte Carlo study based on two sets of simulated data demonstrates that the variance of the estimated parameter maps can be reduced considerably, even below the Cramér-Rao lower bound, when using spatial prior knowledge. Long-TE 1H MRSI at 1.5T of a patient with a brain tumor shows that the use of the spatial prior resolves the overlapping peaks of choline and creatine when a single voxel method fails to do so. Improved and detailed metabolic maps can be derived from high-spatial-resolution, short-TE 1H MRSI at 3T. Finally, the evaluation of four series of long-TE brain MRSI data with various signal-to-noise ratios shows the general benefit of the proposed approach.

Original languageEnglish (US)
Pages (from-to)1-13
Number of pages13
JournalNMR in biomedicine
Volume25
Issue number1
DOIs
Publication statusPublished - Jan 1 2012
Externally publishedYes

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Keywords

  • MRSI
  • Quantification
  • Spatial prior knowledge
  • Spectral fitting

ASJC Scopus subject areas

  • Molecular Medicine
  • Radiology Nuclear Medicine and imaging
  • Spectroscopy

Cite this

Kelm, B. M., Kaster, F. O., Henning, A., Weber, M. A., Bachert, P., Boesiger, P., ... Menze, B. H. (2012). Using spatial prior knowledge in the spectral fitting of MRS images. NMR in biomedicine, 25(1), 1-13. https://doi.org/10.1002/nbm.1704