MRS quality assessment in a multicentre study on MRS-based classification of brain tumours

Marinette van der Graaf, Margarida Julià-Sapé, Franklyn A. Howe, Anne Ziegler, Carles Majós, Angel Moreno-Torres, Mark Rijpkema, Dionisio Acosta, Kirstie S. Opstad, Yvonne M. van der Meulen, Carles Arús, Arend Heerschap

Research output: Contribution to journalArticleResearchpeer-review

35 Citations (Scopus)

Abstract

This paper reports on quality assessment of MRS in the European Union-funded multicentre project INTERPRET (International Network for Pattern Recognition of Tumours Using Magnetic Resonance; http://azi-zu.uab.es/INTERPRET), which has developed brain tumour classification software using in vivo proton MR spectra. The quality assessment consisted of both MR system quality assurance (SQA) and quality control (QC) of spectral data acquired from patients and healthy volunteers. The system performance of the MR spectrometers at all participating centres was checked bimonthly by a short measurement protocol using a specially designed INTERPRET phantom. In addition, a more extended SQA protocol was performed yearly and after each hardware or software upgrade. To compare the system performance for in vivo measurements, each centre acquired MR spectra from the brain of five healthy volunteers. All MR systems fulfilled generally accepted minimal system performance for brain MRS during the entire data acquisition period. The QC procedure of the MR spectra in the database comprised automatic determination of the signal-to-noise ratio (SNR) in a water-suppressed spectrum and of the line width of the water resonance (water band width, WBW) in the corresponding non-suppressed spectrum. Values of SNR > 10 and WBW < 8Hz at 1.5 T were determined empirically as conservative threshold levels required for spectra to be of acceptable quality. These thresholds only hold for SNR and WBW values using the definitions and data processing described in this article. A final QC check consisted of visual inspection of each clinically validated water-suppressed metabolite spectrum by two, or, in the case of disagreement, three, experienced MR spectroscopists, to detect artefacts such as large baseline distortions, exceptionally broadened metabolite peaks, insufficient removal of the water line, large phase errors, and signals originating from outside the voxel. In the end, 10% of 889 spectra with completed spectroscopic judgement were discarded. Copyright © 2007 John Wiley & Sons, Ltd.
Original languageEnglish
Pages (from-to)148-158
JournalNMR in Biomedicine
Volume21
DOIs
Publication statusPublished - 1 Feb 2008

Keywords

  • 1 H MRS
  • MR spectra
  • Multicentre study
  • Phantom
  • Quality assessment
  • Quality control
  • System quality assurance

Fingerprint Dive into the research topics of 'MRS quality assessment in a multicentre study on MRS-based classification of brain tumours'. Together they form a unique fingerprint.

Cite this