Achieving sufficient spectral bandwidth for volumetric 1H echo-planar spectroscopic imaging at 4 Tesla

Andreas Ebel, Andrew A. Maudsley, Michael W. Weiner, Norbert Schuff

Research output: Contribution to journalArticlepeer-review

14 Scopus citations


Complete coverage of the in vivo proton metabolite spectrum, including downfield resonances, requires a spectral bandwidth of approximately 9 ppm. Spectral bandwidth of in vivo echoplanar spectroscopic imaging (EPSI) is primarily limited by gradient strength of the oscillating readout gradient, gradient slew rate, and limits on peripheral nerve stimulation for human subjects. Furthermore, conventional EPSI reconstruction, which utilizes even and odd readout echoes separately, makes use of only half the spectral bandwidth. In order to regain full spectral bandwidth in EPSI, it has previously been suggested to apply an interlaced Fourier transform (iFT), which uses even and odd echoes simultaneously. However, this method has not been thoroughly analyzed regarding its usefulness for in vivo 3D EPSI. In this Note, limitations of the iFT method are discussed and an alternative, cyclic spectral unwrapping, is proposed, which is based on prior knowledge of typical in vivo spectral patterns.

Original languageEnglish (US)
Pages (from-to)697-701
Number of pages5
JournalMagnetic Resonance in Medicine
Issue number3
StatePublished - Sep 2005


  • Brain
  • In vivo MR spectroscopic imaging
  • Interlaced Fourier transform
  • Spectral bandwidth

ASJC Scopus subject areas

  • Radiology Nuclear Medicine and imaging
  • Radiological and Ultrasound Technology


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