title: Flexible proton 3D MR spectroscopic imaging of the prostate with low-power adiabatic pulses for volume selection and spiral readout.
abstract: Cartesian k-space sampling in three-dimensional magnetic resonance spectroscopic imaging (MRSI) of the prostate limits the selection of voxel size and acquisition time. Therefore, large prostates are often scanned at reduced spatial resolutions to stay within clinically acceptable measurement times. Here we present a semilocalized adiabatic selective refocusing (sLASER) sequence with gradient-modulated offset-independent adiabatic (GOIA) refocusing pulses and spiral k-space acquisition (GOIA-sLASER-Spiral) for fast prostate MRSI with enhanced resolution and extended matrix sizes.
  
  
  
  MR was performed at 3 tesla with an endorectal receive coil. GOIA-sLASER-Spiral at an echo time (TE) of 90 ms was compared to a point-resolved spectroscopy sequence (PRESS) with weighted, elliptical phase encoding at an TE of 145 ms using simulations and measurements of phantoms and patients (n = 9).
  
  
  
  GOIA-sLASER-Spiral acquisition allows prostate MR spectra to be obtained in ∼5 min with a quality comparable to those acquired with a common Cartesian PRESS protocol in ∼9 min, or at an enhanced spatial resolution showing more precise tissue allocation of metabolites. Extended field of views (FOVs) and matrix sizes for large prostates are possible without compromising spatial resolution or measurement time.
  
  
  
  The flexibility of spiral sampling enables prostate MRSI with a wide range of resolutions and FOVs without undesirable increases in acquisition times, as in Cartesian encoding. This approach is suitable for routine clinical exams of prostate metabolites. Magn Reson Med 77:928-935, 2017. © 2016 International Society for Magnetic Resonance in Medicine.
authors.affiliation: Department of Radiology and Nuclear Medicine (667), Radboud University Medical Center, Nijmegen, The Netherlands.
authors.forename: Isabell K
authors.initials: IK
authors.lastname: Steinseifer
authors.affiliation: Department of Radiology and Nuclear Medicine (667), Radboud University Medical Center, Nijmegen, The Netherlands.
authors.forename: Bart W J
authors.initials: BW
authors.lastname: Philips
authors.affiliation: Fetal-Neonatal Neuroimaging & Developmental Science Center, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, USA.
authors.forename: Borjan
authors.initials: B
authors.lastname: Gagoski
authors.affiliation: MR Pre-Development, Siemens Healthcare, Erlangen, Germany.
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Weiland
authors.affiliation: Department of Radiology and Nuclear Medicine (667), Radboud University Medical Center, Nijmegen, The Netherlands.
authors.forename: Tom W J
authors.initials: TW
authors.lastname: Scheenen
authors.affiliation: Department of Radiology and Nuclear Medicine (667), Radboud University Medical Center, Nijmegen, The Netherlands.
authors.forename: Arend
authors.initials: A
authors.lastname: Heerschap
mesh_terms: D000465:Algorithms; D014408:Biomarkers, Tumor / Q000378:metabolism*; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D007090:Image Interpretation, Computer-Assisted / Q000379:methods; D021621:Imaging, Three-Dimensional / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D057054:Molecular Imaging / Q000379:methods*; D011471:Prostatic Neoplasms / Q000000981:diagnostic imaging / Q000378:metabolism*; D066244:Proton Magnetic Resonance Spectroscopy / Q000379:methods*; D012680:Sensitivity and Specificity; D012815:Signal Processing, Computer-Assisted
chemical_list: D014408:Biomarkers, Tumor
keywords: GOIA; adiabatic pulses; prostate; semi-LASER; spectroscopic imaging; spiral k-space sampling