Premium
Flexible proton 3 D MR spectroscopic imaging of the prostate with low‐power adiabatic pulses for volume selection and spiral readout
Author(s) -
Steinseifer Isabell K.,
Philips Bart W.J.,
Gagoski Borjan,
Weiland Elisabeth,
Scheenen Tom W. J.,
Heerschap Arend
Publication year - 2017
Publication title -
magnetic resonance in medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.696
H-Index - 225
eISSN - 1522-2594
pISSN - 0740-3194
DOI - 10.1002/mrm.26181
Subject(s) - spiral (railway) , volume (thermodynamics) , selection (genetic algorithm) , adiabatic process , proton , nuclear magnetic resonance , prostate , chemistry , physics , medicine , computer science , cancer , nuclear physics , mathematics , mathematical analysis , artificial intelligence , quantum mechanics , thermodynamics
Purpose 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. Methods 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). Results 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. Conclusion 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