Spectroscopy - SEMI-LASER (SVS)

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The semi-LASER single-voxel spectroscopy sequence is now available for use at other institutions on compatible Siemens scanners by C2P agreement with CMRR and Siemens. This compact short TE sLASER sequence was developed as a collaboration between Gülin Öz and Dinesh Deelchand and features interleaved adiabatic refocusing, an optimized gradient scheme and 3D outer volume suppression (OVS) [10, 12]. It was harmonized across vendors [12] and developed as a plug-n-play protocol on the Siemens platform to facilitate acquisition of high-quality spectroscopic data without local MRS expertise [13]. The VD, VE and XA versions of the sequence feature automated FAST(EST)MAP shimming [13]. Finally, the sequence is set up to communicate with the AutoVOI automatic voxel placement tool [14], also available from the CMRR for research use, on VD and VE platforms.

This page is for SEMI_LASER: Compact short TE sLASER spectrsocopy sequence[10,12]. You may also be interested in the Spectroscopy sequences for LASER, PRESS, and STEAM or FAST(EST)MAP.

The sequence includes the following options, which can be enabled and disabled on a per-protocol basis by the user:

  • VAPOR water suppression with optimized timing and RF for 3 T and 7 T
  • Metabolite cycling water suppression option on XA
  • Optimized channel combination for multi-channel RF coils using an integrated reference scan
  • Automatic 3D OVS
  • Automatic FAST(EST)MAP shimming (VD, VE, XA versions)
  • 3D RF pulse selection profile readout with online display
  • Optional output to DICOM of unsummed averages (for offline processing)
  • Calibration loops (for optimizing flip angles, delays, water suppression, frequency offsets, et al.) with online display
  • Automatic calibration of reference voltage and water suppression flip angle
  • Option to acquire water reference and metabolite scans in one protocol (single DICOM)
  • Option to measure macromolecules using inversion-recovery technique
  • Option to receive automatically prescribed VOI from AutoVOI (VD, VE versions)

License

Obtaining a license

The available supported software versions are listed below. If you are interested in obtaining these sequences, please follow this process to obtain a CMRR license:

  1. Obtain authorization from your Siemens Regional Collaboration Manager for the specific software you would like to license. 
    1. Contact your Siemens Regional Collaboration Manager for authorization. Please ask them to use the following text in the agreement: "developed by Dr. Gülin Öz and colleagues (“DEVELOPER”), employees of the University of Minnesota." If you are experiencing any delays working with your Siemens Regional Collaboration Manager please contact Colin Giambrone (colin.giambrone@siemens-healthineers.com). 
    2. Send the completed authorization form to Gülin Öz
  2. Select the license from the OTC website and complete the license agreement.
  3. CMRR will send you your account information and instructions for downloading the software.

Please note that the entire licensing process may take up to two weeks to process.

Once you have executed a C2P agreement and have been given an access password, the sequence binaries can be downloaded here by selecting the desired release number.

Citation

If you publish or present results obtained using the software or sequences in this package, please acknowledge the researchers who developed the sequences using the following language:

The MRS package was developed by Gülin Öz and Dinesh Deelchand; and provided by the University of Minnesota under a C2P agreement.

In addition, please cite the associated references:

Oz G and Tkáč I. Short-echo, single-shot, full-intensity proton magnetic resonance spectroscopy for neurochemical profiling at 4 T: validation in the cerebellum and brainstem. Magn Reson Med. 2011; 65:901-10. doi: 10.1002/mrm.22708

Deelchand DK, et al. Across-vendor standardization of semi-LASER for single-voxel MRS at 3T. NMR Biomed. 2021; 34:e4218. doi: 10.1002/nbm.4218

Deelchand DK, et al. Plug-and-play advanced magnetic resonance spectroscopy. Magn Reson Med. 2022; 87:2613-2620. doi: 10.1002/mrm.29164

Contact

If you have noticed a bug or have a request for a new feature in a future release, please contact

Dinesh Deelchand. Be sure to include the sequence variant and the model of scanner you are using in the problem description.

Download SEMI-LASER (MRM 2011, NMB 2019)

SEMI-LASER (MRM 2011, NMB 2019) - Version Release 2016-12


References

  1. Marjańska M, et al. Localized 1H NMR spectroscopy in different regions of human brain in vivo at 7 T: T2 relaxation times and concentrations of cerebral metabolites. NMR Biomed. 2012; 25:332-9. doi: 10.1002/nbm.1754

  2. Klomp DW, et al. Proton spectroscopic imaging of the human prostate at 7 T. NMR Biomed. 2009; 22:495-501. doi: 10.1002/nbm.1360

  3. Tremblay S, et al. The use of magnetic resonance spectroscopy as a tool for the measurement of bi-hemispheric transcranial electric stimulation effects on primary motor cortex metabolism. J Vis Exp. 2014; (unknown volume):e51631. doi: 10.3791/51631

  4. Marjańska M, et al. Brain dynamic neurochemical changes in dystonic patients: a magnetic resonance spectroscopy study. Mov Disord. 2013; 28:201-9. doi: 10.1002/mds.25279

  5. Garwood M and DelaBarre L. The return of the frequency sweep: designing adiabatic pulses for contemporary NMR. J Magn Reson. 2001; 153:155-77. doi: 10.1006/jmre.2001.2340

  6. Mescher M, et al. Simultaneous in vivo spectral editing and water suppression. NMR Biomed. 1998; 11:266-72. doi: 10.1002/(sici)1099-1492(199810)11:6<266::aid-nbm530>3.0.co;2-j

  7. Tkác I, et al. In vivo 1H NMR spectroscopy of rat brain at 1 ms echo time. Magn Reson Med. 1999; 41:649-56. doi: 10.1002/(sici)1522-2594(199904)41:4<649::aid-mrm2>3.0.co;2-g

  8. Gruetter R and Tkác I. Field mapping without reference scan using asymmetric echo-planar techniques. Magn Reson Med. 2000; 43:319-23. doi: 10.1002/(sici)1522-2594(200002)43:2<319::aid-mrm22>3.0.co;2-1

  9. Kaiser LG, et al. Elimination of spatial interference in PRESS-localized editing spectroscopy. Magn Reson Med. 2007; 58:813-8. doi: 10.1002/mrm.21407

  10. Oz G and Tkáč I. Short-echo, single-shot, full-intensity proton magnetic resonance spectroscopy for neurochemical profiling at 4 T: validation in the cerebellum and brainstem. Magn Reson Med. 2011; 65:901-10. doi: 10.1002/mrm.22708

  11. Allaïli N, et al. Single-voxel (1)H spectroscopy in the human hippocampus at 3 T using the LASER sequence: characterization of neurochemical profile and reproducibility. NMR Biomed. 2015; 28:1209-17. doi: 10.1002/nbm.3364

  12. Deelchand DK, et al. Across-vendor standardization of semi-LASER for single-voxel MRS at 3T. NMR Biomed. 2021; 34:e4218. doi: 10.1002/nbm.4218

  13. Deelchand DK, et al. Plug-and-play advanced magnetic resonance spectroscopy. Magn Reson Med. 2022; 87:2613-2620. doi: 10.1002/mrm.29164

  14. Park YW, et al. AutoVOI: real-time automatic prescription of volume-of-interest for single voxel spectroscopy. Magn Reson Med. 2018; 80:1787-1798. doi: 10.1002/mrm.27203

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