Considerations in applying 3D PRESS H-1 brain MRSI with an eight-channel phased-array coil at 3 T

T1 and T2 Metabolite Relaxation Times in Normal Brain at 3T and 7T

“…The linewidths in the TE-averaged spectra at 3T were close to those previously reported [19], however, the linewidths of the TE-averaged spectra were worse than those acquired with a single echo time using spectral-spatial pulses at 7T. The linewidths in the single echo time spectra at 7T were close to values published previously as well [1][2][3]28].…”

“…The t1 was incremented by 2.5 ms from 35 ms to 192.5 ms for a total of 64 steps at 3T [5], while at 7T, 48 spectra were acquired at 5 ms increments starting at TE of 35 ms. With a TR of 2 s and a number of excitations (NEX) of 2, the total acquisition time was ~ 5 minutes at 3T and ~ 4 minutes at 7T. Overpress factors of 1.2 at 3T [19] and 1.4 at 7T were utilized to reduce chemical shift artifact, and very selective suppression (VSS) pulses [20] of 40 mm width were played out around the prescribed volume for outer volume suppression at both field strengths. The manufacturer's linear autoshim procedure was applied at 3T, and an in-house, higher-order shimming routine [14] was performed at 7T.…”

“…Eight-channel data were combined in the time-domain using the unsuppressed water signal [22] at 3T, and using in-house developed software which utilized the theory based on a sensitivity encoding (SENSE) reconstruction with a reduction factor (R) of 1.0 as described in a previous article [19] at 7T. The spectral data were apodized by a 4 Hz Lorentzian filter at both 3T and 7T, and then spectra were processed with a Fast Fourier Transform (FFT).…”

A systematic review of the utility of 1.5 versus 3 Tesla magnetic resonance brain imaging in clinical practice and research

“…On angiography, SNR was higher at 3 T by a factor of 1.8-2.3 [13][14][15][16]. On spectroscopy, SNR was clearly increased, although the 100 % theoretical increase was not achieved, even in phantoms, the documented increases being 23 [20], or 50 % [21]. Most gain in SNR was with short echo time spectroscopy with little improvement at long echo times [18,19,22].…”

Association of early changes in1H MRSI parameters with survival for patients with newly diagnosed glioblastoma receiving a multimodality treatment regimen

“…15,16 In brief, the start point was the raw data file obtained from the lactate edited MRSI sequence. This comprised 8 channels of interleaved acquisitions (or cycles) obtained with radiofrequency pulses that modulated the phase of the lactate peak.…”