Glutamate-Weighted CEST Contrast After Removal of Magnetization Transfer Effect in Human Brain and Rat Brain with Tumor

Autor: Ravi Prakash Reddy Nanga, Ayan Debnath, Anup Singh, Ravinder Reddy, Hari Hariharan
Rok vydání: 2020
Předmět:
Zdroj: Molecular Imaging and Biology. 22:1087-1101
ISSN: 1860-2002
1536-1632
Popis: To mitigate the effect of magnetization transfer (MT) from glutamate-weighted chemical exchange saturation transfer (GluCEST) contrast in healthy human brain and its demonstration in a rat brain tumor model. GluCEST data was acquired from six healthy human volunteers at 7T and on a rat brain with tumor at 9.4 T. Single voxel proton magnetic resonance spectroscopy (1HMRS) data was acquired from three human volunteers. The magnetic resonance imaging protocol included CEST data acquisition at multiple frequencies for generating Z-spectra, B0 and B1 map. Partial Z-spectra at offset frequencies from ± 100 to ± 14 ppm were fitted to model semi-solid MT component by Lorentzian, Gaussian, super-Lorentzian, and 6th degree polynomial function lineshapes. Average residual errors per pixel was calculated. The MT effect of the Z-spectra was removed by subtracting fitted MT component from Z-spectra. GluCEST was computed as GluCESTNeg (normalized with signal at − 3 ppm) and GluCESTM0 (normalized with unsaturated signal). The difference between GluCEST maps before and after MT removal was compared using T test. Better accuracy of fitting off-resonance Z-spectra was achieved with super-Lorentzian (σ = 0.0009) and Lorentzian (σ = 0.0017) compared to other lineshapes. There was significant (p
Databáze: OpenAIRE
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