Multi-Echo Gradient-Echo Spin-Echo with Echo-Planar Imaging for simultaneous quantification of T2* and T2

July 13, 2022

Motivation: T2* and T2 contrast-based sequences provide complementary information for MR applications. The Gradient-Echo and Spin-Echo (GESE) sequence has been developed to facilitate the simultaneous acquisition of T2* and T2-weighted images. Objectives: Corroborate the results reported in existing studies that tested the GESE sequence with EPI readout in the myocardium, WM and GM. Methods: The GESE sequence was implemented through pulse programming by modifying the standard implementation of the ME-GE with EPI readout. Two variations tested - with simple and with composite refocusing pulses. Phantom scans and in-vivo scans of two healthy volunteers were conducted. Subsequently, a pixel-wise least squares fit was performed for computing quantitative T2* and T2 maps, from which ROIs were defined and mean values were extracted. Result: Results obtained with simple and composite refocusing pulses, were respectively: for WM T2*: (55 ± 1 ; 52 ± 2) ms , T2: (64 ± 2 ; 64 ± 4) ms , for GM (T2*: 57 ± 2 ; 56 ± 3) ms , T2: (78 ± 5; 80 ± 8) ms and for Myocardium T2*: (25 ± 10 , 27 ± 12) ms; T2: (34 ± 14, 46 ± 32) ms. Conclusions: The values of T2* and T2 using the GESE sequence with composite pulse, for the myocardium and WM were similar to the ones reported in literature and generated relative errors between 1.6 and 6.1%. For GM, both values were more distant from to the ones reported in literature, with relative errors of 12.0% and 12.7%.

Authors in the community:

• 

  J

  Joana Rita Mayer Rodrigues Vera-Cruz

  ist197130

Supervisors of this institution:

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  R

  Rita Homem de Gouveia Costanzo Nunes

  ist31063

industrial-biotechnology - Industrial Biotechnology

eng - English

Instituto Superior Técnico