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Three-dimensional radial echo-planar spectroscopic imaging for hyperpolarized 13 C MRSI in vivo.

Authors :
Awenius M
Abeln H
Müller M
Franke VL
Rincon G
Glowa C
Schmitt M
Bangert R
Ludwig D
Schmidt AB
Kuder TA
Ladd ME
Bachert P
Biegger P
Korzowski A
Source :
Magnetic resonance in medicine [Magn Reson Med] 2025 Jan; Vol. 93 (1), pp. 31-41. Date of Electronic Publication: 2024 Aug 20.
Publication Year :
2025

Abstract

Purpose: To demonstrate the feasibility of 3D echo-planar spectroscopic imaging (EPSI) technique with rapid volumetric radial k-space sampling for hyperpolarized (HP) <superscript>13</superscript> C magnetic resonance spectroscopic imaging (MRSI) in vivo.<br />Methods: A radial EPSI (rEPSI) was implemented on a 3 T clinical PET/MR system. To enable volumetric coverage, the sinusoidal shaped readout gradients per k-t-spoke were rotated along the three spatial dimensions in a golden-angle like manner. A distance-weighted, density-compensated gridding reconstruction was used, also in cases with undersampling of spokes in k-space. Measurements without and with HP <superscript>13</superscript> C-labeled substances were performed in phantoms and rats using a double-resonant <superscript>13</superscript> C/ <superscript>1</superscript> H volume resonator with 72 mm inner diameter.<br />Results: Phantom measurements demonstrated the feasibility of the implemented rEPSI sequence, as well as the robustness to undersampling in k-space up to a factor of 5 without advanced reconstruction techniques. Applied to measurements with HP [1- <superscript>13</superscript> C]pyruvate in a tumor-bearing rat, we obtained well-resolved MRSI datasets with a large matrix size of 12 <superscript>3</superscript> voxels covering the whole imaging FOV of (180 mm) <superscript>3</superscript> within 6.3 s, enabling to observe metabolism in dynamic acquisitions.<br />Conclusion: After further optimization, the proposed rEPSI method may be useful in applications of HP <superscript>13</superscript> C-tracers where unknown or varying metabolite resonances are expected, and the acquisition of dynamic, volumetric MRSI datasets with an adequate temporal resolution is a challenge.<br /> (© 2024 The Author(s). Magnetic Resonance in Medicine published by Wiley Periodicals LLC on behalf of International Society for Magnetic Resonance in Medicine.)

Details

Language :
English
ISSN :
1522-2594
Volume :
93
Issue :
1
Database :
MEDLINE
Journal :
Magnetic resonance in medicine
Publication Type :
Academic Journal
Accession number :
39164797
Full Text :
https://doi.org/10.1002/mrm.30258