Guo J, MacMillan B, Zamiri MS, Balcom BJ. Magnetic resonance T
1-T
2* and T
1ρ-T
2* relaxation correlation measurements in solid-like materials with non-exponential decays.
JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2021;
328:107005. [PMID:
34058713 DOI:
10.1016/j.jmr.2021.107005]
[Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/04/2021] [Revised: 05/11/2021] [Accepted: 05/12/2021] [Indexed: 06/12/2023]
Abstract
Magnetic resonance T1-T2* relaxation correlation is a newly emerging and powerful tool to study the structure and dynamics of materials. However, the T1-T2* of solid-like materials may consist of a linear combination of exponential decays and non-exponential decays, and the traditional methods for processing T1-T2 data would be not applicable. In this paper, a method of processing T1-T2* data with non-exponential decays was proposed. The critical idea is to decompose the data into two sub-datasets, exponential decays and non-exponential decays, employing a non-linear fitting method, and then to invert the sub-datasets and to combine the inversion results. We also introduce a related relaxation correlation measurement, T1ρ-T2*, for examination of solid-like materials. The same data processing strategy as for T1-T2* was implemented. The effectiveness of the proposed method for processing non-exponential data, Sinc Gaussian and Gaussian decay, was validated with simulation and experiment. The results showed that the proposed method recovers T1-T2* and T1ρ-T2* spectra with accurate relative signal intensities. The proposed method provides a platform for further development of MR methods applied to solid-like materials. These relaxation correlations are well suited to measuring composition of mixtures, with solid components in the mixture.
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