A Simultaneous Measurement Method of Angle and Relaxation Time Constant t1 of Gas Spectrum

Abstract

The invention discloses an angle and T1 simultaneous measurement method based on a hyperpolarized gas spectrum, and the method comprises the steps: collecting hyperpolarized gas; enabling a research object to obtain the hyperpolarized gas; fixing an excitation angle theta of a radio frequency pulse in one breath holding process, collecting a magnetic resonance spectrum of the hyperpolarized gas ofthe research object, and obtaining a free induction decay signal FID1 of the hyperpolarized gas of the research object in a variable repetition time TR1 and a free induction decay signal FID2 of thehyperpolarized gas of the research object in a fixed repetition time TR2; processing the FID1 and FID2 signals, and obtaining an actual excitation angle theta(r) of the radio frequency pulse and the spin-lattice relaxation time constant T1 of the hyperpolarized gas of the research object. According to the invention, the method can achieve the simultaneous obtaining of the angle and an analytical solution of T1, shortens the sampling time, reduces the requirements for hardware, is easy for engineering implementation, and is simple in data processing.

Description

technical field [0001] The invention relates to the technical field of magnetic resonance spectroscopy, in particular to a gas spectrum angle and relaxation time constant T 1 Simultaneous measurement method. Suitable for precise control of the excitation angle of radio frequency pulses using hyperpolarized gas as a contrast agent, T 1 measurement etc. Background technique [0002] Magnetic Resonance Spectroscopy (MRS) is based on the observation that the nucleus in the sample is excited by a radio frequency (RF) pulse in a magnetic field to generate nuclear magnetic resonance. The electronic system receives the magnetic resonance signal generated by the sample, and the obtained The digital signal is subjected to spectral transformation, and the magnetic resonance spectrum can be reconstructed. Conventional MRS is mostly used for H atoms in water or lipids. For inert gas atoms, the method of spin exchange optical pump is usually used, so that the magnetization vector at n...

AI Technical Summary

Problems solved by technology

In addition, on the one hand, limited by the hardware of the instrument, only a limited number of RF pulses with different excitation angles can be set in the experiment; collection time of

Currently commonly used methods for measuring the RF pulse angle θ are susceptible to T 1 Influenced by relaxation, the sampling time is too long, the fitting error is large, multiple excitation angles need to be set, and the hardware requirements are high

[0004] There are also magnetic resonance imaging methods for excitation angle measurements of hyperpolarized gases, but these methods require multiple breath-holds, resulting in long acquisition times and are susceptible to varying gas volumes at different breath-holds

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