US 12,593,999 B2Granted

Method and apparatus for measuring brain free water content and MRI system

AssigneesSiemens Healthineers AG, Henan Provincial People's Hospital

InventorsMei Yun Wang, Xian Chang Zhang, Yan Bai, Rui Zhang, Ru Shi Chen

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Abstract

In a method for measuring brain free water content, in response to an RF excitation field generated on the basis of a magnetic resonance fingerprinting sequence and applied to the brain, an equilibrium magnetization mixed term (M0) signal is acquired from radiation emitted by each excited voxel of the brain, to obtain an M0 value of each voxel of the brain; a receive coil sensitivity (RP) value of each voxel of the brain is acquired; the M0 value of each voxel of the brain is divided by the RP value of the corresponding voxel to obtain a proton density (PD) value of each voxel of the brain; a PD value of cerebrospinal fluid is taken to be a reference PD value; and the PD value of each voxel of the brain is divided by the reference PD value to obtain the free water content of each voxel of the brain. The method advantageously increases the speed and accuracy of measurement of brain free water content.

Claims11

Dependent claims

A method for measuring brain free water content, wherein the method comprises:

in response to a radio-frequency (RF) excitation field generated based on a magnetic resonance fingerprinting sequence and applied to the brain, concurrently acquiring, from radiation emitted by each excited voxel of the brain:
an equilibrium magnetization mixed term (M0) signal to obtain an M0 value of each voxel of the brain and a longitudinal relaxation time (T1) signal to obtain a T1 value of each voxel of the brain;
acquiring a receive coil sensitivity (RP) value of each voxel of the brain, the acquisition of the RP value of each voxel of the brain comprising:
obtaining a measured longitudinal relaxation rate (R1) value of each voxel of the brain based on a reciprocal of the T1 value of each voxel of the brain;
generating an R1 image of the brain based on the measured R1 values of all voxels of the brain;
determining a multiplicative bias between an actual R1 value and the measured R1 value of each voxel of the brain;
and
determining the RP value of each voxel of the brain based on the multiplicative bias corresponding to each voxel of the brain;
obtaining a proton density (PD) value of each voxel of the brain based on the M0 value of each voxel of the brain and the RP value of the corresponding voxel;
determining a reference PD value based on a PD value of cerebrospinal fluid;
obtaining the free water content of each voxel of the brain based on the PD value of each voxel of the brain and the reference PD value;
and
determining free water content data corresponding to the obtained free water content and outputting the free water content data in electronic form as a data file.

10 more elements

An apparatus for measuring brain free water content, comprising:

a signal acquisition module configured to, in response to a radio-frequency (RF) excitation field generated based on a magnetic resonance fingerprinting sequence and applied to the brain, concurrently acquire, from radiation emitted by each excited voxel of the brain:
an equilibrium magnetization mixed term (M0) signal to obtain an M0 value of each voxel of the brain and a longitudinal relaxation time (T1) signal to obtain a T1 value of each voxel of the brain;
a receive coil sensitivity (RP) acquisition module configured to acquire a RP value of each voxel of the brain, the acquisition of the RP value of each voxel of the brain comprising:
obtaining a measured longitudinal relaxation rate (R1) value of each voxel of the brain based on a reciprocal of the T1 value of each voxel of the brain;
generating an R1 image of the brain based on the measured R1 values of all voxels of the brain;
determining a multiplicative bias between an actual R1 value and the measured R1 value of each voxel of the brain;
and
determining the RP value of each voxel of the brain based on the multiplicative bias corresponding to each voxel of the brain;
a proton density (PD) acquisition module configured to determine a PD value of each voxel of the brain based on the M0 value of each voxel of the brain and the RP value of the corresponding voxel, a PD value of cerebrospinal fluid being a reference PD value;
and
a free water content acquisition module configured to determine the free water content of each voxel of the brain based on the PD value of each voxel of the brain and the reference PD value.

8 more elements

Dependencies are inferred from the claim text.

Facts

Application: 17/876,734Filed 29 Jul 2022
Priority: CN 202110878454.930 Jul 2021
Published: US 2023/0038549 A19 Feb 2023
Granted: 7 Apr 2026
Term ends: Not estimatedThe source records don’t support an estimate.

Classification9 codes

A61B 5/055
Detecting, measuring or recording for diagnosis by means of electric currents or magnetic fields; Measuring using microwaves or radio waves:…
G01R 33/448
Using nuclear magnetic resonance [NMR]: relaxometry, i.e. quantification of relaxation times or spin density
G01R 33/4828
NMR imaging systems: resolving the MR signals of different chemical species, e.g. water-fat imaging
G01R 33/50
NMR imaging systems: based on the determination of relaxation times , e.g. T1 measurement by IR sequences; T2 measurement by multiple-echo sequences