Systems and methods for determining electrical properties using magnetic resonance imaging

Patent metadata

Field	Value
Publication number	US-9645214-B2
Application number	US-201314095707-A
Country	US
Kind code	B2
Filing date	Dec 3, 2013
Priority date	Nov 27, 2013
Publication date	May 9, 2017
Grant date	May 9, 2017

Abstract

Systems and methods for determining electrical properties using Magnetic Resonance Imaging (MRI) are provided. One method includes applying an ultra-short echo time (TE) pulse sequence in a Magnetic Resonance Imaging (MRI) system and acquiring a complex B 1 + B 1 − quantity from an object following the application of the ultra-short TE pulse sequence, where B 1 + is a complex amplitude of a transmit radio-frequency (RF) magnetic field and B 1 − is a complex amplitude of a receive RF magnetic field. The method also includes estimating, with a processor, one or more electrical properties of the object using the complex amplitudes of the transmit RF magnetic field and the receive RF magnetic field.

First claim

What is claimed is:

1. A non-transitory computer readable storage medium for estimating electrical properties of an object using a processor, the non-transitory computer readable storage medium including instructions to command the processor to:
apply, via one or more coils, an ultra-short echo time (TE) pulse sequence in a Magnetic Resonance Imaging (MRI) system;
acquire, via one or more receivers, a complex B 1 + B 1 − quantity from an object following the application of the ultra-short TE pulse sequence, where B 1 + is a complex value of a transmit radio-frequency (RF) magnetic field and B 1 − is a complex value of a receive RF magnetic field;
estimate one or more electrical properties including a permittivity and conductivity of the object using the complex values of the transceive field B 1 + B 1 − ; and
reconstruct an image of the permittivity and conductivity of the object using the estimated one or more electrical properties, wherein the image is reconstructed using a single MRI acquisition.

2. The non-transitory computer readable storage medium of claim 1 , wherein the instructions command the processor to estimate the one or more electrical properties using the following:
For permittivity

ɛ
r

≈

-

1

μɛ
0

⁢

ω
2

⁢

Re
⁡

(

∇
2

⁢

B
1
+

⁢

B
1
-

B
1
+

⁢

B
1
-

)

For conductivity

σ
≈

-

1
μω

⁢

Im
⁡

(

∇
2

⁢

B
1
+

⁢

B
1
-

B
1
+

⁢

B
1
-

)

where k 2 is a complex wave vector, Re is the real component of the complex B 1 + B 1 − quantity, Im is the imaginary component of the complex B 1 + B 1 − quantity, B 1 + is the complex amplitude of the transmit RF magnetic field at a given three dimensional location and B 1 − is the complex amplitude of the receive RF magnetic field.

3. The non-transitory computer readable storage medium of claim 1 , wherein the instructions command the processor to produce the ultra-short TE pulse sequence as the rotating ultra-fast imaging sequence (RUFIS).

4. The non-transitory computer readable storage medium of claim 1 , wherein the instructions command the processor to use as the ultra-short TE pulse sequence a pulse sequence having an echo time below 1 millisecond, non-selective excitations of about 12 microseconds and incremental gradient updates.

5. The non-transitory computer readable storage medium of claim 1 , wherein the instructions command the processor to determine a tissue abnormality using the image of the permittivity and conductivity reconstructed using the one or more estimated electrical properties.

6. The non-transitory computer readable storage medium of claim 1 , wherein the instructions command the processor to calculate a √{square root over (B 1 + B 1 − )} complex quantity to estimate the one or more electrical properties of the object.

7. A method for non-invasively imaging tissue properties, the method comprising:
applying, with one or more coils, an ultra-short echo time (TE) pulse sequence in a Magnetic Resonance Imaging (MRI) system;
acquiring, with one or more receivers, a complex B 1 + B 1 − quantity from an object following the application of the ultra-short TE pulse sequence, where B 1 + is a complex amplitude of a transmit radio-frequency (RF) magnetic field and B 1 − is a complex amplitude of a receive RF magnetic field;
estimating, with a processor, one or more electrical properties including a permittivity and conductivity of the object using the complex amplitudes of the transmit RF magnetic field and the receive RF magnetic field;
reconstructing an image of the permittivity and conductivity of the object using the estimated one or more electrical properties; and
determining a tissue abnormality using the image of the permittivity and conductivity reconstructed using the one or more estimated electrical properties.

8. The method of claim 7 , wherein the one or more electrical properties are estimated using the following:
For permittivity

ɛ
r

≈

-

1

μɛ
0

⁢

ω

Assignees

• Gen Electric

Inventors

• Hancu Ileana
• Bulumulla Selaka Bandara
• Wiesinger Florian
• Sacolick Laura Irene
• Lee Seung Kyun

Classifications

• G01R33/246

  Spatial mapping of the RF magnetic field B1 · CPC title

• G01R33/4816 Primary

  NMR imaging of samples with ultrashort relaxation times such as solid samples, e.g. MRI using ultrashort TE [UTE], single point imaging, constant time imaging · CPC title