System and method for quantitative magnetic resonance (MR) analysis using T1 mapping

Patent metadata

Field	Value
Publication number	US-10076264-B2
Application number	US-201615169208-A
Country	US
Kind code	B2
Filing date	May 31, 2016
Priority date	Mar 31, 2013
Publication date	Sep 18, 2018
Grant date	Sep 18, 2018

Abstract

Example apparatus and methods concern determining whether a target material appears in a region experiencing nuclear magnetic resonance (NMR). One method acquires a baseline value for a magnetic resonance parameter (MRP) while the region is not exposed to a molecular imaging agent that affects the MRP and acquires a series of quantitative values for the MRP while the sample is influenced by a molecular imaging agent. Quantitative values may be acquired during a clinically relevant time period (e.g., 60 minutes) during which the change in the MRP (e.g., T1) caused by the molecular imaging agent is at least 90% of the peak change caused by the molecular imaging agent. The molecular imaging agent may be SBK2 and may produce a desired change in T1 for at least thirty minutes in glioblastoma.

First claim

What is claimed is:

1. A method, comprising:
acquiring a nuclear magnetic resonance (NMR) data set from a volume during a period of time in which a change in T1 in the volume due to a molecular imaging agent remains within ninety percent of a peak change in spin-lattice relaxation time (T1) in the volume due to the molecular agent, wherein the molecular imaging agent binds to a tumor in the volume and changes T1 in the tumor; and
detecting a tumor that is less than the size of a voxel in the volume based on identifying characteristic changes in T1 over time using quantitative T1 relaxation time mapping of the NMR data set.

2. The method of claim 1 , comprising:
displaying an image of the tumor, where the image is reconstructed from the NMR data set.

3. The method of claim 1 , where acquiring the NMR data from the volume comprises:
acquiring a set of pre-agent NMR data from the volume before the molecular imaging agent is introduced into the volume; and
acquiring one or more sets of post-agent NMR data during a period of time during which a change in T1 caused by the molecular imaging agent in the volume remains within at least 90% of a peak change in T1 caused by the molecular imaging agent in the volume, where the period of time is at least fifteen minutes.

4. The method of claim 3 , where the period of time is at least thirty minutes.

5. The method of claim 3 , where the period of time is at least sixty minutes.

6. The method of claim 3 , where identifying characteristic changes in T1 over time is based on quantitative T1 relaxation time mapping applied to the one or more sets of post-agent NMR data indicating that a concentration of at least 0.08 mM is reached in the volume and that a concentration of Gd of at least 0.07 mM is maintained for the period of time in the volume.

7. The method of claim 3 , where identifying characteristic changes in T1 over time is based on quantitative T1 relaxation time mapping applied to the one or more sets of post-agent NMR data and the set of pre-agent NMR data, where the quantitative T1 relaxation time mapping indicates a concentration of at least 0.08 mM is reached and that a concentration of Gd of at least 0.07 mM is maintained for the period of time.

8. The method of claim 2 , comprising acquiring another set of NMR data from the volume after the molecular imaging agent has been introduced into the volume;
reconstructing a T2 weighted image from the another set of NMR data; and
selecting a sub-volume of the volume from which one or more sets of NMR data will be acquired based, at least in part, on the T2 weighted image.

9. The method of claim 3 , where acquiring members of the one or more sets of NMR data includes acquiring data using a T1 based acquisition approach, a T2 based acquisition approach, or a proton density acquisition approach.

10. The method of claim 9 further comprising acquiring at least one member of the sets of data using magnetic resonance fingerprinting.

11. The method of claim 9 further comprising;
producing a combined data set by adding together two or more members of the one or more sets of NMR data, by subtracting two or more members of the one or more sets of data from each other, by ANDing together two or more members of the one or more sets of data, by ORing together two or more members of the one or more sets of NMR data, or by XORing together two or more members of the sets of NMR data, and
reconstructing an image of the tumor from the combined data set.

12. The method of claim 3 , where acquiring members of the one or more sets of data includes acquiring data in a coronal plane, acquiring data in a sagittal plane, and acquiring data in a transverse plane.

13. The method of claim 12 , where the image of the tumor is a three dimensional image produced from data acquired in a coronal plane, a sagittal plane, and a transverse plane.

14. The method of claim 6 , comprising calculating gadolinium concentration maps from the one or more sets of post-agent NMR data.

15. The method of claim 14 , further comprising calculating gadolinium concentration per voxel according to:

Δ
⁡

(

1

T
1

)

=

1

T

1
,
post

-

1

T

1
,
pre

=

r
⁢

⁢
1
×

[

G

d
⁢

]

where T1 is the measured T1,
r1 is the relaxivity value, and
[Gd] is the gadolinium concentration.

16. The method of claim 3 , where a first portion of the one or more sets of data is acquired while the volume is positioned in a first magnetic resonance apparatus operating with a first main magnetic field strength and where a second portion of the one or more sets of data is acquired while the volume is positioned in a second, different magnetic resonance apparatus operating with a second, magnetic field strength different than the first main magnetic field strength.

17. The method of claim 1 , where detecting the tumor that is less than the size of a voxel in the volume based on identifying characteristic changes in T1 over time using quantitative T1 relaxation time mapping of the NMR data set includes analyzing slope values of the molecular imaging agent.

18. The method of claim 1 , wherein the molecular imaging agent is SBK2 conjugated to Lys-Gd.

19. The method of claim 1 , wherein the molecular imaging agent is SBK2 conjugated to Lys-DOTA that is a Gd chelate.

20. A non-transitory computer-readable medium having instructions stored thereon that when executed by a processor cause the processor to carry out steps comprising:
acquiring a baseline value for a magnetic resonance (MR) parameter of a region in a sample while the sample is not exposed to a molecular imaging agent that affects the MR parameter in the sample;
acquiring a series of quantitative values for the MR parameter, wherein the series of quantitative values for the MR parameter were acquired from the sample over a period of time during which the molecular imaging agent affects the MR parameter to within 90% of a peak influence of the molecular imaging agent on the MR parameter, the period of time being

Assignees

• Univ Case Western Reserve

Inventors

• Brady-Kalnay Susann
• Gulani Vikas
• Griswold Mark

Classifications

• G08C23/06

  through light guides, e.g. optical fibres · CPC title

• G01R33/50

  based on the determination of relaxation times {, e.g. T1 measurement by IR sequences; T2 measurement by multiple-echo sequences} · CPC title

• G16H30/40

  for processing medical images, e.g. editing · CPC title

• A61B5/4244

  liver · CPC title

• A61B2576/026

  for the brain · CPC title