MR fingerprinting for determining performance degradation of the MR system

Patent metadata

Field	Value
Publication number	US-10345407-B2
Application number	US-201615547622-A
Country	US
Kind code	B2
Filing date	Jan 22, 2016
Priority date	Feb 2, 2015
Publication date	Jul 9, 2019
Grant date	Jul 9, 2019

Abstract

The invention provides for a method of operating a magnetic resonance system for acquiring magnetic resonance data ( 152 ) from a phantom ( 124 ) within a measurement (zone 108 ). The phantom comprises a known volume of at least one predetermined substance (( 128 ), 130 ). The method comprises the step of acquiring ( 300 ) the magnetic resonance data by controlling the magnetic resonance system with pulse sequence instructions ( 150 ). The pulse sequence instructions cause the magnetic resonance system to acquire the magnetic resonance data according to a magnetic resonance fingerprinting technique. The pulse sequence instructions specify a train of pulse sequence repetitions. Each pulse sequence repetition has a repetition time chosen from a distribution of repetition times. Each pulse sequence repetition comprises a radio frequency pulse chosen from a distribution of radio frequency pulses. The distribution of radio frequency pulses cause magnetic spins to rotate to a distribution of flip angles. Each pulse sequence repetition comprises a sampling event where the magnetic resonance signal is sampled for a predetermined duration at a sampling time before the end of the pulse sequence repetition. The method further comprises determining ( 302 ) one or more performance degradation conditions of the magnetic resonance system by comparing the magnetic resonance data with a magnetic resonance fingerprinting dictionary ( 154 ). The magnetic resonance fingerprinting dictionary contains a listing of magnetic resonance signals for a set of system states in response to execution of the pulse sequence instructions for each of the at least one predetermined substance.

First claim

The invention claimed is:

1. A method of operating a magnetic resonance system for acquiring magnetic resonance data from a phantom within a measurement zone, wherein the phantom comprises a known volume of at least one predetermined substance, wherein the method comprises the steps of:
acquiring the magnetic resonance data by controlling the magnetic resonance system with pulse sequence instructions, wherein the pulse sequence instructions cause the magnetic resonance system to acquire the magnetic resonance data according to a magnetic resonance fingerprinting technique, wherein the pulse sequence instructions specify a train of pulse sequence repetitions, wherein each pulse sequence repetition has a repetition time chosen from a distribution of repetition times, wherein each pulse sequence repetition comprises a radio frequency pulse chosen from a distribution of radio frequency pulses, wherein the distribution of radio frequency pulses cause magnetic spins to rotate to a distribution of flip angles, and wherein each pulse sequence repetition comprises a sampling event where the magnetic resonance signal is sampled for a predetermined duration at a sampling time before the end of the pulse sequence repetition, wherein the sampling time is chosen from a distribution of sampling times, wherein the magnetic resonance data is acquired during the sampling event; and
determining an occurrence of one or more performance degradation conditions, faults or malfunctions of the magnetic resonance system by comparing the magnetic resonance data with a magnetic resonance fingerprinting dictionary, wherein the magnetic resonance fingerprinting dictionary contains a listing of magnetic resonance signals for a set of system states in response to execution of the pulse sequence instructions for each of the at least one predetermined substance, wherein the set of system states represent faults, malfunctions, and/or performance degradations conditions by different components of the magnetic resonance system.

2. The method of claim 1 , wherein the pulse sequence instructions comprises multiple segments, wherein the magnetic resonance fingerprinting dictionary is arranged as a decision tree for determining the one or more faults that comprises each of the multiple segments, wherein the decision tree has multiple entries, wherein each of the multiple entries connected by branches, wherein the multiple segments of the pulse sequence instructions comprises a first segment, wherein the multiple entries of the decision tree comprise a first entry which corresponds to the first segment, wherein the method further comprises:
controlling the magnetic resonance system with the first segment to acquire a first portion of the magnetic resonance data;
comparing the first portion of the magnetic resonance data to the first entry in the decision tree to choose a branch which identifies a subsequent segment of the pulse sequence data; and
traversing the decision tree to identify the one or more faults by repeatedly controlling the magnetic resonance system with the subsequence segment and re-identifying the subsequence segment using the branches of the decision tree.

3. The method of claim 1 , wherein the one or more faults is two or more faults, wherein the two or more faults are identified as a linear combination of the set of system states.

4. The method of claim 1 , wherein the magnetic resonance system is a magnetic resonance imaging system, wherein the measurement zone is an imaging zone, wherein the magnetic resonance system further comprises:
a magnet for generating a main magnetic field within the measurement zone;
a magnetic field gradient system for generating a gradient magnetic field within the measurement zone to spatially encode the magnetic resonance data; and

wherein the pulse sequence instructions further comprises instructions to control the magnetic field gradient system to perform spatial encoding of the magnetic resonance data during acquisition of the magnetic resonance data, wherein the spatial encoding divides the magnetic resonance data into discrete voxels.

5. The method of claim 4 , wherein execution of the machine executable instructions further causes the processor to calculate the magnetic resonance fingerprinting dictionary by modeling each of the predetermined substances as one or more spins with the Bloch equations for each of the discrete voxels and for each of the set of system states.

6. The method of claim 4 , wherein the at least one predetermined substances is two or more substances, wherein the phantom comprises a separate compartment for each of the two or more substances and for different combinations of the set of system states.

7. The method of claim 1 , wherein the magnetic resonance system is an NMR spectrometer, wherein execution of the machine executable instructions further causes the processor to calculate the magnetic resonance fingerprinting dictionary by modeling each of the predetermined substances with the Bloch equations for each of the discrete voxels and for each of the set of system states.

8. The method of claim 1 , wherein the phantom comprises a temperature control system, wherein the method further comprises maintaining the phantom temperature within a predetermined temperature range during the acquisition of the magnetic resonance data.

9. The method of claim 1 , wherein the magnetic resonance system comprises a phantom mount for mounting the phantom in a predefined location in the measurement zone, wherein the method further comprises placing the phantom into the phantom mount before acquiring the magnetic resonance data.

10. The method of claim 1 , wherein each pulse sequence repetition comprises at least one gradient pulse chosen from a distribution of gradient pulses.

11. The method of claim 1 , wherein the method further comprises providing maintenance instructions by comparing the one or more performance degradation conditions to a repair database.

12. The method of claim 11 , wherein the method further comprises performing the maintenance instructions to repair the magnetic resonance system.

13. A magnetic resonance system for acquiring magnetic resonance data from a phantom within a measurement zone, wherein the phantom comprises a known volume of at least one predetermined substance, wherein the magnetic resonance system comprises:
a memory for storing pulse sequence instructions and machine executable instructions, wherein the pulse sequence instructions cause the magnetic resonance system to acquire the magnetic resonance data according to a magnetic resonance fingerprinting technique, wherein the pulse sequence instructions specify a train of pulse sequence repetitions, wherein each pulse sequence repetition has a repetition time chosen from a distribution of repetition times, wherein each pulse sequence repetition comprises a radio frequency pulse chosen from a distribution of radio frequency pulses, wherein the distribution of radio frequency pulses cause magnetic spins to rotate to a distribution of flip angles, and wherein each pulse sequence repetition comprises a sampling event where the magnetic resonance signal is sampled for a predetermined duration at a sampling time before the end of the pulse sequence repetition, wherein the sampling time is chosen from a distribution of sampling times, wherein the magnetic resonance data is acquired during the sampling event;
a processor for controlling the magnetic resonance system: wherein execution of the machine executable instructions cause the processor to:
acquire the magnetic resonance data by controlling the magnetic resonance system with pulse sequence instructi

Assignees

• Koninklijke Philips Nv

Inventors

• Boernert Peter
• Doneva Mariya Ivanova
• Amthor Thomas Erik
• Koken Peter
• Keupp Jochen

Classifications

• G01R33/546

  Interface between the MR system and the user, e.g. for controlling the operation of the MR system or for the design of pulse sequences · CPC title

• G01R33/4625 Primary

  Processing of acquired signals, e.g. elimination of phase errors, baseline fitting, chemometric analysis · CPC title

• G01R33/4828

  Resolving the MR signals of different chemical species, e.g. water-fat imaging · CPC title

• G16H40/40

  for the management of medical equipment or devices, e.g. scheduling maintenance or upgrades · CPC title

• G01R33/58

  Calibration of imaging systems, e.g. using test probes {, Phantoms; Calibration objects or fiducial markers such as active or passive RF coils surrounding an MR active material} · CPC title