MPI method and system for visually representing MPI image data
A method for establishing a local concentration distribution of magnetic particles of at least one particle class within an examination volume or a variable derived from this concentration distribution. The method includes providing at least one system matrix, providing MPI signal data of at least one sample including magnetic particles of at least one particle class within a measurement volume, and reconstructing spatially resolved MPI image data from the provided MPI signal data. At least one spatial projection of at least one part of the system matrix is carried out along a projection direction and a projected system matrix is generated thereby. The reconstruction of the MPI image data is implemented with the at least partly projected system matrix, as a result of which MPI image data of a spatial projection of the local concentration distribution of the magnetic particles are produced along the projection direction.
1. A method for establishing a local concentration distribution of magnetic particles of at least one particle class within an examination volume or a variable derived from the local concentration distribution, comprising:
providing at least one system matrix;
providing magnetic particle imaging (MPI) signal data, from an MPI installation, of at least one sample comprising the magnetic particles of at least one particle class within a measurement volume;
performing, by a device for providing a projected system matrix, at least one spatial projection of at least one part of the system matrix along a projection direction, to generate a projected system matrix; and
reconstructing, with a reconstruction device, a spatially resolved MPI image data from the provided MPI signal data,
wherein the reconstructing of the MPI image data is implemented with the at least partly projected system matrix, whereby the MPI image data of a spatial projection of the local concentration distribution of the magnetic particles or of the variable derived from the local concentration distribution are produced along the projection direction.
2. The method as claimed in claim 1 , further comprising performing further spatial projections in different projection directions.
3. The method as claimed in claim 1 , further comprising varying the projection direction during MPI measurement.
4. The method as claimed in claim 1 , wherein only selected frequency components of the system matrix are used for the spatial projection and/or the reconstruction.
5. The method as claimed in claim 4 , wherein the selected frequency components of the system matrix used for the reconstruction are only those whose signal-to-noise ratio lies above a threshold value.
6. The method as claimed in claim 1 , wherein only MPI image data from selected regions of the examination volume are used for the reconstruction.
7. The method as claimed in claim 1 , wherein the reconstruction is implemented in a sparse domain.
8. The method as claimed in claim 1 , wherein the system matrix is measured with an MPI calibration measurement.
9. The method as claimed in claim 1 , wherein the system matrix is simulated.
10. The method as claimed in claim 1 , wherein the system matrix is generated from at least two system matrices linked by a mathematical operation.
11. The method as claimed in claim 1 , wherein
providing the at least one system matrix comprises establishing at least two system matrices and generating respectively the projected system matrix for the system matrices, wherein the spatial projections of the system matrices are implemented along a same projection direction,
wherein the method further comprises appending the projected system matrices, and
wherein the MPI image data are reconstructed with the projected and appended system matrix.
12. A system for visually representing MPI image data of a spatial projection of a local concentration distribution of magnetic particles or a spatial projection of a variable derived from the local concentration distribution in a projection direction, comprising:
an MPI installation configured to detect MPI signal data,
a non-transitory electronic storage medium containing: a projected system matrix or a stored computer program configured to generate a system matrix projected along a projection direction, and a stored computer program, configured to reconstruct the MPI image data with the projected system matrix,
and
an indicator apparatus configured to display the reconstructed MPI image data in real-time.
13. The system as claimed in claim 12 , further configured to establish the local concentration distribution of magnetic particles of at least one particle class within an examination volume or a variable derived from this concentration distribution, comprising:
providing the system matrix;
providing the MPI signal data of at least one sample comprising magnetic particles of at least one particle class within a measurement volume;
performing at least one spatial projection of at least one part of the system matrix along a projection direction, to generate a projected system matrix; and
reconstructing spatially resolved MPI image data from the provided MPI signal data,
wherein the reconstructing of the MPI image data is implemented with the at least partly projected system matrix, whereby the MPI image data of a spatial projection of the local concentration distribution of the magnetic particles or of the variable derived from this concentration distribution are produced along the projection direction.