Bruker BioSpin

Computer-implemented method, computer program product and computing system (100) are provided for improving an NMR measurement result obtained by an NMR spectrometer (200) for a sample (240). A magnetic field map (B0ma) for the actual main magnetic field (B0) of the NMR spectrometer including the sample is obtained as a function of spatial location in the sample with measurement points being taken at z-intervals. A time domain NMR measurement (TDM) of the sample is received. A value of a correction function (CFf1) for the NMR measurement is computed in the frequency domain, based on the received magnetic field map, for each of a plurality of predefined frequency intervals covering a frequency range with B0 deviations, as the total length of z-intervals with frequency values in the respective frequency interval. The correction function is transformed into the time domain. The time domain NMR measurement is divided by the transformed correction function (CFt1) to obtain a corrected time domain NMR measurement curve (TDMc) and the corrected time domain NMR measurement curve is transformed into the frequency domain to obtain an NMR spectrum (S1) of the sample with symmetrized peaks and overlapping peaks being resolved.

The invention concerns a method for generating a multi-dimensional image-domain system matrix A using an MPI-sequence with a field free line, using a multi-dimensional sinogram-based system matrix ASinogramtrz∈ℝTNrNz,comprising the following steps:• for each time point t_c, c ∈ [1,T]:∘ get a time slice matrix Ac=ASinogramt=tc,r,z∈ℝNrNz,∘ replicate the time slice matrix A_c N_r - 1 times and copying these replications along a newly added 2^nd offset-dimension, resulting in a time volume matrix Ac′∈ℝNrNrNz,∘ rotate the time volume matrix A'_c by the FFL angle θ_c = θ(t = t_c) at time point t = t_c in its 1^st and 2^nd offset-dimensions, resulting in a rotated matrix Acθc• concatenate the rotated matrices Acθc of all time points along a time-dimension and vectorize the spatial dimensions (x,y,z), resulting in a constructed system matrix cSM∈ℝTNrNrNz,• perform a Fourier transformation on the constructed system matrix cSM on its time-dimension resulting in the multi-dimensional image-domain system matrix A.With the inventive method the total calibration time can be lowered.

The invention concerns a method for generating a multi-dimensional system matrix A for MPI-measurements, the method comprising: • prior to calibration measurements: ∘ determine - target positions for a calibration source, - calibration voxels of a calibration volume - parameters, - FFR-offsets r, by which the field free region FFR is to be shifted within the calibration volume, - acquisition window, ∘ discretize parameters, • perform calibration measurements, wherein during each calibration measurement, data is acquired for a specific parameter value combination, • determine individual acquisition system matrices Ac, wherein each individual acquisition system matrix Ac combines calibration data derived from different calibration measurements that are assigned to the same parameter value combination but different FFR-offsets r, and • determine the multi-dimensional system matrix A by combining individual acquisition system matrices Ac of different parameter value combinations. The resulting system matrix is not limited to specific MPI-sequences, tracer parameters, MPI scanner parameters, or FFR-geometries.

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A system, method and computer program product are disclosed for fast quantitative NMR data acquisition for a plurality of NMR scans performed on a sample. The method performs a plurality of scan batches (B1 to B3) on the sample. Each batch comprises a long delay scan (LDS) performed after a long delay interval ensuring near-full relaxation of said nuclei, followed by a set of short delay scans (SDS*), each short delay scan performed after a short delay interval smaller than the long delay interval. Each scan is associated with a corresponding scan time point (t1 to t6) in relation to the long delay scan time point of the respective scan batch. For each corresponding scan time point, aggregated NMR spectrum portions (Saa to Saf) are determined showing a decay over time. The decay is fitted with an exponential decay function (610). An averaged integral loss is computed for each scan time point. For each NMR spectrum of the scan batches, an integral associated with a respective region of interest is multiplied with a corresponding correction factor. The integrals associated with the corrected NMR spectra in all batches (B1 to B3) are summed up to obtain a representation of the NMR signal intensity in the region of interest for said sample.

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Zusammenfassung wird geladen …

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