A system and method for determining a nuclear magnetic resonance relaxation time of a probe includes polarizing first nuclei and second nuclei by applying a longitudinal static magnetic field to the probe, exchanging the polarizations of the first nuclei and the second nuclei by irradiating a swap sequence of transverse magnetic field pulses, transversely magnetizing the second nuclei by irradiating at least one excitation pulse and measuring the resulting magnetization signal of the second nuclei, and determining the nuclear magnetic resonance relaxation time of the second nuclei based on the measured magnetization signal of the second nuclei.

A method comprising collecting magnetic resonance imaging (MRI) scanner data corresponding to a region of interest, establishing a spectral peak profile associated with at least one metabolite in the region of interest, wherein the spectral peak profile comprises a term in the FID vector signal included in the collected MRI scanner data, selecting at least three counter indices and corresponding points on the spectral peak profile to compute a linear fractional transformation (LFT), computing an N-dimensional vector outlining a spectral circle in a complex plane by applying the LFT to each counter index included in a set of equally-spaced counter indices associated with a three-dimensional spectrum representation of the collected MRI scanner data, shifting the spectral circle to eliminate a baseline offset for a magnitude spectrum associated with the complex plane, rotating the shifted spectral circle to produce a rotated spectral circle.

Correlation information between captured characteristics and chemical shift values of captured NMR spin systems is provided by a model appliance for a fluid class. An NMR spectrum of a sample of the fluid class is recorded. Peaks in the recorded NMR spectrum which belong to defined reference NMR spin systems are identified, and experimental chemical shift values of the peaks from the recorded NMR spectrum are determined. A chemical shift value of at least one of the captured NMR spin systems not belonging to the reference NMR spin systems is predicted by applying the model appliance onto the experimental chemical shift values of the reference NMR spin systems. Peaks in an NMR spectrum of a sample of a fluid class are attributed more quickly and reliably to NMR spins systems of compounds contained in the sample.

A method of determining a NMR prediction result of a sample is provided. The method can include receiving a NMR spectrum of the sample and/or identifying a section of a ppm range in the NMR spectrum having a non-stationary peak. The method can include determining a modified data point for the NMR spectrum based on data points in the identified section. The modified data point can be determined such that the modified data point is a weighted average value of the data points in the identified section in the NMR spectrum. The method can include replacing the identified section in the NMR spectrum with the modified data point for the NMR spectrum to determine a modified NMR spectrum. The method can include determining the NMR prediction result of the sample based on the modified NMR spectrum and a calibration vector (e.g., using a partial least square (PLS) analysis).

An NMR relaxation time inversion method based on an unsupervised neural network includes simulating inversion kernel matrix, simulating continuous NMR relaxation time spectrum, simulating noise, calculating NMR relaxation signals as samples, various samples forming a sample set, constructing an unsupervised neural network model, and defining a loss function of the unsupervised neural network model; and taking the samples in the training sample set as an input of the unsupervised neural network model, to obtain an optimal mapping relationship between the NMR relaxation signals and the NMR relaxation time spectrum with a minimum loss function. The present invention provides the possibility of using experimental data as the sample for training since the trading sample does not need to be labeled, can automatically learn the optimal regularization parameters without depending on the initial value and manual experience, and predicts fast.

The invention provides for a magnetic resonance system (100) for acquiring a magnetic resonance data from a subject (118) within a measurement zone (108) according to a magnetic resonance fingerprinting technique. The pulse sequence comprises a train of pulse sequence repetitions (302, 304). Each pulse sequence repetition has a repetition time chosen from a distribution of repetition times. Each pulse sequence repetition comprises a radio frequency pulse (306) 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, and each pulse sequence repetition comprises a sampling event (310) at a sampling time chosen from a distribution of sampling times. Each pulse sequence repetition of the pulse sequence comprises a first 180 degree RF pulse (308) performed at a first temporal midpoint between the radio frequency pulse and the sampling event to refocus the magnetic resonance signal. Each pulse sequence repetition of the pulse sequence comprises a second 180 degree RF pulse (309) performed at a second temporal midpoint between the sampling event and the start of the next pulse repetition.

The present invention provides a method for quantitative analysis of a compound in a sample characterized in that the quantitative analysis is performed by a method of using an external standard which obtains NMR spectra of a sample and a standard substance and then compares them, and it can be applied even to an insoluble sample.

According to one embodiment, a MRI apparatus includes an RF coil apparatus receiving MR signals by coil elements corresponding to channels, modurating the MR signals to have different frequencies for each of the channels, and outputting an analog multiplexed signal in which the MR signals with different frequencies are composited over the channels, and a receiver including ADC circuitry converting the analog multiplexed signal to a digital multiplexed signal, and predetermined number of separation channels separating the digital multiplexed signal, based on the number of the channels relating to composition of the MR signals with the different frequencies. The receiver stops a separation process of the digital multiplexed signal for separation channels not used in the separation process among the predetermined number of separation channels.

Technologies applicable to NMR spin-echo amplitude estimation are disclosed. Example methods may calibrate for distortion of a shape and estimated amplitude of measured NMR spin or gradient echoes. NMR spin or gradient echo measurements may be performed on a sample. The measured NMR spin or gradient echoes may be used to calculate an echo-shape calibration factor. The echo-shape calibration factor may estimate an effect of echo shape on estimated spin or gradient echo amplitude(s) of the NMR spin or gradient echoes. The echo-shape calibration factor may be used to correct for underestimation or overestimation of the spin or gradient echo amplitude(s).

A method and a system for analysis of raw MRS data, in the form of signal strength versus chemical shift (ppm), from multiple scanners, includes “signal estimation” from each raw data set, followed by cross-scanner “data harmonization” of results. The final resulting MRS signals are consistent from one scanner to another, and are used for analysis by radiologists and other physicians.