18 results about "Arterial spin labeling" patented technology

The invention discloses a self-supervised super-resolution image enhancement method and system based on a conditional diffusion model. The method comprises the following steps: acquiring a T1 weighted image and a first artery spin labeling image acquired by magnetic resonance equipment, and performing up-sampling and registration to obtain a second artery spin labeling image; and based on a 3D U-Net model as a denoising network and a pre-trained conditional diffusion model, generating a super-resolution artery spin labeling image in combination with a dual-condition sampling strategy and a two-stage average acceleration sampling strategy. According to the method, the calculation speed of ASL image super-resolution reconstruction can be improved, the generation quality and stability of the diffusion model are improved, and the resolution and image quality of the low-resolution ASL are obviously improved.

The invention discloses a method for decoding and quantifying a sequential artery spin labeling image, and belongs to the technical field of magnetic resonance imaging. The method comprises the following steps: firstly, acquiring to-be-decoded Hadamard time sequence pCASL data consisting of coded signal images; then decoding the acquired N coded signal images by using the decoding matrix to obtain a multi-time-point pCASL signal image formed by the decoded signal images; wherein the decoding matrix is obtained by performing matrix multiplication operation on an upper triangular matrix and a Hadamard matrix and then removing a first row. According to the invention, the signal strength and the signal-to-noise ratio of the decoded image can be improved, the artery transmission time estimation under different scanning protocols is realized, and the application range is wide.

The application relates to the technical field of medical imaging, in particular to a blood vessel selection arterial spin labeling coding method and device based on signal modulation. The method comprises the following steps: generating a plurality of labeling signal modulation maps on a labeling plane; acquiring the number of blood vessels to be coded and the spatial position of the blood vessels to be coded on the labeling plane; determining a plurality of groups of alternative coding mode combinations; selecting the labeling signal modulation map of each coding mode of each group of alternative coding mode combinations; identifying the corresponding parameter combination and blood vessel labeling signal value in the labeling signal modulation map, so as to form a blood vessel labeling signal value matrix corresponding to each group of alternative coding mode combinations; calculating the loss value of each group of alternative coding mode combinations; selecting a target coding mode combination according to the loss value; feeding back to a magnetic resonance scanner; and performing blood vessel coding and scanning of the blood vessels to be coded by the magnetic resonance scanner. Thus, the problems of the related art, such as the requirement that the signal modulation curve is a cosine function, low universality and low coding accuracy, are solved.

The application provides a one-stop multi-delay arterial spin labeling kidney perfusion measurement method and system, and belongs to the field of magnetic resonance imaging. The method comprises the following steps: acquiring a time-encoding-based kidney arterial spin labeling sequence image of a subject; acquiring a kidney M0 image of the subject, wherein the M0 image is consistent with the number of layers, resolution and image acquisition mode of the kidney arterial spin labeling sequence image; and performing registration on the kidney arterial spin labeling sequence image and the M0 image to obtain a kidney perfusion measurement result of the subject. The application can realize one-stop multi-delay blood perfusion quantitative imaging of the kidney, greatly improves the imaging efficiency of traditional kidney multi-delay arterial spin labeling imaging, and fills the blank of one-stop multi-delay blood perfusion imaging of the kidney.

The invention discloses a magnetic resonance arterial marker image quality evaluation method and system and electronic equipment, and belongs to the technical field of magnetic resonance. The method comprises the following steps: S1, obtaining a to-be-evaluated ASL image, and recognizing a grey matter region and a white matter region in the ASL image; s2, based on signals in a grey matter area and a white matter area in the ASL image, respectively calculating seven quantitative index values including a grey matter-white matter signal ratio, a grey matter variable coefficient, a joint variable coefficient, a contrast noise ratio, an abnormal value ratio, grey matter area connectivity and index structure similarity; and S3, normalizing the seven index values of the ASL image to be evaluated, and inputting the normalized seven index values into a pre-constructed and fitted logistic regression model to obtain an evaluation result representing the quality of the image. The 3D ASL image quality evaluation method can be directly used for quality evaluation of 3D ASL image data acquired clinically and mainstream, and a quick and effective tool is provided for clinical image screening.

Measuring microvascular pulsatility using velocity-selective ASL. An example method includes: magnetically labelling blood flow in a target area of a subject using a velocity-selective arterial spin labeling (VSASL) technique with a cutoff velocity by performing operations including: applying a first velocity-selective (VS) pulse sequence with the cutoff velocity to mark a leading edge of a blood bolus; and applying a second VS pulse sequence with the cutoff velocity to mark a trailing edge of the blood bolus; acquiring VSASL signals of the blood bolus for voxels corresponding to the target area; for each of the voxels, obtaining signal intensity information over a cardiac cycle by performing retroactive cardiac gating on the acquired VSASL signals corresponding to the voxel; and determining a pulsatility index for the voxel based on the signal intensity information; and generating a voxel-wise pulsatility index map for the target area using the pulsatility indexes of the voxels.

A system for performing arterial-spin labeling (“ASL”) includes at least one memory configured to store instructions and at least one processor configured to execute the instructions to cause the system to perform a labelling phase and a control phase. The labelling phase includes a first plurality of radio frequency (“RF”) pulses and each RF pulse of the first plurality of RF pulses has a frequency offset and a phase offset. The control phase includes a second plurality of RF pulses and each RF pulse of the second plurality of RF pulses has the frequency offset and the phase offset and alternating RF pulses of the second plurality of RF pulses has an additional phase shift.

Techniques, systems and apparatus are described for magnetic resonance imaging. A method includes applying a radio frequency (RF) signal of a predetermined time duration towards a target, wherein the RF signal comprises a composite pulse that includes a velocity-selective pulse comprising RF pulses whose phase shift is modulated over the predetermined time duration, acquiring a magnetic resonance signal from the target resulting from the application of the RF signal, and generating an MRI image of the target from the magnetic resonance signal.

The invention relates to the technical field of medical imaging, in particular to a multi-module arterial spin labeling magnetic resonance angiography method, device and equipment, and the method comprises the steps: entering a contrast stage in a magnetic resonance angiography period, applying a contrast multi-module pre-pulse to a target, and after a first delay time, executing a contrast stage; applying a three-dimensional damaged gradient echo sequence to a target, and collecting a magnetic resonance signal in a contrast stage; entering a marking stage after the contrast stage is ended, then applying a marking multi-module pre-pulse to the target, and after a second delay time, acquiring a magnetic resonance signal of the marking stage in the contrast stage; and after the marking stage is finished, entering a next magnetic resonance angiography period, and reconstructing a blood vessel image of the target according to the magnetic resonance signals of the contrast stage and the marking stage acquired in a plurality of periods. Therefore, the problems of insufficient intracranial blood marking, low marking efficiency, long marked blood transfer time and the like in related technologies are solved.

The invention relates to the technical field of medical images, in particular to a blood vessel selection artery spin mark coding method and device based on signal modulation, and the method comprises the steps: generating a plurality of mark signal modulation graphs on a mark plane, obtaining the number of to-be-coded blood vessels and the spatial positions of the to-be-coded blood vessels on the mark plane, determining a plurality of groups of alternative coding mode combinations, selecting a mark signal modulation graph of each coding mode of each group of alternative coding mode combinations, identifying corresponding parameter combinations and blood vessel mark signal values in the mark signal modulation graph to form a blood vessel mark signal value matrix corresponding to each group of alternative coding mode combinations, and calculating loss values of each group of alternative coding mode combinations, a target coding mode combination is selected according to the loss value and fed back to the magnetic resonance scanner, and the magnetic resonance scanner conducts coding and scanning of the blood vessel coding artery spin mark on the to-be-coded blood vessel. Therefore, the problems of low universality, low coding accuracy and the like due to the fact that a signal modulation curve is required to be a cosine function in related technologies are solved.

The present application relates to a target artery selective labeling method, device, electronic equipment and storage medium, comprising: acquiring a blood vessel positioning image of a target artery; determining a selective excitation pulse according to the blood vessel positioning image; and obtaining a perfusion map of the target artery by labeling according to the selective excitation pulse. The present application selects the position of the artery to be labeled, designs a selective excitation pulse targeting the artery based on a single-channel or multi-channel parallel emission platform, and applies the selective excitation pulse to the labeling section in the artery spin labeling sequence, thereby achieving the effect of selectively labeling a specific artery and obtaining a perfusion map of the specific artery.

The embodiment of the invention provides an image generation method, device and equipment and a computer program product. The image generation method comprises the steps that an artery spin labeling ASL image, reference physiological parameters and experiment physiological parameters are obtained, the reference physiological parameters and the ASL image correspond to the same subject in a standard gravity environment, and the experiment physiological parameters correspond to a subject in a microgravity experiment environment; determining an image generation model used for generating an ASL image in the microgravity experiment environment; and processing the ASL image, the reference physiological parameters and the experimental physiological parameters by using an image generation model, and determining a target ASL image of the main body in the microgravity experimental environment. In the embodiment, the ASL image in the microgravity experiment environment is obtained based on the ASL image in the standard gravity environment, the reference physiological parameters and the experiment physiological parameters, and convenience and reliability of ASL image obtaining in the microgravity environment are effectively guaranteed.

A method of operating a magnetic resonance imaging (MRI) system includes configuring the system to receive an input indicative of time intervals to be used for imaging a target object; controlling the one or more RF coils to apply a first order of modules including at least a first control module at a first time point and a first labeling module at a second time point to a target object, controlling the one or more RF coils to operate a second order of modules including at least a second labeling module at a third time point and a second control module at a fourth time point to the target object, wherein all the four modules invert the magnetization of the target object to suppress the MRI signal.

This application discloses a method, control method, system, and device for measuring labeling efficiency in magnetic resonance imaging (MRI) scans. The measurement method includes: performing a measurement sequence scan on a target object; wherein the measurement sequence is used to measure the labeling efficiency of a corresponding arterial spin labeling sequence, the arterial spin labeling sequence including several labeling periods and imaging periods, with a delay time between the labeling periods and imaging periods; dividing the measurement sequence into corresponding measurement sub-sequences based on the delay duration of each delay time, and setting the measurement sub-sequences within their respective delay times; applying a first labeling pulse to the target object in each measurement sub-sequence to obtain a corresponding measurement image; obtaining the labeling efficiency of the first labeling pulse based on the measurement image, and using the labeling efficiency as the labeling measurement result of the arterial spin labeling sequence scan. By using the delay time of the ASL sequence to divide the measurement sequence into delay times, the overall scan time is shortened.

The embodiment of the invention discloses a fat pressing parameter determination method, device and system applied to arterial spin labeling imaging. The method comprises the following steps: according to an acquisition parameter set adopted by the ASL imaging, determining the longitudinal magnetization intensity of fat when a first fat pressing pulse for the ASL imaging begins to be applied; according to the longitudinal magnetization intensity of the fat when the first fat suppression pulse begins to be applied, the overturning angle or overturning duration TI of the first fat suppression pulse is determined, so that the longitudinal magnetization intensity of the fat when the first excitation pulse of the ASL imaging begins to be applied is the expected longitudinal magnetization intensity. According to the embodiment of the invention, accurate acquisition of the overturning angle or the TI of the fat pressing pulse is realized, and the accurate overturning angle and the TI are selected for the fat pressing pulse applied to ASL imaging, so that the ASL imaging quality is finally improved, and fat ghosting in an ASL image is reduced.

The application discloses a kind of self-supervision super-resolution image enhancement method and system based on conditional diffusion model.The method obtains T1 weighted image and first arterial spin labeling image collected by magnetic resonance equipment, and is up-sampled and registered, to obtain second arterial spin labeling image;Then based on the conditional diffusion model with 3D U-Net model as denoising network and pre-training, combined with double conditional sampling strategy and two-stage average acceleration sampling strategy, super-resolution arterial spin labeling image is generated.The application can improve the calculation speed of ASL image super-resolution reconstruction, and improve the generation quality and stability of diffusion model, and has obvious resolution and image quality improvement for low-resolution ASL.

The invention relates to an image visual enhancement processing method, in particular to a visual enhancement processing method based on an artery spin marking perfusion image, and solves the problems that perfusion signals are lost or distorted and a post-processing method is insufficient to effectively correct bias field effects and motion artifacts in an image in the existing artery spin marking. According to the method, the original brain perfusion image is processed, the overall quality and the signal-to-noise ratio of the image are improved, and meanwhile, the signal intensity and consistency are ensured; by utilizing anatomical information of a standard brain template, the accuracy of removing non-brain tissues is improved, and meanwhile, interference caused by motion artifacts is effectively reduced; the contrast ratio of the image is improved through the mirror image overturning and rigid body registration technology; the perfusion difference of the left hemisphere and the right hemisphere is quantified through the ratio image, gridding processing is carried out on the ratio image, the ratio average value in each grid is calculated, then spatial distribution of a high-perfusion area and a low-perfusion area is clearly displayed through a visual colored tape mapping method, and visual enhancement processing is achieved.