G01R33/5635

MRI IMAGE RECONSTRUCTION USING MACHINE LEARNING

In the field of MRI, a model-based MRI image reconstruction technique is provided. The model-based reconstruction technique increases the performance of Time-of-Flight MRA. In a learning phase, a model is calculated from a sufficiently large set of data acquired at both low and high magnetic fields, using deep learning strategies. In a clinical phase, the model is applied to measured data generating high MR image quality.

SYSTEMS AND METHODS FOR BACKGROUND SUPPRESSION IN TIME-OF-FLIGHT MAGNETIC RESONANCE ANGIOGRAPHY
20200400768 · 2020-12-24 ·

Systems and methods for suppressing background in time-of-flight (TOF) magnetic resonance angiography (MRA) are disclosed. An exemplary method includes obtaining a first TOF image through a high-resolution acquisition with a saturation band on one side of an imaging slab, obtaining a second TOF image through a low-resolution acquisition with two saturation bands on both sides of the imaging slab, and subtracting the second TOF image from the first TOF image to obtaining a subtraction TOF image. Post processing such as maximum intensity projection (MIP) is performed on the subtraction TOF image.

Planning support for selective arterial spin labeling MR imaging methods

The invention relates to a method of MR imaging of at least a portion of a body (10) placed in a main magnetic field within the examination volume of a MR device (1). It is an object of the invention to facilitate the planning of an arterial spin labeling (ASL) MR imaging session and to improve the image quality in perfusion weighted MR imaging. The method of the invention comprises the following steps: acquiring angiographic MR signal data by subjecting the portion of the examined body (10) to one or more MR angiography scans; deriving quantitative blood flow parameters from the angiographic MR signal data; computing a labeling efficiency of an ASL sequence from the sequence parameters of the ASL sequence and from the quantitative blood flow parameters; optimizing the sequence parameters by maximizing the labeling efficiency; acquiring perfusion weighted MR signal data by subjecting the portion of the body to the ASL sequence; andreconstructing a MR image from the perfusion weighted MR signal data. Moreover, the invention relates to a MR device (1) and to a computer program for a MR device (1).

Systems and methods for background suppression in time-of-flight magnetic resonance angiography

Systems and methods for suppressing background in time-of-flight (TOF) magnetic resonance angiography (MRA) are disclosed. An exemplary method includes obtaining a first TOF image through a high-resolution acquisition with a saturation band on one side of an imaging slab, obtaining a second TOF image through a low-resolution acquisition with two saturation bands on both sides of the imaging slab, and subtracting the second TOF image from the first TOF image to obtaining a subtraction TOF image. Post processing such as maximum intensity projection (MIP) is performed on the subtraction TOF image.

System and method for semi-projective quantitative flow imaging using accelerated arterial spin-labeled cine MRI

A system and method for controlling a magnetic resonance imaging (MRI) system to create magnetic resonance (MR) cine angiograms of a subject. The method includes controlling the MRI system to acquire MR data from the subject by performing at least one cine acquisition pulse sequence having a plurality of acquisition RF pulse modules applied at constant intervals throughout a cardiac cycle, and at least one labeling pulse sequence including a first and a second /2 module and a labeling RF pulse module for labeling a region of inflowing arterial flow through a vessel of interest. The method further includes reconstructing the MR data to form a series of cine frames that form a cine angiogram, subtracting at least one cine frame from other cine frames reconstructed from the MR data, and displaying the MR cine angiogram of the vessel of interest.

Hybrid inversion pulse for magnetic resonance imaging
10859655 · 2020-12-08 · ·

An imaging system includes determination of a first gradient-modulated offset-independent adiabaticity pulse associated with a first bandwidth and a first gradient strength, determination of a second gradient-modulated offset-independent adiabaticity pulse associated with a second bandwidth less than the first bandwidth and a second gradient strength less than the first gradient strength, determination of a third asymmetric adiabatic pulse based on the first gradient-modulated offset-independent adiabaticity pulse and the second gradient-modulated offset-independent adiabaticity pulse, and control of a radio frequency system and gradient system to apply the third asymmetric adiabatic pulse to patient tissue.

Method for optimizing the predetermination of the time profile of a contrast agent concentration in diagnostic imaging using a magnetic resonance system

A method of predetermining the time profile of a contrast agent concentration at a vessel position is provided in the context of contrast agent-enhanced MRI of a region of interest only during the initial flooding-in phase of the contrast agent into the vessel situated in the region of interest. The method includes establishing a broadening of a contrast agent bolus profile according to the equation W=W2W1 wherein W1 is a first width of the contrast agent bolus profile at a first vessel position and W2 is a second width of a contrast agent concentration profile at a second vessel position within the region of interest. The broadening is established by determining at least one flow parameter which is dependent on at least one blood flow property of the patient at a third vessel position thereof and which correlates with the broadening of the contrast agent profile.

Motion estimation method and apparatus

A medical image processing apparatus comprises processing circuitry configured to: acquire at least one first data set representative of measurements using a medical scanner and including a representation of at least one blood vessel; acquire a plurality of second data sets representative of measurements obtained using the medical scanner and including a representation of said at least one blood vessel, each of the plurality of second data sets representing measurements obtained for a respective different one of a plurality of cardiac phases; and process the plurality of second data sets using a motion estimation procedure to correct for motion between the cardiac phases and, using the at least one first data set, to at least partially remove at least one feature associated with the blood vessel.

Cardiac Late Gadolinium Enhancement MRI for Patients with Implanted Cardiac Devices
20200371183 · 2020-11-26 ·

Disclosed herein are methods and systems for clinical practice of medical imaging on patients with metal-containing devices, such as implanted cardiac devices. In particular, Disclosed herein are methods and systems for improved late gadolinium enhancement (LGE) MRI for assessing myocardial viability for patients with implanted cardiac devices, i.e., cardiac pacemakers and implantable cardiac defibrillators.

Systems and Methods for Using Improved Contrast Agent in Performing and MRI
20200371172 · 2020-11-26 ·

The present invention relates to the use of a formation agent, such as nitric oxide or sodium nitrite to produce methemoglobin as an alternative MRI contrast agent. The formation agent can be infused using either a respiratory system or a delivery mechanism. One embodiment of this invention relates to systems and methods for producing an image of an internal region with a magnetic resonance scanning system. Blood is drawn from the patient. The blood is exposed to formation agent through a delivery system, to produce blood that has a higher saturation of methemoglobin. Where in vitro techniques are used the treated blood is injected back into the patient. The patient is scanned in the magnetic resonance scanner. These systems and methods can be used to produce images of regions which may not otherwise be possible with other contrasting agents. For example, an accurate vascular brain MRI may not be as informative if the patient is injected with an existing contrasting agent. In addition, an alternate embodiment of the invention relates to internally exposing the blood to the formation agent by placing the gas-permeable membrane along a particular blood pathway or intravenous sodium nitrite.