Patent classifications
G01R33/5635
Magnetic resonance imaging of arterial structures
A medical imaging system (100, 1200) includes a memory (136) for storing machine executable instructions (170), and a processor (130) for controlling the medical imaging system. Execution of the machine executable instructions causes the processor to: receive (304, 1000) a tagged arterial spin labeled (ASL) magnitude image (148) of a region of interest of a subject (118); receive (306, 1002) a control ASL magnitude image (150) of the region of interest of the subject; construct (308, 1004) an arterial image (152) by subtracting the control ASL magnitude image and the tagged ASL magnitude image; construct (310, 1006) an arterial mask (154) using the arterial image by identifying arteries in the arterial image; receive (312, 1008) a phase contrast magnetic resonance image (156, 158, 160) of at least a portion of the region of interest of the subject; and construct a venous image (164) at least partially by setting voxels of the phase contrast image within the at least a portion of the region of interest that are within the arterial mask to a predetermined background value.
Magnetic resonance apparatus and method for vascular imaging
In a magnetic resonance method and apparatus for time-of-flight vascular imaging, a magnetic field is applied to an imaging volume and an inflow volume, from which liquid enters into the imaging volume, of an examination person. The imaging volume is excited by an RF pulse, which fulfills a magnetization transfer function and a fat saturation function, while the magnetic field is being applied. The RF pulse has a frequency distribution whose frequencies are higher than the center frequency of water in the imaging volume, and that includes the fat frequency in the imaging volume. The magnetic field has a field distribution with an apex with essentially no spatial gradient in the imaging volume and having a higher spatial gradient in the inflow volume, so that the center frequency of water in the inflow volume is shifted in the direction of lower frequencies and is no longer affected by the RF pulse.
FLUID ANALYSIS APPARATUS, METHOD FOR OPERATING FLUID ANALYSIS APPARATUS, AND FLUID ANALYSIS PROGRAM
The invention provides a fluid analysis apparatus, a method for operating a fluid analysis apparatus, and a fluid analysis program that display a flow velocity vector such that the tendency of a fluid flow is easily checked. A representative two-dimensional flow velocity vector representing a plurality of two-dimensional flow velocity vectors obtained by projecting three-dimensional flow velocity vectors of a plurality of voxels that overlap each other in a projection direction of a projection plane to the projection plane is acquired from three-dimensional volume data that has information of the three-dimensional flow velocity vector indicating the flow velocity of a fluid in an anatomical structure for each voxel and is displayed.
Stimulated echo sequence scanning magnetic resonance method and apparatus for heart diffusion imaging
In a method and magnetic resonance (MR) apparatus for heart diffusion imaging, when an ECG trigger signal by a computer that operates an MR scanner, the MR scanner is operated to acquire a navigator echo before a stimulated echo sequence, in order to detect diaphragm position information. When the first diaphragm position information is not located in an acquisition window, the stimulated echo sequence is not executed, and the computer waits to receive the next ECG trigger signal. The detection time of the navigator echo after the stimulated echo sequence as well as the acquisition time of the stimulated echo sequence, are thus eliminated when the first diaphragm position information does not meet requirements, so can significantly reduce scanning time, and increase the image SNR.
Free-breathing non-contrast MR angiography
A system includes acquisition of a predetermined number of three-dimensional sub-frames from patient tissue using a T1-weighted radial sampling sequence and without contrast agent, determination of a matching one of a plurality of the three-dimensional images reconstructed from respective subsets of the predetermined number of three-dimensional sub-frames, based on a first three-dimensional image reconstructed from a first-acquired one of the predetermined number of three-dimensional sub-frames, and subtraction of the matching one of the plurality of the three-dimensional images from the first three-dimensional image to generate a second three-dimensional image.
Cardiac late gadolinium enhancement MRI for patients with implanted cardiac devices
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.
MAGNETIC RESONANCE IMAGING APPARATUS AND IMAGE PROCESSING APPARATUS
Provided is a new scheme for applying a CS technology in a technology for imaging a target tissue based on a difference from a reference image or a control image. In this way, an imaging time is shortened. A measurement unit of an MRI apparatus executes a first imaging sequence and a second imaging sequence having different contrasts for a target, and measures a nuclear magnetic resonance signal from a subject in each of the imaging sequences. In the second imaging sequence, under-sampling is performed, and a nuclear magnetic resonance signal having a small number of samples is measured. The image processing unit restores measurement data including a nuclear magnetic resonance signal obtained by under-sampling using compressed sensing. At this time, data restoration including a term for minimizing an L1 norm is performed for a difference image between an image obtained by execution of the first imaging sequence and an image obtained by execution of the second imaging sequence.
DUAL-ECHO DIXON-TYPE WATER/FAT SEPARATION MR IMAGING
The invention relates to a method of Dixon-type MR imaging. It is an object of the invention to provide a method that enables efficient and reliable water/fat separation using bipolar readout magnetic field gradients and avoids flow-induced leaking and swapping artifacts. According to the invention, an object (10) is subjected to an imaging sequence, which comprises at least one excitation RF pulse and switched magnetic field gradients, wherein two echo signals, a first echo signal and a second echo signal, are generated at different echo times (TE1, TE2). The echo signals are acquired from the object (10) using bipolar readout magnetic field gradients. A first single echo image is reconstructed from the first echo signals and a second single echo image is reconstructed from the second echo signals. A zero echo time image is computed by extrapolating the phase of the first single echo image at each voxel position to a zero echo time using the phase difference between the first and the second single echo image at the respective voxel position. Flow-induced phase errors are identified and estimated in the zero echo time image, and the phase of the first single echo image is corrected according to the estimated flow-induced phase errors. Finally, a water image and/or a fat image are reconstructed from the echo signals, wherein signal contributions from water and fat to the echo signals are separated using the phase-corrected first single echo image and the second single echo image. Moreover, the invention relates to a MR device (1) and to a computer program to be run on a MR device (1).
Motion corrected simultaneously acquired multiple contrast coronary MRI systems and methods
In various embodiments, the present application discloses systems and methods for magnetic resonance imaging (MRI) of coronary arteries. In various embodiments, the invention allows for motion corrected, simultaneously acquired multiple contrast weighted images with whole-heart coverage and isotropic high resolution. In some embodiments, the invention teaches using interleaved preparatory pulses, a 3D radial golden angle trajectory and 100% respiratory gating efficiency.
CEREBROVASCULAR SEGMENTATION FROM MRA IMAGES
There is provided a method of processing a cerebrovascular medical image, the method comprising receiving magnetic resonance angiography (MRA) image associated with a cerebrovascular tissue comprising blood vessels and brain tissues other than blood vessels; segmenting MRA image using a prior appearance model for generating first prior appearance features representing a first-order prior appearance model and second appearance features representing a second-order prior appearance model of the cerebrovascular tissue, wherein current appearance model comprises a 3D Markov-Gibbs Random Field (MGRF) having a 2D rotational and translational symmetry such that MGRF model is 2D rotation and translation invariant; segmenting MRA image using current appearance model for generating current appearance features distinguishing blood vessels from other brain tissues; adjusting MRA image using first and second prior appearance features and current appearance futures; and generating an enhanced MRA image based on said adjustment. There is also provided a system for doing the same.