Abstract: It is an object of the invention to improve tissue classification in MRI images. In particular it is an object of the invention to improve the classification of bone and air in MRI images. This object is achieved by a method for tissue classification in a region of interest in a magnetic resonance (MR) image comprising a first region and a second region, wherein the first region represents air and the second region represents bone.

Abstract: A pseudo CT Hounsfield Unit value for a volume element within a subject is estimated from a plurality of magnetic resonance images having different contrasts. The method includes determining a relative prevalence of a first tissue class and second tissue class within the volume element from a first magnetic resonance image and a second magnetic resonance image, respectively. Then a relative prevalence of a third tissue class is determined within the volume element based on substraction of a relative prevalence of the first and/or second tissue class from a total tissue prevalence. A reference Hounsfield Unit value is provided for the first, second and third tissue class. Finally, a pseudo Housfield value is estimated for the volume element by determining a weighted sum of the first, second and third reference Hounsfield unit value, with weight factors which are based on the determined relative prevalences of the first, second and third tissue class.

Abstract: The present invention provides a method for magnetic resonance (MR) imaging of a subject of interest (120) using arterial spin labeling, comprising the steps of performing a labeling module (200) by applying magnetic and/or radio frequency (RF) fields to the subject of interest (120) for labeling arterial blood in at least a labeling region (144) thereof, performing a first readout module (202) to obtain first MR information of the subject of interest (120) in a region of interest (142) using first parameters, performing a second readout module (204) to obtain second MR information of the subject of interest (120) in a region of interest (142) using second parameters, and performing MR image generation of a region of interest (142) based on the first and second MR information, wherein the first and second parameters of the first and second readout module (202, 204) are chosen to be different parameters.

Abstract: The application discloses a method for estimating a pseudo CT Hounsfield Unit value for a volume element within a subject from a plurality of magnetic resonance images having different contrasts. The method comprising the steps of: determination of a relative prevalence of a first tissue class and second tissue class within the volume element from a first magnetic resonance image and second magnetic resonance image respectively. Then a relative prevalence of a third tissue class is determined within the volume element based on substraction of a relative prevalence of the first and/or second tissue class from a total tissue prevalence. A reference Hounsfield Unit value is provided for the first, second and third tissue class. Finally, a pseudo Housfield value is estimated for the volume element by determining a weighted sum of the first, second and third reference Hounsfield unit value, with weight factors which are based on the determined relative prevalences of the first, second and third tissue class.

Abstract: Magnetic resonance (MR) spins are inverted by applying an inversion recovery (IR) radio frequency pulse (50). MR signals are acquired at an inversion time (TI) after the IR radio frequency pulse. TI is selected such that a first tissue of interest (e.g., blood) exhibits negative magnetism excited by the IR radio frequency pulse and a second tissue (e.g., intraplaque hemorrhage tissue) exhibits positive magnetism excited by the IR radio frequency pulse. The acquired magnetic resonance signals are reconstructed to generate spatial pixels or voxels wherein positive pixel or voxel values indicate spatial locations of positive magnetism and negative pixel or voxel values indicates spatial locations of negative magnetism. A first image (28) representative of the first tissue is generated from spatial pixels or voxels having negative signal intensities, and a second image (26) representative of the second tissue is generated from spatial pixels or voxels having positive signal intensities.

Abstract: The present invention relates to a magnetic resonance imaging MRI system (100) for acquiring magnetic resonance data from a target volume in a subject (118), the magnetic resonance imaging system (100) comprises: a memory (136) for storing machine executable instructions; and a processor (130) for controlling the MRI system (100), wherein execution of the machine executable instructions causes the processor (130) to: determine an energy distribution (301-305) over a k-space domain of the target volume; receive a reduction factor representing a degree of under-sampling of the k-space domain; derive from the energy distribution (301-305) and the received reduction factor a sampling density function; derive from the sampling density function an energy dependent sampling pattern of the k-space domain; control the MRI system (100) to acquire under-sampled k-space data using a pulse sequence that samples the k-space domain along the derived sampling pattern; apply a compressed sensing reconstruction to the acquired

Abstract: The invention provides for a medical apparatus (300, 400, 500) comprising: a magnetic resonance imaging system (302) for acquiring magnetic resonance data (342) from an imaging zone (308); a processor (330) for controlling the medical apparatus; a memory (336) storing machine executable instructions (350, 352, 354, 356). Execution of the instructions causes the processor to: acquire (100, 200) the magnetic resonance data using a pulse sequence (340) which specifies an echo time greater than 400 ??; reconstruct (102, 202) a magnetic resonance image using the magnetic resonance data; generate (104, 204) a thresholded image (346) by thresholding the magnetic resonance image to emphasize bone structures and suppressing tissue structures in the magnetic resonance image; and generate (106, 206) a bone-enhanced image by applying a background removal algorithm to the thresholded image.

Abstract: A magnetic resonance imaging (MRI) system (100, 600) that generates information indicative of a fluid flow in accordance with a pseudo-continuous arterial spin labeling (pCASL) method. The MRI system may include at least one controller (104, 610) configured to generate a pseudo-continuous arterial spin labeling (pCASL) pulse sequence (200) including at least a first gradient (GR) pulse sequence (207) having a sinusoidal waveform including a plurality of cycles, and a second radio frequency (RF) pulse sequence (205) including a half-wave rectified sinusoidal waveform having a plurality of cycles and which is synchronous with the first GR pulse sequence; label at least part of the fluid flow in a labeling region during a labeling mode using the pCASL pulse sequence; acquire label and control image information of the fluid flow at an imaging region proximal to downstream of the labeling region; and/or generate image information in accordance with a difference of the acquired label and control image information.

Abstract: Magnetic resonance (MR) spins are inverted by applying an inversion recovery (IR) radio frequency pulse (50). MR signals are acquired at an inversion time (TI) after the IR radio frequency pulse. TI is selected such that a first tissue of interest (e.g., blood) exhibits negative magnetism excited by the IR radio frequency pulse and a second tissue (e.g., intraplaque hemorrhage tissue) exhibits positive magnetism excited by the IR radio frequency pulse. The acquired magnetic resonance signals are reconstructed to generate spatial pixels or voxels wherein positive pixel or voxel values indicate spatial locations of positive magnetism and negative pixel or voxel values indicates spatial locations of negative magnetism. A first image (28) representative of the first tissue is generated from spatial pixels or voxels having negative signal intensities, and a second image (26) representative of the second tissue is generated from spatial pixels or voxels having positive signal intensities.