Abstract: An imaging system and method enables 3-D direct segmentation from a series of spatially offset 2-D image slices in a volume scan. The algorithm first smoothes and preserves the interface edges of the image volume using Bottom-Hat gray scale morphological transform followed by 3-D segmentation using fast 3-D level sets by preserving topology constraints, for example, cortical thickness in a brain volume. The method inputs opposite polarity spheres (contracting and expanding spheres) which morph into shapes within the volume using a surface propagation technique. The speed of propagation is controlled by the likelihood statistical component derived under constraints. During the propagation polygonalization extracts the zero-level surface set. The field distribution is computed using the improved shortest distance method or polyline distance method. The morphing algorithm then morphs the input concentric spheres into interface surfaces such as WM-GM and GM-CSF with cortical constraint.

Abstract: A method of a conducting a magnetic resonance imaging experiment with an interleaved phase encoding acquisition includes setting an interleave factor which is an imaging parameter that represents the number of interleaves in the interleaved phase encoding acquisition, and determining an artifact suppression factor. The artifact suppression factor is an imaging parameter that represents an amount of SBA suppression achieved in the imaging experiment being conducted. The method further includes determining if the artifact suppression factor falls within a range. When the artifact suppression factor falls outside the range, notification is provided, and when the artifact suppression factor falls inside the range, a sequence of progression is determined for an excitation slab employed in the imaging experiment.

Abstract: A magnetic resonance imaging method and apparatus includes a navigator region defined within the subject by selective excitation. Blood flow is measured within the selected region using the principles of phase contrast MR angiography. A cardiac cycle plot is constructed from Fourier transformed data that represents measured velocity of blood flow through the navigator region as a function of time. On the basis of the cardiac cycle plot and the navigator measurements, data acquisition is synchronized or gated to portions of the cardiac cycle.

Abstract: To image flowing materials, magnetic resonance preconditioning pulses are applied in an upstream region (28). For scanning a subject, an RF pulse calibration sequence is performed by generating a corresponding magnetic resonance data line (361, . . . , 36n) in each of a plurality of slices (401, . . . , 40n) along a vessel. A processor (54) determines a signal intensity for each slice (56), fits the intensities for the family of slices to a curve (58), and adjusts an RF pulse profile with spatial position in accordance with the curve which is dynamically dependent on the scanned subject. In a subsequent imaging sequence with the adjusted tip angles, data lines from each of the slices are received (52) and reconstructed (62) into an image representation stored in the memory (64).

Abstract: A magnetic resonance angiographic method includes acquiring (70) high resolution volume image data comprising data (74) corresponding to a plurality of high resolution image slices, and acquiring (72) data corresponding to at least one vessel identification image slice (76), said acquired data having selectively enhanced contrast for one of arteries and veins. A high resolution volume image representation (80) is reconstructed from the acquired high resolution volume image data (74). At least one vessel identification slice image representation (82) is reconstructed from the acquired data corresponding to at least one vessel identification image slice (76). At least one of an artery starting point (86) and a vein starting point (88) is identified based on the vessel identification slice image representation (82).

Abstract: A magnetic resonance imaging method includes acquiring a baseline magnetic resonance image of a region of interest in the absence of a contrast agent and simulating an increase in image intensity of a subregion of interest within the region of interest which is subject to increased image intensity in the presence of a contrast agent. The magnetic resonance k-space signal intensity is correlated with contrast agent concentration in the subregion and a contrast agent is administered to the subject. As k-space data for the region of interest is acquired, the signal intensity is monitored to derive contrast agent concentration information. When the peak contrast agent concentration is detected from the monitored k-space data signal intensity, the phase encoding is adjusted so that k-space data with zero phase encoding is acquired. In a further aspect, a magnetic resonance imaging apparatus is also provided.

Abstract: A parameter compilation memory (62, 114) stores patient physiological information and contrast agent arrival or uptake times (tD, tA, tV) from past patients. A triggering or synchronizing window processor (64, 112) sets a triggering window, i.e. estimates the arrival time, based on the past patient information. A subject (16) disposed within an imaging region (12, 90) is injected with a contrast agent (66). Arrival of the contrast agent in the imaging region is detected (72, 110) with a real time tracking method. Diagnostic imaging is commenced on the first to occur of the detection of contrast agent arrival within the window and the end of the triggering window. The uptake times for the subject (16) are compared to those stored in the memory (62, 114) and analyzed to propose a diagnosis.

Abstract: A region of interest of a subject is disposed in an imaging region (10) of a magnetic resonance imaging apparatus. A contrast material (70) is injected into the subject. An operator initiates a series of fast scan imaging sequences to track the position for entry of the contrast material, into the region of interest. A trajectory through a k-space is selected for the fast scan imaging sequences that both generates data lines for the fast scan images and oversamples a common data point (76). A peak intensity of the oversampled common point (76) indicates that the bolus of contrast agent (70) has arrived. A sequence controller (40) initiates a diagnostic imaging sequence (80). The operator views the fast scan image and has the option to abort the diagnostic sequence (80) if the fast scan image does not verify that the contrast agent has arrived in the region of interest. The system continues to taking fast scan images until the arrival of the bolus of contrast agent has been verified.

Abstract: In magnetic resonance angiography (MRA), the MRA data (40) is smoothed and converted into an isotropic format (52). A binary surface fitting mask (56) that differentiates vascular regions from surrounding tissue is generated from the isotropic MRA data. Vascular starting points (60) are identified based on the binary surface fitting mask. The vascular system corresponding to each starting point is tracked (62). The tracked vascular system is graphically displayed (68). Preferably, the arteries and the veins in the binary surface fitting mask data are differentiated (58) based on anatomical constraints. The tracking (62) preferably includes estimating an oblique plane that is orthogonal to the vessel (204), determining the vessel edges in the oblique plane (212), and determining an estimated vessel center in the oblique plane (216). The vessel edges are preferably determined by determining a raw vessel edge (208), and refining the raw vessel edge to obtain a refined vessel edge representation (212).

Abstract: A parameter compilation memory (62, 114) stores patient physiological information and contrast agent arrival or uptake times (tD, tA, tV) from past patients. A triggering or synchronizing window processor (64, 112) sets a triggering window, i.e. estimates the arrival time, based on the past patient information. A subject (16) disposed within an imaging region (12, 90) is injected with a contrast agent (66). Arrival of the contrast agent in the imaging region is detected (72, 110) with a real time tracking method. Diagnostic imaging is commenced on the first to occur of the detection of contrast agent arrival within the window and the end of the triggering window. The uptake times for the subject (16) are compared to those stored in the memory (62, 114) and analyzed to propose a diagnosis.

Abstract: A diagnostic imaging system (100, 200) and method generates a plurality of temporally resolved volume image representations (130, 132, . . . , 134). A time course projection processor (140, 240) temporally collapses the volume image representations. A spatial projection processor (146, 246) performs a maximum or minimum intensity process along rays through voxels of a three-dimensional image representation. By sequentially temporally collapsing and maximum or minimum intensity projecting, in either order, the plurality of temporally resolved volume image representations is reduced to a two-dimensional temporally collapsed and spatially projected image representation (148, 248). In preferred embodiments, the present invention is directed to angiography, and more preferably to magnetic resonance angiography.

Abstract: To image flowing materials, magnetic resonance preconditioning pulses are applied in an upstream region (28). For scanning a subject, an RF pulse calibration sequence is performed by generating a corresponding magnetic resonance data line (361, . . . , 36n) in each of a plurality of slices (401, . . . , 40n) along a vessel. A processor (54) determines a signal intensity for each slice (56), fits the intensities for the family of slices to a curve (58), and adjusts an RF pulse profile with spatial position in accordance with the curve which is dynamically dependent on the scanned subject. In a subsequent imaging sequence with the adjusted tip angles, data lines from each of the slices are received (52) and reconstructed (62) into an image representation stored in the memory (64).

Abstract: A method of magnetic resonance imaging includes supporting a subject in an examination region of an MRI scanner(A). An MRI pulse sequence is applied to produce a detectable magnetic resonance signal (100) in a selected region of the subject. The magnetic resonance signal (100) includes a plurality of echos (102a-h) which are received. The plurality of received echos (102a-h) are subjected to a controllable gain factor such that at least two echos are subjected to different gain factors. In this manner, for example, a multi-contrast acquisition and imaging experiment may be achieved with each set of acquired echos and/or each image having a separately optimized (e.g., optimized for SNR considerations) gain factor individually selected and/or set therefor.

Abstract: A method of magnetic resonance imaging includes subjecting a region of a patient being imaged to magnetic resonance imaging pulse sequences thereby generating magnetic resonance echoes emanating from the region. The echoes are encoded with magnetic gradients and collected as k-space data in separate consecutive acquisitions. Each acquisition successively fills in one of a number of distinct subsets of k-space based on the encoding of the collected echoes for that acquisition. In turn, a reconstruction algorithm is applied to the k-space data after each acquisition to generate a series of temporally updated image representations of the region. Further, a magnetic resonance imaging apparatus for performing the method is also provided.

Abstract: A magnetic resonance imaging method includes acquiring a baseline magnetic resonance image of a region of interest in the absence of a contrast agent and simulating an increase in image intensity of a subregion of interest within the region of interest which is subject to increased image intensity in the presence of a contrast agent. The magnetic resonance k-space signal intensity is correlated with contrast agent concentration in the subregion and a contrast agent is administered to the subject. As k-space data for the region of interest is acquired, the signal intensity is monitored to derive contrast agent concentration information. When the peak contrast agent concentration is detected from the monitored k-space data signal intensity, the phase encoding is adjusted so that k-space data with zero phase encoding is acquired. In a further aspect, a magnetic resonance imaging apparatus is also provided.

Abstract: A plurality of multiple echo imaging sequences are generated and sampled to fill k-space. Each multiple echo sequence includes a plurality of phase and frequency encoded image data echoes and a navigator echo, preferably at the end of the sequence. The navigator echoes are separated from the image data and analyzed to determine their relative phase angle and amplitude. More specifically to a preferred embodiment, a unit vector whose orientation is indicative of navigator echo phase angle relative to a reference angle is determined for each navigator echo. An amplitude correction value indicative of the amplitude of each navigator echo relative to a reference amplitude, such as an average navigator echo amplitude, is determined. The image date is adjusted with the relative phase angle and amplitude of the navigator echo from the same multiple echo sequence.

Abstract: A black blood magnetic resonance angiogram is produced by exciting dipoles (52) and repeatedly inverting the resonance (541, 542, . . . ) to produce a series of magnetic resonance echoes (561, 562, . . . ). Early echoes (e.g., (561, . . . , 568)) are more heavily proton density weighted than later echoes (e.g., (569, . . . , 5616)), which are more heavily T2 weighted. The magnetic resonance echoes are received and demodulated (38) into a series of data lines. The data lines are sorted (60) between the more heavily proton density weighted data lines and T2 weighted data lines which are reconstructed into a proton density weighted image representation and a T2 weighted image representation. The proton density weighted and T2 weighted image representations are combined (90) to emphasize the black blood from the T2 weighted images and the static tissue from the proton density weighted image. The combination processor (90) scales (92) the PDW and T2W images to a common maximum intensity level.

Abstract: A black blood magnetic resonance angiogram is produced by exciting dipoles (52) and repeatedly inverting the resonance (541, 542, . . . ) to produce a series of magnetic resonance echoes (561, 562, . . . ). Early echoes (e.g., (561, . . . , 568)) are more heavily proton density weighted than later echoes (e.g., (569, . . . , 5616)) which are more heavily T2 weighted. The magnetic resonance echoes are received and demodulated (38) into a series of data lines. The data lines are sorted (60) between the more heavily proton density weighted data lines and T2 weighted data lines which are reconstructed into a proton density weighted image representation and a T2 weighted image representation. The proton density weighted and T2 weighted image representations are combined (90) to emphasize the black blood from the T2 weighted images and the static tissue from the proton density weighted image. The combined image is a black blood magnetic resonance angiogram.

Abstract: Resonance is excited in a first slab (12) and manipulated to generate a plurality of data lines (16, 18) which span a fraction of k-space, e.g. a quarter of the phase encoding steps along a y-direction. Resonance is then excited in a second slab (22) displaced from the first slab and another series of data lines are generated. A resonance is excited and data lines generated in a plurality of additional slabs (32, 42). A resonance is excited in a slab (52) which partially overlaps the slab (12), e.g., has three of four slices in common. A series of data lines in the slab (52) are phase encoded with a different fraction of k-space. Two sets of differently phase encoded data sets have been generated in the example of FIGS. 2a and 2b.

Abstract: A 3DFT gradient-recalled echo pulse sequence is employed to acquire NMR data from which an MR angiogram is produced. A thin slab excitation is employed and this thin slab is incremented in slice-thickness steps through the volume of interest as the NMR data is acquired. Navigator echoes are acquired at each thin slab location to correct the NMR data for phase errors produced by the sliding slab technique.