Abstract: Techniques and systems for non-contrast enhanced magnetic resonance angiography and venography (MRAV) are described. For example, within one cardiac cycle of a subject, a single shot acquisition of non-suppressed arterial MR signals and a single shot acquisition of non-suppressed venous MR signals are employed. Radio frequency (RF) saturation pulses may be applied to one or more slabs such that MR signals indicative of venous blood that flows into the arterial imaging slice are substantially suppressed and MR signals indicative of arterial blood that flows in the venous imaging slice are substantially suppressed. The RF saturation pulses and the single shot acquisitions may be timed such that one or more of the single shot acquisitions occur during substantially steady state inflow of blood into the respective imaging slice. In this manner, k-space data may be acquired from arterial specific and venous specific imaging slices occurring within a single cardiac cycle.

Abstract: A magnetic resonance imaging data sampling method includes randomly undersampling a first half of a k-space plane such that a plurality of points in the first half are sampled points and the remaining plurality of points in the first half are unsampled points. The method also includes determining, for each sampled point in the first half, a corresponding point in a second half of the k-space plane that corresponds to the point-wise complex conjugate location of the sampled point.

Abstract: A magnetic resonance imaging data sampling method includes randomly undersampling a first half of a k-space plane such that a plurality of points in the first half are sampled points and the remaining plurality of points in the first half are unsampled points. The method also includes determining, for each sampled point in the first half, a corresponding point in a second half of the k-space plane that corresponds to the point-wise complex conjugate location of the sampled point.

Abstract: Techniques and systems for non-contrast enhanced magnetic resonance angiography and venography (MRAV) are described. For example, within one cardiac cycle of a subject, a single shot acquisition of non-suppressed arterial MR signals and a single shot acquisition of non-suppressed venous MR signals are employed. Radio frequency (RF) saturation pulses may be applied to one or more slabs such that MR signals indicative of venous blood that flows into the arterial imaging slice are substantially suppressed and MR signals indicative of arterial blood that flows in the venous imaging slice are substantially suppressed. The RF saturation pulses and the single shot acquisitions may be timed such that one or more of the single shot acquisitions occur during substantially steady state inflow of blood into the respective imaging slice. In this manner, k-space data may be acquired from arterial specific and venous specific imaging slices occurring within a single cardiac cycle.

Abstract: A dynamic MRA study of a subject is performed using a 3D echo-planar imaging pulse sequence. Four phase encoding views are acquired for each pulse repetition period (TR) and this enables higher resolution images to be acquired without a reduction of temporal frame rate or a loss of image CNR.

Abstract: A dynamic MRA study of a subject is performed using a 3D fast gradient-recalled echo pulse sequence. The frame rate of the resulting series of reconstructed images is increased by sampling a central region of k-space at a higher rate than the peripheral regions of k-space. A difference image is produced by subtracting a mask formed by central region k-space sampling from a selected image frame formed by central region and peripheral regions k-space sampling.

Abstract: A dynamic MRA study of a subject is performed using a 3D fast gradient-recalled echo pulse sequence that employs a non-selective RF excitation pulse. The frame rate of the resulting series of reconstructed images is increased by sampling a central region of k-space at a higher rate than the peripheral regions of k-space. The acquisition is gated using a cardiac trigger signal and the central region of k-space is acquired during diastole and the peripheral regions of k-space are acquired during systole. Image frames are reconstructed at each sampling of the central k-space region using the temporally nearest samples from the peripheral k-space regions. Two of the image frames are subtracted to form an MR angiogram.

Abstract: A dynamic MRA study of a subject is performed using a 3D fast gradient-recalled echo pulse sequence. The frame rate of the resulting series of reconstructed images is increased by sampling a central region of k-space at a higher rate than the peripheral regions of k-space. Image frames are reconstructed at each sampling of the central k-space region using the temporally nearest samples from the peripheral k-space regions.

Abstract: An angiogram is produced using NMR fast pulse sequences in which the views are acquired in shots preceded by a preparatory pulse sequence. Each shot is acquired twice with differing preparatory pulse sequences and the resulting NMR data is subtracted to null the stationary tissues in the reconstructed image.

Abstract: A magnetic resonance angiogram is produced by projecting a 3D array of motion sensitized NMR data. A mask which locates the vessels in the 3D array is produced by thresholding the NMR data, and this mask is combined with the 3D NMR data set to exclude signals produced by surrounding stationary tissues. An integration projection technique is used to produce the angiogram from the masked data set.

Abstract: An NMR angiogram is produced using a line scan data acquisition. Each line of NMR data is acquired twice, once with a velocity sensitizing gradient having a positive first moment and once with a velocity sensitizing gradient having a negative first moment. The two signals from the acquisition are subtracted to cancel signals from stationary spins while enhancing signals from flowing spins. The magnitude of the velocity sensitizing gradient moment is changed during the cardiac cycle so that aliasing does not occur at high blood velocities and the signal strength does not drop too low at low blood velocities. An angiogram is produced by reconstructing an image from line scan data acquired from a series of slices.