Hybrid magnetic aresonance spatial and velocity imaging

Claim 1

A method for simultaneously obtaining magnetic resonance (MR) spatial and velocity image data of a fluid flowing in a preselected volume portion of a sample, within a logical x, y, and z coordinate system, comprising the steps of: (a) applying to said volume a main static magnetic field; (b) selecting a slice within said volume by (i) applying to said volume a magnetic field gradient in the logical z axis direction, wherein said magnetic field gradient is a slice selection gradient; (ii) applying to said volume an RF pulse at a frequency band and of sufficient strength to tip nuclear spins of material in said slice to create a magnetic signal; (c) applying to said volume a magnetic field gradient in the logical y axis direction for spatial phase encoding of said magnetic signal in the logical y axis dimension of said slice, wherein said magnetic field gradient in the logical y axis direction is a y axis phase encoding gradient; (d) applying to said volume a magnetic field gradient in the logical x axis direction for spatial encoding of spatial components of said magnetic signal in the logical x axis direction, wherein said magnetic field gradient in the logical x axis direction is a spatial readout gradient. (e) obtaining measurements of said magnetic signal while said spatial readout gradient is being applied; (f) applying to said volume a second magnetic field gradient in the logical y axis direction for velocity phase encoding of said magnetic signal in the logical y axis direction of said slice, wherein said second magnetic field gradient is of opposite sign and essentially equal in area to said first magnetic field gradient in the logical y direction, and wherein said second magnetic field gradient in the logical y axis direction is a y axis velocity phase encoding gradient; (g) applying to said volume a second magnetic field gradient in the logical x axis direction for spatial encoding of velocity-dependent components of said magnetic signal in the logical x axis direction, wherein said second magnetic field gradient in the logical x axis direction is a velocity readout gradient; (h) obtaining measurements of said magnetic signal while said velocity readout gradient is being applied.

Claim 2

A method for simultaneously obtaining magnetic resonance (MR) spatial and velocity image data of a fluid flowing in a preselected volume portion of a sample, within a logical x, y, and z coordinate system, comprising the steps of: (a) applying to said volume a main static magnetic field; (b) selecting a slice within said volume by (i) applying to said volume a magnetic field gradient in the logical z axis direction, wherein said magnetic field gradient is a slice selection gradient; (ii) applying to said volume an RF pulse at a frequency band and of sufficient strength to tip nuclear spins of material in said slice to create a magnetic signal; (c) applying to said volume a magnetic field gradient in the logical y axis direction for spatial phase encoding of said magnetic signal in the logical y axis dimension of said slice, wherein said magnetic field gradient in the logical y axis direction is a y axis phase encoding gradient; (d) applying to said volume a magnetic field gradient in the logical x axis direction for spatial encoding of spatial components of said magnetic signal in the logical x axis direction, wherein said magnetic field gradient in the logical x axis direction is a spatial readout gradient. (e) obtaining measurements of said magnetic signal while said spatial readout gradient is being applied; (f) applying to said volume a second magnetic field gradient in the logical y axis direction for velocity phase encoding of said magnetic signal in the logical y axis direction of said slice, wherein said second magnetic field gradient is of opposite sign and essentially equal in area to said first magnetic field gradient in the logical y direction, and wherein said second magnetic field gradient in the logical y axis direction is a y axis velocity phase encoding gradient; (g) applying to said volume a second magnetic field gradient in the logical x axis direction for spatial encoding of velocity-dependent components of said magnetic signal in the logical x axis direction, wherein said second magnetic field gradient in the logical x axis direction is a velocity readout gradient; (h) obtaining measurements of said magnetic signal while said velocity readout gradient is being applied.

Claim 6

A method for simultaneously obtaining spatial and velocity image data for providing a three-dimensional nuclear magnetic resonance (MR]image of fluid flowing in a preselected volume portion of a sample, within a logical x, y, and z axes coordinate system, comprising the steps of: (a) applying to said volume a main static magnetic field; (b) selecting a slab within said volume by (i) applying to said volume a magnetic field gradient in the logical z axis direction; and (ii) applying to said volume an RF pulse at a frequency band and of sufficient strength to tip nuclear spins of material in said slab to create a magnetic signal; (c) applying to said volume a magnetic field gradient in the logical y axis direction for spatial phase encoding of said magnetic signal in the logical y axis dimension of said slab, wherein said magnetic field gradient in the logical y axis direction is a y axis phase encoding gradient; (d) applying to said volume a second magnetic field gradient in the logical z axis direction for spatial phase encoding of said magnetic signal in the logical z axis direction of said slab, wherein said magnetic field gradient in the logical z axis direction is a z axis spatial phase encoding gradient; (e) applying to said volume a magnetic field gradient in the logical x axis direction for spatial encoding of spatial components of said magnetic signal in the logical x axis direction, wherein said magnetic field gradient in the logical x axis direction is a spatial readout gradient (f) obtaining measurements of said magnetic signal while said spatial readout gradient is being applied; (g) applying to said volume a third magnetic field gradient in the logical z axis direction for velocity phase encoding of said magnetic signal in the logical z axis direction of said slab, wherein said third magnetic field gradient is of opposite sign and essentially equal in area to said second magnetic field gradient in the logical z direction, and wherein said third magnetic field gradient in the logical z axis direction is a z axis velocity phase encoding gradient; (h) applying to said volume a second magnetic field gradient in the logical x axis direction for spatial encoding of velocity-dependent components of said magnetic signal in the logical x axis direction, wherein said second magnetic field gradient in the logical x axis direction is a velocity readout gradient; (i) obtaining measurements of said magnetic signal while said velocity readout gradient is being applied; and (j) repeating steps a through i multiple times to obtain a sufficient number of measurements to generate data from which three dimensional spatial and velocity images of said slab can be created; wherein said y axis and z axis phase encoding gradients are stepped through a combination of values requisite for the generation of a three dimensional image of said slab; and wherein the direction of said RF pulse is rotated to allow arbitrary slab position in the logical z axis direction.

Claim 7

A method for simultaneously obtaining spatial and velocity image data for providing a three-dimensional nuclear magnetic resonance (MR]image of fluid flowing in a preselected volume portion of a sample, within a logical x, y, and z axes coordinate system, comprising the steps of: (a) applying to said volume a main static magnetic field; (b) selecting a slab within said volume by (i) applying to said volume a magnetic field gradient in the logical z axis direction; and (ii) applying to said volume an RF pulse at a frequency band and of sufficient strength to tip nuclear spins of material in said slab to create a magnetic signal; (c) applying to said volume a magnetic field gradient in the logical y axis direction for spatial phase encoding of said magnetic signal in the logical y axis dimension of said slab, wherein said magnetic field gradient in the logical y axis direction is a y axis phase encoding gradient; (d) applying to said volume a second magnetic field gradient in the logical z axis direction for spatial phase encoding of said magnetic signal in the logical z axis direction of said slab, wherein said magnetic field gradient in the logical z axis direction is a z axis spatial phase encoding gradient; (e) applying to said volume a magnetic field gradient in the logical x axis direction for spatial encoding of spatial components of said magnetic signal in the logical x axis direction, wherein said magnetic field gradient in the logical x axis direction is a spatial readout gradient (f) obtaining measurements of said magnetic signal while said spatial readout gradient is being applied; (g) applying to said volume a third magnetic field gradient in the logical z axis direction for velocity phase encoding of said magnetic signal in the logical z axis direction of said slab, wherein said third magnetic field gradient is of opposite sign and essentially equal in area to said second magnetic field gradient in the logical z direction, and wherein said third magnetic field gradient in the logical z axis direction is a z axis velocity phase encoding gradient; (h) applying to said volume a second magnetic field gradient in the logical x axis direction for spatial encoding of velocity-dependent components of said magnetic signal in the logical x axis direction, wherein said second magnetic field gradient in the logical x axis direction is a velocity readout gradient; (i) obtaining measurements of said magnetic signal while said velocity readout gradient is being applied; and (j) repeating steps a through i multiple times to obtain a sufficient number of measurements to generate data from which three dimensional spatial and velocity images of said slab can be created; wherein said y axis and z axis phase encoding gradients are stepped through a combination of values requisite for the generation of a three dimensional image of said slab; and wherein the direction of said RF pulse is rotated to allow arbitrary slab position in the logical z axis direction.

Claim 16

A method for simultaneously obtaining spatial and velocity image data for providing a three-dimensional nuclear magnetic resonance (MR) image of fluid flowing in a preselected volume portion of a sample, within a logical x, y, and z axes coordinate system, comprising the steps of: (a) applying to said volume a main static magnetic field; (b) selecting a slab within said volume by (i) applying to said volume a magnetic field gradient in the logical z axis direction; and (ii) applying to said volume an RF pulse at a frequency band and of sufficient strength to tip nuclear spins of material in said slab to create a magnetic signal; (c) applying to said volume a magnetic field gradient in the logical y axis direction for spatial phase encoding of said magnetic signal in the logical y axis dimension of said slab, wherein said magnetic field gradient in the logical y axis direction is a y axis phase encoding gradient; (d) applying to said volume a second magnetic field gradient in the logical z axis direction for spatial phase encoding of said magnetic signal in the logical z axis direction of said slab, wherein said magnetic field gradient in the logical z axis direction is a z axis spatial phase encoding gradient; (e) applying to said volume a magnetic field gradient in the logical x axis direction for spatial encoding of said magnetic signal in the logical x axis direction, wherein said magnetic field gradient in the logical x axis direction is a readout gradient. (f) obtaining measurements of said magnetic signal while said readout gradient is being applied; (g) applying to said volume a third magnetic field gradient in the logical z axis direction for velocity phase encoding of said magnetic signal in the logical z axis direction of said slab, wherein said third magnetic field gradient is of opposite sign and essentially equal in area to said second magnetic field gradient in the logical z direction, and wherein said third magnetic field gradient in the logical z axis direction is a z axis velocity phase encoding gradient; (h) applying to said volume a second magnetic field gradient in the logical x axis direction for spatial encoding of velocity-dependent components of said magnetic signal in the logical x axis direction, wherein said second magnetic field gradient is the logical x axis direction is a velocity readout gradient; (i) obtaining measurements of said magnetic signal while said velocity readout gradient is being applied; (j) repeating steps a through i multiple times to obtain a sufficient number of measurements to generate data from which three dimensional spatial and velocity images of said slab can be created; wherein said y axis and z axis phase encoding gradients are stepped through a combination of values requisite for the generation of a three dimensional image of said slab; and (k) repeating steps a through i for the imaging of a desired number of additional slabs, wherein said slabs are overlapped.

Claim 17

A method for simultaneously obtaining spatial and velocity image data for providing a three-dimensional nuclear magnetic resonance (MR) image of fluid flowing in a preselected volume portion of a sample, within a logical x, y, and z axes coordinate system, comprising the steps of: (a) applying to said volume a main static magnetic field; (b) selecting a slab within said volume by (i) applying to said volume a magnetic field gradient in the logical z axis direction; and (ii) applying to said volume an RF pulse at a frequency band and of sufficient strength to tip nuclear spins of material in said slab to create a magnetic signal; (c) applying to said volume a magnetic field gradient in the logical y axis direction for spatial phase encoding of said magnetic signal in the logical y axis dimension of said slab, wherein said magnetic field gradient in the logical y axis direction is a y axis phase encoding gradient; (d) applying to said volume a second magnetic field gradient in the logical z axis direction for spatial phase encoding of said magnetic signal in the logical z axis direction of said slab, wherein said magnetic field gradient in the logical z axis direction is a z axis spatial phase encoding gradient; (e) applying to said volume a magnetic field gradient in the logical x axis direction for spatial encoding of said magnetic signal in the logical x axis direction, wherein said magnetic field gradient in the logical x axis direction is a readout gradient. (f) obtaining measurements of said magnetic signal while said readout gradient is being applied; (g) applying to said volume a third magnetic field gradient in the logical z axis direction for velocity phase encoding of said magnetic signal in the logical z axis direction of said slab, wherein said third magnetic field gradient is of opposite sign and essentially equal in area to said second magnetic field gradient in the logical z direction, and wherein said third magnetic field gradient in the logical z axis direction is a z axis velocity phase encoding gradient; (h) applying to said volume a second magnetic field gradient in the logical x axis direction for spatial encoding of velocity-dependent components of said magnetic signal in the logical x axis direction, wherein said second magnetic field gradient is the logical x axis direction is a velocity readout gradient; (i) obtaining measurements of said magnetic signal while said velocity readout gradient is being applied; (j) repeating steps a through i multiple times to obtain a sufficient number of measurements to generate data from which three dimensional spatial and velocity images of said slab can be created; wherein said y axis and z axis phase encoding gradients are stepped through a combination of values requisite for the generation of a three dimensional image of said slab; and (k) repeating steps a through i for the imaging of a desired number of additional slabs, wherein said slabs are overlapped.

Claim 22

A method for simultaneously obtaining spatial and velocity image data for providing a three-dimensional nuclear magnetic resonance (MR) image of fluid flowing in a preselected volume portion of a sample, within a logical x, y, and z axes coordinate system, wherein fluid flow is phase encoded in a direction which lies in the logical y-z plane at some angle θ relative to the logical z axis, comprising the steps of: (a) applying to said volume a main static magnetic field; (b) selecting a slab within said volume by (i) applying to said volume a magnetic field gradient in the logical z axis direction wherein said magnetic field gradient is a slab selection gradient; and (ii) applying to said volume an RF pulse at a frequency band and of sufficient strength to tip nuclear spins of material in said slab to create a magnetic signal; (c) applying to said volume a magnetic field gradient in the logical y axis direction for spatial phase encoding of said magnetic signal in the logical y axis dimension of said slab, wherein said magnetic field gradient in the logical y axis direction is a y axis phase encoding gradient; (d) applying to said volume a second magnetic field gradient in the logical z axis direction for spatial phase encoding of said magnetic signal in the logical z axis direction of said slab, wherein said magnetic field gradient in the logical z axis direction is a z axis spatial phase encoding gradient; (e) applying to said volume a magnetic field gradient in the logical x axis direction for spatial encoding of spatial components of said magnetic signal in the logical x axis direction, wherein said magnetic field gradient in the logical x axis direction is a spatial readout gradient. (f) obtaining measurements of said magnetic signal while said spatial readout gradient is being applied; (g) applying to said volume a third magnetic field gradient in the logical z axis direction for velocity phase encoding of said magnetic signal in the logical z axis direction of said slab, wherein said third magnetic field gradient is of opposite sign to said second magnetic field gradient in the logical z direction and with a magnitude depending upon the angle θ, and wherein said third magnetic field gradient in the logical z axis direction is a z axis velocity phase encoding gradient; (h) applying to said volume a second magnetic field gradient in the logical y axis direction for velocity phase encoding of said magnetic signal in the logical y axis direction of said slab, wherein said second magnetic field gradient in the logical y direction is of opposite sign to said first magnetic field gradient in the logical y direction and with a magnitude dependent upon the angle θ, and wherein said second magnetic field gradient in the logical y axis direction is a y axis velocity phase encoding gradient; (i) applying to said volume a second magnetic field gradient in the logical x axis direction for spatial encoding of velocity-dependent components of said magnetic signal in the logical x axis direction, wherein said second magnetic field gradient in the logical x axis direction is a velocity readout gradient; (j) obtaining measurements of said magnetic signal while said velocity readout gradient is being applied; and (k) applying a fourth pulse in the logical z direction of opposite sign to said second magnetic field gradient in the z direction and with a magnitude dependent upon the angle θ, wherein said fourth pulse in the logical z direction pulse is a z phase rewinding pulse. (l) applying a third pulse in the logical y direction of opposite sign to said first magnetic field gradient in the logical y direction and with a magnitude dependent upon the angle θ, wherein said third pulse in the logical y direction is a y phase rewinding pulse. (m) repeating steps a through l multiple times to obtain a sufficient number of measurements to generate data from which three dimensional spatial and velocity images of said slab can be created; wherein said y axis and z axis phase encoding gradients are stepped through a combination of values requisite for the generation of a three dimensional image of said slab; and wherein the direction of said RF pulse is rotated to allow arbitrary slab position in the logical z axis direction.

Claim 23

A method for simultaneously obtaining spatial and velocity image data for providing a three-dimensional nuclear magnetic resonance (MR) image of fluid flowing in a preselected volume portion of a sample, within a logical x, y, and z axes coordinate system, wherein fluid flow is phase encoded in a direction which lies in the logical y-z plane at some angle θ relative to the logical z axis, comprising the steps of: (a) applying to said volume a main static magnetic field; (b) selecting a slab within said volume by (i) applying to said volume a magnetic field gradient in the logical z axis direction wherein said magnetic field gradient is a slab selection gradient; and (ii) applying to said volume an RF pulse at a frequency band and of sufficient strength to tip nuclear spins of material in said slab to create a magnetic signal; (c) applying to said volume a magnetic field gradient in the logical y axis direction for spatial phase encoding of said magnetic signal in the logical y axis dimension of said slab, wherein said magnetic field gradient in the logical y axis direction is a y axis phase encoding gradient; (d) applying to said volume a second magnetic field gradient in the logical z axis direction for spatial phase encoding of said magnetic signal in the logical z axis direction of said slab, wherein said magnetic field gradient in the logical z axis direction is a z axis spatial phase encoding gradient; (e) applying to said volume a magnetic field gradient in the logical x axis direction for spatial encoding of spatial components of said magnetic signal in the logical x axis direction, wherein said magnetic field gradient in the logical x axis direction is a spatial readout gradient. (f) obtaining measurements of said magnetic signal while said spatial readout gradient is being applied; (g) applying to said volume a third magnetic field gradient in the logical z axis direction for velocity phase encoding of said magnetic signal in the logical z axis direction of said slab, wherein said third magnetic field gradient is of opposite sign to said second magnetic field gradient in the logical z direction and with a magnitude depending upon the angle θ, and wherein said third magnetic field gradient in the logical z axis direction is a z axis velocity phase encoding gradient; (h) applying to said volume a second magnetic field gradient in the logical y axis direction for velocity phase encoding of said magnetic signal in the logical y axis direction of said slab, wherein said second magnetic field gradient in the logical y direction is of opposite sign to said first magnetic field gradient in the logical y direction and with a magnitude dependent upon the angle θ, and wherein said second magnetic field gradient in the logical y axis direction is a y axis velocity phase encoding gradient; (i) applying to said volume a second magnetic field gradient in the logical x axis direction for spatial encoding of velocity-dependent components of said magnetic signal in the logical x axis direction, wherein said second magnetic field gradient in the logical x axis direction is a velocity readout gradient; (j) obtaining measurements of said magnetic signal while said velocity readout gradient is being applied; and (k) applying a fourth pulse in the logical z direction of opposite sign to said second magnetic field gradient in the z direction and with a magnitude dependent upon the angle θ, wherein said fourth pulse in the logical z direction pulse is a z phase rewinding pulse. (l) applying a third pulse in the logical y direction of opposite sign to said first magnetic field gradient in the logical y direction and with a magnitude dependent upon the angle θ, wherein said third pulse in the logical y direction is a y phase rewinding pulse. (m) repeating steps a through l multiple times to obtain a sufficient number of measurements to generate data from which three dimensional spatial and velocity images of said slab can be created; wherein said y axis and z axis phase encoding gradients are stepped through a combination of values requisite for the generation of a three dimensional image of said slab; and wherein the direction of said RF pulse is rotated to allow arbitrary slab position in the logical z axis direction.