National Research Council of Canada

Other

Scott King

Jonathan C Sharp

Garnette Roy Sutherland

Tim Fielding

Perry Newhook

Alexander Greer

Boguslaw Tomanek

Jarod Matwiy

Lizann Bolinger

Calvin Bewsky

Mike Smith

Methods, devices, and systems for use in accomplishing registration of a patient to a robot to facilitate image guided surgical procedures, such as stereotactic procedures.

Methods, devices, and systems useful in registration

Herein a method for slice selection is provided in an MRI process, the method involves controlling a transmit array by adding low flip angle RF pulses interspersed between refocusing pulses that are used to move a k-space weighting function with respect to one or more B 1 fields used to deposit energy according to a desired k-space weighting function. The low flip angle pulses deposit energy so that an envelope traced by the low flip angle pulses in the k-space weighting function is related to a desired spatially excited region of the sample volume, for example by a Fourier transform, if the phase encoding directions are linear axes that coordinatize the sample volume, and the B 1 fields have linear phase gradients.

RF based spatially selective excitation in MRI

Accumulated spin magnetization phase within a RF MRI procedure can be used for providing an orderly k-space traversal. By operating a transmit array adapted to produce two B1 fields in alternation, where the B1 fields are substantially uniform in amplitude over a sample volume of the MRI setup, and the B1 fields have respective spatial phase distributions such that selection of a difference in spatial derivatives of the spatial phase distributions permits control over a size of a step in k-space applied by successive refocusing pulses for generating the B1 fields in alternation. Each alternating refocusing pulse issued within a T2 time causes a step through k-space in an encoding direction determined by the difference in spatial derivatives.

Method for radio-frequency nuclear magnetic resonance imaging

An array coil for sensing signals in magnetic resonance experiments incorporates the traditional loop-butterfly array elements at spaced positions along an axis of the sample with additional stacked twisted loops and/or twisted butterfly elements. The twisted loop and twisted butterfly elements are centered along between the standard loop-butterfly array elements. The twisted array elements are naturally isolated from both the loop and butterfly. Alternatively, for a two dimensional mesh array of loop elements, additional twisted loop array elements are added with both longitudinal and transverse orientations, again centered between loop elements. The goal is to allow separation of loop and/or butterfly elements of linear (Spine), 2D planar arrays (Cardiac) or cylindrical arrays of curved array elements (Head), for improved parallel MRI capabilities such as the SENSE or SMASH techniques, but to recover the SNR lost in between the elements and improve the g-factor of the total array with additional orthogonal array elements.

Stacked coil array for magnetic resonance experiments

In a method of spatial encoding in magnetic resonance experiments, encoding kernels are imposed into the magnetization signal during the excitation or re-focussing process using a transmit array coil. Separate transmit array coil elements are provided so that in a particular phase encode direction, z in this case, they can be driven to produce partially orthogonal B1 fields, T(r), that exhibit a Fourier phase distribution given by()=.The NMR signal, S(k), received by a coil array element m of the M receive coils, during application of a pulse sequence for the n-th phase encoding step in k-space is then given by()=&#x222b;()()such that&#x3c1;'()=&#x3c1;()()=&#x3c1;()

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Winnipeg, Canada

Scott King