US5713358A — Method for producing a time-resolved series of 3D…

Claim 1

Independent Claim 136 words

A method for acquiring NMR data from a subject after iniection of a contrast agent to produce a series of frame images depicting the passage of contrast agent through a region of interest in the subject by repeatedly acquiring samples from a corresponding k-space during a dynamic study of the subject, the steps comprising: sampling a central region of k-space at intervals during the dynamic study at a selected temporal rate; sampling peripheral regions of k-space at intervals during the dynamic study at a lower temporal rate; producing a series of data sets by forming a data set for each central region k-space sampling, which includes said central region k-space samples and samples derived from temporally adjacent samplings of the peripheral k-space regions; and reconstructing the series of frame images from the series of data sets.

Claim 2

Independent Claim 136 words

A method for acquiring NMR data from a subject after iniection of a contrast agent to produce a series of frame images depicting the passage of contrast agent through a region of interest in the subject by repeatedly acquiring samples from a corresponding k-space during a dynamic study of the subject, the steps comprising: sampling a central region of k-space at intervals during the dynamic study at a selected temporal rate; sampling peripheral regions of k-space at intervals during the dynamic study at a lower temporal rate; producing a series of data sets by forming a data set for each central region k-space sampling, which includes said central region k-space samples and samples derived from temporally adjacent samplings of the peripheral k-space regions; and reconstructing the series of frame images from the series of data sets.

Claim 3

Dependent Claim 21 words

The method as recited in claim 1 in which the NMR data is acquired from a three-dimensional region of the subject.

Claim 4

Dependent Claim 21 words

The method as recited in claim 2 in which a three-dimensional frame image is produced from one of said data sets.

Claim 5

Dependent Claim 20 words

The method as recited in claim 3 in which a two-dimensional image is produced by projecting said three-dimensional frame image.

Claim 6

Independent Claim 130 words

A method for acquiring NMR data from a subject to produce a series of frame images by repeatedly acquiring samples from a selected k-space during a dynamic study of a three-dimensional region of the subject, the steps comprising: sampling a central region of the selected k-space at a temporal rate; sampling peripheral regions of the selected k-space at a lower temporal rate; forming a data set for each set of central region k-space samples, which includes said central region k-space samples and samples derived from the most temporally adjacent samplings of the peripheral k-space regions; and reconstructing a three-dimensional frame image from each data set, and; in which a further three-dimensional image is produced by subtracting one of said three-dimensional frame images from another one of said three-dimensional frame images.

Claim 7

Independent Claim 130 words

A method for acquiring NMR data from a subject to produce a series of frame images by repeatedly acquiring samples from a selected k-space during a dynamic study of a three-dimensional region of the subject, the steps comprising: sampling a central region of the selected k-space at a temporal rate; sampling peripheral regions of the selected k-space at a lower temporal rate; forming a data set for each set of central region k-space samples, which includes said central region k-space samples and samples derived from the most temporally adjacent samplings of the peripheral k-space regions; and reconstructing a three-dimensional frame image from each data set, and; in which a further three-dimensional image is produced by subtracting one of said three-dimensional frame images from another one of said three-dimensional frame images.

Claim 8

Dependent Claim 20 words

The method as recited in claim 5 in which a two-dimensional image is produced by projecting the further three-dimensional image.

Claim 9

Dependent Claim 35 words

The method as recited in claim 1 in which the samples derived from the temporally adjacent samplings of the peripheral k-space regions are derived by selecting the temporally nearest samples of the peripheral k-space regions.

Claim 10

Dependent Claim 37 words

The method as recited in claim 1 in which the samples derived from the temporally adjacent samplings of the peripheral k-space regions are derived by interpolating between the two temporally nearest samples of the peripheral k-space regions.

Claim 11

Dependent Claim 14 words

The method as recited in claim 8 in which the interpolation is linear interpolation.

Claim 12

Independent Claim 136 words

A method for acquiring NMR data from a subject to produce a series of frame images by repeatedly acquiring samples from a selected k-space during a dynamic study of the subject, the steps comprising: sampling a central region of the selected k-space at a temporal rate; sampling peripheral regions of the selected k-space at a lower temporal rate; forming a data set for each set of central region k-space samples, which includes said central region k-space samples and samples derived from the most temporally adjacent samplings of the peripheral k-space regions; and reconstructing a frame image from each data set; and in which there are three different peripheral k-space regions and the k-space is repeatedly sampled during the dynamic study by alternately sampling the central k-space region and one of the three different peripheral k-space regions.

Claim 13

Independent Claim 136 words

A method for acquiring NMR data from a subject to produce a series of frame images by repeatedly acquiring samples from a selected k-space during a dynamic study of the subject, the steps comprising: sampling a central region of the selected k-space at a temporal rate; sampling peripheral regions of the selected k-space at a lower temporal rate; forming a data set for each set of central region k-space samples, which includes said central region k-space samples and samples derived from the most temporally adjacent samplings of the peripheral k-space regions; and reconstructing a frame image from each data set; and in which there are three different peripheral k-space regions and the k-space is repeatedly sampled during the dynamic study by alternately sampling the central k-space region and one of the three different peripheral k-space regions.

Claim 14

Dependent Claim 31 words

The method as recited in claim 1 in which additional data sets are formed by interpolating between successive data sets, and additional frame images are reconstructed from said additional data sets.

Claim 15

Dependent Claim 35 words

The method as recited in claim 1 in which additional data sets are formed by interpolating between successive samplings of the central k-space region, and additional frame images are reconstructed from said additional data sets.

Claim 16

Dependent Claim 29 words

The method as recited in claim 12 in which the additional data sets are formed by also interpolating between the two temporally nearest samples of the peripheral k-space regions.

Claim 17

Dependent Claim 41 words

The method as recited in claim 12 in which the additional data sets are formed by also deriving samples from the most temporally adjacent samplings of the peripheral k-space regions by selecting the temporally nearest samples of the peripheral k-space regions.

Claim 18

Dependent Claim 37 words

The method as recited in claim 1 in which there are a plurality of different peripheral regions of k-space and each different peripheral region of k-space is sampled at a different temporal rate during the dynamic study.

Claim 19

Dependent Claim 44 words

The method as recited in claim 1 in which each frame image is reconstructed by subtracting one of the data sets from each of the other data sets in the series and performing a Fourier transformation on each of said other subtracted data sets.

Claim 20

Dependent Claim 40 words

The method as recited in claim 16 in which each of the other subtracted and transformed data sets is a two-dimensional data set, and a two-dimensional image is produced by projecting on eof said subjected and transformed three-dimensional data sets.

Claim 21

Dependent Claim 38 words

The method as recited in claim 1 in which each frame image is reconstructed by Fourier transforming each data set and then subtracting one of said transformed data sets from each ofhter of the other transformed data sets.

Claim 22

Dependent Claim 36 words

The method as recited in claim 18 in which the subtracted and transformed data sets are three-dimensional data sets, and a two-imdensional image is produced by projecting one of said subtracted and transformed three-dimensional data sets.

Claim 23

Dependent Claim 32 words

The method as recited in claim 1 in which the central region of k-space is a substantially circular central region of k-space and the peripheral regions are surrounding annular-shaped regions of k-space.

Claim 24

Dependent Claim 18 words

The method as recited in claim 1 in which the regions divide k-space along a phase encoding axis.

Claim 25

Dependent Claim 29 words

The method as recited in claim 1 in which the central region of k-space is substantially symmetrically centered about a plane defined by the readout and slice encoding axes.

Claim 26

Dependent Claim 26 words

The method as recited in claim 12 in which the additional data sets are formed by selecting the temporally nearest samples of the peripheral k-space regions.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	2001-02-02	2001-08-04	2002-02-03	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	2005-02-02	2005-08-04	2006-02-03	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	2009-02-02	2009-08-04	2010-02-03	$7700.00	Window Closed / Lapsed

Method for producing a time-resolved series of 3D magnetic resonance angiograms during the first passage of contrast agent

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