Grase-type MR pulse sequences

Claim 1

A method of acquiring MR data by using an MR pulse sequence to acquire lines of MR data and filling a k-space matrix with such lines of data, comprising the following steps: establishing, in the k-space matrix, a plurality of non-overlapping bands, each band including a set of lines to be read out between a maximum phase-encoding gradient and a minimum phase-encoding gradient; establishing, in the MR pulse sequence, an identical plurality of temporally sequential and non-overlapping subsequences of pulses, each subsequence corresponding to one and only one of the bands and reading out lines of MR data at phase-encoding gradients that are between the maximum and minimum phase-encoding gradients for that corresponding one; using said MR pulse sequence to read out lines of MR data; and filling the bands with lines of MR data.

Claim 2

A method of acquiring MR data by using an MR pulse sequence to acquire lines of MR data and filling a k-space matrix with such lines of data, comprising the following steps: establishing, in the k-space matrix, a plurality of non-overlapping bands, each band including a set of lines to be read out between a maximum phase-encoding gradient and a minimum phase-encoding gradient; establishing, in the MR pulse sequence, an identical plurality of temporally sequential and non-overlapping subsequences of pulses, each subsequence corresponding to one and only one of the bands and reading out lines of MR data at phase-encoding gradients that are between the maximum and minimum phase-encoding gradients for that corresponding one; using said MR pulse sequence to read out lines of MR data; and filling the bands with lines of MR data.

Claim 9

A method of acquiring MR data using an MR pulse sequence of the gradient and spin echo (GRASE) type to read out lines of MR data and filling a k-space matrix with such lines of data, comprising the following steps: establishing, in the k-space matrix, three non-overlapping bands of identical phase-encoding width, each band including a set of lines read out between a maximum phase-encoding gradient and a minimum phase-encoding gradient, and one of said bands being a center band and including a line of MR data acquired at phase-encoding gradient which is at least approximately zero; establishing, in the MR pulse sequence, three temporally sequential and non-overlapping subsequences of pulses, each subsequence corresponding to exactly one of the bands and reading out lines of MR data at phase-encoding gradients that are between the maximum and minimum phase-encoding gradients for that corresponding one, one of said subsequences being an initial subsequence and reading out a line of MR data at said at least approximately zero phase-encoding gradient; initially filling said center band with lines of MR data; and subsequently filling the other two bands with lines of MR data.

Claim 10

A method of acquiring MR data using an MR pulse sequence of the gradient and spin echo (GRASE) type to read out lines of MR data and filling a k-space matrix with such lines of data, comprising the following steps: establishing, in the k-space matrix, three non-overlapping bands of identical phase-encoding width, each band including a set of lines read out between a maximum phase-encoding gradient and a minimum phase-encoding gradient, and one of said bands being a center band and including a line of MR data acquired at phase-encoding gradient which is at least approximately zero; establishing, in the MR pulse sequence, three temporally sequential and non-overlapping subsequences of pulses, each subsequence corresponding to exactly one of the bands and reading out lines of MR data at phase-encoding gradients that are between the maximum and minimum phase-encoding gradients for that corresponding one, one of said subsequences being an initial subsequence and reading out a line of MR data at said at least approximately zero phase-encoding gradient; initially filling said center band with lines of MR data; and subsequently filling the other two bands with lines of MR data.