Time-resolved digital subtraction magnetic resonance angiography using echo-planar imaging

Claim 1

A method for acquiring contrast enhanced 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: administering a contrast agent to the subject which enhances NMR signals; performing a series of NMR data acquisitions using an echo-planar pulse sequence to sample a central region of the selected k-space at a temporal rate; and to sample peripheral regions of the selected k-space at a lower temporal rate, each echo-planar pulse sequence acquiring a plurality of NMR signals which each sample a portion of k-space and the number of NMR signals acquired during each echo-planar pulse sequence being limited such that the contrast between contrast enhanced tissues and other tissues is not substantially diminished; 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.

Claim 2

A method for acquiring contrast enhanced 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: administering a contrast agent to the subject which enhances NMR signals; performing a series of NMR data acquisitions using an echo-planar pulse sequence to sample a central region of the selected k-space at a temporal rate; and to sample peripheral regions of the selected k-space at a lower temporal rate, each echo-planar pulse sequence acquiring a plurality of NMR signals which each sample a portion of k-space and the number of NMR signals acquired during each echo-planar pulse sequence being limited such that the contrast between contrast enhanced tissues and other tissues is not substantially diminished; 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.

Claim 11

A method for producing a contrast enhanced NMR image of a subject, the steps comprising: a) administering a contrast agent to the subject which enhances NMR signals; b) performing an echo-planar pulse sequence to acquire substantially four NMR signals which each sample different portions of k-space; c) acquiring a k-space data set from which an image can be reconstructed by repeating step b) a plurality of times; and d) reconstructing an image from the acquired k-space data set.

Claim 12

A method for producing a contrast enhanced NMR image of a subject, the steps comprising: a) administering a contrast agent to the subject which enhances NMR signals; b) performing an echo-planar pulse sequence to acquire substantially four NMR signals which each sample different portions of k-space; c) acquiring a k-space data set from which an image can be reconstructed by repeating step b) a plurality of times; and d) reconstructing an image from the acquired k-space data set.