Method for non-contrast enhanced magnetic resonance angiography

摘要

A method for non-contrast enhanced magnetic resonance angiography (“MRA”) that has a short scan time and is insensitive to patient motion is provided. More particularly, the method provides significant arterial conspicuity and substantial venous signal suppression. A two-dimensional single shot acquisition is employed and timed to occur a specific time period after the occurrence of an R-wave in a contemporaneously recorded electrocardiogram. In this manner, k-space data is acquired that is substantially insensitive to variations in arterial flow velocity, or heart rate, and that further substantially suppresses unwanted venous signal in a prescribed imaging slice. Alternatively, a two-dimensional multi-shot acquisition is employed to acquire k-space data using an echo train length that is sufficiently short so as to suppress flow-related artifacts, and such that cardiac gating is not required.

主权项

1. A method for non-contrast-enhanced magnetic resonance angiography (MRA) using a magnetic resonance imaging (MRI) system to produce an image that depicts a subject's vasculature, the steps of the method comprising:
a) directing the MRI system to perform a pulse sequence that includes:
i) applying at least one radio frequency (RF) saturation pulse to a selected region in the subject such that magnetic resonance signals in the selected region are at least partially suppressed;ii) applying at least one RF saturation pulse to a prescribed imaging slice that is outside of the selected region such that magnetic resonance signals in the prescribed imaging slice are at least partially suppressed;iii) waiting a period of time after at least one of steps i) and ii) during which no RF pulses are applied, the period of time being sufficiently long to allow saturated vascular spins from the selected region to flow into the prescribed imaging slice and to allow unsaturated vascular spins from outside the selected region to flow into the prescribed imaging slice;iv) acquire k-space data from the prescribed imaging slice after waiting the period of time in step iii) by applying an excitation RF pulse to the prescribed imaging slice and sampling k-space using at least one of a single-shot acquisition and a multi-shot acquisition having an echo train sufficient in length so as to suppress blood flow-related artifacts; and b) reconstructing from the k-space data acquired in step a)iv), an image that depicts the unsaturated vascular spins in the subject's vasculature.