T2 restoration and noise suppression of hybrid MR images using Wiener and linear prediction techniques.

The authors address the problem of enhancing hybrid magnetic resonance (MR) images degraded by T2 effects and additive measurement noise. To reduce imaging time, MR signals are acquired using hybrid imaging (HI) sequences such as rapid acquisition relaxation-enhanced (RARE) and fast spin-echo (FSE). With these techniques, T2 effects act as a distortion filter.

Conjugation and hybrid MR imaging.

Purpose: To evaluate the use of conjugation with hybrid magnetic resonance imaging techniques in order to reduce artifacts from inconsistencies introduced by T2 decay.

Materials And Methods: Two phantoms containing either oil or water were used to study edge spread function (ESF) and signal-to-noise ratio (S/N) for three hybrid acquisition strategies (low pass, high pass, and ramp) in which a full set was acquired or with partial acquisition and conjugation.

Results: With half the echoes providing coverage of the same amount of k space, signal inconsistencies were reduced by a factor of at least e.

Evaluation of truncated readout-echo MR images obtained at 0.35 T.

It is possible to acquire a truncated echo, in which part of the information at the beginning or end of the echo is missing, and to restore the missing information by conjugation. This process was shown by means of edge spread function in phantoms and brain images in volunteers to introduce little, if any, degradation of image quality and can be used to improve sequence efficiency or to shorten echo time.

In vivo relaxation times and hydrogen density at 0.063-4.85 T in rats with implanted mammary adenocarcinomas.

Magnetic resonance (MR) imaging at 0.063 T, 0.17 T, 0.

Echo-planar pediatric imager.

Practical constraints make it difficult to build large-aperture echo-planar magnetic resonance (MR) imagers. The implementation of a pediatric imager and its performance are described. Spatial resolution and signal-to-noise levels comparable to those of 1982 state-of-the-art MR imagers have been achieved in imaging times of 0.