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Optimizing 3D EPI f...
Abstract
Ämnesord
Stäng
- PURPOSE: To investigate the use of 3D EPI for rapid T1 -weighted brain imaging, focusing on the RF pulse's influence on the contrast between gray and white matter.METHODS: An interleaved 3D EPI sequence use partial Fourier and CAIPIRINHA sampling was used to acquire T1 -weighted brain volumes with isotropic resolution, low echo times, and low geometric distortions. Five different RF pulses were evaluated in terms of fat suppression performance and gray-white matter contrast. Two binomial RF pulses were compared to a single rectangular (WE-rect) RF pulse exciting only water, and two new RF pulses developed in this work, where one was an extension of the WE-rect, and the other was an SLR pulse. The technique was demonstrated in three clinical cases, where brain tumor patients were imaged before and after gadolinium administration.RESULTS: A fat-suppressed 3D EPI sequence with a phase encoding bandwidth of around 100 Hz was found to exhibit a good trade-off between geometrical distortions and scan duration. Whole-brain T1 -weighted 3D EPI images with 1.2 mm isotropic voxel size could be acquired in 24 seconds. The WE-rect, its extension, and the SLR RF pulses resulted in reduced magnetization transfer effects and provided a 20% mean increase in gray-white matter contrast.CONCLUSION: Using a high phase encoding bandwidth and RF pulses that reduce magnetization transfer effects, a fat-suppressed multi-shot 3D EPI sequence can be used to rapidly acquire isotropic T1 -weighted volumes.
Ämnesord
- MEDICIN OCH HÄLSOVETENSKAP -- Klinisk medicin -- Radiologi och bildbehandling (hsv//swe)
- MEDICAL AND HEALTH SCIENCES -- Clinical Medicine -- Radiology, Nuclear Medicine and Medical Imaging (hsv//eng)
Nyckelord
- 3D
- EPI
- RF
- T1-weighted
- binomial
- brain
Publikations- och innehållstyp
- ref (ämneskategori)
- art (ämneskategori)
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