Extending slice coverage for breathhold fat-suppressed T2-weighted fast spin-echo of the liver at 3.0T: Application of variable-rate selective-excitation (VERSE) RF pulses
✍ Scribed by Indra C. van den Bos; Shahid M. Hussain; Gabriel P. Krestin; Piotr A. Wielopolski
- Publisher
- John Wiley and Sons
- Year
- 2007
- Tongue
- English
- Weight
- 242 KB
- Volume
- 27
- Category
- Article
- ISSN
- 1053-1807
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✦ Synopsis
Abstract
Purpose
To determine the benefits of variable‐rate selective‐excitation (VERSE) radio frequency (RF) pulses for increased slice coverage in breathhold (BH) fat‐suppressed T2‐weighted fast spin‐echo (FS‐T2W‐FSE) liver imaging at 3.0T.
Materials and Methods
A total of 12 healthy volunteers were imaged on 3.0T, using FS‐T2W‐FSE. Slice coverage and specific absorption rate (SAR) levels were monitored for VERSE‐RF and standard‐RF (sRF), respectively. BH time was 25 seconds; slice thickness 3.5 mm. Maximum coverage was recorded for interactive variation of repetition time (TR), bandwidth (BW), and echo‐train length (ETL). Image quality was assessed qualitatively and quantitatively.
Results
Total slice coverage was always higher using VERSE‐RF, but varied depending on the selected parameters. For BW ≥ 62.5 kHz, slice coverage using VERSE increased between 38% (TR = 8200 msec) and 58% (TR = 2500 msec). Maximum coverage was obtained for TR = 5000 msec, ETL = 12, and BW ≥ 62.5 kHz; with a mean of 31.8 slices for VERSE‐RF and 22.5 slices for sRF, respectively (P < 0.005, 41% increased coverage). SAR was lower for VERSE‐RF using BW < 41.67 kHz (P < 0.05), and equal to sRF for higher BW. Image quality was best for TR ≤ 5000 msec (P < 0.05). FS was more homogeneous for lower ETL (P < 0.05). Blood suppression was best for TR ≤ 5000 msec (P < 0.05).
Conclusion
VERSE‐RF pulses can be applied for thin‐slice BH FS‐T2W liver imaging at 3.0T, with significantly improved slice coverage. J. Magn. Reson. Imaging 2007. © 2007 Wiley‐Liss, Inc.