Comparison of HASTE with multiple signal averaging versus conventional turbo spin echo sequence: a new option for T2-weighted MRI of the female pelvis.

OBJECTIVES

This study was conducted in order to evaluate the feasibility of a newly developed half-Fourier acquisition single-shot turbo spin echo (HASTE) sequence for T2-weighted MRI of the female pelvis, in which scanning and post-processing filtering techniques were optimized to minimize blurring and the resultant reduction in signal-to-noise ratio (SNR) was compensated by signal averaging of multiple excitations (multi-NEX), and to compare its image quality with that of a conventional turbo spin echo (TSE) sequence.

METHODS

Fifty females with gynecological disease were prospectively enrolled. They underwent pelvic MRI including sagittal T2-weighted imaging obtained with multi-NEX HASTE (mHASTE) and TSE with acquisition times of 1 m 9 s and 3 m 26 s, respectively. At the prospective reading, mHASTE was reviewed first, and any changes in the image interpretation detected during the subsequent TSE reading were recorded. The SNR and tissue contrast were quantitatively measured. Two radiologists independently assessed tissue conspicuity and overall image quality considering noise, artifacts, and blurring, and visual grading characteristics (VGC) analysis was performed to compare the two sequences.

RESULTS

Adding TSE to mHASTE did not change image interpretations in any case. mHASTE produced an equivalent SNR and significantly higher contrast between the myometrium and junctional zone (p < 0.05) compared with TSE. The area under the VGC curve (AUC) showed that the conspicuity of the uterus, ovaries, and lesions and the overall image quality were significantly higher on mHASTE than on TSE for both readers (AUC, 0.740-0.880; p < 0.01).

CONCLUSION

mHASTE is a feasible option for T2-weighted MRI of the female pelvis, as it allows faster and higher-quality image acquisition than conventional TSE.

KEY POINTS

• High-quality T2-weighted imaging is essential for magnetic resonance imaging of the female pelvis. • A new HASTE sequence was developed, in which a parallel imaging technique, a wide bandwidth, and a post-processing filter were used to minimize blurring, and the resultant reduction in the signal-to-noise ratio was compensated using signal averaging of multiple excitations (multi-NEX). • Multi-NEX HASTE allows fast and high-quality T2-weighted image acquisition.