Single-shot half-Fourier RARE sequence with ultra-short inter-echo spacing for lung imaging.
OBJECTIVE
To improve the image quality of pulmonary magnetic resonance (MR) imaging using an ultra-short inter-echo spacing half-Fourier single shot rapid acquisition with relaxation enhancement (USHA-RARE) sequence.


METHODS
Pulmonary MR images were acquired by USHA-RARE sequence with various inter-echo spacings. The sequence parameters were as follows: repetition time (TR)/effective TE: infinite/39-41 msec; section thickness: 10 mm; acquisition matrix: 128 x 128; field of view: 450 x 450 mm. Inter-echo spacing varied (2.5 msec, 3.0 msec, 3.5 msec, 4.0 msec, 4.5 msec, 5.0 msec), and the respective phase-encoding steps were 80, 77, 75, 74, 73, and 72. Signal-to-noise ratios (SNRs), the signal ratios between lung and fat (lung-to-fat ratio: LFRs), and the signal ratios between the lung and the serratus anterior muscle (lung-to-muscle ratio: LMRs) of each inter-echo spacing were calculated, and statistically evaluated.


RESULTS
The SNRs at inter-echo spacings of < or = 3.0 msec were significantly higher than those > or = 4.0 msec (P < 0.05). The LFRs and LMRs at inter-echo spacing < or = 3.0 msec were significantly higher than those > or = 4.0 msec (P < 0.05).


CONCLUSIONS
USHA-RARE sequence does improve signal intensity from the lung.
Ohno
Yoshiharu
Y
Pulmonary Functional Imaging Research, Department of Radiology, University of Pennsylvania Medical Center, Philadelphia, PA, USA. yosirad@kobe-u.ac.jp
Oshio
Koichi
K
Uematsu
Hidemasa
H
Nakatsu
Masashi
M
Gefter
Warren B
WB
Hatabu
Hiroto
H
D000328:Adult; D005583:Fourier Analysis; D006801:Humans; D008168:Lung / Q000033:anatomy & histology* / Q000473:pathology; D008171:Lung Diseases / Q000175:diagnosis; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D012815:Signal Processing, Computer-Assisted