A novel free-breathing abdominal RAVE T/T hybrid MRI sequence in patients with cystic fibrosis: Preliminary results.

Objectives: Patients with cystic fibrosis (CF) increasingly require imaging for the diagnosis of abdominal complications. We prospectively evaluated the image quality and signal-to-noise ratio (SNR) of a modern radial volumetric encoding (RAVE) T/T hybrid sequence for abdominal magnetic resonance imaging (MRI). RAVET/T is a three-dimensional radial sequence with fat saturation and blood flow suppression that acquires T- and T-weighted contrasts in one scan in an identical slice position during free-breathing.

Methods: Sixteen CF patients underwent axial T HASTE (1000 ms/93 ms TR/TE), T DIXON (6.8 ms/2.4 ms/4.8 ms TR/TE/TE), and RAVE T/T hybrid sequence (1200 ms/1.7 ms/3.3 ms/4.9 ms/102 ms TR/TE/TE/TE/TE) of the upper abdomen at 1.5 Tesla. The SNR values in six different regions were assessed and compared using the Wilcoxon signed-rank test. The image quality criteria were rated on a 5-point Likert scale.

Results: In all regions, the SNR was significantly higher in the T weighted aspect of the RAVE T/T hybrid sequence compared to T HASTE (p < 0.05) and significantly lower in the T weighted in-phase aspect of the RAVE T/T hybrid sequence compared to the T DIXON sequence (p < 0.05). Qualitatively the T weighted aspect of the RAVE T/T hybrid sequence was rated significantly higher than the T HASTE in 6 of 7 categories (p < 0.05) and the T weighted in-phase aspect of the RAVE T/T hybrid sequence was rated significantly higher than the T DIXON in 2 of 6 categories (p < 0.05).

Conclusions: The abdominal radial RAVE T/T hybrid sequence provided higher image quality and SNR than the THASTEsequence. Together with increased robustness against motion artifacts, the RAVE T/T hybrid sequence appears to be a good tool for abdominal imaging in CF patients.