A novel free-breathing abdominal RAVE T2/T1 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) T2/T1 hybrid sequence for abdominal magnetic resonance imaging (MRI). RAVET2/T1 is a three-dimensional radial sequence with fat saturation and blood flow suppression that acquires T2- and T1-weighted contrasts in one scan in an identical slice position during free-breathing. METHODS: Sixteen CF patients underwent axial T2 HASTE (1000 ms/93 ms TR/TE), T1 DIXON (6.8 ms/2.4 ms/4.8 ms TR/TE1/TE2), and RAVE T2/T1 hybrid sequence (1200 ms/1.7 ms/3.3 ms/4.9 ms/102 ms TR/TE1/TE2/TE3/TE4) 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 T2 weighted aspect of the RAVE T2/T1 hybrid sequence compared to T2 HASTE (p < 0.05) and significantly lower in the T1 weighted in-phase aspect of the RAVE T2/T1 hybrid sequence compared to the T1 DIXON sequence (p < 0.05). Qualitatively the T2 weighted aspect of the RAVE T2/T1 hybrid sequence was rated significantly higher than the T2 HASTE in 6 of 7 categories (p < 0.05) and the T1 weighted in-phase aspect of the RAVE T2/T1 hybrid sequence was rated significantly higher than the T1 DIXON in 2 of 6 categories (p < 0.05). CONCLUSIONS: The abdominal radial RAVE T2/T1 hybrid sequence provided higher image quality and SNR than the T2HASTEsequence. Together with increased robustness against motion artifacts, the RAVE T2/T1 hybrid sequence appears to be a good tool for abdominal imaging in CF patients.

Preliminary results of abdominal simultaneous multi-slice accelerated diffusion-weighted imaging with motion-correction in patients with cystic fibrosis and impaired compliance.

OBJECTIVES: The aim of this prospective study was to compare scan time, image quality, signal-to-noise Ratio (SNR), and apparent diffusion coefficient (ADC) values of simultaneous multi-slice accelerated diffusion-weighted imaging with motion-correction (DWI SMS Moco) to standard diffusion-weighted imaging (sDWI) in free-breathing abdominal magnetic resonance imaging (MRI) in pediatric and young adult patients with cystic fibrosis (CF). MATERIAL AND METHODS: 16 patients (7 male and 9 female, 12-41 years old) with CF were examined prospectively in a single-center from November 2020 to March 2021 on a 1.5 Tesla clinical MR scanner. The characteristics of overall image quality and delimitability of mesenteric lymph nodes were evaluated using a 5-point Likert scale by two experienced pediatric radiologists independently from each other. Quantitative parameters with SNR and ADC values were assessed in 8 different locations and compared using a Wilcoxon signed-rank test. RESULTS: The acquisition time for DWI SMS Moco was 32% shorter than for sDWI. Regarding quality comparison, overall image quality and delimitability of mesenteric lymph nodes were significant higher in DWI SMS Moco (p ≤ 0.05 for both readers). The readers preferred DWI SMS Moco to sDWI in all cases (16/16). Mean SNR values from DWI SMS Moco and sDWI were similar in 7 from 8 locations. The ADC values showed no significant difference between DWI SMS Moco and sDWI in any of the evaluated locations (p > 0.05). CONCLUSIONS: The DWI SMS Moco improves overall image quality and delimitability of mesenteric lymph nodes compared to sDWI with similar SNR and ADC values and a distinguished reduction of scan time in free-breathing by one third. We conclude that MRI with DWI SMS Moco could be helpful in monitoring the effect of the high-efficiency modulator (HEM) therapy in cystic fibrosis (CF) patients homozygous or heterozygous for F508del in the abdomen.