RAVE-T2/T1 - Feasibility of a new hybrid MR-sequence for free-breathing abdominal MRI in children and adolescents.

BACKGROUND

The new radial volumetric encoding RAVE-T/T hybrid sequence is a modern three-dimensional sequence with multiparametric approach, which includes T- and T-weighted contrasts obtained in identical slice position during one measurement. However, the RAVE-T/T hybrid sequence is not yet being used in clinical routine.

PURPOSE

The aim of this study was to evaluate the RAVE-T/T hybrid sequence in a pediatric population with a clinical indication for an abdominal MRI examination to demonstrate that the hybrid imaging may be less challenging to perform on children.

MATERIALS AND METHODS

Our retrospective observational study included pediatric patients of all age groups and required for an abdominal MRI examination. Non-contrast standard axial T DIXON and non-contrast RAVE-T/T hybrid sequence were obtained at 3 T. MRI studies were analyzed independently by two pediatric radiologists using a 5-point Likert-type scale in five different categories. T- and T-weighted sequences were each compared with the RAVE-T/T-sequence using a Wilcoxon signed-rank test.

RESULTS

The analysis included 15 children (mean age, 11 years and 4 months, 7 girls and 8 boys). The Cohens Kappa of interrater agreement measured 0.62. The T weighted part of the RAVE-T/T sequence was significantly better than the standard T HASTE sequence in four of five image quality categories: overall image quality (2.2 ± 0.7 vs 1.8 ± 0,7, p = 0.03), respiratory motion artefacts (3.8 ± 0.4 vs 2.0 ± 0.7, p <= 0.01), portal vein clarity (3.3 ± 0.8 vs 2.2 ± 0.7, p <= 0.01), hepatic margin sharpness (2.4 ± 1,0 vs 1.8 ± 0.7, p <= 0.01). The T weighted part of the RAVE-T/T sequence was significantly better than the standard T DIXON weighted sequence in three of five image quality categories: respiratory motion artefacts (4.0 ± 0.2 vs 3.6 ± 0.8, p = 0.01), portal vein clarity (2.7 ± 0.9 vs 2.1 ± 0.7, p <= 0.01), hepatic margin sharpness (3.2 ± 0.7 vs 2.6 ± 0.9, p <= 0.01).

CONCLUSIONS

The RAVE-T/T hybrid sequence is feasible and equal compared to standard T- and T-weighted sequences in the assessment of abdominal organs in a pediatric population. Due to non-inferiority to the current standard sequences for abdominal imaging, the RAVE-T/T hybrid sequence is a good alternative for children who cannot be examined in breath-hold technique.