Dynamic contrast-enhanced liver MRI in children: image quality comparison between GRASP-VIBE and CAIPIRINHA-VIBE

OBJECTIVES: To compare image quality between GRASP-VIBE (free-breathing) and CAIPIRINHA-VIBE (breath-hold) sequences in dynamic liver MRI in a pediatric population. MATERIALS AND METHODS: This retrospective study included 70 children who underwent dynamic liver MRI at 3 T with either GRASP-VIBE (n = 40) or CAIPIRINHA-VIBE (n = 40) acquisition. Ten patients underwent both imaging protocols at different time points. Image pairs were matched at four representative anatomical levels using vascular landmarks. Four dynamic contrast phases (pre-contrast, arterial, portal venous, delayed venous) at each anatomic level were independently reviewed by two radiologists, leading to a total of 640 comparisons per reader. Reader preference was assessed using a two-alternative forced-choice paradigm. Inter- and intra-reader agreement were analyzed using binomial tests and Cohen's κ. RESULTS: GRASP-VIBE was preferred over CAIPIRINHA-VIBE across all contrast-enhanced phases of pediatric liver MRI: 82.2% [526/640] in the arterial, 83.1% [532/640] in the portal venous, 71.3% [456/640] in the delayed venous (all p < 0.001). No significant difference was observed for the pre-contrast phase with 59.4% [380/640] GRASP-VIBE preference (p = 0.45). Strongest GRASP-VIBE preferences were observed in older children and adolescents and in examinations performed without anesthesia. Across all anatomical levels, GRASP consistently outperformed Caipirinha-VIBE in contrast-enhanced phases. Inter-reader agreement was moderate in the arterial (κ = 0.51) and delayed venous (κ = 0.48) phases, and slight in pre-contrast (κ = 0.19) and portal venous (κ = 0.20) phases (intra-reader agreement, κ = 0.56, κ = 0.60, κ = 0.28 and κ = 0.42). CONCLUSION: GRASP-VIBE offered superior subjective image quality compared to CAIPIRINHA-VIBE in pediatric liver MRI, especially in early contrast phases. Its free-breathing approach might be particularly advantageous regarding image quality in children unable to perform breath-holds. KEY POINTS: Question Does free-breathing GRASP-VIBE provide superior image quality compared to breath-hold CAIPIRINHA-VIBE for dynamic liver MRI in pediatric patients? Findings GRASP-VIBE was preferred across all contrast phases, delivering consistently higher-quality images than CAIPIRINHA-VIBE, particularly in children unable to perform breath-holds. Clinical relevance Using GRASP-VIBE enables high-quality dynamic pediatric liver MRI. Further research is needed to determine whether this sequence can reduce the need for sedation or general anesthesia in children.