Innovative 4D FreeBreathing technique in pediatric abdominal MRI improves feasibility and image quality.

Objectives: To compare the feasibility and imaging quality of a golden angle radial stack-of-stars dynamic three-dimensional free-breathing T1w turbo field echo acquisition (4D FreeBreathing) with a conventional dynamic cartesian breath-hold T1w sequence in young children undergoing abdominal magnetic resonance imaging (MRI).

Materials and methods: Fifty consecutive pediatric patients (34 females; 3.4 ± 2.0 years) underwent abdominal MRI: 25 were examined with 4D FreeBreathing and 25 with conventional dynamic T1w sequence. The image quality was evaluated subjectively on a 5-point scale by two radiologists. Interobserver agreement, as well as signal-to-noise ratio for arterial (SNRart) and portal venous (SNRpv) phases, were evaluated separately. Additionally, the image quality of 4D FreeBreathing sequence was compared to a non-dynamic post-contrast radial stack-of-stars free-breathing T1w fast field echo acquisition (3D T1w Vane mDixon). Interobserver agreement of both assessors was calculated using quadratic weighted Cohen's kappa test (ϰ), while independent samples Student's t-test was employed to compare mean SNR values among the two groups.

Results: Using 4D FreeBreathing, SNRart and SNRpv were significantly higher from 500 ± 170 and 550 ± 160 to 900 ± 210 and 820 ± 260 (p < 0.001); the diagnostic image quality increased from 77.6 to 89.6%; respiratory artifacts decreased from 22.4 to 10.4%, with an almost perfect interobserver agreement. Compared to 3D T1w Vane mDixon sequence, SNR and image quality were equal.

Conclusion: 4D FreeBreathing pediatric abdominal MRI improves the feasibility and image quality compared to conventional dynamic exams while showing an image quality equivalent to post-contrast 3D T1w Vane mDixon.

Key points: Question During dynamic abdominal MRI in young children, it is important to conduct a brief yet robust examination without respiratory artifacts. Findings 4D FreeBreathing MRI technique for pediatric abdominal imaging enhances both image quality and feasibility when compared to conventional dynamic scans that require breath-holding. Clinical relevance Dynamic abdominal MRI using the 4D FreeBreathing sequence provides significant benefits for pediatric patients. The absence of breath-holding requirements improves patient cooperation, reduces the need for general anesthesia, and results in higher-quality diagnostic images.