Background: Newborns and small infants have shallow breathing.
Objective: To suggest criteria for when respiratory gating is necessary during cardiac MRI in newborns and infants.
Materials and methods: One-hundred ten data sets of newborns and infants with (n = 92, mean age: 1.9 ± 1.7 [SD] years) and without (n = 18, mean age: 1.6 ± 1.8 [SD] years) navigator gating were analysed retrospectively. The respiratory motion of the right hemidiaphragm was recorded and correlated to age, weight, body surface area and qualitative image quality on a 4-point score. Quantitative image quality assessment was performed (sharpness of the delineation of the ventricular septal wall) as well as a matched-pair comparison between navigator-gated and non-gated data sets.
Results: No significant differences were found in overall image quality or in the sharpness of the ventricular septal wall between gated and non-gated scans. A navigator acceptance of >80% was frequently found in patients ages <12 months, body surface area <0.40 m(2), body weight <10 kg and a size of <80 cm.
Conclusion: Sequences without respiratory gating may be used in newborns and small infants, in particular if age <12 months, body surface area <0.40 m(2), body weight <10 kg and height <80 cm.