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Updated: May 28, 2026
MRI and PET in Mouse Models of Myocardial Infarction
Published on: December 19, 2013
Optimization of myocardial nulling in pediatric cardiac MRI
Edythe B Tham1, Ryan W Hung, Kimberley A Myers
1Department of Pediatrics, Division of Pediatric Cardiology, Stollery Children's Hospital, University of Alberta, Walter C Mackenzie Health Science Centre, 8440 112th St, Edmonton, Alberta, Canada. etham@ualberta.ca
Background:
Current protocols to determine optimal nulling time in late enhancement imaging using adult techniques may not apply to children.
Objective:
To determine the optimal nulling time in anesthetised children, with the hypothesis that this occurs earlier than in adults.
Materials And Methods:
Sedated cardiac MRI was performed in 12 children (median age: 12 months, range: 1-60 months). After gadolinium administration, scout images at 2, 3, 4 and 10 min and phase sensitive inversion recovery (PSIR) images from 5 to 10 min were obtained. Signal-to-noise ratio (SNR) and inversion time (TI) were determined. Quality of nulling was assessed according to a grading score by three observers. Data was analysed using linear regression, Kruskal-Wallis and quadratic-weighted kappa statistics.
Results:
One child with a cardiomyopathy had late enhancement. Good agreement in nulling occurred for scout images at 2 (κ = 0.69) and 3 (κ = 0.66) min and moderate agreement at 4 min (κ = 0.57). Agreement of PSIR images was moderate at 7 min (κ = 0.44) and poor-fair at other times. There were significant correlations between TI and scout time (r = 0.61, P < 0.0001), and SNR and kappa (r = 0.22, P = 0.017).
Conclusion:
Scout images at 2-4 min can be used to determine the TI with little variability. Image quality for PSIR images was highest at 7 min and SNR optimal at 7-9 min. TI increases with time and should be adjusted frequently during imaging. Thus, nulling times in children differ from nulling times in adults when using standard adult techniques.
