Optimization of myocardial deformation imaging in term and preterm infants.
OBJECTIVE
Myocardial deformation imaging is now used to assess regional ventricular function in infants but their small size presents particular technical challenges. We therefore investigated the determinants of reproducibility of myocardial longitudinal strain (ε) in term and preterm infants, in order to determine optimal technical settings.


RESULTS
Repeated longitudinal ε measurements of the mid-segments of the septum, and the left and right ventricular free walls, were performed using five different computation distances (CDs; also called strain length) in 20 infants. The coefficients of variation (CV) were calculated for each CD. Overall, ε measurements were most reproducible with a CD of 6 mm (CV 11.7%). In preterm infants (<34 weeks gestation; mean ± SD diastolic LV length, 20.3 ± 3.5 mm), ε measurements were most reproducible with CD of 6 mm (CV 7.2%); in term infants (>37 weeks gestation; mean ± SD diastolic LV length, 29.6 ± 3.0 mm), ε measurements were most reproducible with CD of 10 mm (CV 13.2%). The reproducibility of measuring ε increased with higher frame rates, from CV of 17.3% at frame rates <180 per s to 11.7% for frame rates >180 per s and 9.6% for rates >248 per s.


CONCLUSIONS
In newborn infants, tissue Doppler loops should be acquired at frame rates above 180 per s. Myocardial deformation analysis of preterm infants should be performed using a CD of 6 mm, whereas a CD of 10 mm is more reproducible in term infants.
Department of Child Health, School of Medicine, Cardiff University, Cardiff, UK.
Chuen Y
CY
Poon
Julie M
JM
Edwards
Suchita
S
Joshi
Sailesh
S
Kotecha
Alan G
AG
Fraser
D000704:Analysis of Variance; D015331:Cohort Studies; D018619:Echocardiography, Doppler, Pulsed; D005260:Female; D006352:Heart Ventricles / Q000000981:diagnostic imaging* / Q000503:physiopathology; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D007231:Infant, Newborn; D007234:Infant, Premature; D008297:Male; D009200:Myocardial Contraction / Q000502:physiology; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D018709:Statistics, Nonparametric; D047929:Term Birth; D016277:Ventricular Function, Left / Q000502:physiology; D016278:Ventricular Function, Right / Q000502:physiology