Evaluation of neonatal cerebral perfusion using three-dimensional power Doppler ultrasound volumes.

AIM: Despite improvement in preterm survival, neurological morbidity remains high. 3D fractional moving blood volume (3D-FMBV) quantifies neonatal cerebral perfusion by calculating a standardised measure of the amount of moving blood in a region of interest and correlates with tissue perfusion in animal studies. However, its feasibility and reproducibility are yet to be assessed in newborn infants. METHODS: Fractional moving blood volume analysis was performed on three-dimensional power Doppler ultrasound (PD-US) volumes from a cohort of preterm infants recruited in 2015 from the Royal Hospital for Women Neonatal Intensive Care Unit. The volumes were acquired by two sonographers and analysed by two different observers. The 3D-FMBV algorithm was applied to calculate an estimate for perfusion. Reproducibility and agreement were assessed using intra-class correlation coefficients (ICC) and Bland-Altman plots. RESULTS: All 3D PD-US volumes were analysed successfully. Intra-observer reliability was excellent with an ICC of 0.907 (95% CI 0.751-0.968) and 0.906 (95% CI 0.741-0.967) for two independent observers respectively. The inter-observer reliability of the entire technique was good with an ICC of 0.752 (CI: 0.404-0.909). CONCLUSION: We have successfully shown the feasibility and reliability of applying the 3D-FMBV technique to the neonatal brain in a healthy preterm population.

Basal ganglia perfusion in the preterm infant during transition.

BACKGROUND: The preterm brain is susceptible to changes in blood flow. Using power Doppler images, digital imaging techniques have been developed to measure the total amount of blood flow in a defined area, giving the index: fractional moving blood volume (FMBV). The aim of this study was to investigate temporal changes in basal ganglia perfusion during the transitional period after birth. METHODS: Twenty-four preterm infants were examined with serial cranial ultrasounds at four time points during the first 48 h of life. FMBV was calculated using power Doppler images at each time point. RESULTS: All infants had analyzable data and FMBV was successfully calculated at all time points. Twenty-three of the 24 infants had an increasing trend in FMBV over time. The median FMBV increased from 17% at 6 h to 25% at 48 h. One-way repeated measures ANOVA showed a significant increase in values at P < 0.001 at each of the four time points. CONCLUSION: We have demonstrated changes in basal ganglia blood flow as the cerebral circulation adapts to extrauterine life. With further investigation, this technique may be useful in the assessment of preterm circulatory adaptation, either alone or in conjunction with other modes of evaluating cerebral blood flow.

Reference Ranges for Neonatal Basal Ganglia Perfusion as Measured by Fractional Moving Blood Volume.

BACKGROUND: Regional changes in cerebral blood flow and perfusion are implicated in the pathogenesis of adverse neurological events that lead to death and severe disability in the newborn infant. The basal ganglia, in particular, are extremely sensitive to acute hypoxia in the perinatal period, but normal perfusion to this area is unknown. OBJECTIVES: To establish a reference range for regional basal ganglia perfusion using fractional moving blood volume (FMBV) as an index. METHODS: Head ultrasounds were performed on neonates from 25 to 41 weeks' gestation. Power Doppler images were obtained from a pre-specified coronal plane. FMBV was calculated offline after selecting the basal ganglia as a region of interest. The average of five calculations was considered to be representative of the regional perfusion for each neonate. The data were analysed, and a neonatal reference range was defined. RESULTS: 124 neonates were included in the study, and all had analysable data. The mean FMBV was 28.8% (±9.6) with a reference range defined as 10-48%. The mean FMBV for neonates <32 weeks', 32-35 weeks' and >35 weeks' gestation were 29.4% (±7.8), 29.2% (±11.0) and 27.4% (±9.7), respectively. Analysis of variance showed no significant difference between neonates based on gestation. CONCLUSIONS: We have successfully used the index FMBV to define a reference range for perfusion in the basal ganglia. These data can be used as a reference for subsequent studies that evaluate basal ganglia perfusion in pathological conditions.