Novel Quantitative Contrast-Enhanced Ultrasound Detection of Hypoxic Ischemic Injury in Neonates and Infants: Pilot Study 1

Abstract

Objectives: To investigate whether quantitative contrast-enhanced ultrasound (CEUS) can accurately identify neonates and infants with hypoxic ischemic brain injury.

Methods: In this prospective cohort study, 8 neonates and infants with a suspicion of hypoxic ischemic injury were evaluated with CEUS.

Results: An interesting trend was observed in the central gray nuclei-to-cortex perfusion ratios. The ratios at the peak enhancement, wash-in area under the curve, perfusion index, and maximum wash-in slopes were lower in all of the affected cases compared to the normal group but not statistically significant given the small sample size (P = .0571). Additionally, when the central gray nuclei-to-cortex perfusion ratio was plotted for all time points along the time-intensity curve, it was observed that the affected cases showed a trend that was qualitatively different from that of the normal cases. In the affected cases, the ratio time-intensity curves either stayed below 1.0 for the entire enhancement period or reached 1.0 close to peak wash-in before falling just below 1.0 for the remaining period of enhancement. However, in the unaffected patients, there was a steep wash-in that crossed the 1.0 threshold and remained above 1.0 for most of the enhancement period.

Conclusions: Bedside CEUS is an easily obtainable brain-imaging modality that has the potential to effectively identify infants and neonates with evolving brain injury. A larger prospective study evaluating the correlation between CEUS findings and the reference standard of diffusion- and perfusion-weighted magnetic resonance imaging is needed to establish it as a diagnostic tool.

Keywords: brain; contrast-enhanced ultrasound; hypoxic ischemic encephalopathy; hypoxic ischemic injury; infant; neonate.