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Updated: Jun 5, 2025
State of the Art Cranial Ultrasound Imaging in Neonates
Published on: February 2, 2015
Re-evaluating the timing of sequential cranial ultrasound screening in very preterm infants for predicting
Sunaina Ramdass1,2, Tim Disher3, Michael Vincer2,4
1Department of Diagnostic Radiology, Division of Pediatric Radiology, Dalhousie University, IWK Health, 5850/5980 University Avenue, PO Box 9700, Halifax, NS, B3K 6R8, Canada.
Insights
A single 6-week cranial ultrasound can accurately predict neurodevelopmental impairment in very preterm infants. This finding simplifies screening protocols and optimizes resource allocation for infant care.
Area of Science:
- Neonatal neurology
- Pediatric neuroimaging
- Developmental pediatrics
Background:
- Early prediction of neurodevelopmental impairment (NDI) is vital for very preterm infants (<31 weeks' gestation).
- Cranial ultrasound is standard for evaluating preterm brain injury, but optimal screening timing and frequency lack consensus.
- Current practice at IWK Health Centre includes ultrasounds at 1, 2, 6 weeks, and term age.
Purpose of the Study:
- To evaluate the necessity of multiple ultrasound time points for NDI prognostication.
- To determine if a simplified ultrasound model can accurately predict NDI at 36 months corrected age.
- To test the hypothesis that a three-time-point model is sufficient for NDI prognostication.
Main Methods:
- Retrospective cohort study of very preterm infants (22-30 weeks' gestation) born between 2004-2018.
- Compared three NDI prediction models: 1) gestational age, sex, 2-week & 6-week ultrasound; 2) gestational age, sex, 6-week ultrasound; 3) gestational age, sex, 2-week ultrasound.
- Neurodevelopmental assessment at 36 months corrected age was the primary outcome.
Main Results:
- 656 survivors included (mean GA 27.5 weeks); 30% developed NDI by 36 months.
- All models showed comparable discrimination (AUCs).
- The 6-week ultrasound model (AUC 0.68) and the reference model (AUC 0.68) performed similarly, outperforming the 2-week model (AUC 0.66). The 6-week model had the lowest AIC (766).
Conclusions:
- A 6-week ultrasound-only model is comparable to a 2-week and 6-week combined model for predicting NDI.
- Eliminating the 2-week ultrasound does not impact predictive performance for NDI at 36 months corrected age.
- Simplifying ultrasound screening to a 6-week assessment promotes efficient resource use without compromising prognostic accuracy.
Objective:
Accurate and early prediction of neurodevelopmental impairment is a crucial endeavor in caring for very preterm infants (<31 weeks' gestation). Sequential cranial ultrasound is the standard of care for the evaluation of preterm brain injury. However, there is no consensus on the timing and frequency of ultrasound screening. At Izaak Walton Killam (IWK) Health Centre, Halifax, Canada, four-time points for routine ultrasound of very preterm infants are performed at weeks 1, 2, 6, and term age. The hypothesis behind this work is that a three-time-point model will be appropriate for neurodevelopmental impairment prognostication.
Materials And Methods:
In this retrospective cohort, all very preterm infants (220-306 weeks) born between January 2004 and December 2018 with a neurodevelopmental assessment at 36 months corrected age were included. Three prediction models of neurodevelopmental impairment were compared: 1. A reference model including the gestational age, infant sex, and 2-week and 6-week ultrasound 2. A model including the gestational age, infant sex, and 6-week ultrasound 3. A model including the gestational age, infant sex, and 2-week ultrasound RESULTS: Of 786 eligible preterm infants born during the study period, 656/786 survivors were included in the analysis (mean gestational age 275 weeks, mean birth weight 1,133 g, and 55% male infants). At 36 months of corrected age, 30% developed neurodevelopmental impairment. All three models provided comparable discrimination areas under the curve (AUC) of neurodevelopmental impairment at 36 months of corrected age. Both the 6-week and the reference model had similar AUC of 0.68 (95% CI 0.63-0.72) and were not noticeably different from the 2-week model (AUC 0.66 (95% CI 0.61-0.70)). The 6-week model provided the best prediction with the lowest Akaike information criterion (AIC) of 766 for the 6-week-only model, AIC 769 for combined weeks 2 and 6 (reference model), and AIC 784 for the 2-week-only model.
Conclusion:
In this cohort of very preterm infants, a model including 6-week ultrasound only was comparable to a reference model combining 2-week and 6-week ultrasound and showed nearly identical predictive performance of neurodevelopmental impairment at 36 months corrected age across a broad set of metrics; thus, it is redundant to do both the 2-week and 6-week ultrasound.
Clinical Relevance Statement:
Late ultrasound at 6 weeks of age provided comparable diagnostic and prognostic information to a reference model combining 2-week and 6-week ultrasound and, if anything, was slightly superior to the 2-week ultrasound model, across a broad set of metrics. The 2-week ultrasound can be eliminated with no impact on the prediction of neurodevelopmental impairment at 36 months, promoting prudent resource allocation and stewardship in healthcare.
