Neonatal neurosonography

Feasibility and Safety of Neonatal Brain Contrast-Enhanced Ultrasound: A Prospective Study Using MRI as Reference Standard

Background: MRI is the gold standard for neonatal brain imaging but is expensive, time-consuming, potentially limited by availability and accessibility, and may be contraindicated in some patients. Transfontanelle neonatal head ultrasound is an excellent alternative but may be less sensitive and specific than MRI. Contrast-enhanced ultrasound (CEUS) has the potential to improve ultrasound's capabilities. Objective: To prospectively evaluate the feasibility, safety, and diagnostic performance of transfontanelle neonatal brain contrast-enhanced ultrasound (CEUS), using MRI as the reference standard. Methods: Neonates in the institutional neonatal ICU undergoing MRI as part of clinical care were prospectively recruited to undergo portable brain ultrasound and CEUS for research purposes. Brain ultrasound and CEUS were performed portably, without moving the patient from the isolette or crib in the NICU. Adverse events were recorded. Two radiologists independently evaluated ultrasound and CEUS images for abnormalities and then reached consensus for discrepancies. A separate radiologist reviewed MRI examinations. Sensitivity, specificity, and inter-reader agreement were evaluated, using MRI as reference. Qualitative post hoc image review was performed. Results: Twenty-six neonates (9 boys, 17 girls; mean age 15.2 ± 14.0 days) were included. No significant alteration in patient vital signs or adverse reaction to the ultrasound contrast agent (UCA) occurred. Mean examination duration was significantly shorter for CEUS than MRI (21 ± 4.7 minutes vs 74 ± 34.8 minutes, p<.001). Inter-rater agreement for any abnormality was almost perfect for both ultrasound and CEUS (k= 0.92 and 0.85, respectively). Sensitivity for any abnormality was 86.7% for ultrasound and 93.0% for CEUS; specificity was 100.0% for both. CEUS exhibited sensitivity of 87.5% for acute or subacute ischemia and 100.0% for chronic ischemia, and specificity of 100.0% for acute or subacute ischemia and chronic ischemia. Sensitivity for subdural and intraparenchymal hemorrhage was poor (22.2%-50.0%) at both ultrasound and CEUS. Post hoc review demonstrated a case of post-ischemic hyperperfusion, confirmed by subsequent contrast-enhanced CT, on CEUS but not on MRI. Conclusion: Portable brain CEUS in neonates is feasible, safe, and more rapid than MRI. Clinical Impact: The potential diagnostic utility of brain neonatal CEUS relative to conventional ultrasound, particularly for ischemia, warrants further investigation.

Analyses of pathological cranial ultrasound findings in neonates that fall outside recent indication guidelines: results of a population-based birth cohort: survey of neonates in Pommerania (SNiP-study)

Background

Recent guidelines recommend a cranial ultrasound (CU) in neonates born at < 30 weeks gestation, admitted to the neonatal intensive care unit (NICU), or with a CU indication. Here, we addressed the need to extend these recommendations.

Methods

We retrospectively reviewed 5107 CUs acquired in the population-based Survey of Neonates in Pomerania, conducted in 2002 to 2008. Neonates with conspicuous CUs that were ≥ 30 weeks gestation without recent indications for CU were identified and assigned to the following groups: with (I) or without (II) admission to neonatal care. We designated CU conspicuities as mild (MC) or significant (SC), and we investigated related neurodevelopment during follow-up.

Results

Of 5107 neonates, 5064 were born at ≥30 weeks gestation and of those, 4306 received CUs without any indication for this examination. We found conspicuities in 7.7% (n = 47/610) of group I (n = 30 MC, n = 17 SC), and 3.2% (n = 117/3696) of group II (n = 100 MC, n = 17 SC). In group II, SC comprised, e.g., bilateral cysts, partial agenesis of the corpus callosum, and periventricular leukomalacia. Follow-up was available in 75% of infants in group II with MCs and SCs; of these, 12.8% had an abnormal neurological follow-up.

Conclusions

We detected a high number of conspicuities in neonates without a CU indication. However, we could not demonstrate that ultrasound findings were associated with the neurological follow-up or any advantage to an earlier diagnosis. Our data did not support extending current guidelines or a general CU screening policy for all neonates.