Definitions of the classification of diagnostic evidence (Class I-IV), classification of prognostic evidence (Class I-IV), and strength of recommendations (A, B, C, U) are provided at the end of the "Major Recommendations" field.
Very Low Birth Weight (VLBW) Preterm (PT) Infants
Which pre-term infants should undergo routine screening cranial ultrasonography (US)?
Recommendations (Level B): Close to 25% of infants with gestational age (GA) of <30 weeks have significant cranial US abnormalities which trigger important changes in acute and long-term care. Therefore, routine screening cranial US should be performed on all infants with GA of <30 weeks.
When should screening cranial US studies be performed?
Recommendation (Level B): Screening cranial US should be performed on all infants with GA of <30 weeks at 7 to 14 days of age and should be optimally repeated at 36 to 40 weeks’ postmenstrual age. This recommendation is designed to detect both clinically unsuspected intraventricular hemorrhage (IVH), which may require additional clinical and/or radiologic monitoring and changes in management plans, and evidence for periventricular leukomalacia (PVL) and/or ventriculomegaly, which are useful for prognosis and best seen when the infants are examined at term.
Do abnormalities on neonatal screening cranial US require follow-up magnetic resonance imaging (MRI) either to obtain information for patient management or to provide long-term prognostic data?
Recommendation (Level C): Currently, data available from class II studies do not provide sufficient evidence that routine MRI should be performed on all very low birth weight (VLBW) infants for whom results of screening cranial US are abnormal.
What is the ability of neonatal cranial US to predict long-term neurodevelopmental outcome in VLBW PT infants?
Recommendation (Level A): For VLBW PT infants, US should be used to predict long-term neurodevelopmental outcome. The findings of grades 3 and 4 intraventricular hemorrhage, periventricular cystic lesions, and moderate to severe ventriculomegaly are all associated with adverse outcome.
Term Infants with Neonatal Encephalopathy
Which neonatal neuroimaging strategies can detect cerebral abnormalities that will affect the immediate and long-term management of the infant with neonatal encephalopathy?
Recommendations for Diagnostic Assessment
- For infants with a history of neonatal encephalopathy, significant birth trauma, and evidence for low hematocrit or coagulopathy:
- Noncontrast computed tomography (CT) should be performed to look for hemorrhage (Level B)
- If the CT findings cannot explain the clinical status of the neonate, MRI should be performed (Level A).
- For other neonates with acute encephalopathy:
- MRI should be performed between days 2 and days 8 of life (Level A).
- If single-voxel proton magnetic resonance spectroscopy (MRS) is available, MRI should include MRS (Level B).
- At the time of the MRI, diffusion-weighted MRI (DWI) should also be performed if this modality is available (Level C).
- CT should be performed only if MRI is not available, or if the neonate is too unstable for MRI (Level A).
Can MRI studies provide prognostic data for term infants with neonatal encephalopathy?
Recommendation. MRI should be performed within the first 2 to 8 days of life to provide predictive data for neurodevelopmental outcome in encephalopathic term infants (Level A). DWI (Level C) and MRS (Level B), when available, should also be performed within the first 2 to 8 days of life to provide prognostic data concerning neurodevelopmental outcome in these patients.
Definitions:
Definitions for classification of diagnostic evidence
Class I: Evidence provided by a prospective study in a broad spectrum of persons with the suspected condition, using a "gold standard" for case definition, where test is applied in a blinded evaluation, and enabling the assessment of appropriate tests of diagnostic accuracy.
Class II: Evidence provided by a prospective study of a narrow spectrum of persons with the suspected condition, or a well designed retrospective study of a broad spectrum of persons with an established condition (by "gold standard") compared to a broad spectrum of controls, where test is applied in a blinded evaluation, and enabling the assessment of appropriate tests of diagnostic accuracy.
Class III: Evidence provided by a retrospective study where either persons with the established condition or controls are of a narrow spectrum, and where test is applied in a blinded evaluation.
Class IV: Any design where test is not applied in blinded evaluation OR evidence provided by expert opinion alone or in descriptive case series (without controls).
Definitions for classification of prognostic evidence
Class I: Evidence provided by a prospective study of a broad spectrum of persons who may be at risk for developing the outcome (e.g., target disease, work status). The study measures the predictive ability using an independent gold standard for case definition. The predictor is measured in an evaluation that is masked to clinical presentation, and the outcome is measured in an evaluation that is masked to the presence of the predictor.
Class II: Evidence provided by a prospective study of a narrow spectrum of persons who may be at risk for developing the outcome, or by a retrospective study of a broad spectrum of persons with the outcome compared to a broad spectrum of controls. The study measures the predictive ability using an acceptable independent gold standard for case definition. The risk factor is measured in an evaluation that is masked to the outcome.
Class III: Evidence provided by a retrospective study where either the persons with the condition or the controls are of a narrow spectrum. The study measures the predictive ability using an acceptable independent gold standard for case definition. The risk factor is measured in an evaluation that is masked to the outcome.
Class IV: Any design where the predictor is not applied in a masked evaluation OR evidence provided by expert opinion or case series without controls.
Definitions for strength of recommendations
Level A: Established as useful/predictive or not useful/predictive for the given condition in the specified population (requires at least one convincing class I study or at least two consistent, convincing class II studies).
Level B: Probably useful/predictive or not useful/predictive for the given condition in the specified population (requires at least one convincing class II study or at least three consistent class III studies).
Level C: Possibly useful/predictive or not useful/predictive for the given condition in the specified population (requires at least two convincing and consistent class III studies).
Level U: Data inadequate or conflicting. Given current knowledge, test/predictor is unproven.