MRI Timing for Hypoxic-Ischemic Encephalopathy
MRI is recommended for term neonates with hypoxic-ischemic encephalopathy (HIE), including those treated with therapeutic hypothermia (TH), after completion of TH when feasible. [1]
Core MRI Sequences for Hypoxic-Ischemic Encephalopathy
A basic neonatal brain MRI protocol should include the following sequences. [1]
- Axial and coronal T2-weighted spin-echo (T2SE) sequences for brain anatomy and assessment of cortical and white-matter maturation. [1]
- Axial diffusion-weighted imaging (DWI) with ADC mapping for detection of recent acute hypoxic-ischemic and inflammatory lesions. [1]
- Axial and sagittal T1-weighted gradient-echo images for brain anatomy and myelination assessment. [1]
- Axial T2*-weighted gradient-recalled echo (GRE) sequence or susceptibility-weighted imaging (SWI) for hemorrhagic lesions, calcifications, and vascular anomalies. [1]
Suggested Scan Parameters for the Basic Neonatal Protocol
Suggested parameters for the basic neonatal protocol sequences include the following. [1]
- Axial and coronal T2SE: TR 4300 and TE 135. [1]
- Axial DWI (including ADC mapping): B 1000. [1]
- Axial and sagittal T1-weighted GRE: TR 9.9 and TE 4.2. [1]
Optimal Timing Windows for Initial MRI
For infants treated with TH, optimal timing of MRI is 4–7 days post birth. [1]
- Valid timing includes 4–14 days post birth. [1]
- Early imaging at 2–4 days post birth is considered in settings such as redirection of care. [1]
Indications for Repeat MRI
Repeat MRI between days 10 and 14 of life is recommended when imaging and clinical features are discordant or when diagnostic ambiguity persists. [2]
Additional MRI Sequences Based on Clinical Scenario
Additional sequences should be added as indicated by clinical history and suspected competing diagnoses. [1]
- Magnetic resonance spectroscopy (MRS) is recommended in all cases of acute encephalopathy with unknown etiology and is considered in HIE in settings such as mild HIE with atypical presentation or abnormal cranial ultrasound findings. [1]
- For suspected neonatal ischemic stroke, non-contrast cerebral and cervical MR angiography (3D-TOF) is recommended within a week of onset. [1]
- For suspected cerebral venous thrombosis, SWI is recommended and MR venography is considered when cerebral venous thrombosis is suspected. [1]
Practical Reporting Elements for Injury Characterization
MRI reporting should include lesion distribution across major regions because topographic injury patterns correlate with neurodevelopmental outcomes. [1]
- In reporting, injury extent should specifically document involvement of basal ganglia and thalami. [1]
- Mammillary body injury should be documented because mammillary body signal abnormality on axial or coronal T2-weighted images is associated with increased risk of later learning and memory problems. [1]
Suggested Timing and Scope Summary for Hypoxic-Ischemic Encephalopathy Assessment
An initial MRI should be performed at 4–7 days post birth when possible in infants with HIE treated with TH. [1]
The core protocol should include T2-weighted sequences, DWI with ADC mapping, T1-weighted sequences, and an additional hemorrhage-sensitive sequence (T2* GRE or SWI). [1]
Repeat MRI between days 10 and 14 is indicated when discordance or diagnostic ambiguity persists. [2]