What are negative prognostic findings on a computed tomography (CT) scan in a patient with asphyxia?

From the Guidelines

Negative prognostic findings on a CT scan in a patient with asphyxia include reduced gray-white matter ratio (GWR) at the level of the basal ganglia and global cerebral edema, which predict poor outcome with a false positive rate (FPR) of 0%. These findings are based on the 2015 American Heart Association guidelines update for cardiopulmonary resuscitation and emergency cardiovascular care 1. The reduced GWR at the level of the basal ganglia on brain CT predicted poor outcome, with FPR ranging from 0% to 8%, while global cerebral edema on brain CT at a median of 1 day after cardiac arrest also predicted poor outcome (FPR, 0%; 95% CI, 0%–5%) 1.

Some key points to consider when evaluating CT scans in patients with asphyxia include:

• Reduced GWR at the level of the basal ganglia
• Global cerebral edema
• Diffuse brain swelling on CT at 72 hours after cardiac arrest
• GWR between the caudate nucleus and the posterior limb of internal capsule below 1.22 within 24 hours or below 1.18 within 48 hours after cardiac arrest

It is essential to note that these findings should be considered in the context of the patient's overall clinical status and other prognostic indicators, such as neurological examination, electroencephalography, and biomarkers 1. Early CT findings may be subtle, so serial imaging and correlation with clinical status are crucial for comprehensive prognostication after asphyxial injury.

From the Research

Negative Prognostic Findings on CT Scan in Asphyxia

• Cerebral edema on arrival computed tomographic (CT) scan is a negative prognostic finding in patients resuscitated after asphyxiation, as seen in a study where four out of five non-survivors showed cerebral edema already on arrival CT scan, while none of the nine survivors did 2.
• Middle cerebral artery hyperdensity, sulcal effacement, liquoral space asymmetry, and hypodensity of grey matter are early signs of ischemic cerebral infarction that can be detected by noncontrast CT scan, and their presence can indicate a poor prognosis 3.
• Extraparenchymal bleeding and cerebral edema are significant independent prognostic findings on CT scan in the subacute phase of ischemic stroke, and are associated with an unfavorable outcome 4.
• CT evaluation of mild brain injury induced by asphyxia or intrauterine fetal distress is not of any value, and the role of CT evaluation on the grade of hypoxic-ischemic encephalopathy (HIE) is uncertain and doubtful 5.

Specific CT Scan Findings

• Cerebral edema: indicates a poor prognosis in patients resuscitated after asphyxiation 2.
• Extraparenchymal bleeding: associated with an unfavorable outcome in ischemic stroke patients 4.
• Middle cerebral artery hyperdensity: an early sign of ischemic cerebral infarction, indicating a poor prognosis 3.
• Sulcal effacement: an early sign of ischemic cerebral infarction, indicating a poor prognosis 3.
• Hypodensity of grey matter: an early sign of ischemic cerebral infarction, indicating a poor prognosis 3.