Hypoxic Ischemic Encephalopathy: MRI

6 day old  full term baby ,clinically suspected to be of neonatal hypoxic sequelae  shows 1-2-3-4 sign of T1W bright signal intensity alterations of basal ganglia of  severe &Total variety and  deep watershed ischemia of Partial  &Prolonged varieties  of  Hypoxic ischemic encephalopathy, suggesting overlap of the varieties does occur 

Teaching points by Dr MGK Murthy 

Techologist : Mr Venkat 

(a)Neonatal hypoxia  findings vary from full term baby to premature bay , and  sudden &Total or  partial &Prolonged  variety ,depending on the  aetiology  of hypoxia 

(b)  Sudden, Severe and Total  variety of  hypoxia  occurs in abruptio placentae  etc  AND produces classical 1-2-3-4 sign as enumerated  below 

 

1. Increased T1W bright signal of basal ganglia (first 3 days of life)(stays for 2-4 months) (Cf-subtle increase may be False +ve in some normal infants )

2. Thalamus increase signal on T1W (better on sagittal T1)(Cf- subtle ventrolateral nuclei bright signal may be seen in normal neonate) (Basal ganglia/ thalamus being metabolically active >involved than others) 

3. Absent Posterior limb sign referring to absent (normally seen) T2 Low signal of  Posterior limb of internal capsule(min of 25% should be dark on T2WI at birth)

4.DW bright signals with reduced ADC values of basal ganglia/ Thalami 

(c) Partial and prolonged variety of hypoxia as seen in prolonged labour / decreased heart rate etc,  would display hypo perfusion signs  like  Periventricular leukomalacia  (PVL)( in prematures) and "deep watershed Ischemia" in full term neonates at junctions of ACA/MCA and MCA/PCA  frontal and occipital  periventricular regions symmetrically  as seen in our case