Hyperechogenicity of the thalamus and basal ganglia in very preterm infants: radiological findings and short-term neurological outcome.

Cerebral ultrasound of preterm infants may show diffuse, bilateral, hyperechogenic "haze" over the thalami and basal ganglia (hyperechogenicity BGT). We explored whether this could be a pathological phenomenon. All cerebral ultrasound examinations performed in 2001 on infants < 35 weeks of age were reviewed. This resulted in a hyperechogenicity and non-hyperechogenicity group. The character of the hyperechogenicity BGT and the presence of concomitant brain lesions were noted. Detailed clinical and follow-up data from a selected group of infants < 32 weeks were reviewed and compared between the 2 groups. The incidence of hyperechogenicity BGT was 11 % (39/359) in infants < 35 weeks and 26 % (37/143) in infants < 32 weeks. Birth weight and gestational age were significantly lower and clinical course was more complicated in the hyperechogenicity group. Concomitant brain lesions were always present. In 12/39 infants with hyperechogenicity BGT, MRI (always performed for other reasons) was available, showing signal intensity changes in thalamic region in 5 infants. The neurological outcome at term was less favorable in the hyperechogenicity group, but similar at 1 year. Thus hyperechogenicity BGT mainly occurred in very small, sick infants and was always associated with cerebral pathology. MRI did not consistently show abnormalities in the thalamic region. It was not associated with a poorer outcome at 1 year.