Ultrasound abnormalities preceding cerebral palsy in high-risk preterm infants.

Abstract

To assess sequential high-resolution cranial ultrasound (US) in high-risk preterm infants to predict cerebral palsy (CP). Preterm infants were prospectively studied (n=2139), 1636 <or=32 weeks gestational age (GA) (group A) and 503 with a GA of 33 to 36 weeks (group B). US was performed once a week until discharge and at 40 weeks postmenstrual age (PMA), using a 7.5-MHz transducer. Grade III and IV hemorrhage, cystic periventricular leukomalacia (c-PVL), and focal infarction were considered major US abnormalities. A diagnosis of CP was made at a minimum age of 24 months. Seventy-six (5%) of the 1460 survivors in group A developed CP. US abnormalities were present in 70 of 76 (92%) infants, being major in 58 (83%) and minor in 12 (17%). In 29% of the CP cases with major US abnormalities, cysts were first detected beyond day 28. A further 6 infants without US abnormalities developed CP, and 3 of these infants developed ataxic CP. Twenty-nine (6%) of the 469 survivors in group B developed CP. US abnormalities were present in 28 of 29 (96%) infants, being major in 25 (89%) and minor in 3 (11%). One infant without US abnormalities developed CP. Considering the major US abnormalities, a specificity of 95% and 99% and a sensitivity of 76% and 86% were found for group A and B, respectively. The positive predictive value was 48% in group A and 83% in group B. Seventy-nine percent of our CP cases had major US abnormalities. To detect c-PVL, the most predictive US marker for CP, sequential scans with a 7.5-MHz transducer are required.