Head Ultrasound in NICU Can Predict Cerebral Palsy
Neurology Today
4 December 2008;
Volume 8(23);
pp 1,10
FRIEDMAN, ROBERTA PHD
Back to topARTICLE IN BRIEF
Echolucent lesions on head ultrasound had a positive predictive value of 52 percent for cerebral palsy in 1,500 preterm babies born at less than 28 weeks gestation.
SANTA CLARA, CA-Lesions detected by ultrasound examination in the neonatal intensive care unit can predict which low birth-weight babies willdevelop cerebral palsy (CP), according to results from the ELGAN (Extremely Low Gestational Age Newborns) study reported here at the annual meeting of the Child Neurology Society on Nov. 7
Figure. A CRANIAL ULTRASOUND OF A PREMATURE INFANT AT SIX WEEKS. The dark areas in the center of the image represent CSF within the lateral ventricles. The black arrows point to areas within the white matter that appear dark, rather than grey, indicating the replacement of normal tissue with fluid filled damaged tissue. Also, the ventricles are larger than normal (ventriculomegaly) possible indicating more extensive white matter loss.
Karl Kuban, MD, chief of the division of pediatric neurology at Boston University's Boston Medical Center, described the findings from more than 1,500 preterm infants in the study, born at less than 28 weeks gestation.
Echolucent lesions or enlarged ventricles (ventriculomegaly) were more predictive of cerebral palsy and its severity, Dr. Kuban said, with more severe limb paresis. He said that ventriculomegaly was scored only if it appeared on the last ultrasound taken for the prospective trial.
Echolucent lesions on head ultrasound had a positive predictive value of 52 percent for any CP, Dr. Kuban noted, which occurred in 11.5 percent of all enrolled infants. Three-quarters of these children had quadriparesis, and nearly two of three could neither sit nor walk independently.
The strongest newborn predictor of quadriparesis and more severe cerebral palsy are echolucency on head ultrasound and late ventriculomegaly on head ultrasound, Dr. Kuban said, noting that nearly half of children destined to have cerebral palsy do not have an abnormality on head ultrasound exam.
The ultrasound records, read by two independent ultrasonographers, were scored for features that included intraventricular bleeding, enlarged ventricles, and echogenic or echolucent lesions. Three scans were carried out - between days three and five, six and fifteen, and as close as possible to the eighth to tenth week after birth. All discordant readings of the ultrasound scan were sent to a third sonographer at a different center.
The ultrasound interpreters did not diagnose cerebral palsy, Dr. Kuban emphasized. They were asked to fill out a form and send it to us, he said. The investigators referred to their paper published in the October Journal of Pediatrics for standards to diagnose cerebral palsy, a classification algorithm that the study investigators had devised and made available on compact discs.
Figure. DR. KARL KUBAN: The strongest newborn predictor of quadriparesis and more severe cerebral palsy are echolucency on head ultrasound and late ventriculomegaly onhead ultrasound.
ASSESSING CP
Cerebral palsy was assessed in a neurologic evaluation at 24 months corrected age (real age minus weeks premature) based on ratings of functional impairment using the Gross Motor Function Classification scoring system of 1-5, with the higher numbers indicating greater disability.)
Half of the children who had cerebral palsy in the study had a score of two or greater - they could not walk independently. Children with echolucent lesions were 24 times more likely to have quadriparesis or hemiparesis. Those with ventriculomegaly were more than 17 times more likely to have either type of motor weakness.
EXPERTS COMMENT
Stanley Johnsen, MD, a child neurologist at the Children's Health Center and Barrow Neurological Institute and St Joseph's Hospital in Phoenix, AZ, noted in discussion after the session that cerebellar abnormalities could also be predictive of cerebral palsy, and Dr. Kuban agreed, adding that cerebellar abnormalities are probably underestimated as a contributor to cerebral palsy.
In, 2005 Dr. Johnsen and colleagues reported in the Journal of Child Neurology that MR indicated injury to the cerebellum in nearly half of 67 low- birth weight children - under 1000 grams or born at 28 weeks or younger. Those with cerebellar injury were much more likely to be microcephalic and unable to walk or talk. In children with known cerebellar injury and cerebral palsy (who had been born extremely premature), 35 of 47 patients had prominent injury to the inferior cerebellum, suggesting infarction, whereas the remainder demonstrated varying degrees of cerebellar atrophy with or without asymmetry and four also had enlarged fourth ventricles.
The methods used by Kuban did not include good views of the posterior fossa, Dr. Johnsen said. At the time his study was done, our articles on cerebellar involvement in cerebral palsy in the extremely premature as defined by MRI had not been published.
A moderator of the session, Miya Asato, MD, assistant professor of pediatrics and psychiatry in the division of child neurology at Children's Hospital of Pittsburgh, commented, This study illustrates the predictive ability of cranial ultrasound to detect early abnormalities such as echolucency and ventriculomegaly leading to cerebral palsy by the age of 2.
But, she added: Some patients who had normal ultrasound were later found to have cerebral palsy at follow up, suggesting limitations in the sensitivity of this imaging modality. Prospective investigation and increased clinical use of other imaging methods, such as MRI, should be considered to optimally predict patient outcomes. •
