Intracranial compliance in infants: evaluation with Doppler US.

PURPOSE

To test graded fontanelle compression during Doppler ultrasound (US) scanning to identify and monitor infants with altered cranial compliance.

MATERIALS AND METHODS

An ophthalmodynamometer exerted pressure on the anterior fontanelle during Doppler US scanning of the middle cerebral artery. Sixty examinations were performed in 43 infants--13 full-term and 11 premature healthy control subjects, 10 with increased intracranial volume, and nine with suspected abnormal cranial compliance but without increased intracranial volume. Resistive index (RI) and angle-corrected time-averaged mean velocities (TAV) of blood flow were compared at three different pressures.

RESULTS

Baseline RI values in healthy full-term infants were significantly lower than in healthy premature infants and infants with abnormal compliance (P < .05). Values for healthy premature infants and infants with abnormal compliance were indistinguishable (P > .5). Neither RI nor TAV changed significantly in healthy infants, but both changed significantly with compression in infants with abnormal cranial compliance.

CONCLUSION

This procedure may be more useful than measurement of RI of the anterior cerebral artery alone to evaluate infants with altered cranial compliance.