Late neurosonographic screening is important to the diagnosis of periventricular leukomalacia and ventricular enlargement in preterm infants.

BACKGROUND: Recent cost-containment strategies suggest limiting screening neurosonograms to the second week of life in premature infants with lower gestational ages (< 30 weeks), birth weights (< 1250 g), or more complicated clinical courses.

OBJECTIVE: To determine if such strategies reduce detection of cystic periventricular leukomalacia (cPVL) and persistent ventricular enlargement (pVE)--late sonographic abnormalities highly predictive of adverse neurodevelopment in preterm infants.

METHODS: Timing, findings, and number of neurosonograms were reviewed for all survivors born at < or = 32 weeks' gestation at University Hospital, Denver, Colo., between January 1992 and June 1995.

RESULTS: Of 236 surviving infants, 61 (26%) were never scanned, and 175 (74%) had a total of 432 scans. Only 106 infants (45%) had a neurosonogram on or after 28 days (timed to detect all cPVL/pVE). Eleven infants (4.7%) had cPVL, and 19 (8%) had pVE. Severity of clinical course did not predict development of cPVL, but was a better predictor of pVE. Initial neurosonograms were normal in 6/11 (55%) with cPVL and 5/19 (26%) with pVE. Screening declined from 86% of infants in 1992 (average 2.54 neurosonograms each), to 64% by 1994-1995 (average of 2.22 neurosonograms each). Infants > 30 weeks' gestation comprised 55 of 61 patients without any neurosonograms (90%), 4 of 11 patients with cPVL (36%), and 4 of 19 patients with pVE (21%).

CONCLUSION: Screening neurosonography has declined from 1992 to 1995, particularly in larger premature infants (30-32 weeks' gestation) who remain at risk for cPVL and pVE. Clinical course or results of initial studies do not always predict the development of these late abnormalities. We recommend that one neurosonogram be done at > or = 4 weeks of age in all premature infants < or = 32 weeks' gestation, regardless of birth weight, clinical course, or results of prior studies. An earlier neurosonogram should be obtained for infants < 30 weeks' gestation in the second week of life to detect complications of intracranial hemorrhage.