Original Article
Journal of Perinatology (2003) 23, 104–110. doi:10.1038/sj.jp.7210869
Serial Head Ultrasound Studies in Preterm Infants: How Many Normal Studies Does One Infant Need to Exclude Significant Abnormalities?
Presented in part at the Society for Pediatric Research, May 2001.
Victoria N Nwafor-Anene MD1, Joseph D DeCristofaro MD1 and Stephen Baumgart MD1
1Division of Neonatology, Department of Pediatrics, University Hospital and Medical Center, State University of New York at Stony Brook, Stony Brook, New York, USA
Correspondence: Joseph D. DeCristofaro, MD, Division of Neonatology, Department of Pediatrics, T11-060 Health Sciences Center, SUNY at Stony Brook, Stony Brook, NY 11794-8111, USA
Abstract
OBJECTIVE: We hypothesized that preterm infants with two normal head ultrasound (HUS) screening studies 
7 days apart would have subsequently normal follow-up studies.
POPULATION: We reviewed reports of all HUS studies performed in preterm infants 
32 weeks gestation admitted to our nursery between January 1998 and July 2000.
SETTING: Regional perinatal referral center.
DESIGN: A normal HUS screening study was defined as either no findings; or grade I intraventricular hemorrhage (IVH) (Papile classification), germinal matrix irregularity or cyst, or normal but unequal ventricular size. An abnormal study was defined as any with IVH grade II, periventricular leukomalacia (PVL), ventriculomegaly (VM), or periventricular echogenicity (PVE).
RESULTS: Of 98 infants, 92 infants (94%) who had two normal HUS studies 7 days apart had normal repeat studies subsequently, and six (6%) were abnormal. Four of the six abnormal infants were <25 weeks gestation at birth. One infant (27 weeks) became abnormal after culture-positive bacterial sepsis and necrotizing enterocolitis with bowel perforation requiring surgery. The remaining infant (29 weeks) had a question of PVE, and a normal repeat study. The positive predictive value for having a normal HUS after two previously normal studies 7 days apart was 94% with a specificity of 86%.
CONCLUSION: Stable premature infants 25 weeks gestation without intervening deterioration may not need repeat screening HUSs after having had two normal studies 7 days apart. Unstable or extremely premature infants <25 weeks gestation may be subject to late severe IVH, VM, and PVL, and therefore need a repeat study before hospital discharge, even if two initial studies 7 days apart were normal.
