Comparison of findings on cranial ultrasound and magnetic resonance imaging in preterm infants

Objective. To compare findings on hard copies of cranial ultrasound (US) an d magnetic resonance imaging (MRI) obtained between birth and term in a gro up of preterm infants. Participants and Methods. Infants born at or below a gestational age of 30 weeks who underwent cranial US scan and MRI on the same day were eligible f or this study. Infants underwent, whenever possible, 3 scans between birth and term. We calculated the predictive probability (PP) of US findings as a predictor of findings on MRI. Results. Sixty-two paired MRI and US studies were performed between birth a nd term in 32 infants born at a median gestational age of 27 (range: 23-30) weeks and a median birth weight of 918 (530-1710) grams. US predicted some MRI findings accurately: germinal layer hemorrhage (GLH) on US had a PP of 0.8 with a 95% confidence interval of (0.70-0.90) for the presence of GLH on MRI, intraventricular hemorrhage (IVH) on US had a PP of 0.85 (0.76-0.94 ) for the presence of IVH on MRI, and severe white matter (WM) echogenicity on US had a PP of 0.96 (0.92-1.0) for the presence of WM hemorrhagic paren chymal infarction on MRI. Other MRI changes were less well-predicted: mild or no WM echogenicity on US had a PP of 0.54 (0.41-0.66) for the presence o f normal WM signal intensity on MRI, and moderate or severe WM echogenicity on US had a PP of 0.54 (0.42-0.66) for the presence of small petechial WM hemorrhage and/or diffuse excessive high-signal intensity (DEHSI) in the WM on T2-weighted images on MRI. However, mild/moderate or severe WM echogeni city on US scans performed at greater than or equal to7 days after birth ha d a PP of 0.72 (0.58-0.87) for the presence of WM hemorrhage and/or DEHSI o n MRI. There were no cases of cystic periventricular leukomalacia. Conclusion. US accurately predicted the presence of GLH, IVH, and hemorrhag ic parenchymal infarction on MRI. However, its ability to predict the prese nce of DEHSI and small petechial hemorrhages in the WM on T2-weighted image s is not as good, but improves on scans performed at greater than or equal to7 days after birth. In addition, normal WM echogenicity on US is not a go od predictor of normal WM signal intensity on MRI.