Sonographic diagnosis of cisternal subarachnoid hemorrhage in the premature infant.

PURPOSE To evaluate sonographic criteria for the diagnosis of subarachnoid, and particularly cisternal, hemorrhage in the preterm infant. METHODS The subarachnoid cisterns were studied on cadaveric anatomic sections and on postmortem ultrasonograms, as well as on in vivo ultrasonograms of healthy neonates. Based on the normal ultrasound appearances of these cisterns, criteria were developed for the recognition of abnormal cisternal fluid collections, which strongly suggest the presence of subarachnoid hemorrhage in the premature infant. These criteria were evaluated prospectively in a group of 63 preterm infants who underwent subsequent autopsy. RESULTS In the 63 infants with neuropathologic verification, increased echogenicity and/or increased echo-free content of the subarachnoid cisterns correctly predicted subarachnoid hemorrhage with an accuracy of 75%, sensitivity of 69%, and specificity of 93%. The positive and negative predictive values were 97% and 46%, respectively. In 47% of the cases, ultrasound correctly detected cisternal subarachnoid hemorrhage before intraventricular hemorrhage could be diagnosed. CONCLUSION A highly specific, although somewhat insensitive, sonographic diagnosis of subarachnoid hemorrhage can be made from the appearance of the subarachnoid cisterns. The diagnosis of subarachnoid hemorrhage may predate the ultrasound diagnosis of intraventricular hemorrhage and may alert the neonatologist to the need for follow-up sonograms in the absence of ultrasound evidence of intraventricular hemorrhage.