Sonography of ventricular size and germinal matrix hemorrhage in premature infants

Using the anterior fontanelle as an acoustic window, high resolution gray scale sonography brain scans with mobile apparatus were obtained in 35 premature infants. The sonographic technique provided accurate assessment of ventricular size and detected the subependymal germinal matrix and intraventricular hemorrhages. Ventricular size measurements correlated closely with computed tomography (CT) determinations (r = 0.83--0.92) in 29 infants. Sonography imaged the hemorrhages as areas of increased echogenicity with mass effect located characteristically in the region of the caudate nucleus. The size of the hemorrhages could be grossly estimated, but the full extent of hemorrhages was better delineated by CT. Sonography seemed superior in detecting small hemorrhages that were isodense with surrounding brain on CT. Despite its advantages of benignancy, accuracy, ease of examination, and cost, our sonography technique had limitations. False-negative sonograms occurred when the hemorrhage was located only in the posterior aspects of the ventricular system. Small hemorrhages in the caudate could be missed by either CT or sonography because of sampling error. Recognition of other disease processes was limited with sonography. The sonographic brain scan is a good initial test for high risk premature infants suspected of having subependymal germinal matrix and intraventricular hemorrhages. If the sonogram is negative or not typical for subependymal germinal matrix and intraventricular hemorrhages, CT is indicated.