ULTRASONIC IMAGING OF BRAIN PARENCHYMA

Ultrasonic imaging has not been used for primary visualization of brain parenchyma in fetuses or neonates, although it is applied routinely for evaluation of ventricles (and other fluid collections) and for the detection of intracranial hemorrhage and neoplasms. We have begun investigating cerebal parenchymal appearance directly with a large aperture, dynamically focused array immaging system having improved signal to noise ratio and regional magnification features.We find that bone is not an absolute deterant to imaging, through 6 weeks post term, although some refraction effects are noted when molded heads (i.e. surviving small premature infants) are viewed in coronal planes through a water path. Convolutional markings in the cengulate region in midsagittal views in fetuses and in newborn infants show a progression in complexity between 28 and 32 weeks and after 37 weeks in accord with the necropsy correclation with gestational age. The definition of markings and primary reflectivity increases progressively in the third trimester. An Increased reflectivity and damped anterior cerebral branch artery pulsations occur after asphyxial episodes and are interpreted as an extracellular fluid shift. Decreased echodensity and splaying of markings are typical of edema. Thickened sulci herald aophy in subjects beyond 4 months of age.