TY - JOUR T1 - CT scanning phantom for normalization of infant brain attenuation. JF - American Journal of Neuroradiology JO - Am. J. Neuroradiol. SP - 167 LP - 170 VL - 5 IS - 2 AU - J R Thompson AU - P J Triolo AU - R J Moore AU - D B Hinshaw, Jr AU - A N Hasso Y1 - 1984/03/01 UR - http://www.ajnr.org/content/5/2/167.abstract N2 - The x-ray attenuation values of brain studied with computed tomography (CT) are strikingly affected by the ages of the subjects. Premature neonates, for example, may have brain attenuation values 20-30 H below adult values. These lower attenuation values for developing compared with adult brain can be ascribed partly to machine-related effects (beam-hardening, adult algorithms, scanning geometry, etc.). A scanning phantom made from aluminum was developed that can be used to develop a nomogram for any particular scanner from which normalized brain attenuation may be derived for any small head size. Using this nomogram, predicted neonatal attenuations are still 10-15 H higher than those actually observed in scanning neonates. The model predicts that, at the most, 3-4 H of this discrepancy can be accounted for by less beam-hardening from the lower bone attenuation of the thinner developing skull. Presumably, the rest is from a lower brain density in neonates (higher water content). By normalizing to cerebrospinal fluid (water) with special care to avoid partial-volume artifacts, one can predict attenuation values for developing brain more accurately. ER -