RT Journal Article
SR Electronic
T1 CT scanning phantom for normalization of infant brain attenuation.
JF American Journal of Neuroradiology
JO Am. J. Neuroradiol.
FD American Society of Neuroradiology
SP 167
OP 170
VO 5
IS 2
A1 Thompson, J R
A1 Triolo, P J
A1 Moore, R J
A1 Hinshaw, D B
A1 Hasso, A N
YR 1984
UL http://www.ajnr.org/content/5/2/167.abstract
AB 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.