[Falx images on CT scan (author's transl)].

It has been reported that falx images usually are not visualized on CT scan except in the case with brain atrophy of falx calcification. But we have often experienced the falx images on CT scan in the case of normal child, and we have an idea that falx images do not always mean a calcification of the falx. Evaluation of falx images on CT scan was done in 964 normal or abnormal cases in relation to different CT slice level, age, sex, pineal body and habenula and choroid plexus. Results are as follows; 1) Slice of higher level revealed higher incidence of falx image. 2) Incidence of falx images was lowest in the second decade, and showed gradual increase in relation to aging process. 3) Incidence of falx images revealed no sex difference. 4) Incidence of falx images showed a following tendency: a) Under 10 years; falx greater than pineal body and habenula greater than choroid plexus. b) Between 11 years to 20: pineal body and habenula greater than choroid plexus greater than or equal to falx. c) Over 21 years: pineal body and habenula greater than choroid plesus greater than falx. 5) The case with brain edema showed a higher incidence of falx images than the normal case, but the case with brain atrophy did not show a higher incidence. 6) Difference of CT number of falx region between the case of positive falx image and negative could not be recognized.