Presentation
History of headache for 2 weeks.
Patient Data
Age: 30 years
Gender: Male
From the case:
Corpus callosum agenesis
non-contrast

Axial CT images show widely spaced lateral ventricles:
- asymmetrical dilatation of the occipital horns of the lateral ventricles known as colpocephaly
- 'tear-drop' configuration of the atrial trigones
- dilatation of the temporal horns noted
- high-riding 3rd ventricle which also appears dilated
- absent septum pellucidum
- widened interhemispheric fissure
- 'racing car' sign with dilated frontal horns forming the front tyres and dilated occipital horns the rear tyres. Dilated 3rd ventricle forms the midsection of the F1 car
Case Discussion
Corpus callosum agenesis was an incidental finding in this case. Widely spaced ventricles are due vertically oriented white matter tracts called Probst bundles. Temporal horns appear dilated due to hippocampal hypoplasia.