Question:medium
Identify the condition as shown in the image given below.
Identify the condition as shown in the image given below.
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Widely spaced lateral ventricles resembling a Formula One car from above is the racing car sign.
Updated On: Jun 23, 2026
- Callosal dysgenesis
- Dandy walker syndrome
- Aicardi syndrome
- Septo optic dysplasia
Show Solution
The Correct Option is A
Solution and Explanation
Step 1: Recognise the imaging pattern. Parallel, widely separated lateral ventricles that look like a top-down view of a race car point straight to agenesis of the corpus callosum, i.e. callosal dysgenesis.
Step 2: Understand the cause. Without the corpus callosum, longitudinal Probst bundles run along the medial walls and push the ventricles apart, generating the racing car outline.
Step 3: Note the supporting features. Colpocephaly (disproportionate dilation of the occipital horns and trigones) and high-riding third ventricle accompany the sign.
Step 4: Exclude the rest. A posterior fossa cyst suggests Dandy-Walker, missing septum pellucidum suggests septo-optic dysplasia, and chorioretinal lacunae plus infantile spasms suggest Aicardi. Only callosal dysgenesis fits.
\[\boxed{Callosal\ dysgenesis}\]
Step 2: Understand the cause. Without the corpus callosum, longitudinal Probst bundles run along the medial walls and push the ventricles apart, generating the racing car outline.
Step 3: Note the supporting features. Colpocephaly (disproportionate dilation of the occipital horns and trigones) and high-riding third ventricle accompany the sign.
Step 4: Exclude the rest. A posterior fossa cyst suggests Dandy-Walker, missing septum pellucidum suggests septo-optic dysplasia, and chorioretinal lacunae plus infantile spasms suggest Aicardi. Only callosal dysgenesis fits.
\[\boxed{Callosal\ dysgenesis}\]
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