This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Nervous System, Subject name: Radiology
CT skull giving tram track appearance is diagnostic of- 
Select and explain. 
A. Neurofibroma, B. Tuberous sclerosis, C. Von Hippel Lindau disease, D. Sturge Weber syndrome
D: Sturge Weber syndrome
Answer: D: Sturge Weber syndrome 
Explanation: Ans is 'd' i.e. Sturge Weber syndrome * CT scans in Sturge Weber syndrome show the tramline gyriform calcification of apposing gyri that underlies the contrast-enhancing leptomeningeal vascular malformation.Other CT scan findings Sturge Weber syndrome* Cortical atrophy* Abnormal draining veins* Enlarged choroid plexus* Blood-brain barrier breakdown (during seizures)* Contrast enhancement