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
Which imaging modality can help to study CSF dynamics? 
Select and explain. 
A. MR CSF flowmetry, B. Trans cranial ultrasound doppler, C. CT ventriculography, D. PET scan
A: MR CSF flowmetry
Answer: A: MR CSF flowmetry 
Explanation: Ans AMRI CSF flowmetry is a novel imaging technique which works on the principle that CSF is a slow flowing fluid which is influenced by the pulsations transmitted by adjacent arteries. Using this method it is possible to determine the CSF flow rate as well as classify them communicating or non communicating