Hi Kong,, very interesting question. These are the modalities that can image cerebral vasoconstriction..

Transcranial Doppler ultrasound

Digital subtraction angiography

CT angiography

MR angiography

PET scan

SPECT scan

133xenone clearance technique

Xenone enhance CT scan

Dynamic perfusion CT scan... Following article might help you.. Thanks

Hi Kong,, your question is very relevant in diagnosing a clinical situation called reversible cerebral vasoconstriction syndrome or Call Flaming syndrome. It is clinically manifested by thunderclap headache, photophobia, focal neurodeficit or rarely seizure. Condition usually improve after three weeks and death usually rare. It is generally associated with vasoactive drug use or pregnancy and pre-eclampsia. Rarely it may be associated with unruptured cerebral aneurysm also. All the above mentioned investigation may be helpful to diagnose it... Thanks

Thanks Mr Majumder. I have read briefly about this vasoconstriction syndrome. I am wondering with the above imaging procedures, do we just get a series of still images or a time-lapse video of the vasoconstriction process is also possible?

Hi Kong.. You have to show cerebral arterial vasoconstriction by the above mentioned investigations. By angiography, CT angiography or by MR angiography 70percent of cases can be diagnosed. Multiple imaging may be required. Because many other conditions may produce similar picture like cerebral vasculitis, diffuse atherosclosis etc,spontaneous improvement of vasospasm after 12weeks is required to diagnose the condition.. Thanks