What is the best method to determine what causes decreased blood floor in a vertebral artery and where exactly it happens, when the reason is vertebrogenic?
I've researched some papers, for example: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3836934/ They did VA (vertebral artery) angiography to determine where the VA blood flow is disrupted.
Some other articles I've researched:
https://spine5.com/spina/sindrom-pozvonochnoj-arterii/ [in Russian] It's said there that cervical X-Ray, MRI, VA ultrasound are used to diagnose vertebral artery syndrome, however I'm looking for a way that would be best at visualization and determining the exact mechanics of how a VA is being affected.
https://vertebra.ua/chto-myi-lechim/sindrom-pozvonochnoj-arterii.html [in Russian] They suggest these methods for diagnosis: X-ray of the cervical spine, angiography and ultrasound of the neck vessels, examination of the vertebral artery syndrome using MRI of the cervical spine with angiography.
I've also researched some VA ultrasound examinations in the case of the VA syndrome. One of them (triplex vascular ultrasound of the extracranial region of the brachiocephalic arteries) determines that the right VA is tortuous at the level of C3-C4 vertebraes (S-shape tortuosity). Also it determines that there is a decrease in the blood flow of the right VA, which may be caused by vertebrogenic influences.
Unfortunately, they didn't provide visualization of the problem or accurately determine the exact area where the VA blood flow gets disrupted.
Is it the limitation of this particular examination or the doctor who performed it didn't have a goal to determine the reason accurately or provide more visualization / information?
What are the best methods (or a group of methods) to get the best visualization of the VA syndrome mechanics (most importantly the exact place where the VA gets affected), when the reason is vertebrogenic?