@Rather_b_hiking you must be really good at reading MRIs if you can spot the styloid/c1 compressions on MRI images because MRIs are good at showing soft tissues but hard to decipher bones in the images. It takes a knowledge of the anatomy to understand & locate bones in MRIs. So my conclusion on these limited images are, that your left Jugular Vein (Blue arrow) is being severely compressed by Styloid (Cyan arrow) and C1 (Red arrow). Styloid compresses it first starting with the rightmost image and then as you move from right to left in the images below, you see C1 compression coming into play. Your right Jugular Vein is also compressed by C1 primarily and the styloid to some extent but does not appear to be as bad as the left one. You can also see that collateral dilation (Yellow arrow) is worse on the left side compared to the right indicating impaired Jugular veins. I can also see the venous plexus (Orange Arrows) at the skull base being dilated on the left more as well. I could be wrong as I did not examine the whole MRI in this case but you do have the tale tale sign of Jugular Vein Compressions by Styloid & C1. CT scan would definitely show the bony compression better.
Do you feel the symptoms more on the left side ?
Styloid (cyan arrow - appears black on MRI), C1 (Red arrow), Jugular Vein (Blue arrow), Collaterals (Yellow arrow), Suboccipital Cavernous Sinus (SOCs) (Orange Arrows) and Vertebral Artery (Green Arrows).
As far as the Sagittal images go, I can see the C1 (Red arrow) and the Jugular Vein (Blue arrow) narrowing better. I also see the dilated collaterals (Yellow arrow) in the second image but because this is an MRI, the interaction between blood vessels and the bones are not very clear. So can’t much more than that
As far as spinal cord involvement is concerned, not many literature exists but few hypothesize venous hypertension/compression as cause of hemiparesis/quadraparesis. See this article (Dilated Collaterals Cause Progressive Weakness on All Limbs as result of Bilateral Jugular Vein Occlusion - Interesting IJV Bypass Treatment)
Also in this image you can see the dilated Internal Vertebral Venous Plexus (IVVP) (Red circles) on the left side more than the right side. This could be, in theory, causing venous hypertension at the upper cord or exerting pressure on the spinal dura. Do you feel body tightness or weaknesses when the IIH symptoms are on steriod? I do from time to time.
