Mri notes small layering fluids in sphenoid sinus:what might thisbe? Wouldnormal sinus mucous layer?

Sinusitis. Layering fluids in a sinus on MRI is an indication of sinusitis, but anything that causes swelling and blockage of the normal drainage of a sinus will cause fluid to collect. Most common causes include viral upper respiratory infections (colds), allergies, and bacterial infections. Rarely fungal infections occur.
Sinus infection. Fluid levels in a sinus usually mean infection. Normal sinus mucus would not layer to the point of standing out on an mri.