The radiologists findings “Mild edema of the inferior joint capsule. This is a finding that can be seen in adhesive capsulitis, a clinical diagnosis.” are correct. He can see edema (inflammation) and is suggesting you determine if adhesive capsulitis (a clinical diagnosis not a radiological diagnosis).
Can capsule adhesion or adhesive capsulitis be seen on MRI? Capsule adhesion can not be seen. Sometime you can see thickening, which can be normal, degenerative or possibly adheison. Either way thickness is an unreliable finding. You can see edema, but this doesn’t tell you the cause.
To put this into better context Shoulder abduction is full but with a pinch at the end of the motion. I mention this because with adhesive capsulitis, I would not suspect the range to be nearly this good, where with some adhesion in the capsule I would, and I do feel tension in the capsule at end ROM. This data suggests she has capsulitis but not adhesion. We would need the full history to unpack it. Metabolic, strength, load, stress etc. may all be factors.